template for research article

How to format and use a journal template for your research paper

When writing your research paper it is crucial to understand what format your target journal requires, and what journal template you should use (if one at all). Although many of our journals have the basic elements of style in common, each journal can have its own guidelines for formatting. This defines how an article will look when it is published online or in print.

Read on to find out how to format your research paper for submission to your target journal.

How to format your research paper

Go to  Taylor & Francis Online  and search for the title of your chosen journal using the search bar.

Select the relevant journal and click on the instructions for authors tab.

Read your target journal’s instructions for authors, and find out about its formatting guidelines.

Below are a list of Word templates which can be used for many of our journals. Please download the relevant template and apply it to your research paper format.

Each version of the template has its own instructions file. Read the instructions to learn how to save and use the template.

Get familiar with the journal’s instructions for authors

Be prepared, speed up your submission, and make sure nothing is forgotten by understanding the journal’s individual requirements.

Using Taylor & Francis word templates for journal articles

Check to see which version of Word is installed on your computer

Read the instructions for the relevant version of the template in the list below

Download and save the template file to your computer

Apply these styles to your paper as appropriate

Taylor & Francis templates

Format-free submission

Many Taylor & Francis journals allow format-free submission .

If you use a consistent citation format and include all the necessary information, you may be able to submit your work without worrying about formatting your manuscript.

To find out if your journal allows format-free submission, go to your journal’s homepage on Taylor & Francis Online .

Read the instructions for authors’ for your chosen journal to find out if it operates format-free submission.

Submitting your article format-free?

Read our guide for more information on how to submit your article format-free.

Other journal format options

Latex templates.

Some of our journals accept manuscripts that use a LaTeX template.

Please check the instructions for authors on your chosen journal’s homepage on Taylor & Francis Online to know if LaTeX is an accepted format.

Your journal may provide a link to its specific template in the instructions for authors’ section of the journal’s homepage on Taylor & Francis Online.

If no template is provided, please  contact us  for advice.

What is LaTex?

LaTeX is a software system used to design documents for typesetting. It is most often used for mathematicians and researchers in the physical sciences, but it can be used for almost any form of publishing.

It permits advanced formatting of symbols and variables and structuring of formula. LaTeX has to be converted during the document structuring process during typesetting.”

F1000Research

F1000Research publishes different article types offering flexibility in format and structure, although specific requirements may apply to some article types.

You can find out more about article type-specific instructions for submission with F1000Research in the F1000Research Article Guidelines .

To submit to F1000Research, your manuscript can be submitted as:

Word (DOC or DOCX)

Rich text format (RTF) files

What is F1000Research?

This is an Open Research publishing platform offering rapid article publication and other research outputs without editorial bias.

Save time – let us help format your manuscript

Consider using expert editors to help you meet deadlines and make sure your manuscript complies to your target journal’s requirements.

Related resources

Journal manuscript layout guide

Journal submission support

Your submission checklist

Guide to improve your submission experience

• Search Menu
• Sign in through your institution
• Advance articles
• Editor's Choice
• Supplements
• French Abstracts
• Portuguese Abstracts
• Spanish Abstracts
• Author Guidelines
• Submission Site
• Open Access
• About International Journal for Quality in Health Care
• About the International Society for Quality in Health Care
• Editorial Board
• Advertising and Corporate Services
• Journals Career Network
• Self-Archiving Policy
• Dispatch Dates
• Contact ISQua
• Journals on Oxford Academic
• Books on Oxford Academic

Article Contents

Primacy of the research question, structure of the paper, writing a research article: advice to beginners.

• Article contents
• Figures & tables
• Supplementary Data

Thomas V. Perneger, Patricia M. Hudelson, Writing a research article: advice to beginners, International Journal for Quality in Health Care , Volume 16, Issue 3, June 2004, Pages 191–192, https://doi.org/10.1093/intqhc/mzh053

• Permissions Icon Permissions

Writing research papers does not come naturally to most of us. The typical research paper is a highly codified rhetorical form [ 1 , 2 ]. Knowledge of the rules—some explicit, others implied—goes a long way toward writing a paper that will get accepted in a peer-reviewed journal.

A good research paper addresses a specific research question. The research question—or study objective or main research hypothesis—is the central organizing principle of the paper. Whatever relates to the research question belongs in the paper; the rest doesn’t. This is perhaps obvious when the paper reports on a well planned research project. However, in applied domains such as quality improvement, some papers are written based on projects that were undertaken for operational reasons, and not with the primary aim of producing new knowledge. In such cases, authors should define the main research question a posteriori and design the paper around it.

Generally, only one main research question should be addressed in a paper (secondary but related questions are allowed). If a project allows you to explore several distinct research questions, write several papers. For instance, if you measured the impact of obtaining written consent on patient satisfaction at a specialized clinic using a newly developed questionnaire, you may want to write one paper on the questionnaire development and validation, and another on the impact of the intervention. The idea is not to split results into ‘least publishable units’, a practice that is rightly decried, but rather into ‘optimally publishable units’.

What is a good research question? The key attributes are: (i) specificity; (ii) originality or novelty; and (iii) general relevance to a broad scientific community. The research question should be precise and not merely identify a general area of inquiry. It can often (but not always) be expressed in terms of a possible association between X and Y in a population Z, for example ‘we examined whether providing patients about to be discharged from the hospital with written information about their medications would improve their compliance with the treatment 1 month later’. A study does not necessarily have to break completely new ground, but it should extend previous knowledge in a useful way, or alternatively refute existing knowledge. Finally, the question should be of interest to others who work in the same scientific area. The latter requirement is more challenging for those who work in applied science than for basic scientists. While it may safely be assumed that the human genome is the same worldwide, whether the results of a local quality improvement project have wider relevance requires careful consideration and argument.

Once the research question is clearly defined, writing the paper becomes considerably easier. The paper will ask the question, then answer it. The key to successful scientific writing is getting the structure of the paper right. The basic structure of a typical research paper is the sequence of Introduction, Methods, Results, and Discussion (sometimes abbreviated as IMRAD). Each section addresses a different objective. The authors state: (i) the problem they intend to address—in other terms, the research question—in the Introduction; (ii) what they did to answer the question in the Methods section; (iii) what they observed in the Results section; and (iv) what they think the results mean in the Discussion.

In turn, each basic section addresses several topics, and may be divided into subsections (Table 1 ). In the Introduction, the authors should explain the rationale and background to the study. What is the research question, and why is it important to ask it? While it is neither necessary nor desirable to provide a full-blown review of the literature as a prelude to the study, it is helpful to situate the study within some larger field of enquiry. The research question should always be spelled out, and not merely left for the reader to guess.

Typical structure of a research paper

The Methods section should provide the readers with sufficient detail about the study methods to be able to reproduce the study if so desired. Thus, this section should be specific, concrete, technical, and fairly detailed. The study setting, the sampling strategy used, instruments, data collection methods, and analysis strategies should be described. In the case of qualitative research studies, it is also useful to tell the reader which research tradition the study utilizes and to link the choice of methodological strategies with the research goals [ 3 ].

The Results section is typically fairly straightforward and factual. All results that relate to the research question should be given in detail, including simple counts and percentages. Resist the temptation to demonstrate analytic ability and the richness of the dataset by providing numerous tables of non-essential results.

The Discussion section allows the most freedom. This is why the Discussion is the most difficult to write, and is often the weakest part of a paper. Structured Discussion sections have been proposed by some journal editors [ 4 ]. While strict adherence to such rules may not be necessary, following a plan such as that proposed in Table 1 may help the novice writer stay on track.

References should be used wisely. Key assertions should be referenced, as well as the methods and instruments used. However, unless the paper is a comprehensive review of a topic, there is no need to be exhaustive. Also, references to unpublished work, to documents in the grey literature (technical reports), or to any source that the reader will have difficulty finding or understanding should be avoided.

Having the structure of the paper in place is a good start. However, there are many details that have to be attended to while writing. An obvious recommendation is to read, and follow, the instructions to authors published by the journal (typically found on the journal’s website). Another concerns non-native writers of English: do have a native speaker edit the manuscript. A paper usually goes through several drafts before it is submitted. When revising a paper, it is useful to keep an eye out for the most common mistakes (Table 2 ). If you avoid all those, your paper should be in good shape.

Common mistakes seen in manuscripts submitted to this journal

Huth EJ . How to Write and Publish Papers in the Medical Sciences , 2nd edition. Baltimore, MD: Williams & Wilkins, 1990 .

Browner WS . Publishing and Presenting Clinical Research . Baltimore, MD: Lippincott, Williams & Wilkins, 1999 .

Devers KJ , Frankel RM. Getting qualitative research published. Educ Health 2001 ; 14 : 109 –117.

Docherty M , Smith R. The case for structuring the discussion of scientific papers. Br Med J 1999 ; 318 : 1224 –1225.

Email alerts

Citing articles via.

• Recommend to your Library

Affiliations

• Online ISSN 1464-3677
• Print ISSN 1353-4505
• Copyright © 2024 International Society for Quality in Health Care and Oxford University Press
• About Oxford Academic
• Publish journals with us
• University press partners
• What we publish
• New features  
• Open access
• Institutional account management
• Rights and permissions
• Get help with access
• Accessibility
• Advertising
• Media enquiries
• Oxford University Press
• Oxford Languages
• University of Oxford

Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide

• Copyright © 2024 Oxford University Press
• Cookie settings
• Cookie policy
• Privacy policy
• Legal notice

This Feature Is Available To Subscribers Only

Sign In or Create an Account

This PDF is available to Subscribers Only

For full access to this pdf, sign in to an existing account, or purchase an annual subscription.

Word templates for journal articles

Though it is not necessary to use this file, using these Word templates for journal articles may help to speed the publication of accepted articles.

Check the peer review model for the journal you are submitting to when preparing the Word version of your manuscript. You can find out the peer review model for our journals on the “About the Journal” section of our journal homepages.

View Journals

Double-anonymous

Use our double-anonymous template

We also have a double-anonymous checklist , so you can be sure you’ve fully anonymised your paper before submission.

Single-anonymous

Use our single-anonymous template

Related information:

• Privacy Policy

Home » Research Paper Format – Types, Examples and Templates

Research Paper Format – Types, Examples and Templates

Table of Contents

Research paper format is an essential aspect of academic writing that plays a crucial role in the communication of research findings . The format of a research paper depends on various factors such as the discipline, style guide, and purpose of the research. It includes guidelines for the structure, citation style, referencing , and other elements of the paper that contribute to its overall presentation and coherence. Adhering to the appropriate research paper format is vital for ensuring that the research is accurately and effectively communicated to the intended audience. In this era of information, it is essential to understand the different research paper formats and their guidelines to communicate research effectively, accurately, and with the required level of detail. This post aims to provide an overview of some of the common research paper formats used in academic writing.

Research Paper Formats

Research Paper Formats are as follows:

• APA (American Psychological Association) format
• MLA (Modern Language Association) format
• Chicago/Turabian style
• IEEE (Institute of Electrical and Electronics Engineers) format
• AMA (American Medical Association) style
• Harvard style
• Vancouver style
• ACS (American Chemical Society) style
• ASA (American Sociological Association) style
• APSA (American Political Science Association) style

APA (American Psychological Association) Format

Here is a general APA format for a research paper:

• Title Page: The title page should include the title of your paper, your name, and your institutional affiliation. It should also include a running head, which is a shortened version of the title, and a page number in the upper right-hand corner.
• Abstract : The abstract is a brief summary of your paper, typically 150-250 words. It should include the purpose of your research, the main findings, and any implications or conclusions that can be drawn.
• Introduction: The introduction should provide background information on your topic, state the purpose of your research, and present your research question or hypothesis. It should also include a brief literature review that discusses previous research on your topic.
• Methods: The methods section should describe the procedures you used to collect and analyze your data. It should include information on the participants, the materials and instruments used, and the statistical analyses performed.
• Results: The results section should present the findings of your research in a clear and concise manner. Use tables and figures to help illustrate your results.
• Discussion : The discussion section should interpret your results and relate them back to your research question or hypothesis. It should also discuss the implications of your findings and any limitations of your study.
• References : The references section should include a list of all sources cited in your paper. Follow APA formatting guidelines for your citations and references.

Some additional tips for formatting your APA research paper:

• Use 12-point Times New Roman font throughout the paper.
• Double-space all text, including the references.
• Use 1-inch margins on all sides of the page.
• Indent the first line of each paragraph by 0.5 inches.
• Use a hanging indent for the references (the first line should be flush with the left margin, and all subsequent lines should be indented).
• Number all pages, including the title page and references page, in the upper right-hand corner.

APA Research Paper Format Template

APA Research Paper Format Template is as follows:

Title Page:

• Title of the paper
• Author’s name
• Institutional affiliation
• A brief summary of the main points of the paper, including the research question, methods, findings, and conclusions. The abstract should be no more than 250 words.

Introduction:

• Background information on the topic of the research paper
• Research question or hypothesis
• Significance of the study
• Overview of the research methods and design
• Brief summary of the main findings
• Participants: description of the sample population, including the number of participants and their characteristics (age, gender, ethnicity, etc.)
• Materials: description of any materials used in the study (e.g., survey questions, experimental apparatus)
• Procedure: detailed description of the steps taken to conduct the study
• Presentation of the findings of the study, including statistical analyses if applicable
• Tables and figures may be included to illustrate the results

Discussion:

• Interpretation of the results in light of the research question and hypothesis
• Implications of the study for the field
• Limitations of the study
• Suggestions for future research

References:

• A list of all sources cited in the paper, in APA format

Formatting guidelines:

• Double-spaced
• 12-point font (Times New Roman or Arial)
• 1-inch margins on all sides
• Page numbers in the top right corner
• Headings and subheadings should be used to organize the paper
• The first line of each paragraph should be indented
• Quotations of 40 or more words should be set off in a block quote with no quotation marks
• In-text citations should include the author’s last name and year of publication (e.g., Smith, 2019)

APA Research Paper Format Example

APA Research Paper Format Example is as follows:

The Effects of Social Media on Mental Health

University of XYZ

This study examines the relationship between social media use and mental health among college students. Data was collected through a survey of 500 students at the University of XYZ. Results suggest that social media use is significantly related to symptoms of depression and anxiety, and that the negative effects of social media are greater among frequent users.

Social media has become an increasingly important aspect of modern life, especially among young adults. While social media can have many positive effects, such as connecting people across distances and sharing information, there is growing concern about its impact on mental health. This study aims to examine the relationship between social media use and mental health among college students.

Participants: Participants were 500 college students at the University of XYZ, recruited through online advertisements and flyers posted on campus. Participants ranged in age from 18 to 25, with a mean age of 20.5 years. The sample was 60% female, 40% male, and 5% identified as non-binary or gender non-conforming.

Data was collected through an online survey administered through Qualtrics. The survey consisted of several measures, including the Patient Health Questionnaire-9 (PHQ-9) for depression symptoms, the Generalized Anxiety Disorder-7 (GAD-7) for anxiety symptoms, and questions about social media use.

Procedure :

Participants were asked to complete the online survey at their convenience. The survey took approximately 20-30 minutes to complete. Data was analyzed using descriptive statistics, correlations, and multiple regression analysis.

Results indicated that social media use was significantly related to symptoms of depression (r = .32, p < .001) and anxiety (r = .29, p < .001). Regression analysis indicated that frequency of social media use was a significant predictor of both depression symptoms (β = .24, p < .001) and anxiety symptoms (β = .20, p < .001), even when controlling for age, gender, and other relevant factors.

The results of this study suggest that social media use is associated with symptoms of depression and anxiety among college students. The negative effects of social media are greater among frequent users. These findings have important implications for mental health professionals and educators, who should consider addressing the potential negative effects of social media use in their work with young adults.

References :

References should be listed in alphabetical order according to the author’s last name. For example:

• Chou, H. T. G., & Edge, N. (2012). “They are happier and having better lives than I am”: The impact of using Facebook on perceptions of others’ lives. Cyberpsychology, Behavior, and Social Networking, 15(2), 117-121.
• Twenge, J. M., Joiner, T. E., Rogers, M. L., & Martin, G. N. (2018). Increases in depressive symptoms, suicide-related outcomes, and suicide rates among U.S. adolescents after 2010 and links to increased new media screen time. Clinical Psychological Science, 6(1), 3-17.

Note: This is just a sample Example do not use this in your assignment.

MLA (Modern Language Association) Format

MLA (Modern Language Association) Format is as follows:

• Page Layout : Use 8.5 x 11-inch white paper, with 1-inch margins on all sides. The font should be 12-point Times New Roman or a similar serif font.
• Heading and Title : The first page of your research paper should include a heading and a title. The heading should include your name, your instructor’s name, the course title, and the date. The title should be centered and in title case (capitalizing the first letter of each important word).
• In-Text Citations : Use parenthetical citations to indicate the source of your information. The citation should include the author’s last name and the page number(s) of the source. For example: (Smith 23).
• Works Cited Page : At the end of your paper, include a Works Cited page that lists all the sources you used in your research. Each entry should include the author’s name, the title of the work, the publication information, and the medium of publication.
• Formatting Quotations : Use double quotation marks for short quotations and block quotations for longer quotations. Indent the entire quotation five spaces from the left margin.
• Formatting the Body : Use a clear and readable font and double-space your text throughout. The first line of each paragraph should be indented one-half inch from the left margin.

MLA Research Paper Template

MLA Research Paper Format Template is as follows:

• Use 8.5 x 11 inch white paper.
• Use a 12-point font, such as Times New Roman.
• Use double-spacing throughout the entire paper, including the title page and works cited page.
• Set the margins to 1 inch on all sides.
• Use page numbers in the upper right corner, beginning with the first page of text.
• Include a centered title for the research paper, using title case (capitalizing the first letter of each important word).
• Include your name, instructor’s name, course name, and date in the upper left corner, double-spaced.

In-Text Citations

• When quoting or paraphrasing information from sources, include an in-text citation within the text of your paper.
• Use the author’s last name and the page number in parentheses at the end of the sentence, before the punctuation mark.
• If the author’s name is mentioned in the sentence, only include the page number in parentheses.

Works Cited Page

• List all sources cited in alphabetical order by the author’s last name.
• Each entry should include the author’s name, title of the work, publication information, and medium of publication.
• Use italics for book and journal titles, and quotation marks for article and chapter titles.
• For online sources, include the date of access and the URL.

Here is an example of how the first page of a research paper in MLA format should look:

Headings and Subheadings

• Use headings and subheadings to organize your paper and make it easier to read.
• Use numerals to number your headings and subheadings (e.g. 1, 2, 3), and capitalize the first letter of each word.
• The main heading should be centered and in boldface type, while subheadings should be left-aligned and in italics.
• Use only one space after each period or punctuation mark.
• Use quotation marks to indicate direct quotes from a source.
• If the quote is more than four lines, format it as a block quote, indented one inch from the left margin and without quotation marks.
• Use ellipses (…) to indicate omitted words from a quote, and brackets ([…]) to indicate added words.

Works Cited Examples

• Book: Last Name, First Name. Title of Book. Publisher, Publication Year.
• Journal Article: Last Name, First Name. “Title of Article.” Title of Journal, volume number, issue number, publication date, page numbers.
• Website: Last Name, First Name. “Title of Webpage.” Title of Website, publication date, URL. Accessed date.

Here is an example of how a works cited entry for a book should look:

Smith, John. The Art of Writing Research Papers. Penguin, 2021.

MLA Research Paper Example

MLA Research Paper Format Example is as follows:

Your Professor’s Name

Course Name and Number

Date (in Day Month Year format)

Word Count (not including title page or Works Cited)

Title: The Impact of Video Games on Aggression Levels

Video games have become a popular form of entertainment among people of all ages. However, the impact of video games on aggression levels has been a subject of debate among scholars and researchers. While some argue that video games promote aggression and violent behavior, others argue that there is no clear link between video games and aggression levels. This research paper aims to explore the impact of video games on aggression levels among young adults.

Background:

The debate on the impact of video games on aggression levels has been ongoing for several years. According to the American Psychological Association, exposure to violent media, including video games, can increase aggression levels in children and adolescents. However, some researchers argue that there is no clear evidence to support this claim. Several studies have been conducted to examine the impact of video games on aggression levels, but the results have been mixed.

Methodology:

This research paper used a quantitative research approach to examine the impact of video games on aggression levels among young adults. A sample of 100 young adults between the ages of 18 and 25 was selected for the study. The participants were asked to complete a questionnaire that measured their aggression levels and their video game habits.

The results of the study showed that there was a significant correlation between video game habits and aggression levels among young adults. The participants who reported playing violent video games for more than 5 hours per week had higher aggression levels than those who played less than 5 hours per week. The study also found that male participants were more likely to play violent video games and had higher aggression levels than female participants.

The findings of this study support the claim that video games can increase aggression levels among young adults. However, it is important to note that the study only examined the impact of video games on aggression levels and did not take into account other factors that may contribute to aggressive behavior. It is also important to note that not all video games promote violence and aggression, and some games may have a positive impact on cognitive and social skills.

Conclusion :

In conclusion, this research paper provides evidence to support the claim that video games can increase aggression levels among young adults. However, it is important to conduct further research to examine the impact of video games on other aspects of behavior and to explore the potential benefits of video games. Parents and educators should be aware of the potential impact of video games on aggression levels and should encourage young adults to engage in a variety of activities that promote cognitive and social skills.

Works Cited:

• American Psychological Association. (2017). Violent Video Games: Myths, Facts, and Unanswered Questions. Retrieved from https://www.apa.org/news/press/releases/2017/08/violent-video-games
• Ferguson, C. J. (2015). Do Angry Birds make for angry children? A meta-analysis of video game influences on children’s and adolescents’ aggression, mental health, prosocial behavior, and academic performance. Perspectives on Psychological Science, 10(5), 646-666.
• Gentile, D. A., Swing, E. L., Lim, C. G., & Khoo, A. (2012). Video game playing, attention problems, and impulsiveness: Evidence of bidirectional causality. Psychology of Popular Media Culture, 1(1), 62-70.
• Greitemeyer, T. (2014). Effects of prosocial video games on prosocial behavior. Journal of Personality and Social Psychology, 106(4), 530-548.

Chicago/Turabian Style

Chicago/Turabian Formate is as follows:

• Margins : Use 1-inch margins on all sides of the paper.
• Font : Use a readable font such as Times New Roman or Arial, and use a 12-point font size.
• Page numbering : Number all pages in the upper right-hand corner, beginning with the first page of text. Use Arabic numerals.
• Title page: Include a title page with the title of the paper, your name, course title and number, instructor’s name, and the date. The title should be centered on the page and in title case (capitalize the first letter of each word).
• Headings: Use headings to organize your paper. The first level of headings should be centered and in boldface or italics. The second level of headings should be left-aligned and in boldface or italics. Use as many levels of headings as necessary to organize your paper.
• In-text citations : Use footnotes or endnotes to cite sources within the text of your paper. The first citation for each source should be a full citation, and subsequent citations can be shortened. Use superscript numbers to indicate footnotes or endnotes.
• Bibliography : Include a bibliography at the end of your paper, listing all sources cited in your paper. The bibliography should be in alphabetical order by the author’s last name, and each entry should include the author’s name, title of the work, publication information, and date of publication.
• Formatting of quotations: Use block quotations for quotations that are longer than four lines. Indent the entire quotation one inch from the left margin, and do not use quotation marks. Single-space the quotation, and double-space between paragraphs.
• Tables and figures: Use tables and figures to present data and illustrations. Number each table and figure sequentially, and provide a brief title for each. Place tables and figures as close as possible to the text that refers to them.
• Spelling and grammar : Use correct spelling and grammar throughout your paper. Proofread carefully for errors.

Chicago/Turabian Research Paper Template

Chicago/Turabian Research Paper Template is as folows:

Title of Paper

Name of Student

Professor’s Name

I. Introduction

A. Background Information

B. Research Question

C. Thesis Statement

II. Literature Review

A. Overview of Existing Literature

B. Analysis of Key Literature

C. Identification of Gaps in Literature

III. Methodology

A. Research Design

B. Data Collection

C. Data Analysis

IV. Results

A. Presentation of Findings

B. Analysis of Findings

C. Discussion of Implications

V. Conclusion

A. Summary of Findings

B. Implications for Future Research

C. Conclusion

VI. References

A. Bibliography

B. In-Text Citations

VII. Appendices (if necessary)

A. Data Tables

C. Additional Supporting Materials

Chicago/Turabian Research Paper Example

Title: The Impact of Social Media on Political Engagement

Name: John Smith

Class: POLS 101

Professor: Dr. Jane Doe

Date: April 8, 2023

I. Introduction:

Social media has become an integral part of our daily lives. People use social media platforms like Facebook, Twitter, and Instagram to connect with friends and family, share their opinions, and stay informed about current events. With the rise of social media, there has been a growing interest in understanding its impact on various aspects of society, including political engagement. In this paper, I will examine the relationship between social media use and political engagement, specifically focusing on how social media influences political participation and political attitudes.

II. Literature Review:

There is a growing body of literature on the impact of social media on political engagement. Some scholars argue that social media has a positive effect on political participation by providing new channels for political communication and mobilization (Delli Carpini & Keeter, 1996; Putnam, 2000). Others, however, suggest that social media can have a negative impact on political engagement by creating filter bubbles that reinforce existing beliefs and discourage political dialogue (Pariser, 2011; Sunstein, 2001).

III. Methodology:

To examine the relationship between social media use and political engagement, I conducted a survey of 500 college students. The survey included questions about social media use, political participation, and political attitudes. The data was analyzed using descriptive statistics and regression analysis.

Iv. Results:

The results of the survey indicate that social media use is positively associated with political participation. Specifically, respondents who reported using social media to discuss politics were more likely to have participated in a political campaign, attended a political rally, or contacted a political representative. Additionally, social media use was found to be associated with more positive attitudes towards political engagement, such as increased trust in government and belief in the effectiveness of political action.

V. Conclusion:

The findings of this study suggest that social media has a positive impact on political engagement, by providing new opportunities for political communication and mobilization. However, there is also a need for caution, as social media can also create filter bubbles that reinforce existing beliefs and discourage political dialogue. Future research should continue to explore the complex relationship between social media and political engagement, and develop strategies to harness the potential benefits of social media while mitigating its potential negative effects.

Vii. References:

• Delli Carpini, M. X., & Keeter, S. (1996). What Americans know about politics and why it matters. Yale University Press.
• Pariser, E. (2011). The filter bubble: What the Internet is hiding from you. Penguin.
• Putnam, R. D. (2000). Bowling alone: The collapse and revival of American community. Simon & Schuster.
• Sunstein, C. R. (2001). Republic.com. Princeton University Press.

IEEE (Institute of Electrical and Electronics Engineers) Format

IEEE (Institute of Electrical and Electronics Engineers) Research Paper Format is as follows:

• Title : A concise and informative title that accurately reflects the content of the paper.
• Abstract : A brief summary of the paper, typically no more than 250 words, that includes the purpose of the study, the methods used, the key findings, and the main conclusions.
• Introduction : An overview of the background, context, and motivation for the research, including a clear statement of the problem being addressed and the objectives of the study.
• Literature review: A critical analysis of the relevant research and scholarship on the topic, including a discussion of any gaps or limitations in the existing literature.
• Methodology : A detailed description of the methods used to collect and analyze data, including any experiments or simulations, data collection instruments or procedures, and statistical analyses.
• Results : A clear and concise presentation of the findings, including any relevant tables, graphs, or figures.
• Discussion : A detailed interpretation of the results, including a comparison of the findings with previous research, a discussion of the implications of the results, and any recommendations for future research.
• Conclusion : A summary of the key findings and main conclusions of the study.
• References : A list of all sources cited in the paper, formatted according to IEEE guidelines.

In addition to these elements, an IEEE research paper should also follow certain formatting guidelines, including using 12-point font, double-spaced text, and numbered headings and subheadings. Additionally, any tables, figures, or equations should be clearly labeled and referenced in the text.

AMA (American Medical Association) Style

AMA (American Medical Association) Style Research Paper Format:

• Title Page: This page includes the title of the paper, the author’s name, institutional affiliation, and any acknowledgments or disclaimers.
• Abstract: The abstract is a brief summary of the paper that outlines the purpose, methods, results, and conclusions of the study. It is typically limited to 250 words or less.
• Introduction: The introduction provides a background of the research problem, defines the research question, and outlines the objectives and hypotheses of the study.
• Methods: The methods section describes the research design, participants, procedures, and instruments used to collect and analyze data.
• Results: The results section presents the findings of the study in a clear and concise manner, using graphs, tables, and charts where appropriate.
• Discussion: The discussion section interprets the results, explains their significance, and relates them to previous research in the field.
• Conclusion: The conclusion summarizes the main points of the paper, discusses the implications of the findings, and suggests future research directions.
• References: The reference list includes all sources cited in the paper, listed in alphabetical order by author’s last name.

In addition to these sections, the AMA format requires that authors follow specific guidelines for citing sources in the text and formatting their references. The AMA style uses a superscript number system for in-text citations and provides specific formats for different types of sources, such as books, journal articles, and websites.

Harvard Style

Harvard Style Research Paper format is as follows:

• Title page: This should include the title of your paper, your name, the name of your institution, and the date of submission.
• Abstract : This is a brief summary of your paper, usually no more than 250 words. It should outline the main points of your research and highlight your findings.
• Introduction : This section should introduce your research topic, provide background information, and outline your research question or thesis statement.
• Literature review: This section should review the relevant literature on your topic, including previous research studies, academic articles, and other sources.
• Methodology : This section should describe the methods you used to conduct your research, including any data collection methods, research instruments, and sampling techniques.
• Results : This section should present your findings in a clear and concise manner, using tables, graphs, and other visual aids if necessary.
• Discussion : This section should interpret your findings and relate them to the broader research question or thesis statement. You should also discuss the implications of your research and suggest areas for future study.
• Conclusion : This section should summarize your main findings and provide a final statement on the significance of your research.
• References : This is a list of all the sources you cited in your paper, presented in alphabetical order by author name. Each citation should include the author’s name, the title of the source, the publication date, and other relevant information.

In addition to these sections, a Harvard Style research paper may also include a table of contents, appendices, and other supplementary materials as needed. It is important to follow the specific formatting guidelines provided by your instructor or academic institution when preparing your research paper in Harvard Style.

Vancouver Style

Vancouver Style Research Paper format is as follows:

The Vancouver citation style is commonly used in the biomedical sciences and is known for its use of numbered references. Here is a basic format for a research paper using the Vancouver citation style:

• Title page: Include the title of your paper, your name, the name of your institution, and the date.
• Abstract : This is a brief summary of your research paper, usually no more than 250 words.
• Introduction : Provide some background information on your topic and state the purpose of your research.
• Methods : Describe the methods you used to conduct your research, including the study design, data collection, and statistical analysis.
• Results : Present your findings in a clear and concise manner, using tables and figures as needed.
• Discussion : Interpret your results and explain their significance. Also, discuss any limitations of your study and suggest directions for future research.
• References : List all of the sources you cited in your paper in numerical order. Each reference should include the author’s name, the title of the article or book, the name of the journal or publisher, the year of publication, and the page numbers.

ACS (American Chemical Society) Style

ACS (American Chemical Society) Style Research Paper format is as follows:

The American Chemical Society (ACS) Style is a citation style commonly used in chemistry and related fields. When formatting a research paper in ACS Style, here are some guidelines to follow:

• Paper Size and Margins : Use standard 8.5″ x 11″ paper with 1-inch margins on all sides.
• Font: Use a 12-point serif font (such as Times New Roman) for the main text. The title should be in bold and a larger font size.
• Title Page : The title page should include the title of the paper, the authors’ names and affiliations, and the date of submission. The title should be centered on the page and written in bold font. The authors’ names should be centered below the title, followed by their affiliations and the date.
• Abstract : The abstract should be a brief summary of the paper, no more than 250 words. It should be on a separate page and include the title of the paper, the authors’ names and affiliations, and the text of the abstract.
• Main Text : The main text should be organized into sections with headings that clearly indicate the content of each section. The introduction should provide background information and state the research question or hypothesis. The methods section should describe the procedures used in the study. The results section should present the findings of the study, and the discussion section should interpret the results and provide conclusions.
• References: Use the ACS Style guide to format the references cited in the paper. In-text citations should be numbered sequentially throughout the text and listed in numerical order at the end of the paper.
• Figures and Tables: Figures and tables should be numbered sequentially and referenced in the text. Each should have a descriptive caption that explains its content. Figures should be submitted in a high-quality electronic format.
• Supporting Information: Additional information such as data, graphs, and videos may be included as supporting information. This should be included in a separate file and referenced in the main text.
• Acknowledgments : Acknowledge any funding sources or individuals who contributed to the research.

ASA (American Sociological Association) Style

ASA (American Sociological Association) Style Research Paper format is as follows:

• Title Page: The title page of an ASA style research paper should include the title of the paper, the author’s name, and the institutional affiliation. The title should be centered and should be in title case (the first letter of each major word should be capitalized).
• Abstract: An abstract is a brief summary of the paper that should appear on a separate page immediately following the title page. The abstract should be no more than 200 words in length and should summarize the main points of the paper.
• Main Body: The main body of the paper should begin on a new page following the abstract page. The paper should be double-spaced, with 1-inch margins on all sides, and should be written in 12-point Times New Roman font. The main body of the paper should include an introduction, a literature review, a methodology section, results, and a discussion.
• References : The reference section should appear on a separate page at the end of the paper. All sources cited in the paper should be listed in alphabetical order by the author’s last name. Each reference should include the author’s name, the title of the work, the publication information, and the date of publication.
• Appendices : Appendices are optional and should only be included if they contain information that is relevant to the study but too lengthy to be included in the main body of the paper. If you include appendices, each one should be labeled with a letter (e.g., Appendix A, Appendix B, etc.) and should be referenced in the main body of the paper.

APSA (American Political Science Association) Style

APSA (American Political Science Association) Style Research Paper format is as follows:

• Title Page: The title page should include the title of the paper, the author’s name, the name of the course or instructor, and the date.
• Abstract : An abstract is typically not required in APSA style papers, but if one is included, it should be brief and summarize the main points of the paper.
• Introduction : The introduction should provide an overview of the research topic, the research question, and the main argument or thesis of the paper.
• Literature Review : The literature review should summarize the existing research on the topic and provide a context for the research question.
• Methods : The methods section should describe the research methods used in the paper, including data collection and analysis.
• Results : The results section should present the findings of the research.
• Discussion : The discussion section should interpret the results and connect them back to the research question and argument.
• Conclusion : The conclusion should summarize the main findings and implications of the research.
• References : The reference list should include all sources cited in the paper, formatted according to APSA style guidelines.

In-text citations in APSA style use parenthetical citation, which includes the author’s last name, publication year, and page number(s) if applicable. For example, (Smith 2010, 25).

About the author

Muhammad Hassan

Researcher, Academic Writer, Web developer

You may also like

Research Paper Introduction – Writing Guide and...

Research Contribution – Thesis Guide

Limitations in Research – Types, Examples and...

Tables in Research Paper – Types, Creating Guide...

Implications in Research – Types, Examples and...

Chapter Summary & Overview – Writing Guide...

Purdue Online Writing Lab Purdue OWL® College of Liberal Arts

APA Sample Paper

Welcome to the Purdue OWL

This page is brought to you by the OWL at Purdue University. When printing this page, you must include the entire legal notice.

Copyright ©1995-2018 by The Writing Lab & The OWL at Purdue and Purdue University. All rights reserved. This material may not be published, reproduced, broadcast, rewritten, or redistributed without permission. Use of this site constitutes acceptance of our terms and conditions of fair use.

Note:  This page reflects the latest version of the APA Publication Manual (i.e., APA 7), which released in October 2019. The equivalent resource for the older APA 6 style  can be found here .

Media Files: APA Sample Student Paper  ,  APA Sample Professional Paper

This resource is enhanced by Acrobat PDF files. Download the free Acrobat Reader

Note: The APA Publication Manual, 7 th Edition specifies different formatting conventions for student  and  professional  papers (i.e., papers written for credit in a course and papers intended for scholarly publication). These differences mostly extend to the title page and running head. Crucially, citation practices do not differ between the two styles of paper.

However, for your convenience, we have provided two versions of our APA 7 sample paper below: one in  student style and one in  professional  style.

Note: For accessibility purposes, we have used "Track Changes" to make comments along the margins of these samples. Those authored by [AF] denote explanations of formatting and [AWC] denote directions for writing and citing in APA 7. 

APA 7 Student Paper:

Apa 7 professional paper:.

30 Editable Research Paper Templates (MLA Formats)

A research paper template is a document that contains research questions, variable interpolation, thesis, methodology, and results evaluation. To create an effective research paper, make sure that everything you present comes from reliable sources.

• 1 Research Paper Templates
• 2 What is a research paper?
• 3 Career Research Papers
• 4 What are the 5 parts of research paper?
• 5 College Research Papers
• 6 How do you write a research paper?

Research Paper Templates

What is a research paper.

In most cases, a research paper template is a piece of academic writing that contains analysis, argument, and interpretation based on independent comprehensive research. A research MLA format template is a lot like academic essays except that these are typically longer and have more details.

These assess your academic writing skills along with your scholarly research skills. To write this document, you need:

• To show a strong knowledge of the topic.
• The ability to use various resources.
• To make an original contribution through your writing.

Career Research Papers

What are the 5 parts of research paper.

One thing worth remembering about a student or career research paper is that you should base it on an hourglass structure. To do this, you need to include the important parts of this document:

• Introduction This is the first part where you set the direction of your paper by making an exact outline of what you want to achieve. Although for many, this is the initial step, others save writing the introduction for last because it serves as a quick summary of their document. Either approach is fine and is usually a matter of preference. As long as you plan a logical structure for the parts of the research paper, you can use either method.
• Method Many consider this as the easiest part of the document to write because it is simply a rundown of the methodology and design used to conduct your research. The exact methodology may vary depending on the exact kind of experiment or field of research.
• Results Depending on the results and objectives of your experiment, this is the most variable section of your paper. For quantitative research, you would present numerical data and results. For qualitative research, it involves a broader discussion without giving too many unnecessary details.
• Discussion All information in your discussions should be directly related to your thesis statement. Otherwise, you will risk creating cluttered findings. Just stick with the hourglass principle where you expand on your topic in the next section.
• Conclusion In this section, you build your discussion by trying to relate your findings to other studies and research or to the real world. In a shorter research paper, you may only have a conclusion of just 1 to 2 paragraphs or even just a couple of lines.

In addition, a complete research paper template should always have a reference list where you document all of the sources you used. Format this according to MLA, APA or some other academic format .

College Research Papers

How do you write a research paper.

You can use these steps as a guide when writing a college research paper or a scientific research paper template:

• Familiarize yourself with the assignment Allot ample time to go over your assignment. Consider every bit of information that your instructor has given. Carefully go through the assignment, grading rubric, prompts, and other related materials. To keep track of all the important notes in each of the sources, highlight them or take notes .
• Choose a topic After understanding what you have to write about in your research paper template, the next step is to decide the topic. This could be a challenging undertaking but it shouldn’t discourage you. Choose a topic you’re passionate about or interested in without having to worry about finding the “perfect topic.”
• Research You should always base your research on reliable resources. That way, you won’t run into any issues after you have submitted your completed research paper template for review.
• Organize your research What comes next once you have gathered all the information needed to write your paper? The next step is about getting things organized. Like any other research, various people have various preferences. It may also depend on your assignment. For instance, having some sort of bibliography can be very helpful when it comes to organizing your research.
• Form your thesis This is simply a short statement that you, as the researcher, would put forward for the readers of your paper as to what you’re trying to prove or explain.
• Come up with an outline As in a bibliography, how you will create an outline depending on your assignment. Even if an outline isn’t required, it can still be a very useful tool.
• Write the content After completing all of the previous steps, you are now ready to write your research paper. Some think that they should have begun to write the paper sooner and that all the preliminaries are not that necessary. This is a wrong assumption. Everything you have accomplished up to this point is essential as the preparations will help you come up with a clear, interesting, and strong research paper.
• Edit the content This means examining your paper’s organization, structure, length, and wording. If your paper is either too short or too long, you need to revise it by either building it up or cutting it down to a more acceptable length. Just be very careful when making these edits. If there is a need to add more content, don’t just add words randomly or repeat the information you have stated already. Identify areas where you can expand or what you can include that still fits in with the rest of the content. You can also choose to further the ideas you have presented or add valuable information to concepts you have explained.
• Check the grammar Another important part of the process is to check your grammar. This may seem difficult but there are resources and tools that you can use to perform this task. These tools offer editing for substance, editing for grammar, and so on. If you think you need to take a break before checking, take a break. This could refresh your mind and you might even come back feeling more focused. This is important so that you can catch and fix errors in your document.
• Proofread before submitting After checking your research paper, you can re-read it again just to make sure that your paper delivers everything your assignment asks for. When you have polished and improved it enough, it’s for you to submit.

Related Posts

34 useful study guide templates [word, pdf], 27 best children’s book templates (& layouts), 16 funny & cute cuddle buddy application.

Type above and press Enter to search. Press Esc to cancel.

Recent searches

Institutions, conferences, journals gallery.

40,000+ journal templates to choose from for your next paper

Flexible pricing plans that caters to everyone’s needs

Plagiarism check

Detect plagiarism early. Powered by Turnitin.

Journal Submission

Get accepted in top journals.

For Publishers

Streamline publishing process with automated workflows

Client Stories

Read what our clients have yielded with our products and services

Convert from Word

Word file to JATS XML, PMC XML, DOAJ XML and more

Convert from PDF

PDF file to SciELO XML, CrossRef XML and more

Convert from JATS XML

JATS XML to Redalyc XML, DataCite XML and more

Adhere to standard of all global publishing bodies

Compliance for medical journals in PubMed database

Generate standardized XML for SciELO indexed journals

Template for Scientific Research Publishing articles — Template for authors

— or sign up using email —

Template for Scientific Research Publishing articles

Guideline source: View

All company, product and service names used in this website are for identification purposes only. All product names, trademarks and registered trademarks are property of their respective owners.

Use of these names, trademarks and brands does not imply endorsement or affiliation. Disclaimer Notice

Scientific Research Publishing

Approved by publishing and review experts on SciSpace, this template is built as per for Template for Scientific Research Publishing articles formatting guidelines as mentioned in Scientific Research Publishing author instructions. The current version was created on and has been used by 499 authors to write and format their manuscripts to this journal.

SciSpace is a very innovative solution to the formatting problem and existing providers, such as Mendeley or Word did not really evolve in recent years.

- Andreas Frutiger, Researcher, ETH Zurich, Institute for Biomedical Engineering

(Before submission check for plagiarism via Turnitin)

What to expect from SciSpace?

Speed and accuracy over ms word.

With SciSpace, you do not need a word template for Template for Scientific Research Publishing articles.

It automatically formats your research paper to Scientific Research Publishing formatting guidelines and citation style.

You can download a submission ready research paper in pdf, LaTeX and docx formats.

Time taken to format a paper and Compliance with guidelines

Plagiarism Reports via Turnitin

SciSpace has partnered with Turnitin, the leading provider of Plagiarism Check software.

Using this service, researchers can compare submissions against more than 170 million scholarly articles, a database of 70+ billion current and archived web pages. How Turnitin Integration works?

Freedom from formatting guidelines

One editor, 100K journal formats – world's largest collection of journal templates

With such a huge verified library, what you need is already there.

Easy support from all your favorite tools

Automatically format and order your citations and bibliography in a click.

SciSpace allows imports from all reference managers like Mendeley, Zotero, Endnote, Google Scholar etc.

Frequently asked questions

1. can i write template for scientific research publishing articles in latex.

Absolutely not! Our tool has been designed to help you focus on writing. You can write your entire paper as per the Template for Scientific Research Publishing articles guidelines and auto format it.

2. Do you follow the Template for Scientific Research Publishing articles guidelines?

Yes, the template is compliant with the Template for Scientific Research Publishing articles guidelines. Our experts at SciSpace ensure that. If there are any changes to the journal's guidelines, we'll change our algorithm accordingly.

3. Can I cite my article in multiple styles in Template for Scientific Research Publishing articles?

Of course! We support all the top citation styles, such as APA style, MLA style, Vancouver style, Harvard style, and Chicago style. For example, when you write your paper and hit autoformat, our system will automatically update your article as per the Template for Scientific Research Publishing articles citation style.

4. Can I use the Template for Scientific Research Publishing articles templates for free?

Sign up for our free trial, and you'll be able to use all our features for seven days. You'll see how helpful they are and how inexpensive they are compared to other options, Especially for Template for Scientific Research Publishing articles.

5. Can I use a manuscript in Template for Scientific Research Publishing articles that I have written in MS Word?

Yes. You can choose the right template, copy-paste the contents from the word document, and click on auto-format. Once you're done, you'll have a publish-ready paper Template for Scientific Research Publishing articles that you can download at the end.

6. How long does it usually take you to format my papers in Template for Scientific Research Publishing articles?

It only takes a matter of seconds to edit your manuscript. Besides that, our intuitive editor saves you from writing and formatting it in Template for Scientific Research Publishing articles.

7. Where can I find the template for the Template for Scientific Research Publishing articles?

It is possible to find the Word template for any journal on Google. However, why use a template when you can write your entire manuscript on SciSpace , auto format it as per Template for Scientific Research Publishing articles's guidelines and download the same in Word, PDF and LaTeX formats? Give us a try!.

8. Can I reformat my paper to fit the Template for Scientific Research Publishing articles's guidelines?

Of course! You can do this using our intuitive editor. It's very easy. If you need help, our support team is always ready to assist you.

9. Template for Scientific Research Publishing articles an online tool or is there a desktop version?

SciSpace's Template for Scientific Research Publishing articles is currently available as an online tool. We're developing a desktop version, too. You can request (or upvote) any features that you think would be helpful for you and other researchers in the "feature request" section of your account once you've signed up with us.

10. I cannot find my template in your gallery. Can you create it for me like Template for Scientific Research Publishing articles?

Sure. You can request any template and we'll have it setup within a few days. You can find the request box in Journal Gallery on the right side bar under the heading, "Couldn't find the format you were looking for like Template for Scientific Research Publishing articles?”

11. What is the output that I would get after using Template for Scientific Research Publishing articles?

After writing your paper autoformatting in Template for Scientific Research Publishing articles, you can download it in multiple formats, viz., PDF, Docx, and LaTeX.

12. Is Template for Scientific Research Publishing articles's impact factor high enough that I should try publishing my article there?

To be honest, the answer is no. The impact factor is one of the many elements that determine the quality of a journal. Few of these factors include review board, rejection rates, frequency of inclusion in indexes, and Eigenfactor. You need to assess all these factors before you make your final call.

13. What is Sherpa RoMEO Archiving Policy for Template for Scientific Research Publishing articles?

• Pre-prints as being the version of the paper before peer review and
• Post-prints as being the version of the paper after peer-review, with revisions having been made.

14. What are the most common citation types In Template for Scientific Research Publishing articles?

15. How do I submit my article to the Template for Scientific Research Publishing articles?

16. can i download template for scientific research publishing articles in endnote format.

Yes, SciSpace provides this functionality. After signing up, you would need to import your existing references from Word or Bib file to SciSpace. Then SciSpace would allow you to download your references in Template for Scientific Research Publishing articles Endnote style according to Elsevier guidelines.

with Template for Scientific Research Publishing articles format applied

Fast and reliable, built for complaince.

Instant formatting to 100% publisher guidelines on - SciSpace.

No word template required

Typset automatically formats your research paper to Template for Scientific Research Publishing articles formatting guidelines and citation style.

Verifed journal formats

One editor, 100K journal formats. With the largest collection of verified journal formats, what you need is already there.

Trusted by academicians

I spent hours with MS word for reformatting. It was frustrating - plain and simple. With SciSpace, I can draft my manuscripts and once it is finished I can just submit. In case, I have to submit to another journal it is really just a button click instead of an afternoon of reformatting.

Academic Articles

Academic articles, also known as papers, are used to share the results of academic research, primarily with other researchers in the same field. They usually feature a two column layout and are dense with technical language, figures, tables and references. This format is suitable for any highly technical content which has extensive sectioning and displays research results.

Journal Article

This article template aims to emulate scientific journal publications with a formal conservative style and a two-column layout for text. Extensive examples of common content found in scientific papers are provided.

• View Template Information

Stylish Article

This article template attempts to emulate the design of contemporary scientific publications. It does this by including colored boxes behind the abstract and headings and a succinct text layout. The template features a table of contents, something usually not seen in articles, which makes it ideal for longer articles with significant structure or for archival purposes.

Arsclassica Article

This article uses the Arsclassica package to specify the document layout and structure. The template features a single column layout which makes it suitable for a greater number of applications such as for academic articles, business articles and reports. The page layout is very clean and minimal to focus on the content at hand in an elegant way.

Wenneker Article

This article template features a large eye-catching title section with space for multiple authors and affiliations per author. The article has a traditional two column layout to make content easy to read. An abstract section is present to provide a lead-in or summary of the article and features a large lettrine to further draw the reader’s eye. The template contains examples of sectioning, referencing, equations, tables, figures and lists to make it easy for you to get started.

LaTeX Templates Information

General enquiries [email protected]

Most templates licensed under CC BY-NC-SA 4.0

LaTeX Templates is developed in New Zealand

© Creodocs Limited. All Rights Reserved.

• -3 more templates
• No results for

Academic Research templates

Advance your scholarly work with notion's academic research templates. organize literature reviews, track research progress, and collaborate on publications. essential for academics, researchers, and students in pursuit of organized, impactful research endeavors..

Notion + creators

Free + paid

Most duplicated

Recently added

Thesis Writing Companion

Ernest Keith Arthur

Research Paper Planner

Workspace Template for Ph.D. Students

Ch'Ree Essary

Writing Tracker focus Thesis

Academia - Academic Management System for University Students

Jamie Butler

Research Hub

Notion Nest

Notes Manager

Research Paper Tracker

NavaneethPK

Reading List for Journal Papers

PhD Dashboard – Purple

Real Housewife of Bath

Productivity Powerhouse

Dissertation/Research Planner

Powered By Digital

⫷ CODEX ⫸ A Knowledge Portfolio

Notable Blueprints

Research resource list

Thesis Dashboard

Lab Notebook

Madan Mohan

Writing Assignment Word Count Tracker

Simplicity Designs

Literature review template

Odette Jansen

Literature Review

Maria Majchrowska

the PhDiaries | basic PhD dashboard

Chrissie Thwaites | the PhDiaries

dissertation organisation

Thesis Work Template

Roman Shamray

USMLE Step 2 Study Hub

Falconnotes

Related Collections

Top 10 free academic research templates, 10 templates.

Top 10 Notes & Knowledge Templates in Notion

The researcher's toolkit: Notion edition

8 templates.

Places to start

Free academic research templates, 82 templates, top academic research templates, 174 templates.

Free Download 📥

Literature review catalogue (excel template).

Crafting a high-quality literature review is a lot of work . Failure to keep track of all the literature you consume can result in a  lot of wasted time . You need to get (and stay) organized – in other words, you need a literature review catalog .

We developed a template, just for you.

Now you can keep on top of your literature using our intuitive literature review spreadsheet-based catalogue template. The spreadsheet will not only keep everything organized; it will also provide a summary of key metrics. 

Need a template for the actual literature review chapter ? You can get that here .

How to use the Excel template effectively.

A quick overview. The first tab (labelled “Literature”) is where you’ll record specific details of all the reading you’ll do. The second tab (labelled “Literature Summary”) will auto-populate with descriptive statistics of the input as you enter data.

The last two tabs are simply scratchpads for you to dump any additional resources you find along the way. In particular, we’ve made a tab for theoretical frameworks (you can simply dump screengrabs here and caption them) and a tab for measures and scales (the same principle applies). Measures and scales are specific to quantitative methodologies, but you could just as easily use this tab to jot down existing questionnaires if you’re taking a qualitative approach. 

Getting started.

The process is straightforward. For every piece of literature that you read , you log it as a line item. We’d encourage you to record everything you read. Something might seem irrelevant at first read, but you’ll be surprised how the focus of your research can change over time, leading you to inevitably ask the dreaded question, “where did I see that article again?”. Therefore, l og every piece of reading, regardless of perceived relevance at the time of reading . You’ll thank yourself later.

While you’re doing this, we’d encourage you to simultaneously capture the literature piece in your reference manager. We usually recommend Mendeley , but any of the popular reference management tools will do the trick. The key thing is to capture the references while you’re reading (and not when you’re writing, as this breaks your flow).

What goes where.

For every piece of literature you read, you’ll need to capture the following details:

• Author – Enter the author(s) surname(s). The format you use here is up to you – just be consistent.
• Year – Straightforward. Enter the year of publication only – no month is required.
• Title – Enter the title exactly as it is shown on the book cover, journal article front page, presentation deck, etc. If you can copy and paste, do so. It’s easy to make mistakes on the long titles.
• Category 1, 2 and 3 – Here, you’ll create categories and subcategories, which you can use at a later stage to help you find relevant literature. It is up to you what categories you want to use and how much detail you want to add here. At the very least, your choice of categories should be logical, comprehensive and mutually exclusive.
• Document type – Click the drop-down arrow next to the cell and select an appropriate document type, for example, journal article, blog post, etc. If nothing matches your document type, you can use the “Other” field.
• Publication setting – the two main options here are academic and practitioner. Academic refers to the classic academic sources such as textbooks and journal articles, while practitioner refers to publications such as industry reports, company reports, industry magazines, etc. There is also a mixed option here.
• Theoretical refers to situations where an author is proposing a hypothetical theory or concept, but not testing it.
• Empirical refers to situations where an author is testing the said theory by using some form of real-world observation.
• Naturally, some literature will feature both of these (i.e. a model is hypothesized and then tested empirically).
• Key arguments – Here you need to note the key takeaways of the respective piece of literature in relation to your research question(s) and objective(s). This is the most important column , so spend some time providing rich, detailed notes here. Keep in mind that you will be able to search and filter this column at a later stage, so use keywords that make sense.
• Context – Here you should briefly note the context of the specific literature piece. For example, what industry, country, competitive context, etc. did it take place in? When it comes time to justify why your research is worth undertaking, you will likely need to draw on this column’s contents to demonstrate that research has not been undertaken within your specific context (i.e. is it unique?).
• Methodology – Use this drop-down to note the primary methodology (qualitative, quantitative or mixed) used within the specific literature piece. As with the previous item (context), you will likely draw on this when you justify the choice of methodology for your research (i.e. which methodology is commonly used in the field?).
• Key quotes – If there are any specific author quotations that you feel might be useful in your dissertation, add them here. Remember to include the page number if you’re using the Harvard referencing system.
• My notes – Lastly, if there is anything else you feel might be useful, drop it here. You can also create additional columns if you need them.

Finding what you need.

Over time, you will build up a substantial list of literature. When you need to find something, whether it’s a specific piece of literature, a collection of literature within a category, or a summary of a specific author’s publication, you can use the following Excel features:

• Find (Ctrl + F) – good for searching for specific keywords
• Filter – good for filtering groups (for example, categories 1- 3, methodology or publication setting)
• Sort – good for arranging numerical data (for example, publication year)

Once you’ve completed your reading, remember to have a look at the second tab (“Literature Summary”) for an overview of key statistics. As mentioned previously, some of these statistics can help you justify your choice of topic or methodology. Additionally, a review here may reveal that your literature is aged , or that you need to improve your balance of academic and practitioner literature.

Psst… there’s more!

This post is an extract from our bestselling short course, Literature Review Bootcamp . If you want to work smart, you don't want to miss this .

You Might Also Like:

161 Comments

Hi, I can’t open the excel file, can you please check it? Thank you so much for your helpful contents!

Sure, no problem. We’ve checked the file and it is opening correctly. Please give it another go.

Hi,do you have a vidoe on how to popolate the informatino in the spreed sheet ?if you have it i will like to have one.

Please may I know what you mean by categories or subcategories on your literature review catalogue? This also includes keywords.

I’ve downloaded it, but unable to enter any information. Is it possible to receive it as an excel document that I can save onto my documents, as I’m using an android phone?

The Theoretical Framework of the Excel File is empty, sir…

This document is a template for you to populate with the relevant literature, models and frameworks from your reading. As such, it doesn’t contain any literature.

Thank you for such a useful video tutorial. Learnt a lot!

Pleasure, Zhanna!

you are amazing….the way you patiently reply to almost every enquiry is remarkable. Keep it up Derek.

Very helpful as usual. Thank you so much.

I need an examplary literature review in mycology (botany) if you can provide it on any botanical topic so I would be able to start my Lit.review.

Why don’t you just ask him to do your thesis for you?

What an invaluable presentation. Makes literature review so simple.

Thanks for the feedback, Tebogo. Good luck writing your literature review 🙂

Very useful! Thanks.

Pleasure, Maureen 🙂

Great tips! Just starting mine now….so I am using your template….to a mil!!

I need this tamplate, its amazing, I will need your consideration on related work. Thank you

Really agreed

Hello, I am trying to download the excel but I am not receiving the email. Can it be that there is a technical problem or does it take some time to send it?

Thanks for your comment. It can take a few minutes for the email to go through. Please also check your spam box.

Yes, I am also facing the same problem brother. Just check it once. Thanking you..!

Thanks for this very nice explanation

Great to hear that 🙂

very useful

Glad to hear that 🙂

Thanks for the template. It helped in organizing my literature review and writing process

You’re welcome

Hi, thanks for sharing this file, very helpful! I’d like to share it with my students. Could you please advise on how to give proper credits (reference) to your work? Cheers, G

Hi Gianpiero

That’s great. Here’s the Harvard reference:

Jansen, D., 2019. Literature Review Excel Template (Spreadsheet/Matrix) – Grad Coach. [online] Grad Coach. Available at: https://gradcoach.com/how-to-manage-the-literature-review/ > [Accessed 6 April 2020].

Kind regards,

Thank u Derek Your lectures are effectively informative and easily understood. They are clear and organized.

I’m so glad I came across this website. Thank you Derek !!!

You’re welcome, Rabia 🙂

Dear Derek,

Thanks for your extremely useful video tutorials. Please can you send me a link to open your Lit Review Excel Templates.

Thanks for your feedback. You can download the template following the instructions in the orange box.

All the best with your studies!

great effort

Thank you for this document. I am in the beginning stages of the dissertation process.

You’re welcome, Jerry 🙂

The video on literature review was very useful. I especially like the cataloging suggestion.

Great to hear that, Rishi. All the best for your research!

I`m busy writing my minor dissertation my master’s in engineering. I’m following your videos on youtube for writing a literature review. I’m looking for the excel sheet to save a list of references.

The literature video was helpful. Thank you. I haven’t received the excel template its been a week now . Please assist me .

Hi Morakane

That’s very unusual. At most, it should take a few minutes. Please re-attempt the download (use an alternative address if need be).

Thank you for the template. it seems useful to organize my literature review.

You’re very welcome.

Thank you for this informative site and all the tips. Very useful for my research.

You’re welcome, Feyi.

Currently writing a dissertation for a masters in social sciences. Found the youtube videos which are of great help.

You’re most welcome 🙂 Good luck with your literature review.

Thank you very much for the support!!

your videos are great helpful.

Glad to hear that! Good luck with your lit review.

You are the BEST

Thanks for the feedback, Annie. I wish you best of luck with your literature review.

where is the download link for the excel template?

Hi Lebogang

The download is below the first image. Good luck with your literature review!

Your videos literally saved me!!!! Due to recent issues, most of my classes were cancelled and i was completely lost. No words can explain how much grateful i am to you!!

Glad to hear we helped you! Good luck with your literature review.

You guys are the kinds of people who should survive covid-19. You are the type of people we really need in this planet. You are a star. You really saved me from many headaches. Thank you very much for the useful videos and the literature organisation spreadsheet.

Thanks for the kind words, Abel. All the best for your literature review!

Thanks so much for your video. I have consistently received comments that my arguments don’t flow well and I could never figure out how to successfully fix this issue. Now I feel I have a plan and someone to help me and provide feedback if I still don’t get it quite well. Looking forward to getting an improved mark on my next Lit review Thank you

Great to hear that, Helen. Good luck with your future literature reviews!

Excellent lecture

Thanks Biren – good luck with your literature review

i have watched your video on three steps to write a literature review and i found it very useful. thank you for sharing. keep it up.

Thanks again

Thank you for providing such excellent information and sources. Your videos helped me so much. I was on the verge of quitting. Thank you again for your videos and recommended tools.

Great to hear that, Tanya. All the best for your literature review, and for your research.

The video was very informative and timely for me. I am about to start, so Gradcoach is a source I will be revisiitng

Thanks, Nina – glad to hear that. Good luck with your literature review 🙂

hey your video is awesome I had to make an assignment on literature Review and it helped me to get an outline on how I should start ! i was fed of reading books and online articles. Your video served as a boon and clarified my thought process – how I should move forward .Thank you so much!

Great to hear that, Kavita. All the best with your literature review!

Hi Derek, I have tried unsuccessfully to download the Excel template but it keeps bringing me back to this comment section. Is it a technical issue? Kindly help.

Sorry about that. Can you please send me a screenshot of what you’re seeing – [email protected] . I will send you the template as well.

Best of luck with your literature review.

This is so very helpful!! I am writing my first lit review within a proposal (rather last minute, yikes) and this is so helpful to stay organized!

Pleasure. Good luck with your lit review 🙂

Hi i like the video,it is very helpful especially now that I am working on my proposal for thesis project….Hope I will be able to use the excel template to organize for my literature review

Great to hear that, Faith. All the best with your literature review!

hey Derek this video is absolutely amazing. One problem though I’m one of the few that are struggling to download excel. I keep clicking on it and nothing happens.

Thanks for letting us know. Please email me a screenshot of your error and I’ll sort you out – [email protected]

Thanks, Derek

Thanks a lot! Very well explained and easy to follow…now I guess I have no excuse to actually do the work 😉

Thanks for your comment! Good luck with your literature review.

Your video is very informative and useful. Thanks a lot. I also want to try the template but I can’t the find the download link…

The download button is below the main image.

Very helpful thank you

Hi! It is a big help for beginners, such as me. Thanks a lot for sharing!

Thank you. All the best with your literature review.

This is brilliant, Pls sir, in writing a review article, how deep can u go. Is it necessary to go down to the inception of your area of research?

How do I know the country/region of research article?

This will usually be covered somewhere in the article itself.

I would like this free resource

You’re welcome to download it. The download button is below the main image. Good luck with your literature review 🙂

I’d love to have this resource pls. Thank you so much

You’re welcome to download it. The download button is below the main image.

Thanks for the you tube videos. they are very informative

Thank you so much for the full tutorial with so much detailed information. I’m a Ph.D. Candidate in China. The whole syllabus of the Ph.D. program sucks. Thanks again for sharing all this helpful information. I hope your team will getting better in the future!

You’re very welcome. Good luck writing your literature review.

It’s such a big help for me. Thank you!

I’ve watched your video on writing a research proposal. I am interested in the lit review excel template.

I have watched your lecture video on writing a research proposal. I am interested in the literature review excel template and the book write smarter not harder.

It is very helpful. Thank you for your experience sharing.

You’re welcome – good luck with your literature review 🙂

Good afternoon, I recall listening/seeing in 1 of your videos *of saving the abstract (PDF) together with the excel database. How do you do this? is it also with this excel sheet

Thank you ..your videos are a confidence booster

*How To Write A Literature Review In 3 Steps (Full Tutorial)

Wonderful work !!! Please share more !!!! I will be very happy.

Thanks so much for your precision in your presentation. I have not yet started practicing but it’s one of the best I have come across. More grease to your elbows.

I love every video on research that you ve made so far. Thanks a lot

انت رائع جدا

You’re welcome. Good luck with your literature review 🙂

Excellent work. Very helpful. I am starting in this beautiful activity of writing papers with my research . I am learning a lot. Thank you very much.

Glad to hear that. Good luck writing up your research papers!

Thank you so much for the free Excel document! It’s such a huge time-saver!

You’re most welcome, Rebecca. Good luck writing your literature review 🙂

I am so grateful that I have found you on YouTube!

In the meantime, is it better to make another excel file for another variable of the same thesis or just put all articles of all variables in 1 excel file?

Thank you very much!

The notes have been very helpful to me thank you very much for sharing

You’re most welcome, Juan 🙂

Just recently seen your youtube video. Its very information. I usually gets running out of words while writing literature review. Example: XX et al investigated, YY et al shown that, ZZ et al demonstrated…….. After 4-5 references, I feels like again am repeating the words investigated, demonstrated… Could you please shoe some references with a set of vocabularies that can be used while writing literature review section.

Thank you in advance

Thank you so much. Amazing tutorial. Am feeling educated now. Lol…

Glad to hear that, Frank. Good luck with your literature review!

Very helpful stuff, thank you so much for the free Excel! I’m going to use it for my DBA and get your YT channel.

Hi, thank you for the great insights! I was unable download the template even though I completed the form. Would you be able to help me?

Derek thanks for sharing your sacrifices. I love the clarity and confidence, it takes experience to do such.

I just downloaded the excel template for LR coupled with the explanation on how to use. I found it useful, thank you!

Do you have any recommendations for adding Key quotes from a reference ?

Great content. Template very useful

Awesome! An answer to my prayer. I found this in time I need it most. Thank you for the spirit of service.

You’re most welcome, Jojo. Good luck with your literature review.

I am really impressed. This discussion helped me a lot to reconsider a lot of issues.

Thanks for the kind words. Good luck with your literature review!

This is amazing! I really like the guidance you are giving here. However, can you throw more light on the ‘category’ columns for me? I’m really nit clear on that. Thanks

Thanks for your comment. Please see my reply to Sasquia’s question re the same thing.

Good luck with your research!

I have been sitting on an enormous amount of articles for months with difficulties in organizing them until i discovered your video on literature review (YouTube). It brought me to this page where you also had a free template for us. Research process is so much bearable now than i expected. Highly recommended for all researchers. Thank you very much.

Great template. Quick question: Are the categories KEYWORDS that I draw from each source? or pre-planned TOPICS that I come up with to organize the source content?

Thanks for your comment. You can use the category columns in whichever way works for you. It would be different for each student depending on the nature of their research and their research objectives.

Hi there, can you suggest how the corresponding literature resources are best saved into a document folder for retrieval later.

I have seen some suggesting using a unique identifier in a master tab in the spreadsheet so as to be able to create a separate tab for quotes or similar thus using the id as the link

But no one has gone on to say if they are also saving the source document in a folder and naming it 57 or author last name, title or other.

I checked out your Literature Kickstarter and the screen shot of the articles didn’t look to correspond with the catalogue. Have been meaning to sort out my reference folders for sometime and am inspired by the use of an excel spreadsheet but not sure what to name files (currently saved in theme folders) Any help would be gratefully received. Thanks

I am happy if I get a catalogue excel template on the research are of zeolite synthesis from local clay for water treatment mechanism. I need help.

I love the template! But I would like to change the name of some of the headings, used in the dropdown, i.e. change “Audio Recording” to “Podcast”. How could I do that?

Very helpful!

Great!!! Very handy.

Thankyou so much. The excel file is really helpful. This really means and is helping a lot for me.

Hello, please, how can i get your excel document to catacogue the ideas for my literature review. Can you also assist on how to build the methodology section of my literature review? Thank you in advance.

I’m a student from Indonesia..This is very useful for me.. Thank you Derek..

What is the better, download all literatures and then log them into the excel sheet or do that for one by one?

Dear Derek.

I was utterly stressed when taking on an MSc Educational Leadership distance learning degree after 30 years of no academic studying. However, I found your literature review tutorial on Youtube and I immediately experienced a sense of calm direction. I am working full time in the Cayman Islands and am native Afrikaans speaking, so it was such a great help with my literature review for my first assignment. However, I have to write an evaluative essay for my second module and can not find any tutorial done by you about this. Do you perhaps have a template I could use? I have also used your services for editing and proofreading and am super grateful for the amazing help I have received! THANK YOU!

Hi Mr Derek,

It really really helps me to summarise my LR in Excel form and start-up writing

Hi Derek I have tried to download the template and it has failed to. I am not receiving the email either, could this be network issues.

Hi Derek I have been able to download the template. thank you for all your support. let me get started

I have downloaded the template. I would like to print out the guide so I can easily follow. Hope that is fine with you.

THANKS A LOTTTTT This template is exactly the one I needed when reading the literature review for my Bachelor’s dissertation

Thank you so much for your support ,I have downloaded your template and it is amazing .

Derek, The products you and the team members have put together continue to provide exemplary help as I finish the journey toward completing my dissertation! I wish I would have known of GradCoach during both of my MBAs. It could have helped alleviate a lot of time and frustration! I look forward to learning and seeing new things as I complete the dissertation.

Thanks for the kind words 🙂

Can data will be entered in excel sheet automatically like in Mendeley or i have to enter manually, pl?

Thank you GRADCOACH, I’m keenly following your tutorials as I’m about to start my literature review. These videos have been very helpful. So for the literature review you recommend only checking abstract, introduction and conclusion of the relevant literature?

Thanks for providing such an amazing resource.

I wish I knew about this when I was doing my masters. I’m doing my PhD now and sitting on Word files of reference lists and quotes I made for my MEd. This catalog will help me to keep everything more organized in one place. I’ve already started making your template my own by adding additional columns that are important for my research topic. One of the best features of your template is the Literature summary page. My question is how do I get the information I put into my new columns to auto-populate with descriptive statistics on the Literature Summary page?

Hi, I still don’t understand what you would put as ‘Category 1’, ‘Category 2’, ‘Category X’. Are they like the sort of big topics covered in the paper?

This is very helpful

Thank you so much for this summary of the process. I found your advice so helpful, and will apply it to improve the way I write. One small problem: I can´t get the Excel spreadsheet to download: every time I press on the button, it takes me back to the top of the screen.

Trackbacks/Pingbacks

• What Is A Literature Review (In A Dissertation Or Thesis) - Grad Coach - […] theses and any other credible sources of information that relate to your topic. You’ll then summarise and catalogue these for easy…

Submit a Comment Cancel reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

• Print Friendly

Paper Templates

13+ Research Paper Templates

Preparing a thesis can be extremely stressful for a student. They have to collect the relevant data, prepare the questionnaire, run the relevant tests to find the results for their hypothesis, and finally put everything in an appropriate format. When it comes to writing down all the information on paper, it can be extremely tough for some students since they would not be aware of the correct layout, however, a research paper template can be of great assistance and would help the students to write the perfect research paper.

Here are some research paper samples and templates to help you.

Research Outline Paper

A research paper template MLA format would guide a researcher to write the research paper according to the MLA guidelines. They have to provide the relevant citations and it would be a lot easier to keep the template in front. With the assistance of a certain template, it becomes a lot easier to follow the MLA format, which otherwise can be a little difficult.

Research Paper Report

How to Write Research Paper PDF

Research Paper Template PDF

Action Research Paper

Apa Research Paper

Research Paper Sample

A research paper template for word would enable a user to find the relevant style and layout in the word file, which is usually .doc. With the assistance of a template in word format, it becomes a lot easier to follow the specific guidelines. Most universities or colleges would require submitting the research papers in a specific style and it is wise to go through the relevant templates for finding all the information, which is necessary for the completion of the research paper.

Research Paper Template

Research Paper Outline to Print

A research paper outline template would guide a researcher about the outline of the research paper. When writing a research paper, it is important to follow the correct guidelines and sometimes it becomes very difficult if there is no sample or template available to follow. With the help of a template, an individual would know about the outline of the research paper and thus would be able to write the research paper perfectly.

Research Paper Outline PDF

A research paper template APA format as the name implies give information on how to write a research paper based on the APA style of formatting. A researcher would know how to give the relevant citations and what to include and exclude from their research paper.

Research Paper Template for Kids

Essay Research Outline Template

Research Paper Outline Example

A research paper template example would guide a researcher to follow the pattern in a perfect manner. For example, they need to include a table of contents, abstract, introduction, literature review, research and methodology, analysis of the results, and a conclusion. For example, an individual would also get information on how to manage the content in a systematic manner. They would also know what writing style to follow for the research.

Research Paper Outline Sample

A research paper template for PDF would be available in a PDF format thus assisting an individual to go through all the specific requirements. Going through the entire document in the PDF format would be necessary to write the perfect research paper, which captures the attention of the readers as well.

Writing a research paper means a person is qualified enough to present their ideas in a certain way, which tells the reader about the acceptance or rejection of their hypothesis. It is wise to follow a certain template or a research paper sample in order to write it according to the guidelines whether they are based on MLA, APA, Chicago, or Harvard style of referencing.

How did our templates helped you today?

Opps what went wrong, related posts.

22 FREE Divorce Papers (Real and Fake)

20+ Real & Fake Pregnant Papers

Lined Paper Template | 38+ Free in Word, PDF

Thank you for your feedback.

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

• View all journals
• Explore content
• About the journal
• Publish with us
• Sign up for alerts
• Published: 01 July 2024

Time of sample collection is critical for the replicability of microbiome analyses

• Celeste Allaband   ORCID: orcid.org/0000-0003-1832-4858 1 , 2 , 3 ,
• Amulya Lingaraju 2 ,
• Stephany Flores Ramos   ORCID: orcid.org/0000-0002-1918-9769 1 , 2 , 3 ,
• Tanya Kumar 4 ,
• Haniyeh Javaheri 2 ,
• Maria D. Tiu 2 ,
• Ana Carolina Dantas Machado 2 ,
• R. Alexander Richter 2 ,
• Emmanuel Elijah 5 , 6 ,
• Gabriel G. Haddad 3 , 7 , 8 ,
• Vanessa A. Leone 9 ,
• Pieter C. Dorrestein   ORCID: orcid.org/0000-0002-3003-1030 3 , 5 , 6 , 10 ,
• Rob Knight   ORCID: orcid.org/0000-0002-0975-9019 3 , 6 , 11 , 12 , 13 &
• Amir Zarrinpar   ORCID: orcid.org/0000-0001-6423-5982 2 , 6 , 13 , 14 , 15  

Nature Metabolism ( 2024 ) Cite this article

Metrics details

• Animal disease models
• Circadian regulation
• Research management

As the microbiome field moves from descriptive and associative research to mechanistic and interventional studies, being able to account for all confounding variables in the experimental design, which includes the maternal effect 1 , cage effect 2 , facility differences 3 , as well as laboratory and sample handling protocols 4 , is critical for interpretability of results. Despite significant procedural and bioinformatic improvements, unexplained variability and lack of replicability still occur. One underexplored factor is that the microbiome is dynamic and exhibits diurnal oscillations that can change microbiome composition 5 , 6 , 7 . In this retrospective analysis of 16S amplicon sequencing studies in male mice, we show that sample collection time affects the conclusions drawn from microbiome studies and its effect size is larger than those of a daily experimental intervention or dietary changes. The timing of divergence of the microbiome composition between experimental and control groups is unique to each experiment. Sample collection times as short as only 4 hours apart can lead to vastly different conclusions. Lack of consistency in the time of sample collection may explain poor cross-study replicability in microbiome research. The impact of diurnal rhythms on the outcomes and study design of other fields is unknown but likely significant.

This is a preview of subscription content, access via your institution

Access options

Access Nature and 54 other Nature Portfolio journals

Get Nature+, our best-value online-access subscription

24,99 € / 30 days

cancel any time

Subscribe to this journal

Receive 12 digital issues and online access to articles

111,21 € per year

only 9,27 € per issue

Buy this article

• Purchase on Springer Link
• Instant access to full article PDF

Prices may be subject to local taxes which are calculated during checkout

Data availability

Literature review data are at https://github.com/knightlab-analyses/dynamics/data/ . Figure 1 , mock data are at https://github.com/knightlab-analyses/dynamics/data/MockData . Figure 2 (Allaband/Zarrinpar 2021) data are under EBI accession ERP110592 . Figure 3 data (longitudinal IHC) are under EBI accession ERP110592 and (longitudinal circadian TRF) EBI accession ERP123226 . Figure 4 data (Zarrinpar/Panda 2014) are in the Supplementary Excel file attached to the source paper 13 ; (Leone/Chang 2015) figshare for the 16S amplicon sequence data are at https://doi.org/10.6084/m9.figshare.882928 (ref. 63 ). Extended Data Fig. 2 data (Caporaso/Knight 2011) are at MG-RAST project mgp93 (IDs mgm4457768.3 and mgm4459735.3). Extended Data Fig. 3 data (Wu/Chen 2018) are under ENA accession PRJEB22049 . Extended Data Fig. 4 data (Tuganbaev/Elinav 2021) are under ENA accession PRJEB38869 .

Code availability

All relevant code notebooks are on GitHub at https://github.com/knightlab-analyses/dynamics/notebooks .

Schloss, P. D. Identifying and overcoming threats to reproducibility, replicability, robustness, and generalizability in microbiome research. mBio 9 , e00525–18 (2018).

Article   PubMed   PubMed Central   Google Scholar  

Gilbert, J. A. et al. Current understanding of the human microbiome. Nat. Med. 24 , 392–400 (2018).

Article   CAS   PubMed   PubMed Central   Google Scholar  

Knight, R. et al. Best practices for analysing microbiomes. Nat. Rev. Microbiol. 16 , 410–422 (2018).

Article   CAS   PubMed   Google Scholar  

Ley, R. E. et al. Obesity alters gut microbial ecology. Proc. Natl Acad. Sci. USA 102 , 11070–11075 (2005).

Deloris Alexander, A. et al. Quantitative PCR assays for mouse enteric flora reveal strain-dependent differences in composition that are influenced by the microenvironment. Mamm. Genome 17 , 1093–1104 (2006).

Friswell, M. K. et al. Site and strain-specific variation in gut microbiota profiles and metabolism in experimental mice. PLoS ONE 5 , e8584 (2010).

Sinha, R. et al. Assessment of variation in microbial community amplicon sequencing by the Microbiome Quality Control (MBQC) project consortium. Nat. Biotechnol. 35 , 1077–1086 (2017).

Alvarez, Y., Glotfelty, L. G., Blank, N., Dohnalová, L. & Thaiss, C. A. The microbiome as a circadian coordinator of metabolism. Endocrinology 161 , bqaa059 (2020).

Frazier, K. & Chang, E. B. Intersection of the gut microbiome and circadian rhythms in metabolism. Trends Endocrinol. Metab. 31 , 25–36 (2020).

Heddes, M. et al. The intestinal clock drives the microbiome to maintain gastrointestinal homeostasis. Nat. Commun. 13 , 6068 (2022).

Leone, V. et al. Effects of diurnal variation of gut microbes and high-fat feeding on host circadian clock function and metabolism. Cell Host Microbe 17 , 681–689 (2015).

Thaiss, C. A. et al. Transkingdom control of microbiota diurnal oscillations promotes metabolic homeostasis. Cell 159 , 514–529 (2014).

Zarrinpar, A., Chaix, A., Yooseph, S. & Panda, S. Diet and feeding pattern affect the diurnal dynamics of the gut microbiome. Cell Metab. 20 , 1006–1017 (2014).

Liang, X., Bushman, F. D. & FitzGerald, G. A. Rhythmicity of the intestinal microbiota is regulated by gender and the host circadian clock. Proc. Natl Acad. Sci. USA 112 , 10479–10484 (2015).

Thaiss, C. A. et al. Microbiota diurnal rhythmicity programs host transcriptome oscillations. Cell 167 , 1495–1510 (2016).

Yu, F. et al. Deficiency of intestinal Bmal1 prevents obesity induced by high-fat feeding. Nat. Commun. 12 , 5323 (2021).

Leone, V. A. et al. Atypical behavioral and thermoregulatory circadian rhythms in mice lacking a microbiome. Sci. Rep. 12 , 14491 (2022).

Thaiss, C. A., Zeevi, D., Levy, M., Segal, E. & Elinav, E. A day in the life of the meta-organism: diurnal rhythms of the intestinal microbiome and its host. Gut Microbes 6 , 137–142 (2015).

Mukherji, A., Kobiita, A., Ye, T. & Chambon, P. Homeostasis in intestinal epithelium is orchestrated by the circadian clock and microbiota cues transduced by TLRs. Cell 153 , 812–827 (2013).

Weger, B. D. et al. The mouse microbiome is required for sex-specific diurnal rhythms of gene expression and metabolism. Cell Metab. 29 , 362–382 (2019).

Kaczmarek, J. L., Musaad, S. M. & Holscher, H. D. Time of day and eating behaviors are associated with the composition and function of the human gastrointestinal microbiota. Am. J. Clin. Nutr. 106 , 1220–1231 (2017).

Skarke, C. et al. A pilot characterization of the human chronobiome. Sci. Rep. 7 , 17141 (2017).

Jones, J., Reinke, S. N., Ali, A., Palmer, D. J. & Christophersen, C. T. Fecal sample collection methods and time of day impact microbiome composition and short chain fatty acid concentrations. Sci. Rep. 11 , 13964 (2021).

Collado, M. C. et al. Timing of food intake impacts daily rhythms of human salivary microbiota: a randomized, crossover study. FASEB J. 32 , 2060–2072 (2018).

Kohn, J. N. et al. Differing salivary microbiome diversity, community and diurnal rhythmicity in association with affective state and peripheral inflammation in adults. Brain. Behav. Immun. 87 , 591–602 (2020).

Takayasu, L. et al. Circadian oscillations of microbial and functional composition in the human salivary microbiome. DNA Res. 24 , 261–270 (2017).

Reitmeier, S. et al. Arrhythmic gut microbiome signatures predict risk of type 2 diabetes. Cell Host Microbe 28 , 258–272 (2020).

Allaband, C. et al. Intermittent hypoxia and hypercapnia alter diurnal rhythms of luminal gut microbiome and metabolome. mSystems https://doi.org/10.1128/mSystems.00116-21 (2021).

Tuganbaev, T. et al. Diet diurnally regulates small intestinal microbiome-epithelial-immune homeostasis and enteritis. Cell 182 , 1441–1459 (2020).

Wu, G. et al. Light exposure influences the diurnal oscillation of gut microbiota in mice. Biochem. Biophys. Res. Commun. 501 , 16–23 (2018).

Nelson, R. J. et al. Time of day as a critical variable in biology. BMC Biol. 20 , 142 (2022).

Dantas Machado, A. C. et al. Diet and feeding pattern modulate diurnal dynamics of the ileal microbiome and transcriptome. Cell Rep. 40 , 111008 (2022).

Morton, J. T. et al. Establishing microbial composition measurement standards with reference frames. Nat. Commun. 10 , 2719 (2019).

Caporaso, J. G. et al. Moving pictures of the human microbiome. Genome Biol. 12 , R50 (2011).

Bisanz, J. E., Upadhyay, V., Turnbaugh, J. A., Ly, K. & Turnbaugh, P. J. Meta-analysis reveals reproducible gut microbiome alterations in response to a high-fat diet. Cell Host Microbe 26 , 265–272.e4 (2019).

Kohsaka, A. et al. High-fat diet disrupts behavioral and molecular circadian rhythms in mice. Cell Metab. 6 , 414–421 (2007).

Hatori, M. et al. Time-restricted feeding without reducing caloric intake prevents metabolic diseases in mice fed a high-fat diet. Cell Metab. 15 , 848–860 (2012).

Baker, F. Normal rumen microflora and microfauna of cattle. Nature 149 , 220 (1942).

Article   Google Scholar  

Zhang, L., Wu, W., Lee, Y.-K., Xie, J. & Zhang, H. Spatial heterogeneity and co-occurrence of mucosal and luminal microbiome across swine intestinal tract. Front. Microbiol. 9 , 48 (2018).

Klymiuk, I. et al. Characterization of the luminal and mucosa-associated microbiome along the gastrointestinal tract: results from surgically treated preterm infants and a murine model. Nutrients 13 , 1030 (2021).

Kim, D. et al. Comparison of sampling methods in assessing the microbiome from patients with ulcerative colitis. BMC Gastroenterol. 21 , 396 (2021).

Tripathi, A. et al. Intermittent hypoxia and hypercapnia reproducibly change the gut microbiome and metabolome across rodent model systems. mSystems 4 , e00058–19 (2019).

Uhr, G. T., Dohnalová, L. & Thaiss, C. A. The Dimension of Time in Host-Microbiome Interactions. mSystems 4 , e00216–e00218 (2019).

Voigt, R. M. et al. Circadian disorganization alters intestinal microbiota. PLoS ONE 9 , e97500 (2014).

McDonald, D. et al. American gut: an open platform for citizen science microbiome research. mSystems 3 , e00031–18 (2018).

Borodulin, K. et al. Cohort profile: the National FINRISK Study. Int. J. Epidemiol. 47 , 696–696i (2018).

Article   PubMed   Google Scholar  

Ren, B. et al. Methionine restriction improves gut barrier function by reshaping diurnal rhythms of inflammation-related microbes in aged mice. Front. Nutr. 8 , 746592 (2021).

Beli, E., Prabakaran, S., Krishnan, P., Evans-Molina, C. & Grant, M. B. Loss of diurnal oscillatory rhythms in gut microbiota correlates with changes in circulating metabolites in type 2 diabetic db/db mice. Nutrients 11 , E2310 (2019).

Wang, L. et al. Methionine restriction regulates cognitive function in high-fat diet-fed mice: roles of diurnal rhythms of SCFAs producing- and inflammation-related microbes. Mol. Nutr. Food Res. 64 , e2000190 (2020).

Guo, T. et al. Oolong tea polyphenols ameliorate circadian rhythm of intestinal microbiome and liver clock genes in mouse model. J. Agric. Food Chem. 67 , 11969–11976 (2019).

Mistry, P. et al. Circadian influence on the microbiome improves heart failure outcomes. J. Mol. Cell. Cardiol. 149 , 54–72 (2020).

Shao, Y. et al. Effects of sleeve gastrectomy on the composition and diurnal oscillation of gut microbiota related to the metabolic improvements. Surg. Obes. Relat. Dis. 14 , 731–739 (2018).

Bolyen, E. et al. Reproducible, interactive, scalable and extensible microbiome data science using QIIME 2. Nat. Biotechnol. 37 , 852–857 (2019).

Amir, A. et al. Deblur rapidly resolves single-nucleotide community sequence patterns. mSystems 2 , e00191–16 (2017).

Mirarab, S., Nguyen, N. & Warnow, T. in Biocomputing 2012 , 247–258 (World Scientific, 2011).

Lozupone, C., Lladser, M. E., Knights, D., Stombaugh, J. & Knight, R. UniFrac: an effective distance metric for microbial community comparison. ISME J. 5 , 169–172 (2011).

Lauber, C. L., Zhou, N., Gordon, J. I., Knight, R. & Fierer, N. Effect of storage conditions on the assessment of bacterial community structure in soil and human-associated samples: Influence of short-term storage conditions on microbiota. FEMS Microbiol. Lett. 307 , 80–86 (2010).

Marotz, C. et al. Evaluation of the effect of storage methods on fecal, saliva, and skin microbiome composition. mSystems 6 , e01329–20 (2021).

Song, S. J. et al. Preservation methods differ in fecal microbiome stability, affecting suitability for field studies. mSystems 1 , e00021–16 (2016).

Wu, G. D. et al. Sampling and pyrosequencing methods for characterizing bacterial communities in the human gut using 16S sequence tags. BMC Microbiol. 10 , 206 (2010).

Piedrahita, J. A., Zhang, S. H., Hagaman, J. R., Oliver, P. M. & Maeda, N. Generation of mice carrying a mutant apolipoprotein E gene inactivated by gene targeting in embryonic stem cells. Proc. Natl Acad. Sci. USA 89 , 4471–4475 (1992).

Chaix, A., Zarrinpar, A., Miu, P. & Panda, S. Time-restricted feeding is a preventative and therapeutic intervention against diverse nutritional challenges. Cell Metab. 20 , 991–1005 (2014).

Gibbons, S. Diel Mouse Gut Study (HF/LF diet) . figshare https://doi.org/10.6084/m9.figshare.882928 (2015).

Download references

Acknowledgements

C.A. was supported by NIH T32 OD017863. S.F.R. is supported by the Soros Foundation. A.L. is supported by the AHA Postdoctoral Fellowship grant. T.K. is supported by NIH T32 GM719876. A.C.D.M. is supported by R01 HL148801-02S1. G.G.H. and A.Z. are supported by NIH R01 HL157445. A.Z. is further supported by the VA Merit BLR&D Award I01 BX005707 and NIH grants R01 AI163483, R01 HL148801, R01 EB030134 and U01 CA265719. All authors receive institutional support from NIH P30 DK120515, P30 DK063491, P30 CA014195, P50 AA011999 and UL1 TR001442.

Author information

Authors and affiliations.

Division of Biomedical Sciences, University of California, San Diego, La Jolla, CA, USA

Celeste Allaband & Stephany Flores Ramos

Division of Gastroenterology, University of California, San Diego, La Jolla, CA, USA

Celeste Allaband, Amulya Lingaraju, Stephany Flores Ramos, Haniyeh Javaheri, Maria D. Tiu, Ana Carolina Dantas Machado, R. Alexander Richter & Amir Zarrinpar

Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA

Celeste Allaband, Stephany Flores Ramos, Gabriel G. Haddad, Pieter C. Dorrestein & Rob Knight

Medical Scientist Training Program, University of California San Diego, La Jolla, CA, USA

Tanya Kumar

Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA

Emmanuel Elijah & Pieter C. Dorrestein

Center for Microbiome Innovation, University of California, San Diego, La Jolla, CA, USA

Emmanuel Elijah, Pieter C. Dorrestein, Rob Knight & Amir Zarrinpar

Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA

Gabriel G. Haddad

Rady Children’s Hospital, San Diego, CA, USA

Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI, USA

Vanessa A. Leone

Center for Computational Mass Spectrometry, University of California, San Diego, La Jolla, CA, USA

Pieter C. Dorrestein

Department of Computer Science and Engineering, University of California, San Diego, La Jolla, CA, USA

Halıcıoğlu Data Science Institute, University of California, San Diego, La Jolla, CA, USA

Shu Chien-Gene Lay Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA

Rob Knight & Amir Zarrinpar

Division of Gastroenterology, Jennifer Moreno Department of Veterans Affairs Medical Center, La Jolla, CA, USA

Amir Zarrinpar

Institute of Diabetes and Metabolic Health, University of California, San Diego, La Jolla, CA, USA

You can also search for this author in PubMed   Google Scholar

Contributions

C.A. and A.Z. conceptualized the work. C.A., E.E., P.C.D., R.K. and A.Z. determined the methodology. C.A., A.L., S.F.R., T.K., H.J., M.D.T., A.C.D.M. and R.A.R. were involved in data investigation. C.A., S.F.R., T.K., H.J., M.D.T., A.C.D.M. and R.A.R. created visualizations. A.Z. acquired funding and was the project administrator. R.K. and A.Z. supervised the work. G.G.H. and V.A.L. provided resources. C.A., A.L., S.F.R., T.K., H.J., M.D.T. and A.Z. wrote the first draft. All authors contributed to the review and editing of the manuscript.

Corresponding author

Correspondence to Amir Zarrinpar .

Ethics declarations

Competing interests.

A.Z. is a co-founder and a chief medical officer, and holds equity in Endure Biotherapeutics. P.C.D. is an advisor to Cybele and co-founder and advisor to Ometa and Enveda with previous approval from the University of California, San Diego. All other authors declare no competing interests.

Peer review

Peer review information.

Nature Metabolism thanks Robin Voigt-Zuwala, Jacqueline M. Kimmey, John R. Kirby and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: Yanina-Yasmin Pesch, in collaboration with the Nature Metabolism team.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended data fig. 1 microbiome literature review..

A ) 2019 Literature Review Summary. Of the 586 articles containing microbiome (16 S or metagenomic) data, found as described in the methods section, the percentage of microbiome articles from each of the publication groups. B ) The percentage of microbiome articles belonging to each individual journal in 2019. Because the numerous individual journals from Science represented low percentages individually, they were grouped together. C ) The percentage articles where collection time was explicitly stated (yes: 8 AM, ZT4, etc.), implicitly stated (relative: ‘before surgery’, ‘in the morning’, etc.), or unstated (not provided: ‘daily’, ‘once a week’, etc.). D ) Meta-Analysis Inclusion Criteria Flow Chart. Literature review resulting in the five previously published datasets for meta-analysis 11 , 13 , 28 , 29 , 30 .

Extended Data Fig. 2 Single Time Point (Non-Circadian) Example.

A ) Weighted UniFrac PCoA Plot - modified example from Moving Pictures Qiime2 tutorial data [ https://docs.qiime2.org/2022.11/tutorials/moving-pictures/ ]. Each point is a sample. Points were coloured by body site of origin. There are 8 gut, 8 left palm, 9 right palm, and 9 tongue samples. B ) Within-Condition Distances (WCD) boxplot/stripplot for each body site (n = 8–9 mouse per group per time point). C ) Between Condition Distances (BCD) boxplot/stripplot for each unique body site comparison (n = 8–9 mouse per group per time point). D ) All pairwise grouping comparisons, both WCD and BCD, are shown in the boxplots/stripplots (n = 8–9 mouse per group per time point). Only WCD to BCD statistical differences are shown. Boxplot centre line indicates median, edges of boxes are quartiles, error bars are min and max values. Significance was determined using a paired Mann-Whitney-Wilcoxon test two-sided with Bonferroni correction. Notation: ns (not significant) = p > 0.05, * = p < 0.05; ** = p < 0.01; *** = p < 0.001, **** = p < 0.00001.

Extended Data Fig. 3 Additional Analysis of Apoe-/- Mice Exposed to IHC Conditions.

A ) Weighted UniFrac PCoA stacked view (same as Fig. 2b but different orientation). Good for assessing overall similarity not broken down by time point. Significance determined by PERMANOVA (p = 0.005). B ) Weighted UniFrac PCoA of only axis 1 over time. C ) Boxplot/scatterplot of within-group weighted UniFrac distance values for the control group (Air, n = 3–4 samples per time point). Unique non-zero values in the matrix were kept. Dotted line indicates the mean of all values presented. No significant differences (p > 0.05) found. D ) Boxplot/scatterplot of within-group weighted UniFrac distance values for the experimental group (IHC, n = 3–4 samples per time point)). Unique non-zero values in the matrix were kept. Dotted line indicates the mean of all values presented. No significant differences (p > 0.05) found. E ) Boxplot/scatterplot of within-group weighted UniFrac distance values for both control (Air) and experimental (IHC) groups [n = 3–4 samples per group per time point]. Mann-Whitney-Wilcoxon test with Bonferroni correction used to determine significant differences between groups. Boxplot centre line indicates median, edges of boxes are quartiles, error bars are min and max values. Notation: ns = not significant, p > 0.05; * = p < 0.05; ** = p < 0.01; *** = p < 0.001.

Extended Data Fig. 4 Irregular differences in diurnal rhythm patterns leads to generally minor shifts in BCD when comparing LD vs DD mice.

A ) Experimental design. Balb/c mice were fed NCD ad libitum under 0:24 L:D (24 hr darkness, DD) experimental conditions and compared to 12:12 L:D (LD) control conditions. After 2 weeks, mice from each group were euthanized every 4 hours for 24 hours (N = 4–5 mice/condition) and samples were collected from the proximal small intestine (‘jejunum’) and distal small intestine (‘ileum’) contents. B ) BCD for luminal contents of proximal small intestine samples comparing LD to DD mice (N = 4–5 mice/condition). Dotted line is the average of all shown weighted UniFrac distances. Significance was determined using a paired Mann-Whitney-Wilcoxon test two-sided with Bonferroni correction; notation: **** = p < 0.00001. C ) BCD for luminal contents of distal small intestine samples comparing LD to DD mice (N = 4–5 mice/condition). Dotted line is the average of all shown weighted UniFrac distances. Boxplot centre line indicates median, edges of boxes are quartiles, error bars are min and max values.

Extended Data Fig. 5 Localized changes in BCD between luminal and mucosal contents.

A ) Experimental design and sample collection for a local site study. Small intestinal samples were collected every 4 hours for 24 hours (N = 4–5 mice/condition, skipping ZT8). Mice were fed ad libitum on the same diet (NCD) for 4 weeks before samples were taken. B ) BCD for luminal vs mucosal conditions (N = 4–5 mice/condition). The dotted line is the average of all shown weighted UniFrac distances. Significance is determined using the Mann-Whitney-Wilcoxon test two-sided with Bonferroni correction. C ) Heatmap of mean BCD distances comparing luminal and mucosal by time point (N = 4–5 mice/condition). Highest value highlighted in navy, lowest value highlighted in gold. Boxplot centre line indicates median, edges of boxes are quartiles, error bars are min and max values. Significance was determined using a paired Mann-Whitney-Wilcoxon test two-sided with Bonferroni correction. Notation: * = p < 0.05; ** = p < 0.01; *** = p < 0.001, **** = p < 0.00001. D ) Experimentally relevant log ratio, highlighting the changes seen at ZT20 (N = 4–5 mice/condition). Boxplot center line indicates median, edges of boxes are quartiles, error bars are min and max values. Significance was determined using a paired Mann-Whitney-Wilcoxon test two-sided with Bonferroni correction. Notation: * = p < 0.05; ** = p < 0.01; *** = p < 0.001, **** = p < 0.00001.

Supplementary information

Reporting summary, rights and permissions.

Reprints and permissions

About this article

Cite this article.

Allaband, C., Lingaraju, A., Flores Ramos, S. et al. Time of sample collection is critical for the replicability of microbiome analyses. Nat Metab (2024). https://doi.org/10.1038/s42255-024-01064-1

Download citation

Received : 27 October 2022

Accepted : 08 May 2024

Published : 01 July 2024

DOI : https://doi.org/10.1038/s42255-024-01064-1

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

Quick links

• Explore articles by subject
• Guide to authors
• Editorial policies

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

ORIGINAL RESEARCH article

The relationship between gut microbiota and insomnia: a bi-directional two-sample mendelian randomization research.

• Department of Neurology, Hangzhou Children’s Hospital, Hangzhou, Zhejiang, China

Introduction: Insomnia is the second most common mental health issue, also is a social and financial burden. Insomnia affects the balance between sleep, the immune system, and the central nervous system, which may raise the risk of different systemic disorders. The gut microbiota, referred to as the “second genome,” has the ability to control host homeostasis. It has been discovered that disruption of the gut-brain axis is linked to insomnia.

Methods: In this study, we conducted MR analysis between large-scale GWAS data of GMs and insomnia to uncover potential associations.

Results: Ten GM taxa were detected to have causal associations with insomnia. Among them, class Negativicutes , genus Clostridiuminnocuumgroup , genus Dorea , genus Lachnoclostridium , genus Prevotella7 , and order Selenomonadalesare were linked to a higher risk of insomnia. In reverse MR analysis, we discovered a causal link between insomnia and six other GM taxa.

Conclusion: It suggested that the relationship between insomnia and intestinal flora was convoluted. Our findings may offer beneficial biomarkers for disease development and prospective candidate treatment targets for insomnia.

Introduction

Insomnia disorder, defined by self-reported sleep difficulties, is characterized by persistent difficulty initiating or sustaining sleep as well as related daytime dysfunction. With 10% to 20% of the population affected, insomnia is the second most common mental health issue (after anxiety disorder), and it is more common in older people and women. In adults, 5.8% to 20% of the population suffers from insomnia, but the prevalence of insomnia in the elderly ranges from 30% to 48%. Insomnia disorder is among the top 10 reasons for general practitioners’ consultations ( Lo Yun et al., 2022 ). It is also a social and financial burden, raising questions about public health. Insomnia affects the balance between sleep, the immune system, and the central nervous system, which may raise the risk of infection, depression, cardiovascular disease, gastrointestinal disorders, and respiratory illnesses. Chronic insomnia contributes to a variety of negative outcomes, including decreased physical and mental health (e.g., cardiovascular disease and stroke), worsened health-related life quality, and poorer mental health (e.g., chronic pain, anxiety, depression, substance misuse, and suicide). Given the severity of the negative impacts of insomnia, identifying risk factors is essential for treatments ( Jia et al., 2022 ; Yao et al., 2022 ; Gibson et al., 2023 ).

The intestinal flora, also referred to as the “second genome,” has the ability to control host homeostasis, which includes metabolic rate, immune/inflammatory response, and cardiovascular function ( Le Chatelier et al., 2013 ). The gut microbiome (GM) is also linked to neuropsychiatric illnesses, as it may regulate brain function and behavior through the microbiota-gut-brain axis ( Iannone et al., 2019 ; Zhang et al., 2021 ; Wang Z. et al., 2022 ). There are variations in GM taxa among people with epilepsy, depression, autistic spectrum disorder, and Parkinson’s disease. Recent research has shown that the gut-brain axis is dysregulated in relation to insomnia and that abnormalities in the gut microbiota can make the condition worse. To date, there have been few investigations into the relationship between intestinal flora and insomnia ( Qi et al., 2022 ; Bundgaard-Nielsen et al., 2023 ; Chalet et al., 2023 ).

Fortunately, large-scale genome-wide association studies (GWASs) on gut microbiota and insomnia are now available, allowing for a meaningful assessment of association in MR analysis. Through instrumental variables (IV) that are genetic variants strongly related to the exposure of interest, Mendelian randomization (MR) analysis is used to investigate the causal relationship between exposure and outcome. In MR research, single nucleotide polymorphisms (SNPs) are used as instrumental variables (IV) ( Burgess and Thompson, 2017 ; Burgess et al., 2017 ). SNPs adhere to the principle of random genetic variation assignment at meiosis, which eliminates the influence of confounding factors and the potential impact of reverse causation because genetic variants exist prior to the start of the disease ( Lawlor et al., 2008 ). Therefore, when compared to RCT, MR analysis can more quickly identify the causal relationships between relevant exposure components and outcomes. Currently, no MR studies on insomnia and GM have been undertaken. Here, we conduct an MR analysis through large-scale GWAS summary statistics of GMs and insomnia to uncover potential GM taxa that could support some current findings and offer novel viewpoints on the identification and management of insomnia.

Materials and methods

Study design.

The overall flow chart of this study is shown in Figure 1 . The three presumptions below must be satisfied by MR studies: (i) IVs are highly linked with exposure variables, (ii) IVs are independent of confounding factors, and (iii) IVs are only associated with outcomes via exposure factors ( Burgess et al., 2017 ). Our results followed the STROBE-MR guidelines ( Skrivankova et al., 2021a ).

Figure 1 Flowchart of current study.

Data sources of the exposure and outcome

From the MiBioGen project, we obtained the gut microbiota statistics summary-level data, the largest genome-wide meta-analysis to date ( Kurilshikov et al., 2021 ). In the MiBioGen project, the 16S rRNA gene sequencing profiles of 18,340 individuals were assembled and evaluated, and 211 GM taxa were identified (from genus to phylum level, including 9 phyla, 16 classes, 20 orders, 35 families, and 131 genera). The GWAS summary statistics for GMs can be found at https://mibiogen.gcc.rug.nl ( Swertz and Jansen, 2007 ; Swertz et al., 2010 ; van der Velde et al., 2019 ). Insomnia GWAS summary data were obtained from the UK Biobank Sleep Traits GWAS: Self-report (insomnia associations and sleep duration associations) ( https://sleep.hugeamp.org/downloads.html ). Insomnia symptoms were self-reported by European-ancestry UK Biobank participants (n=453,379). Participants were asked the question: “Do you have trouble falling asleep at night or do you wake up in the middle of the night?” and were asked to select from responses of “never/rarely”, “sometimes”, “usually”, and “prefer not to answer” in this sample; twenty-nine percent of people self-reported experiencing frequent insomnia symptoms on a regular basis (or “usually”) ( Gibson et al., 2023 ).

Identification of IVs

In this MR study, IVs were SNPs that were highly correlated with each GM taxon. We obtained the number of IVs for gut microbiota data with the threshold (p<5×10 -5 ), and the threshold in reverse MR analyses was set under p<5×10 -8 for insomnia data. Additionally, we removed SNPs within a window size of 500 kb and a threshold of r 2 <0.1 to reduce linkage disequilibrium (LD) for gut microbiota data, whereas for insomnia data in reverse MR analysis, the window size was set at kb=10000 and a threshold of r 2 <0.001. Then, we eliminated palindromic SNPs and SNPs that were not present in the IV results. Finally, to measure the degree of weak instrumental bias, the F-statistic of IVs was computed. If the F-statistic was >10, it was assumed that no bias was caused by weak IVs. The formula for calculating the F-value is F = ( R 2 1 − R 2 ) ( n − k − 1 ) k , R 2 = 2 × ( 1 − M A F ) × M A F × ( β ) 2 ( Pierce et al., 2011 ).

Statistical methods

The principal MR method for determining causation was the inverse variance weighted random effect (IVW-RE). Based on the meta-analysis principles, the IVW approach is a Wald ratio estimator extension ( Pagoni et al., 2019 ). Methods of MR-Egger, weighted median, simple mode, and weighted mode were carried out for each GM taxon on insomnia ( Bowden et al., 2016 ; Burgess and Thompson, 2017 ; Davies et al., 2018 ). If the IVW approach revealed a causal association for that taxon (p<0.05), these four MR methods were used to supplement the IVW findings. The criterion of the weighted median method is that at least 50% of the SNPs must satisfy the premise that they are valid IVs ( Davies et al., 2018 ; Verbanck et al., 2018 ). The MR-Egger method provides unbiased estimates even when all selected IVs are multivariate ( Burgess and Thompson, 2017 ). Finally, odds ratios (OR) and 95% confidence intervals (CI) were utilized to present the findings of causal connections. The significance cutoff was established at p<0.05.

Only exposure-outcome pairs that were discovered using all MR techniques and had the same direction were thought to have a causal relationship. We also carried out a number of sensitivity studies to examine the consistency of the causal association. First, horizontal pleiotropy was identified through the MR-Egger and MR-PRESSO tests ( Rees et al., 2017 ; Verbanck et al., 2018 ; Skrivankova et al., 2021b ). Additionally, the leave-one-out and Funnel plots analyses were conducted to evaluate the reliability of the findings. In this study, “TwoSampleMR” and “MR-PRESSO” packages of R software (version 4.3.0) were used to carry out the MR analysis.

To investigate the reverse causality of insomnia (as exposures) on gut microbiota (as outcomes), a reverse MR analysis was carried out for insomnia on each GM taxa. The process followed the same guidelines as the methodology indicated above for the two-sample MR. This bidirectional MR and sensitivity analysis follows the rules of the TwoSample MR and MR-PRESSO packages.

Two-sample Mendelian randomization of gut microbiota (exposure) on insomnia (outcome)

Details of ivs.

Under a suggestive significance level of P<1×10 -5 , 2,284 SNPs were discovered, and three duplicated SNPs (rs10805326, rs2728491, and rs2704155) were deleted. These SNPs were grouped into five categories as final IVs: class, family, order, genus, and phylum. Particularly, there were 200 IVs in 18 classes, 439 IVs in 35 families, 245 IVs in 20 orders, 1,483 IVs in 131 genera, and 112 IVs in 9 phyla. Furthermore, all IVs were shown to be more strongly related to exposure than to outcome ( p exposure < p outcome ), and all F-statistics were greater than 10. Details of the IVs of insomnia are presented in Supplementary Table 1 .

MR analysis

First, 211 GM taxa with five methods (IVW-RE, MR-Egger, weighted median, simple mode, and weighted mode) were evaluated using MR analysis to determine their causal relationship with insomnia ( Figure 2 ). The IVW-FE results revealed that 10 GM taxa had a significant association with insomnia. Family FamilyXIII (ID: 1957) [OR=0.982 (0.966, 0.997), p =0.020], genus Odoribacter (ID: 952) [OR=0.976(0.954,0.999), p =0.044], genus Oscillibacter (ID: 2063) [OR=0.985(0.974,0.996), p =0.005], and phylum Verrucomicrobia (ID: 3982) [OR=0.986(0.974,0.999), p =0.032] were related to a lower risk for insomnia, while class Negativicutes (ID: 2164) [OR=1.031(1.016,1.047), p =7.53E-05], genus Clostridiuminnocuumgroup (ID: 14397) [OR=1.018(1.005,1.031), p =0.006], genus Dorea (ID: 1997) [OR=1.017(1.001,1.034), p =0.039], genus Lachnoclostridium (ID: 11308) [OR=1.029(1.007,1.052), p =0.009], genus Prevotella7 (ID: 11182) [OR=1.009(1.002,1.017), p =0.017], and order Selenomonadales (ID: 2165) [OR=1.031(1.016,1.047), p =7.53E-05] were associated with a higher risk of insomnia. Additionally, the findings of Cochran’s Q test showed that there was no heterogeneity.

Figure 2 Results [OR (95%CI)] for MR analyses for GWAS data of 211 GM taxa (exposure) on insomnia (outcome) through inverse variance weighted random effect (IVW-RE) method: 9 phyla, 16 classes, 20 orders, 35 families, and 131 genera. It showed that 10 GM taxa, including class Negativicutes (ID: 2164), Family FamilyXIII (ID: 1957), order Selenomonadales (ID: 2165), phylum Verrucomicrobia (ID: 3982), genus Odoribacter (ID: 952), genus Oscillibacter (ID: 2063), genus Clostridiuminnocuumgroup (ID: 14397), genus Dorea (ID: 1997), genus Lachnoclostridium (ID: 11308), and genus Prevotella7 (ID: 11182), had causality with insomnia.

Additionally, four additional methods, MR-Egger, weighted median, simple mode, and weighted mode, were performed to assess the causal effect of these 10 GM taxa on insomnia ( Figure 3 ). The results were consistent with the IVW-FE results. Family FamilyXIII (ID: 1957), phylum Verrucomicrobia (ID: 3982), genus Odoribacter (ID: 952), and genus Oscillibacter (ID: 2063) were related with a lower risk for insomnia, while the other six GMs [class Negativicutes (ID: 2164), genus Clostridiuminnocuumgroup (ID: 14397), genus Dorea (ID: 1997), genus Lachnoclostridium (ID: 11308), genus Prevotella7 (ID: 11182), and order Selenomonadales (ID: 2165)] showed a higher risk of insomnia. There was no indication of heterogeneity, pleiotropy, or weak instrument bias in the heterogeneity (IVW test and MR-Egger regression), pleiotropy (MR-PRESSO test and MR-Egger regression), or weak instrument bias (F statistic) tests. Additional details are summarized in Supplementary Table 2 .

Figure 3 Five methods’ (MR-Egger, weighted median, inverse variance weighted, simple mode, and weighted mode) results (OR[95%CI]) of MR analyses for 10 GM taxa on insomnia.

Reverse Mendelian randomization analysis of insomnia (exposure) on gut microbiota (outcome)

IVs were retrieved from GWAS datasets of insomnia in a previous MR analysis of the relationship between gut microbiota and insomnia, with a significance of P-value at 1×10 -8 . Forty SNPs were discovered from 2,500 SNPs (SNPs of insomnia GWAS data at P<1×10 -8 ) after removing SNPs with linkage disequilibrium. First, we conducted MR analysis to determine the relationship between insomnia and 10 GM taxa, including the class Negativicutes (ID: 2164), family FamilyXIII (ID: 1957), genera Odoribacter (ID: 952), Oscillibacter (ID: 2063), Clostridiuminnocuumgroup (ID: 14397), Dorea (ID: 1997), Lachnoclostridium (ID: 11308), Prevotella7 (ID: 11182), order Selenomonadales (ID: 2165), and phylum Verrucomicrobia (ID: 3982). It demonstrated the lack of a causal relationship between insomnia and these 10 GM taxa, which was consistent with our prior MR findings. Additional details are summarized in Supplementary Table 3 and Supplementary Figure S1 .

Reverse MR analysis was then used to investigate the other 201 GM taxa for insomnia. According to the IVW-FE results, six GM taxa substantially correlate with insomnia. Insomnia could increase the abundance of the gut microbiota of family Oxalobacteraceae (ID:2966) [OR=3.075 (1.453, 6.511), p =0.003], genus Butyrivibrio (ID:1993) [OR=2.656(1.005, 7.016), p =0.049], genus Clostridiumsensustricto1 (ID:1873) [OR=1.708 (1.085, 2.687), p =0.021], and genus Oxalobacter (ID:2978) [OR=2.434(1.104,5.370), p =0.028], while insomnia could decrease the abundance of genus Eubacteriumnodatumgroup (ID:11297) [OR=0.310(0.098,0.961), p =0.042] and genus RuminococcaceaeUCG013 (ID:11370)[OR=0.522(0.345, 0.791), p =0.002]. Furthermore, four additional methods, MR-Egger, weighted median, simple mode, and weighted mode, were performed to assess the causal effect of insomnia on these GM taxa ( Figure 4 ). The outcomes matched those of the IVW in a similar way. In this investigation, neither the IVW test nor the MR-Egger regression showed any evidence of heterogeneity, pleiotropy, or weak instrument bias. The MR-PRESSO test and the MR-Egger regression also showed no evidence of these phenomena. Then, we conducted scatter plots and leave-one-out plots for insomnia on six GM taxa [family Oxalobacteraceae (ID:2966), genus Butyrivibrio (ID:1993), genus Clostridiumsensustricto1 (ID:1873), genus Oxalobacter (ID:2978), genus Eubacteriumnodatumgroup (ID:11297), and genus RuminococcaceaeUCG013 (ID:11370)]. Furthermore, the inverse variance weighted, MR-Egger, and weighted median results of the MR Steiger directionality test demonstrated a strong direction from insomnia to the six GM taxa. The robustness of our findings was demonstrated by the leave-one-out sensitivity analysis, which showed that no one SNP drives a causal association ( Figure 5 ). Funnel plots of Inverse variance weighted and MR Egger results excluded a potential bias ( Supplementary Figure S2 ).

Figure 4 Reverse MR analyses results (OR[95%CI]) of five methods (MR-Egger, weighted median, inverse variance weighted, simple mode, and weighted mode) for insomnia on six GM taxa (family Oxalobacteraceae , genus Butyrivibrio , genus Clostridiumsensustricto1 , genus Oxalobacter , genus Eubacteriumnodatumgroup , and genus RuminococcaceaeUCG013 ).

Figure 5 The scatter plot and leave-one-out plot of MR analyses for insomnia on six GM taxa. (A) : exposure: insomnia, outcome: family Oxalobacteraceae (ID:2966). (B) : exposure: insomnia, outcome: genus Eubacteriumnodatumgroup (ID:11297). (C) : exposure: insomnia, outcome: genus Butyrivibrio (ID:1993). (D) : exposure: insomnia, outcome: genus Clostridiumsensustricto1 (ID:1873). (E) : exposure: insomnia, outcome: genus Oxalobacter (ID:2978). (F) : exposure: insomnia, outcome: genus RuminococcaceaeUCG013 (ID:11370).

To the best of our knowledge, this is the first MR investigation using huge GWAS summary-level data to indicate a probable causal connection between gut microbiota and insomnia. This study examined the causative impact of 211 GM taxa (from the class, family, order, genus, and phylum level) on insomnia. In this study design, we checked and confirmed the assumptions of Mendelian Randomization (MR). We discovered 10 GM taxa that are connected to insomnia, and reverse MR analysis revealed that 6 GM taxa may be affected. The gut microbiome’s potential protective or contributing effects on insomnia suggest a close connection between the two conditions.

Nowadays, the gut microbiome and its impact on humans are receiving increasing attention. Growing data suggest that the gut microbiota (GM) can control host homeostasis in both health and disease, for example, through the gut-brain axis, gut-lung axis, gut-kidney axis, gut-skin axis, gut-liver axis, and gut-immune axis. Researchers have discovered links between gut microbiota and many diseases, such as autism spectrum disorder, depression, epilepsy, Alzheimer’s disease, type 2 diabetes, obesity, chronic obstructive pulmonary disease, atopic dermatitis, COVID-19 illness, psoriasis, and systemic autoimmune diseases. Clinical trials on intestinal flora have shown efficacy in the treatment of disorders such as epilepsy, autism, Alzheimer’s disease, inflammatory bowel disease, rheumatoid arthritis, and psoriasis ( Iannone et al., 2019 ; Orru et al., 2020 ; Mahmud et al., 2022 ; Mousa et al., 2022 ; Qin et al., 2022 ). Recent research has shown that GMs are involved in neuropsychiatric disorders because they affect brain activity and behavior through the microbiota-gut-brain axis ( Johnson and Foster, 2018 ). It has been discovered that disruption of the gut-brain axis is linked to insomnia. In our study, we identified six GMs in the reverse MR. Given that gut microbiota was related to many diseases, these disorders may directly or indirectly arise in the six GMs. The gut microbiota’s particular metabolites have been reported to be related to insomnia, and alterations in the gut microbiota may worsen the condition. Its molecular mechanism is not yet fully understood ( Haimov et al., 2022 ; Feng et al., 2023 ).

Insomnia is believed to have a negative impact on the quality of life in adults and the elderly population around the world. In general, insomnia affects 5.8 to 20% of the adult population, whereas it affects 30% to 48% of the elderly population. Insomnia is the result of a complex interaction of behavioral (such as stress, lifestyle, workplace culture, environment, and sleeping arrangements), physiological, and genetic factors. The negative effects of insomnia on many organs lead to abnormal sleep patterns, cognitive performance, and emotional reactions ( Li et al., 2020 ; Jia et al., 2022 ; Gibson et al., 2023 ). In addition to contributing to the pathological progression of the immunological, endocrine, and cardiovascular systems, it also causes neuropsychiatric illnesses such as depression, dementia, mania, schizophrenia, and anxiety disorders. The risk of hypertension, diabetes mellitus, arthritis, stomach ulcers, gastroesophageal reflux illness, migraine, depression, obesity, heart attack or stroke, asthma, menstruation issues, obesity, and infection has also been linked to insomnia. These conditions and consequences have a cumulative effect on insomnia. Multiple attempts have been made to build models to interpret and explain the onset and evolution of insomnia; nevertheless, these models are insufficient to represent comprehensive knowledge ( Reynolds et al., 2017 ; Gao et al., 2019 ; Cai et al., 2021 ; Jiang et al., 2022 ; Wang Q. et al., 2022 ; Zeng et al., 2023 ).

In this study, through MR analysis of the GWAS database, we investigated whether there is a connection between intestinal flora and insomnia. The findings demonstrated a strong relationship and potential interaction between gut flora and insomnia. Studies have suggested that gut bacteria play a role in the development of insomnia, but the specific mechanism is unknown. Growing evidence points to a critical function for the gut microbiota in the regulation of sleep behavior, both directly and indirectly, as well as a potential role in the pathophysiology and etiology of sleep disorders. It has been found that in older people with insomnia, differences in the composition of the gut microbiota and the abundance of particular genera are associated with poor sleep and poor cognitive function. Studies revealed that insomniacs had considerably higher relative abundances of Lactobacillus crispatus and Streptococcus compared to healthy controls. Five metabolic pathways, including those for glycerophospholipid metabolism, glutathione metabolism, nitrogen metabolism, aspartate, glutamate, alanine metabolism, and aminoacyl-tRNA production, may be involved in the gut microbiota’s ability to cause insomnia ( Le Chatelier et al., 2013 ; Ning et al., 2022 ). In both human studies and animal models, it has been suggested by researchers that gut bacteria may contribute to sleep issues.

When compared to the findings of earlier studies, this study’s findings exhibit parallels and discrepancies. Pro-inflammatory activation may be one major component causing insomnia. According to studies, chronic sleep deprivation is linked to higher levels of IL-1 and TNF-α in the brain, as well as higher levels of IL-6 in the blood during the day. According to research ( Wang Q. et al., 2022 ), people with acute and chronic insomnia disorders have lower abundances of several anaerobic gut flora taxa, including Lachnospira , Roseburia , and Prevotella 9 . We discovered that the genera Prevotella7 (ID:11182) and Lachnoclostridium (ID:11308) are associated with a significant incidence of insomnia. Prevotella is a Gram-negative bacterium that helps break down protein and carbohydrate foods. Prevotella is frequently believed to have a lower abundance in certain diseases ( Ley, 2016 ). Studies ( Feng et al., 2023 ) also identified that several Prevotella (such as Prevotella amnii , Prevotella buccalis , Prevotella colorans , and Prevotella timonensis ) were associated with changes in inflammatory and metabolite levels, indicating that Prevotella may affect sleep by regulating metabolites and promoting inflammation. However, more is not always better; recent human research has showed an increase in Prevotella to systemic illnesses such as periodontitis, bacterial vaginosis, rheumatoid arthritis, metabolic problems, low-grade systemic inflammation, and schizophrenia ( Bertelsen et al., 2021 ; Iljazovic et al., 2021 ). The gut taxon Lachnoclostridium is a genus of Gram-positive bacteria, and people with ulcerative colitis and irritable bowel syndrome tend to have higher concentrations of Lachnoclostridium ( Cai et al., 2022 ). Lachnoclostridium was more prevalent in patients with COVID-19 and was identified by MR analysis as having a high risk of AD ( Iannone et al., 2019 ; Zhang and Zhou, 2023 ).

In contrast to earlier research, our findings show that the genus Dorea (ID:1997) has a high risk of sleeplessness. According to studies ( Zhang et al., 2021 ), patients with major depressive illnesses and sleep disorders had lower levels of Streptococcus , Dorea , Barnesiella , and Intestinibacter . Dorea bacteria is a member of the thick-walled bacterial porophyllium group, which is widely distributed in the human intestine. By inducing Treg cells and preventing Th17 cell differentiation and function, Dorea bacteria can control the intestinal immune response and preserve the stability and integrity of the gut mucous barrier. Dorea is more prevalent and is suspected to have an inflammatory effect in patients with multiple sclerosis, inflammatory bowel disease, colorectal cancer, autism spectrum disorders, and obesity. Studies have shown that the composition, diversity, and metabolic activity of the gut microbiota change significantly between healthy individuals and insomniacs. Bacteroides and Clostridiales are considered to be the two most crucial biomarkers for differentiating between insomniacs and healthy people. Additionally, the mechanism behind the connection between gut microbiota and insomnia is unclear. Research has found that the microbial ecosystem in the human gut is complex and diverse, and the collaborative relationships between different types of bacteria can disrupt the stability of the microbial ecosystem; the competitive relationship between different bacterial communities helps maintain the stability of the intestinal ecosystem. Rakoff-Nahoum S ( Rakoff-Nahoum et al., 2016 ) evolved cooperation within the Bacteroidales , the dominant Gram-negative bacteria of the human intestine. We know little about cooperation within this important ecosystem and studies are few. Our research provides guidance and a foundation for the management of insomnia. This current study is also incomplete, we did not identify GMs and the associated SNPs to understand the meaning of the SNPs to the GM. It will be very meaningful to figure out the function of SNPs to the GMs in the future.

The current study has a number of limitations that need to be mentioned. Firstly, because the study only included participants with primarily European ancestry, there could be already many genomic variations within European ancestry. It may be possible that the SNPs in the host can directly or indirectly cause insomnia. Therefore, in order to strengthen the conclusion, additional research involving participants from diverse parts of the world would be necessary to extend the findings to other groups without constraint. Secondly, a higher permissive threshold (p<1×10 -5 ) was used because there were so few IVs that met the rigorous criteria (p<5×10 -8 ) for screening. Thirdly, self-reporting insomnia symptoms has limitations, including recall bias and lack of granularity; the cases of insomnia in this study were not strictly defined, so future analysis based on strict criteria for insomnia GWAS data is required to strengthen confidence in a conclusion. Fourthly, the GM GWAS data included in this analysis was based solely on 16S rRNA sequencing from genus to phylum level; additional metagenomic and multiomic techniques should target gut microbiota composition at a more precise level to prevent bias. Fifthly, MR analysis relies on three important assumptions mentioned above. In this study, SNPs are used as instrumental variables (IV), GMs as exposure, and insomnia as outcome (GMs>SNPs>insomnia); in reverse MR analysis, insomnia is used as exposure and GMs as outcome (insomnia>SNPs>GMs); considering the complicated links between insomnia and GMs, it may be possible that host SNPs may affect insomnia through GMs; another MR study (GMs as IV, SNPs as exposure, and insomnia as outcome; SNPs>GMs>insomnia) could be conducted to explore the causality between host SNPs and insomnia in the future. Finally, the identified GMs might exist in both insomnia and healthy individuals; therefore, it is necessary to regroup the individuals with or without the GM-associated significant IVs, and intervening with GMs in insomnia research can help strengthen the causal link in the future.

Overall, we detected 10 causal associations after performing an MR analysis on the causal impacts of 211 GM taxa on insomnia. Among them, class Negativicutes , genus Clostridiuminnocuumgroup , genus Dorea , genus Lachnoclostridium , genus Prevotella7 , and order Selenomonadalesare were significantly associated with increased insomnia risk. We discovered a causal link between insomnia and six other GM taxa through reverse MR analysis. It suggested that the relationship between insomnia and intestinal flora is convoluted. However, since the current work was based on a GWAS summary-level dataset derived from 16S rRNA sequencing, more in-depth analyses based on more advanced large-scale studies generated from metagenomics sequencing are required. Nevertheless, our findings may offer beneficial biomarkers for disease development and prospective candidate treatment targets for insomnia.

Data availability statement

The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found in the article/ Supplementary Material .

Ethics statement

This study of “The relationship between gut microbiota and insomnia: a bi-directional two-sample Mendelian randomization research” relied on publicly available de-identified data from participant studies that had been authorized by an ethical standards committee. There was hence no need for extra, separate ethical approval for this investigation. Written informed consent for participation was not required from the participants or the participants’ legal guardians/next of kin in accordance with the national legislation and institutional requirements.

Author contributions

YL: Conceptualization, Data curation, Formal Analysis, Funding acquisition, Investigation, Methodology, Project administration, Software, Visualization, Writing – original draft, Writing – review & editing. QD: Data curation, Supervision, Writing – review & editing. ZL: Project administration, Supervision, Visualization, Writing – review & editing.

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This research was funded by the Medical and Health Technology Plan Project of Zhejiang Province (2023RC247).

Acknowledgments

We appreciate the MiBioGen group for releasing GM-related GWAS summary data. We want to acknowledge the participants and investigators of the UK Biobank Sleep Traits.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher’s note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Supplementary material

The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fcimb.2023.1296417/full#supplementary-material

Bertelsen, A., Elborn, J. S., Schock, B. C. (2021). Microbial interaction: Prevotella spp. reduce P. aeruginosa induced inflammation in cystic fibrosis bronchial epithelial cells. J. Cystic Fibrosis 20 (4), 682–691. doi: 10.1016/j.jcf.2021.04.012

CrossRef Full Text | Google Scholar

Bowden, J., Davey Smith, G., Haycock, P. C., Burgess, S. (2016). Consistent estimation in mendelian randomization with some invalid instruments using a weighted median estimator. Genet. Epidemiol 40, 304–314. doi: 10.1002/gepi.21965

PubMed Abstract | CrossRef Full Text | Google Scholar

Bundgaard-Nielsen, C., Lauritsen, M. B., Knudsen, J. K., Rold, L. S., Larsen, M. H., Hindersson, P., et al. (2023). Children and adolescents with attention deficit hyperactivity disorder and autism spectrum disorder share distinct microbiota compositions. Gut Microbes 15 (1), 2211923. doi: 10.1080/19490976.2023.2211923

Burgess, S., Small, D. S., Thompson, S. G. (2017). A review of instrumental variable estimators for Mendelian randomization. Stat. Methods Med. Res. 26, 2333–2355. doi: 10.1177/0962280215597579

Burgess, S., Thompson, S. G. (2017). Interpreting findings from Mendelian randomization using the Mr-Egger method. Eur. J. Epidemiol 32, 377–389. doi: 10.1007/s10654-017-0255-x

Cai, L., Bao, Y. R., Fu, X. Q., Cao, H. B., Baranova, A., Zhang, X. R., et al. (2021). Causal links between major depressive disorder and insomnia: a Mendelian randomisation study. Gene 768, 145271. doi: 10.1016/j.gene.2020.145271

Cai, Y. Y., Huang, F. Q., Lao, X., Lu, Y., Gao, X., Alolga, R. N., et al. (2022). Integrated metagenomics identifies a crucial role for trimethylamine-producing Lachnoclostridium in promoting atherosclerosis. NPJ Biofilms Microbiomes 8 (1), 11. doi: 10.1038/s41522-022-00273-4

Chalet, F.-X., Saskin, P., Ahuja, A., Thompson, J., Olopoenia, A., Modi, K., et al. (2023). The associations between insomnia severity and health outcomes in the United States. J. Clin. Med. 12 (6). doi: 10.3390/jcm12062438

Davies, N. M., Holmes, M. V., Davey Smith, G. (2018). Reading Mendelian randomisation studies: a guide, glossary, and checklist for clinicians. BMJ 362, k601. doi: 10.1136/bmj.k601

Feng, W., Yang, Z., Liu, Y., Chen, R., Song, Z., Pan, G., et al. (2023). Gut microbiota: A new target of traditional Chinese medicine for insomnia. Biomed Pharmacother 160, 114344. doi: 10.1016/j.biopha.2023.114344

Gao, X., Meng, L. X., Ma, K. L., Liang, J., Wang, H., Gao, Q., et al. (2019). The bidirectional causal relationships of insomnia with five major psychiatric disorders: a Mendelian randomization study. Eur. Psychiat. 60, 79–85. doi: 10.1016/j.eurpsy.2019.05.004

Gibson, M. J., Lawlor, D. A., Millard, L. A. C. (2023). Identifying the potential causal role of insomnia symptoms on 11,409 health-related outcomes: a phenome-wide Mendelian randomisation analysis in UK Biobank. BMC Med. 21, 128. doi: 10.1186/s12916-023-02832-8

Haimov, I., Magzal, F., Tamir, S., Lalzar, M., Asraf, K., Milman, U., et al. (2022). Variation in gut microbiota composition is associated with sleep quality and cognitive performance in older adults with insomnia. Nat. Sci. Sleep. 14, 1753–1767. doi: 10.2147/nss.s377114

Iannone, L. F., Preda, A., Blottière, H. M., Clarke, G., Albani, D., Belcastro, V., et al. (2019). Microbiota-gut brain axis involvement in neuropsychiatric disorders. Expert Rev. Neurother 19, 1037–1050. doi: 10.1080/14737175.2019.1638763

Iljazovic, A., Roy, U., Gálvez, E. J. C., Lesker, T. R., Zhao, B., Gronow, A., et al. (2021). Perturbation of the gut microbiome by Prevotella spp. enhances host susceptibility to mucosal inflammation. Mucosal Immunol. 14 (1), 113–124. doi: 10.1038/s41385-020-0296-4

Jia, Y., Guo, D., Sun, L., Shi, M., Zhang, K., Yang, P., et al. (2022). Self-reported daytime napping, daytime sleepiness, and other sleep phenotypes in the development of cardiometabolic diseases: a Mendelian randomization study. Eur. J. Prev. Cardiol. 29 (15), 1982–1991. doi: 10.1093/eurjpc/zwac123

Jiang, Z., Zhuo, L., He, Y., Fu, Y., Shen, L., Xu, F., et al. (2022). The gut microbiota-bile acid axis links the positive association between chronic insomnia and cardiometabolic diseases. Nat. Commun. 13, 3002. doi: 10.1038/s41467-022-30712-x

Johnson, K. V., Foster, K. R. (2018). Why does the microbiome affect behaviour? Nat. Rev. Microbiol. 16, 647–655. doi: 10.1038/s41579-018-0014-3

Kurilshikov, A., Medina-Gomez, C., Bacigalupe, R., Radjabzadeh, D., Wang, J., Demirkan, A., et al. (2021). Large-scale association analyses identify host factors influencing human gut microbiome composition. Nat. Genet. 53, 156–165. doi: 10.1038/s41588-020-00763-1

Lawlor, D. A., Harbord, R. M., Sterne, J. A., Timpson, N., Davey, S. G. (2008). Mendelian randomization: using genes as instruments for making causal inferences in epidemiology. Stat. Med. 27, 1133–1163. doi: 10.1002/sim.3034

Le Chatelier, E., Nielsen, T., Qin, J., Prifti, E., Hildebrand, F., Falony, G., et al. (2013). Richness of human gut microbiome correlates with metabolic markers. Nature 500, 541–546. doi: 10.1038/nature12506

Ley, R. E. (2016). Prevotella in the gut: choose carefully. Nat. Rev. Gastroenterol. Hepatol 13 (2), 69–70. doi: 10.1038/nrgastro.2016.4

Li, Y. Y., Zhang, B., Zhou, Y., Wang, D. M., Christina, W. H. (2020). Gut microbiota changes and their relationship with inflammation in patients with acute and chronic insomnia. Nat. Sci. Sleep. 12, 895–905. doi: 10.2147/nss.s271927

Lo, Y. J., Mishra, V. K., Lo, H. Y., Navneet, K. D., Lo, W. C. (2022). Clinical spectrum and trajectory of innovative therapeutic interventions for insomnia: A perspective. Aging Dis . doi: 10.14336/ad.2022.1203

Mahmud, M., Akter, S., Tamanna, S. K., Mazumder, L., Esti, I. Z., Banerjee, S., et al. (2022). Impact of gut microbiome on skin health: gut-skin axis observed through the lenses of therapeutics and skin diseases. Gut Microbes 14, 2096995. doi: 10.1080/19490976.2022.2096995

Mousa, W. K., Chehadeh, F., Husband, S. (2022). Microbial dysbiosis in the gut drives systemic autoimmune diseases. Front. Immunol. 13. doi: 10.3389/fimmu.2022.906258

Ning, J., Huang, S.-Y., Chen, S.-D., Zhang, Y.-R., Huang, Y.-Y., Yu, J.-T. (2022). Investigating casual associations among gut microbiota, metabolites, and neurodegenerative diseases: A mendelian randomization study. J. Alzheimers Dis. 87, 211–222. doi: 10.3233/jad-215411

Orru, V., Steri, M., Sidore, C., Marongiu, M., Serra, V., Olla, S., et al. (2020). Complex genetic signatures in immune cells underlie autoimmunity and inform therapy. Nat. Genet. 52 (10), 1036–1045. doi: 10.1038/s41588-020-0684-4

Pagoni, P., Dimou, N. L., Murphy, N., Stergiakouli, E. (2019). Using Mendelian randomisation to assess causality in observational studies. Evid Based Ment. Health 22, 67–71. doi: 10.1136/ebmental-2019-300085

Pierce, B. L., Ahsan, H., Vanderweele, T. J. (2011). Power and instrument strength requirements for Mendelian randomization studies using multiple genetic variants. Int. J. Epidemiol 40, 740–752. doi: 10.1093/ije/dyq151

Qi, X., Ye, J., Wen, Y., Liu, L., Zhang, F. (2022). Evaluating the effects of diet-gut microbiota interactions on sleep traits using the UK biobank cohort. Nutrients 14 (6). doi: 10.3390/nu14061134

Qin, Y., Havulinna, A. S., Liu, Y., Jousilahti, P., Ritchie, S. C., Tokolyi, A., et al. (2022). Combined effects of host genetics and diet on human gut microbiota and incident disease in a single population cohort. Nat. Genet. 54 (2), 134–142. doi: 10.1038/s41588-021-00991-z

Rakoff-Nahoum, S., Foster, K. R., Comstock, L. E. (2016). The evolution of cooperation within the gut microbiota. Nature 533 (7602), 255–259. doi: 10.1038/nature17626

Rees, J. M. B., Wood, A. M., Burgess, S. (2017). Extending the Mr-Egger method for multivariable Mendelian randomization to correct for both measured and unmeasured pleiotropy. Stat. Med. 36, 4705–4718. doi: 10.1002/sim.7492

Reynolds, A. C., Paterson, J. L., Ferguson, S. A., Stanley, D., Wright, K. P., Dawson, D. (2017). The shift work and health research agenda: Considering changes in gut microbiota as a pathway linking shift work, sleep loss and circadian misalignment, and metabolic disease. Sleep Med. Rev. 34, 3–9. doi: 10.1016/j.smrv.2016.06.009

Skrivankova, V. W., Richmond, R. C., Woolf, B. A. R., Davies, N. M., Swanson, S. A., VanderWeele, T. J., et al. (2021a). Strengthening the reporting of observational studies in epidemiology using mendelian randomisation (STROBE-MR): explanation and elaboration. BMJ 375, n2233. doi: 10.1136/bmj.n2233

Skrivankova, V. W., Richmond, R. C., Woolf, B. A. R., Yarmolinsky, J., Davies, N. M., Swanson, S. A., et al. (2021b). Strengthening the reporting of observational studies in epidemiology using mendelian randomization: the STROBE-MR statement. JAMA 326, 1614–1621. doi: 10.1001/jama.2021.18236

Swertz, M. A., Dijkstra, M., Adamusiak, T., van der Velde, J. K., Kanterakis, A., Roos, E. T., et al. (2010). The Molgenis toolkit: rapid prototyping of biosoftware at the push of a button. BMC Bioinf. 11, S12. doi: 10.1186/1471-2105-11-S12-S12

Swertz, M. A., Jansen, R. C. (2007). Beyond standardization: dynamic software infrastructures for systems biology. Nat. Rev. Genet. 8, 235–243. doi: 10.1038/nrg2048

van der Velde, K. J., Imhann, F., Charbon, B., Pang, C., van Enckevort, D., Slofstra, M., et al. (2019). Molgenis research: advanced bioinformatics data software for non-Bioinformaticians. Bioinformatics 35, 1076–1078. doi: 10.1093/bioinformatics/bty742

Verbanck, M., Chen, C. Y., Neale, B., Do, R. (2018). Detection of widespread horizontal pleiotropy in causal relationships inferred from Mendelian randomization between complex traits and diseases. Nat. Genet. 50, 693–698. doi: 10.1038/s41588-018-0099-7

Wang, Q., Chen, B., Sheng, D., Yang, J., Fu, S., Wang, J., et al. (2022). Multiomics analysis reveals aberrant metabolism and immunity linked gut microbiota with insomnia. Microbiol. Spectrum 10 (5), e0099822. doi: 10.1128/spectrum.00998-22

Wang, Z., Wang, Z., Lu, T. S., Chen, W. H., Lu, L. (2022). The microbiota-gut-brain axis in sleep disorders. Sleep Med. Rev. 65, 101691. doi: 10.1016/j.smrv.2022.101691

Yao, Y., Jia, Y., Wen, Y., Cheng, B., Cheng, S., Liu, L., et al. (2022). Genome-wide association study and genetic correlation scan provide insights into its genetic architecture of sleep health score in the UK biobank cohort. Nat. Sci. Sleep. 14, 1–12. doi: 10.2147/nss.s326818

Zeng, Y., Cao, S., Yang, H. (2023). Roles of gut microbiome in epilepsy risk: A Mendelian randomization study. Front. Microbiol. 14. doi: 10.3389/fmicb.2023.1115014

Zhang, Q., Yun, Y. J., An, H. M., Zhao, W. X., Yang, F. (2021). Gut microbiome composition associated with major depressive disorder and sleep quality. Front. Psychiatry 12. doi: 10.3389/fpsyt.2021.645045

Zhang, H., Zhou, Z. (2023). Association of gut microbiota and dietary component intake with COVID-19: A mendelian randomization study. Clin. Nutr. 42 (8), 1308–1313. doi: 10.1016/j.clnu.2023.06.017

Keywords: gut microbiome, insomnia, sleep disorders, bi-directional Mendelian randomization analysis, relationship

Citation: Li Y, Deng Q and Liu Z (2023) The relationship between gut microbiota and insomnia: a bi-directional two-sample Mendelian randomization research. Front. Cell. Infect. Microbiol. 13:1296417. doi: 10.3389/fcimb.2023.1296417

Received: 18 September 2023; Accepted: 07 November 2023; Published: 28 November 2023.

Reviewed by:

Copyright © 2023 Li, Deng and Liu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Yan Li, [email protected]

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

EXAMINING THE EFFICIENCY OF MALAYSIAN PUBLIC RESEARCH UNIVERSITIES IN SECURING WORLD UNIVERSITY RANKING

Article sidebar, main article content.

University ranking is crucial as it attracts prospective students and academics. The ranking of public research universities in Malaysia works as a catalyst for securing government and other corporate research funding. This study measures the technical efficiency of five public research universities in Malaysia (PRUMs). This study employs a triangular fuzzy number in the Banker, Charnes, and Cooper (BCC) Fuzzy Data Envelopment Analysis (BCC-FDEA) model. The three world ranking indicators employed as output variables are teaching and research reputations and citations, and the input variables are the number of full-time students and staff. Data gathered for the academic years from 2018/2019 to 2020/2021 are used to project the efficiency scores for 2021/2022. The BCC-FDEA model is also used to consider five public research universities in Asia (APRUs) as the decision-making units (DMUs) to solve the issue of sample size adequacy. This study projects three PRUMs as technically inefficient due to input factor issues. Two main contributions of this study are: (1) QS world ranking indicators are profound parameters that research universities should consider to attain a better position in the world ranking; (2) fuzzy efficiency scores shed light on how inefficient PRUMs can improve their operations by emulating their referent DMUs.

Article Details

JATI PUBLICATION ETHICS & PUBLICATION MALPRACTICE STATEMENT: These guidelines are fully consistent with the COPE Principles of Transparency and Best Practice Guidelines and the COPE Code of Conduct ( https://publicationethics.org ).  We encourage the best standards of publication ethics and take all possible principles of transparency and measures against publication malpractices. The Department of Southeast Asian Studies, as the publisher, plays its role of guardianship over all processes of publishing seriously, and we perform our ethical and other tasks. 

• General duties and responsibilities of editors Editors should be accountable for everything published in their journals. This means the editors should strive to meet the needs of readers and authors; constantly improve their journal; have processes in place to assure the quality of the material they publish; champion freedom of expression; maintain the integrity of the academic record; preclude business needs from compromising intellectual and ethical standards; and always be willing to publish corrections, clarifications, retractions and apologies when needed. In addition to these general duties, the editors accept the obligation to apply best will and practice to cope with the following responsibilities: 
• Editorial Board Will generate editorial board from recognized experts in the field. The editor will provide full names and affiliations of the members and updated contact information for the editorial office on the journal webpage. 
• Duties of Reviewers Contribution to Editorial Decisions  Peer review assists the editor in making editorial decisions, and through the editorial communications with the author may also assist the author in improving the paper. 
• Duties of Authors Reporting standards Authors should follow the format of reporting the original research with accurate data gathered. The author should include sufficient detail and references to allow others to replicate the work. It is unacceptable if the author performs malpractices in the paper.
• Originality and Plagiarism The authors should ensure that they have produced original articles and must appropriately cite or quote if the authors have used the work and words of others.
• Concurrent Publication  It is ethical and acceptable for an author to submit or publish the same research or manuscripts in more than one journal or primary publication. 
• Acknowledging the Sources   Authors should cite properly publications that have been influential in determining the nature of the reported work. 
• Paper authorship  Those who have contributed significantly to the paper should be named as an author and co-authors. Those who have participated in the aspects of the research should be listed as contributors. All co-authors should have seen and approved the final version of the paper and have agreed to its submission for publication. 
• Announcement and Conflicts of Interest  All authors should include the financier or grant giver if the manuscript or research is financed by the research grant or any financial support body. 
• Errors in published works  The author is responsible for communicating and co-operating with the editor to retract or correct the paper when a significant error or inaccuracy in their published work. 
• Publication decisions  The editor should decide which of the articles submitted to the journal should be published. The validation of the work in question and its importance to researchers and readers must always drive such decisions. The editor may be guided by the policies of the journal's editorial board and constrained by such legal requirements, copyright infringement, and plagiarism. The editor may confer with other editors or reviewers in making this decision. 
• Peer review process  All journal's content (articles) are subjected to a double-blind, peer-review process. Articles are first reviewed by editors and may be rejected because it is not dealing with the subject matter. Articles that are found suitable for review are then sent to two experts who are unknown to each other in the field of the paper.  Reviewers are asked to classify the paper as publishable, with amendments and improvements, or rejected. Reviewer's evaluations usually include what to do with the article. The author then sees the reviewer's comments.  Editors should be ready to justify any important points from the described process. Editors should not reverse decisions on publication. Editors should publish guidance to both authors and reviewers on everything expected of them. This guidance should be regularly updated and referred to or linked to this code. 
• Fair play The editor should evaluate manuscripts for their intellectual content without regard to race, gender, sexual orientation, religious belief, ethnic origin, citizenship, or political philosophy of the authors. Editors' decision to accept or reject a paper for publication should be based only on the paper's importance, originality and clarity, and the study's relevance to the journal's aim.
• Digital Archiving The editor will ensure digital access to the journal content by the University of Malaya Journal depository section at http://jati-dseas.um.edu.my and MyJournal at http://www.myjurnal.my/public/browse-journal-view.php?id=39.
• Confidentiality Editor and any editorial staff must keep confidential all information about the manuscript's submitted and review process to anyone except the corresponding author, reviewers, potential reviewers, other editorial advisers, and the publisher.
• Publication and Submission fee Authors are freed from submission fees. Authors are required to pay the Article Processing Fee, RM300 or USD80. 
• Open Access Policy The journal is freely available online. Authors must agree with this open access policy which enables unrestricted access and reuse of all published articles. The articles are published under the Creative Commons copyright license policy CC-BY.
• Reporting standards Authors of papers should present an accurate account of the work performed and an objective discussion of its significance. Underlying data should be represented accurately in the article. An article should contain sufficient detail and references to permit others to replicate the work. Fraudulent or knowingly inaccurate statements constitute unethical behaviour and are unacceptable. Review and professional publication articles should also be accurate and objective, and editorial 'opinion' works should be identified as such.
• Originality and Plagiarism The authors should ensure that they have written entirely original works and if the authors have used the work and words of others, this has been appropriately cited or quoted.

Have a language expert improve your writing

Run a free plagiarism check in 10 minutes, generate accurate citations for free.

• Knowledge Base

Methodology

• What Is a Research Design | Types, Guide & Examples

What Is a Research Design | Types, Guide & Examples

Published on June 7, 2021 by Shona McCombes . Revised on November 20, 2023 by Pritha Bhandari.

A research design is a strategy for answering your   research question  using empirical data. Creating a research design means making decisions about:

• Your overall research objectives and approach
• Whether you’ll rely on primary research or secondary research
• Your sampling methods or criteria for selecting subjects
• Your data collection methods
• The procedures you’ll follow to collect data
• Your data analysis methods

A well-planned research design helps ensure that your methods match your research objectives and that you use the right kind of analysis for your data.

Table of contents

Step 1: consider your aims and approach, step 2: choose a type of research design, step 3: identify your population and sampling method, step 4: choose your data collection methods, step 5: plan your data collection procedures, step 6: decide on your data analysis strategies, other interesting articles, frequently asked questions about research design.

• Introduction

Before you can start designing your research, you should already have a clear idea of the research question you want to investigate.

There are many different ways you could go about answering this question. Your research design choices should be driven by your aims and priorities—start by thinking carefully about what you want to achieve.

The first choice you need to make is whether you’ll take a qualitative or quantitative approach.

Qualitative research designs tend to be more flexible and inductive , allowing you to adjust your approach based on what you find throughout the research process.

Quantitative research designs tend to be more fixed and deductive , with variables and hypotheses clearly defined in advance of data collection.

It’s also possible to use a mixed-methods design that integrates aspects of both approaches. By combining qualitative and quantitative insights, you can gain a more complete picture of the problem you’re studying and strengthen the credibility of your conclusions.

Practical and ethical considerations when designing research

As well as scientific considerations, you need to think practically when designing your research. If your research involves people or animals, you also need to consider research ethics .

• How much time do you have to collect data and write up the research?
• Will you be able to gain access to the data you need (e.g., by travelling to a specific location or contacting specific people)?
• Do you have the necessary research skills (e.g., statistical analysis or interview techniques)?
• Will you need ethical approval ?

At each stage of the research design process, make sure that your choices are practically feasible.

Here's why students love Scribbr's proofreading services

Discover proofreading & editing

Within both qualitative and quantitative approaches, there are several types of research design to choose from. Each type provides a framework for the overall shape of your research.

Types of quantitative research designs

Quantitative designs can be split into four main types.

• Experimental and   quasi-experimental designs allow you to test cause-and-effect relationships
• Descriptive and correlational designs allow you to measure variables and describe relationships between them.

With descriptive and correlational designs, you can get a clear picture of characteristics, trends and relationships as they exist in the real world. However, you can’t draw conclusions about cause and effect (because correlation doesn’t imply causation ).

Experiments are the strongest way to test cause-and-effect relationships without the risk of other variables influencing the results. However, their controlled conditions may not always reflect how things work in the real world. They’re often also more difficult and expensive to implement.

Types of qualitative research designs

Qualitative designs are less strictly defined. This approach is about gaining a rich, detailed understanding of a specific context or phenomenon, and you can often be more creative and flexible in designing your research.

The table below shows some common types of qualitative design. They often have similar approaches in terms of data collection, but focus on different aspects when analyzing the data.

Your research design should clearly define who or what your research will focus on, and how you’ll go about choosing your participants or subjects.

In research, a population is the entire group that you want to draw conclusions about, while a sample is the smaller group of individuals you’ll actually collect data from.

Defining the population

A population can be made up of anything you want to study—plants, animals, organizations, texts, countries, etc. In the social sciences, it most often refers to a group of people.

For example, will you focus on people from a specific demographic, region or background? Are you interested in people with a certain job or medical condition, or users of a particular product?

The more precisely you define your population, the easier it will be to gather a representative sample.

• Sampling methods

Even with a narrowly defined population, it’s rarely possible to collect data from every individual. Instead, you’ll collect data from a sample.

To select a sample, there are two main approaches: probability sampling and non-probability sampling . The sampling method you use affects how confidently you can generalize your results to the population as a whole.

Probability sampling is the most statistically valid option, but it’s often difficult to achieve unless you’re dealing with a very small and accessible population.

For practical reasons, many studies use non-probability sampling, but it’s important to be aware of the limitations and carefully consider potential biases. You should always make an effort to gather a sample that’s as representative as possible of the population.

Case selection in qualitative research

In some types of qualitative designs, sampling may not be relevant.

For example, in an ethnography or a case study , your aim is to deeply understand a specific context, not to generalize to a population. Instead of sampling, you may simply aim to collect as much data as possible about the context you are studying.

In these types of design, you still have to carefully consider your choice of case or community. You should have a clear rationale for why this particular case is suitable for answering your research question .

For example, you might choose a case study that reveals an unusual or neglected aspect of your research problem, or you might choose several very similar or very different cases in order to compare them.

Data collection methods are ways of directly measuring variables and gathering information. They allow you to gain first-hand knowledge and original insights into your research problem.

You can choose just one data collection method, or use several methods in the same study.

Survey methods

Surveys allow you to collect data about opinions, behaviors, experiences, and characteristics by asking people directly. There are two main survey methods to choose from: questionnaires and interviews .

Observation methods

Observational studies allow you to collect data unobtrusively, observing characteristics, behaviors or social interactions without relying on self-reporting.

Observations may be conducted in real time, taking notes as you observe, or you might make audiovisual recordings for later analysis. They can be qualitative or quantitative.

Other methods of data collection

There are many other ways you might collect data depending on your field and topic.

If you’re not sure which methods will work best for your research design, try reading some papers in your field to see what kinds of data collection methods they used.

Secondary data

If you don’t have the time or resources to collect data from the population you’re interested in, you can also choose to use secondary data that other researchers already collected—for example, datasets from government surveys or previous studies on your topic.

With this raw data, you can do your own analysis to answer new research questions that weren’t addressed by the original study.

Using secondary data can expand the scope of your research, as you may be able to access much larger and more varied samples than you could collect yourself.

However, it also means you don’t have any control over which variables to measure or how to measure them, so the conclusions you can draw may be limited.

Receive feedback on language, structure, and formatting

Professional editors proofread and edit your paper by focusing on:

• Academic style
• Vague sentences
• Style consistency

See an example

As well as deciding on your methods, you need to plan exactly how you’ll use these methods to collect data that’s consistent, accurate, and unbiased.

Planning systematic procedures is especially important in quantitative research, where you need to precisely define your variables and ensure your measurements are high in reliability and validity.

Operationalization

Some variables, like height or age, are easily measured. But often you’ll be dealing with more abstract concepts, like satisfaction, anxiety, or competence. Operationalization means turning these fuzzy ideas into measurable indicators.

If you’re using observations , which events or actions will you count?

If you’re using surveys , which questions will you ask and what range of responses will be offered?

You may also choose to use or adapt existing materials designed to measure the concept you’re interested in—for example, questionnaires or inventories whose reliability and validity has already been established.

Reliability and validity

Reliability means your results can be consistently reproduced, while validity means that you’re actually measuring the concept you’re interested in.

For valid and reliable results, your measurement materials should be thoroughly researched and carefully designed. Plan your procedures to make sure you carry out the same steps in the same way for each participant.

If you’re developing a new questionnaire or other instrument to measure a specific concept, running a pilot study allows you to check its validity and reliability in advance.

Sampling procedures

As well as choosing an appropriate sampling method , you need a concrete plan for how you’ll actually contact and recruit your selected sample.

That means making decisions about things like:

• How many participants do you need for an adequate sample size?
• What inclusion and exclusion criteria will you use to identify eligible participants?
• How will you contact your sample—by mail, online, by phone, or in person?

If you’re using a probability sampling method , it’s important that everyone who is randomly selected actually participates in the study. How will you ensure a high response rate?

If you’re using a non-probability method , how will you avoid research bias and ensure a representative sample?

Data management

It’s also important to create a data management plan for organizing and storing your data.

Will you need to transcribe interviews or perform data entry for observations? You should anonymize and safeguard any sensitive data, and make sure it’s backed up regularly.

Keeping your data well-organized will save time when it comes to analyzing it. It can also help other researchers validate and add to your findings (high replicability ).

On its own, raw data can’t answer your research question. The last step of designing your research is planning how you’ll analyze the data.

Quantitative data analysis

In quantitative research, you’ll most likely use some form of statistical analysis . With statistics, you can summarize your sample data, make estimates, and test hypotheses.

Using descriptive statistics , you can summarize your sample data in terms of:

• The distribution of the data (e.g., the frequency of each score on a test)
• The central tendency of the data (e.g., the mean to describe the average score)
• The variability of the data (e.g., the standard deviation to describe how spread out the scores are)

The specific calculations you can do depend on the level of measurement of your variables.

Using inferential statistics , you can:

• Make estimates about the population based on your sample data.
• Test hypotheses about a relationship between variables.

Regression and correlation tests look for associations between two or more variables, while comparison tests (such as t tests and ANOVAs ) look for differences in the outcomes of different groups.

Your choice of statistical test depends on various aspects of your research design, including the types of variables you’re dealing with and the distribution of your data.

Qualitative data analysis

In qualitative research, your data will usually be very dense with information and ideas. Instead of summing it up in numbers, you’ll need to comb through the data in detail, interpret its meanings, identify patterns, and extract the parts that are most relevant to your research question.

Two of the most common approaches to doing this are thematic analysis and discourse analysis .

There are many other ways of analyzing qualitative data depending on the aims of your research. To get a sense of potential approaches, try reading some qualitative research papers in your field.

If you want to know more about the research process , methodology , research bias , or statistics , make sure to check out some of our other articles with explanations and examples.

• Simple random sampling
• Stratified sampling
• Cluster sampling
• Likert scales
• Reproducibility

 Statistics

• Null hypothesis
• Statistical power
• Probability distribution
• Effect size
• Poisson distribution

Research bias

• Optimism bias
• Cognitive bias
• Implicit bias
• Hawthorne effect
• Anchoring bias
• Explicit bias

A research design is a strategy for answering your   research question . It defines your overall approach and determines how you will collect and analyze data.

A well-planned research design helps ensure that your methods match your research aims, that you collect high-quality data, and that you use the right kind of analysis to answer your questions, utilizing credible sources . This allows you to draw valid , trustworthy conclusions.

Quantitative research designs can be divided into two main categories:

• Correlational and descriptive designs are used to investigate characteristics, averages, trends, and associations between variables.
• Experimental and quasi-experimental designs are used to test causal relationships .

Qualitative research designs tend to be more flexible. Common types of qualitative design include case study , ethnography , and grounded theory designs.

The priorities of a research design can vary depending on the field, but you usually have to specify:

• Your research questions and/or hypotheses
• Your overall approach (e.g., qualitative or quantitative )
• The type of design you’re using (e.g., a survey , experiment , or case study )
• Your data collection methods (e.g., questionnaires , observations)
• Your data collection procedures (e.g., operationalization , timing and data management)
• Your data analysis methods (e.g., statistical tests  or thematic analysis )

A sample is a subset of individuals from a larger population . Sampling means selecting the group that you will actually collect data from in your research. For example, if you are researching the opinions of students in your university, you could survey a sample of 100 students.

In statistics, sampling allows you to test a hypothesis about the characteristics of a population.

Operationalization means turning abstract conceptual ideas into measurable observations.

For example, the concept of social anxiety isn’t directly observable, but it can be operationally defined in terms of self-rating scores, behavioral avoidance of crowded places, or physical anxiety symptoms in social situations.

Before collecting data , it’s important to consider how you will operationalize the variables that you want to measure.

A research project is an academic, scientific, or professional undertaking to answer a research question . Research projects can take many forms, such as qualitative or quantitative , descriptive , longitudinal , experimental , or correlational . What kind of research approach you choose will depend on your topic.

Cite this Scribbr article

If you want to cite this source, you can copy and paste the citation or click the “Cite this Scribbr article” button to automatically add the citation to our free Citation Generator.

McCombes, S. (2023, November 20). What Is a Research Design | Types, Guide & Examples. Scribbr. Retrieved July 1, 2024, from https://www.scribbr.com/methodology/research-design/

Is this article helpful?

Shona McCombes

Other students also liked, guide to experimental design | overview, steps, & examples, how to write a research proposal | examples & templates, ethical considerations in research | types & examples, "i thought ai proofreading was useless but..".

I've been using Scribbr for years now and I know it's a service that won't disappoint. It does a good job spotting mistakes”

• Open access
• Published: 26 June 2024

Association between waist circumference and lung function in American middle-aged and older adults: findings from NHANES 2007–2012

• Zichen Xu 1 ,
• Lingdan Zhuang 1 ,
• Luqing Jiang 1 ,
• Jianjun Huang 1 ,
• Daoqin Liu 2 &
• Qiwen Wu 1  

Journal of Health, Population and Nutrition volume  43 , Article number:  98 ( 2024 ) Cite this article

106 Accesses

Metrics details

There is a major epidemic of obesity, and many obese patients suffer from respiratory symptoms and disease. However, limited research explores the associations between abdominal obesity and lung function indices, yielding mixed results. This study aims to analyze the association between waist circumference (WC), an easily measurable marker of abdominal obesity, and lung function parameters in middle-aged and older adults using the National Health and Nutrition Examination Survey (NHANES).

This study utilized data obtained from the National Health and Nutrition Examination Survey (NHANES) spanning 2007 to 2012, with a total sample size of 6089 individuals. A weighted multiple regression analysis was conducted to assess the relationship between WC and three pulmonary function parameters. Additionally, a weighted generalized additive model and smooth curve fitting were applied to capture any potential nonlinear relationship within this association.

After considering all confounding variables, it was observed that for each unit increase in WC, in males, Forced Vital Capacity (FVC) increased by 23.687 ml, Forced Expiratory Volume in one second (FEV1) increased by 12.029 ml, and the FEV1/FVC ratio decreased by 0.140%. In females, an increase in waist circumference by one unit resulted in an FVC increase of 6.583 ml and an FEV1 increase of 4.453 ml. In the overall population, each unit increase in waist circumference led to a FVC increase of 12.014 ml, an FEV1 increase of 6.557 ml, and a decrease in the FEV1/FVC ratio by 0.076%. By constructing a smooth curve, we identified a positive correlation between waist circumference and FVC and FEV1. Conversely, there was a negative correlation between waist circumference and the FEV1/FVC ratio.

Conclusions

Our findings indicate that in the fully adjusted model, waist circumference, independent of BMI, positively correlates with FVC and FEV1 while exhibiting a negative correlation with FEV1/FVC among middle-aged and older adults in the United States. These results underscore the importance of considering abdominal obesity as a potential factor influencing lung function in American middle-aged and older adults.

Introduction

Obesity has emerged as a significant global public health challenge. Obesity has markedly increased in over 70 countries since 1980 and continues to rise in most others [ 1 , 2 ]. In 2015, the global population of individuals classified as obese surpassed one-third [ 3 ], and this number is projected to reach a staggering 1.12 billion by 2030 [ 4 ]. Obesity constitutes a substantial risk factor for numerous ailments, including metabolic disorders, cardiovascular and cerebrovascular diseases, dyslipidemia, asthma, chronic obstructive pulmonary disease (COPD), and cancer [ 5 , 6 , 7 , 8 ]. Obesity is commonly categorized into two types: abdominal obesity, assessed by waist circumference, and general obesity, determined by body mass index (BMI) [ 9 ]. However, BMI has inherent limitations, as it relies on weight and height measurements [ 10 , 11 ]. Consequently, BMI may not be a perfect indicator of obesity, particularly among men with higher muscle mass [ 12 ]. Furthermore, BMI fails to accurately assess the relationship between obesity and associated diseases due to its inability to account for variations in body fat distribution [ 13 , 14 , 15 ]. The commonly utilized pulmonary function parameters in the respiratory system include FVC, FEV1, and the FEV1/FVC ratio. The normal reference range for FVC is approximately 3000 ml to 5000 ml, while the normal reference range for FEV1 typically falls between 2000 ml and 4000ml [ 16 ]. However, these values are more influenced by factors such as age, gender, height, and weight [ 16 ]. A strong association between obesity, particularly abdominal obesity, and lung function has been established in the literature [ 17 , 18 ].

In addition, obesity can be divided into android obesity (fat distribution in the chest, abdomen and internal organs) and gynoid obesity (fat distribution in the subcutaneous tissue of the limbs and buttocks) according to the characteristics of fat distribution [ 19 ]. This difference in fat distribution leads to android obesity having a more direct effect on lung mechanics than female obesity, because the increase in chest fat and the increase in abdominal volume can affect diaphragm contraction and reduce lung volume [ 20 ]. Not only that, android obesity will also secrete more pro-inflammatory adipokines because of its special fat distribution, aggravating the activation of immune cells and metabolic disorders [ 20 ].

However, existing research has focused mainly on children and adolescents, with mixed results. A study of Chinese people aged 20–80 years showed that WC was positively correlated with FEV1 and FVC [ 21 ] whereas another study of Chinese elderly people reported that an increase in WC was associated with a decrease in FEV1 and FVC [ 22 ]. Marga et al. [ 23 ] reported no significant association between WC and FVC or FEV1 in 8-year-olds. In contrast, Feng et al. [ 24 ] found that WC in Chinese children was negatively correlated with lung function. Zhang et al. [ 10 ] discovered that abdominal obesity was associated with impaired lung function among adults with asthma. Since the decline in lung function is closely related to changes in body size, we hypothesize that WC, independent of BMI, may be associated with impairment of lung function.

Therefore, our study aimed to use the National Health and Nutrition Survey (NHANES) database to investigate the correlation between WC and lung function in middle-aged and older adults. By using WC as a measure, we aim to elucidate the potential association between abdominal obesity and lung function in this particular population.

Study sample

The data for our study were sourced from the National Health and Nutrition Examination Survey (NHANES), a comprehensive survey conducted by the Centers for Disease Control and Prevention (CDC). Our study drew on data from NHANES spanning 2007 to 2012. The dataset comprises demographic, examination, laboratory, and questionnaire information. After an initial screening of the NHANES database, we identified that lung function data were available only for the period mentioned. Consequently, we included all participants ( n  = 30,442) from the NHANES conducted between 2007 and 2012. We excluded individuals (1) aged < 40 years old ( n  = 18,679) (2); missing lung function test results data (FEV1 or FVC) or having low data quality (C, D, F) ( n  = 4619) (3); missing WC data ( n  = 159) (4); missing data about covariates at least one of following ( n  = 896): BMI, the ratio of family income to poverty (PIR), total cholesterol, total bilirubin, total protein, aspartate aminotransferase (AST), or alanine aminotransferase (ALT). Ultimately, our study incorporated a substantial and nationally representative sample of middle-aged and older adults from the United States. A flowchart illustrating the screening process is presented in Fig.  1 for clarity. This study was approved by the ethics review board of the National Center for Health Statistics (NCHS) and obtained written informed consent from all participants.

Flowchart for selecting analyzed participants FEV1, forced expiratory volume in one second; FVC, forced vital capacity; NHANES, National Health and Nutrition Examination Survey

Lung function assessment

Lung function tests are performed by trained professional researchers and are tested in a standing position, unless the participant was physically limited. Lung function assessments were conducted using the Ohio 822/827 dry-roll volume spirometer, following the recommended guidelines from the American Thoracic Society (ATS) and the European Respiratory Society (ERS). The spirometry variables utilized in this study included FEV1, FVC, and the FEV1/FVC ratio. To ensure the reliability and accuracy of the spirometry measurements, the ATS/ERS criteria for acceptability and reproducibility were applied, resulting in spirometry quality grades ranging from A to F. Grades A and B indicated measurements that fulfilled or exceeded the ATS criteria. In contrast, grade C could still be considered for analysis. Grades D to F, conversely, were deemed less likely to be useful.

It is important to note that our study only included data with spirometry quality grades A and B for FEV1 and FVC. This rigorous selection criterion was employed to guarantee the accuracy and reliability of the measurement data while excluding data with lower quality grades (C, D, and F).

Waist circumference measurement

WC measurements were conducted by trained health technicians in the Mobile Examination Center as part of the NHANES survey. The measurement procedure involved determining the waist circumference at the uppermost lateral border of the right ilium, with precision recorded to the nearest 0.1 cm.

Other covariates

The criteria for selecting covariates in this study were: (1) demographic data; (2) variables affecting WC and lung function parameters in the published literature [ 25 , 26 ]; (3) according to the recommendation of the STROBE statement, covariates with regression coefficients on the outcome variables with a P value < 0.10 or covariates that resulted in more than a 10% change in the regression coefficients of the risk factors after introduction of the covariates in the base model; (4) other variables accumulated on the basis of clinical experience.The demographic data consisted of age (in years), gender, race/ethnicity (including Mexican American, other Hispanic, non-Hispanic white, non-Hispanic black, and others), poverty-to-income ratio, educational level (categorized as less than high school, high school, and more than high school), and marital status (married, single, living with a partner). Furthermore, examination data and personal life history variables were included in our analysis. These variables encompassed BMI (in kg/m²), alcohol consumption (defined as having consumed at least 12 alcoholic drinks/1 year), smoking history (defined as having smoked at least 100 cigarettes in life), histories of diabetes, hypertension, and respiratory diseases. Last, laboratory data variables were incorporated, comprising measurements of total protein levels (in g/L), total cholesterol levels (in mmol/L), total bilirubin levels (in µmol/L), aspartate aminotransferase (AST) levels (in U/L), and alanine aminotransferase (ALT) levels (in U/L). For more detailed information regarding these variables, including specific measurement methods and ranges, ( https://www.cdc.gov/nchs/nhanes/ ) provides comprehensive access to publicly available data.

Statistical analysis

Statistical analyses were conducted following the guidelines provided by the Centers for Disease Control and Prevention (CDC) [CDC guideline criteria: https://wwwn.cdc.gov/nchs/nhanes/tutorials/default.aspx ]. Continuous variables were reported as the means ± standard deviations (SD). Categorical variables are presented as percentages. Initially, weighted χ^2 tests were employed for categorical variables, while weighted linear regression models were used for continuous variables. Subsequently, we constructed four weighted linear regression models (Model 1, Model 2, Model 3, and Model 4), adjusting various variables to examine the association between WC and lung function parameters. A stratified analysis was also performed based on the fully adjusted model to explore potential stratified associations between WC and lung function. Additionally, a generalized additive model (GAM) with a penalty spline method was utilized to construct a smoothed curve-fitting fully adjusted model, treating WC as a continuous variable. We also calculated the variance inflation factor (VIF) for the variables, with VIF values of 5.8 and 6.6 for BMI and WC (supplementary Table 1 ), respectively. As a rule of thumb, the threshold for VIF values with multicollinearity between variables is 10 [ 27 ].

All statistical analyses were performed using Empower Stats software and R version 4.2.0. A p value of less than 0.05 was considered statistically significant in our study.

Baseline characteristics of the participants

Table  1 shows the weighted distribution of baseline characteristics, including demographic, examination, laboratory, and questionnaire data, for the participants selected from the NHANES survey conducted between 2007 and 2012. A total of 6,089 participants aged 40–79 years were included in our study. The average age of the selected participants was 56.49 years (± 10.65), and non-Hispanic whites constituted the majority of the study population. The distribution of all included variables across the quartiles demonstrated statistically significant differences (p values < 0.05).

The associations between waist circumference and lung function parameters

Weighted multiple regression analysis was conducted to examine the association between WC and lung function parameters, as presented in Table  2 . In males, both Model 1 and Model 2, representing unadjusted and age, race adjusted associations, revealed a negative correlation between WC and FVC as well as FEV1, while a positive correlation was observed with FEV1/FVC. In Model 3, which additionally adjusted for BMI based on Model 2, WC exhibited a positive correlation with FVC and FEV1, and a negative correlation with FEV1/FVC. Finally, in the fully adjusted Model 4, WC showed a positive correlation with FVC (β = 23.687, 95% CI: 18.523, 28.852) and FEV1 (β = 12.029, 95% CI: 7.789, 16.270), but a negative correlation with FEV1/FVC (β = -0.140, 95% CI: -0.192, -0.088).Similar results were observed in females and the total population. In fully adjusted analyses for females, WC exhibited a positive correlation with FVC (β = 6.583, 95% CI: 3.629, 9.538) and FEV1 (β = 4.453, 95% CI: 1.988, 6.918), and a negative correlation with FEV1/FVC (β = -0.034, 95% CI: -0.072, 0.004), although without statistical significance. In the fully adjusted analysis for the total population, WC showed a positive correlation with FVC (β = 12.014, 95% CI: 9.251, 14.777) and FEV1 (β = 6.557, 95% CI: 4.284, 8.831), and a negative correlation with FEV1/FVC (β = -0.076, 95% CI: -0.107, -0.046). Due to partial collinearity between WC and BMI, we assessed individual associations between WC, BMI, and pulmonary function to elucidate the potential mediating role of BMI in the relationship between WC and pulmonary function (Supplementary Figs.  1 – 4 ).

Stratified associations between waist circumference and lung function parameters

To assess the stability of the multivariate regression analysis results, we conducted stratified analyses to examine the associations between WC and lung function parameters in different subgroups. The results are presented in Table  3 .

In the subgroup analyses, WC demonstrated a positive relationship with FVC in most subgroups, except for the subgroup of other races, less than high school, living with a partner, BMI > 30, and borderline diabetes history. Similarly, WC showed a positive relationship with FEV1 in most subgroups, except for the subgroup of age > 60, other race, less than high school, high school, living with a partner, BMI25-30, BMI > 30 (negative correlation with statistical significance), at least 12 alcohol drinks/1 year, with diabetes history, borderline diabetes history, and respiratory diseases history. On the other hand, WC exhibited a negative relationship with FEV1/FVC in most subgroups, except for the non-Hispanic Black, other race, more than high school, living with a partner, all BMI subgroups, no smoking, borderline diabetes history and hypertension history subgroups. Furthermore, gender and BMI have a significant interaction with FVC (p for interaction < 0.0001); BMI and diabetes history have a significant interaction with FEV1 (p for interaction < 0.0001).

Using GAM to explore the possible relationship between waist circumference and lung function parameters

To ensure the reliability of the regression analysis results, we used a generalized additive model (GAM) to investigate whether there is a linear or nonlinear correlation between WC and lung function parameters. In our study, based on Model 4 (adjusted for all covariates), we constructed a smooth-fitting curve to observe potential correlations. Figure  2 shows the results obtained from the GAM analysis. We observed a nonlinear relationship between WC and lung function parameters. After adjusting for all covariates, we found that WC, FVC and FEV1 were positively correlated and nonlinear. Conversely, we observe a nonlinear negative correlation between WC and FEV1/FVC ratios. With the increase of WC, the FEV1/FVC ratio tends to decrease.

Based on the fully adjusted model, the relationship between waist circumference and lung function

To our knowledge, there has been limited investigation into the relationship between WC and lung function parameters in middle-aged and older adults in the United States, accounting for the influence of BMI. We investigated the correlation between WC and lung function parameters in 6089 middle-aged and older adults who participated in the NHANES survey in the United States between 2007 and 2012. Four weighted multiple linear regression models were used to determine the relationship between WC and three lung function parameters. Based on NHANES data from 2007 to 2012, we found that WC was negatively associated with FVC and FEV1 and positively associated with FEV1/FVC in the unadjusted model and after adjusting for age and race. After adjusting for BMI, the correlation between WC and FVC and FEV1 became positive, and the correlation with FEV1/FVC became negative. Finally, the correlation between WC and lung function parameters in the fully adjusted model was the same as above (Male: FVC, β = 23.687; FEV1, β = 12.029; FEV1/FVC, β = -0.140; Female: FVC, β = 6.583; FEV1, β = 4.453; FEV1/FVC, β = -0.034; Total population: FVC, β = 12.014; FEV1, β = 6.557; FEV1/FVC, β=-0.076). To verify the accuracy and stability of this association, we performed a stratified analysis. Then, we build a smooth curve model to further assess the reliability of the results.

Our study results indicate an association between increased WC and decreased FEV1/FVC ratio, aligning with the majority of previously published findings. A study by Zhang et al. [ 28 ]. in American adults found that abdominal obesity was associated with an increased risk of airflow obstruction defined by FEV1/FVC. A cohort study in the Netherlands by Marga et al. [ 23 ]. found that large WC in girls only, independent of BMI, was associated with lower FEV1/FVC. Feng et al. [ 24 ]. found that waist-to-chest ratio (WCR) was negatively correlated with FVC, FEV1, FVC/FEV1 in Chinese adolescents and children, after adjusting for gender height and BMI. Chen et al [ 29 ]. found that an increase in WC in children aged 6–17 years is associated with an increase in FVC and FEV1, while it is associated with a decrease in the FEV1/FVC ratio. With respect to FVC and FEV1, Zeng et al. [ 21 ]. discovered that in the Chinese population aged 20–80 years, WC and obesity defined by WC are positively correlated with FVC and FEV1. A cohort study by Pan et al. [ 22 ]. reported that abdominal obesity and its indicators (WC, WHtR, WHR and body fat) were associated with decreased FVC and FEV1 in the older Chinese population. Zhang et al. [ 10 ] reported that in adult asthma patients in the United States, the abdominal obesity group was associated with lower FVC and FEV1 compared to the normal group. Our data reveals that in the model without adjusting for BMI, WC is negatively correlated with FVC and FEV1, while after adjusting for BMI, it exhibits a positive correlation. These divergent conclusions about FVC and FEV1 may be attributed to differences in study designs, study population, and the confounding factors included, particularly BMI.

Central obesity is a specific type of obesity characterized by the accumulation of fat in the chest, abdomen, and internal organs [ 30 ]. Obesity reduces respiratory compliance, alters breathing patterns, affecting lung function [ 19 , 31 ]. The fatty deposition also causes narrowing, closure, and hyperresponsiveness of the airways, resulting in uneven ventilation [ 32 , 33 ]. Excess body fat alters respiratory physiology and impairs lung function [ 34 ]. Abdominal fat accumulation can affect the contraction of the diaphragm and impair lung function. The effect of intra-abdominal pressure on the diaphragm is one of the important reasons for the impairment of lung function [ 14 , 35 ]. Thus, abdominal obesity leads to decreased lung compliance, increased airway resistance, and limited daily exercise [ 19 , 36 ]. People with abdominal obesity may also change their breathing pattern to rapid and shallow breathing. This style of breathing increases the risk of airflow limitation, hypoxia, respiratory overload, and respiratory complications [ 37 ]. In addition, inflammation and oxidative stress have been identified as key factors in impaired lung function due to abdominal obesity [ 38 , 39 ]. Systemic adipose tissue inflammation may be responsible for impaired lung function due to abdominal obesity [ 40 ]. Abdominal obesity is considered to be an inflammatory state [ 18 ], and many inflammatory factors come from visceral adipose tissue, such as IL-6, TNF-α, C-reactive protein (CRP), leptin, etc., which may lead to obesity-related airway inflammation [ 41 ]. In addition, CRP is also thought to cause impairment of lung function [ 42 ]. An in vitro study found that CRP is present in human respiratory secretions [ 43 ] and may play a local role in lung tissue, decreasing airway diameter and lung function [ 18 , 44 ]. Besides, studies have demonstrated that the relationship between lung function and abdominal obesity is also affected by CRP gene polymorphisms. The researchers found that the CRP rs1205 CC genotype was associated with impaired lung function [ 45 ], suggesting that the CRP gene plays a partial role in lung function inheritance.

Study strengths and limitations

Compared with previously published articles, our study has the following advantages. First, our sample includes 6089 nationally representative middle-aged and older adults, and the sample size is relatively large. Second, we have taken into account BMI, an important confounding factor, so that WC as an indicator of abdominal fat deposits can be understood in the context of body type so that we can understand its full impact on respiratory function. Also, we performed a stratified analysis that considered the possible impact of BMI and other confounding factors on the results, which helped verify the reliability of the results and identify possible susceptible populations. Finally, based on completely adjusting the model, we performed smooth curve fitting and explored the relationship between WC and lung function parameters.

However, it should be noted that our study design is a cross-sectional study and cannot prove a causal relationship between abdominal obesity and altered lung function, so more prospective cohort studies are needed to validate the conclusions. Second, we chose WC as a marker of abdominal obesity, while other markers, such as waist-to-height ratio or waist-hip ratio, were not included in the study due to lack of data or small sample sizes. Future studies are needed to confirm our results with other methods of measuring abdominal obesity. Third, while we adjusted for many confounders, other potential confounding factors were not considered, similar to other cross-sectional studies. Finally, our survey is based on the NHANES database, which applies to the US population and, therefore, is geographically limited in versatility. More comprehensive studies are needed to determine the relationship between WC and lung function parameters.

Data availability

No datasets were generated or analysed during the current study.

2015 GBD, Collaborators O, Afshin A, Forouzanfar MH, Reitsma MB, Sur P, Estep K et al. Health Effects of Overweight and Obesity in 195 Countries over 25 Years. N Engl J Med. 2017;377:13–27.

Chan M. Obesity and diabetes: the slow-motion disaster. Milbank Q. 2017;95:11–4.

Article   PubMed   PubMed Central   Google Scholar  

Chooi YC, Ding C, Magkos F. The epidemiology of obesity. Metabolism. 2019;92:6–10.

Article   CAS   PubMed   Google Scholar  

Kelly T, Yang W, Chen C-S, Reynolds K, He J. Global burden of obesity in 2005 and projections to 2030. Int J Obes. 2005. 2008;32:1431–7.

McClean KM, Kee F, Young IS, Elborn JS. Obesity and the lung: 1. Epidemiology. Thorax. 2008;63:649–54.

Avgerinos KI, Spyrou N, Mantzoros CS, Dalamaga M. Obesity and cancer risk: emerging biological mechanisms and perspectives. Metabolism. 2019;92:121–35.

Melo LC, Silva MAM da, Calles AC do N. Obesity and lung function: a systematic review. Einstein Sao Paulo Braz. 2014;12:120–5.

Matrone A, Ferrari F, Santini F, Elisei R. Obesity as a risk factor for thyroid cancer. Curr Opin Endocrinol Diabetes Obes. 2020;27:358–63.

Ross R, Neeland IJ, Yamashita S, Shai I, Seidell J, Magni P, et al. Waist circumference as a vital sign in clinical practice: a Consensus Statement from the IAS and ICCR Working Group on visceral obesity. Nat Rev Endocrinol. 2020;16:177–89.

Zhang H, Hu Z, Wang S, Xu J, Li S, Song X. Association of general and abdominal obesity with lung function, FeNO, and blood eosinophils in adult asthmatics: findings from NHANES 2007–2012. Front Physiol. 2023;14:1019123.

Bracht JR, Vieira-Potter VJ, De Souza Santos R, Öz OK, Palmer BF, Clegg DJ. The role of estrogens in the adipose tissue milieu. Ann N Y Acad Sci. 2020;1461:127–43.

von Hafe P, Pina F, Pérez A, Tavares M, Barros H. Visceral fat accumulation as a risk factor for prostate cancer. Obes Res. 2004;12:1930–5.

Article   Google Scholar  

Piché M-E, Poirier P, Lemieux I, Després J-P. Overview of epidemiology and contribution of obesity and body Fat distribution to Cardiovascular Disease: an update. Prog Cardiovasc Dis. 2018;61:103–13.

Article   PubMed   Google Scholar  

Després J-P, Lemieux I. Abdominal obesity and metabolic syndrome. Nature. 2006;444:881–7.

Wehrmeister FC, Menezes AMB, Muniz LC, Martínez-Mesa J, Domingues MR, Horta BL. Waist circumference and pulmonary function: a systematic review and meta-analysis. Syst Rev. 2012;1:55.

Quanjer PH, Stanojevic S, Cole TJ, Baur X, Hall GL, Culver BH, et al. Multi-ethnic reference values for spirometry for the 3–95-yr age range: the global lung function 2012 equations. Eur Respir J. 2012;40:1324–43.

Leone N, Courbon D, Thomas F, Bean K, Jégo B, Leynaert B, et al. Lung function impairment and metabolic syndrome: the critical role of abdominal obesity. Am J Respir Crit Care Med. 2009;179:509–16.

He H, Wang B, Zhou M, Cao L, Qiu W, Mu G, et al. Systemic inflammation mediates the associations between abdominal obesity indices and lung function decline in a Chinese General Population. Diabetes Metab Syndr Obes Targets Ther. 2020;13:141–50.

Article   CAS   Google Scholar  

Dixon AE, Peters U. The effect of obesity on lung function. Expert Rev Respir Med. 2018;12:755–67.

Article   CAS   PubMed   PubMed Central   Google Scholar  

Palma G, Sorice GP, Genchi VA, Giordano F, Caccioppoli C, D’Oria R, et al. Adipose tissue inflammation and pulmonary dysfunction in obesity. Int J Mol Sci. 2022;23:7349.

Zeng X, Liu D, An Z, Li H, Song J, Wu W. Obesity parameters in relation to lung function levels in a large Chinese rural adult population. Epidemiol Health. 2021;43:e2021047.

Pan J, Xu L, Lam TH, Jiang CQ, Zhang WS, Jin YL, et al. Association of adiposity with pulmonary function in older Chinese: Guangzhou Biobank Cohort Study. Respir Med. 2017;132:102–8.

Bekkers MBM, Wijga AH, de Jongste JC, Kerkhof M, Postma D, Gehring U, et al. Waist circumference, BMI, and lung function in 8-year-old children: the PIAMA birth cohort study. Pediatr Pulmonol. 2013;48:674–82.

Feng K, Chen L, Han S-M, Zhu G-J. Ratio of waist circumference to chest circumference is inversely associated with lung function in Chinese children and adolescents. Respirol Carlton Vic. 2012;17:1114–8.

Wen J, Wei C, Giri M, Zhuang R, Shuliang G. Association between serum uric acid/serum creatinine ratios and lung function in the general American population: National Health and Nutrition Examination Survey (NHANES), 2007–2012. BMJ Open Respir Res. 2023;10:e001513.

Chen J, Zhu L, Yao X, Zhu Z. The association between abdominal obesity and femoral neck bone mineral density in older adults. J Orthop Surg. 2023;18:171.

Everitt BS, Howell DC. Encyclopedia of statistics in behavioral science. Hoboken, N.J: Wiley; 2005.

Book   Google Scholar  

Zhang X, Chen H, Gu K, Jiang X. Association of Body Mass Index and Abdominal obesity with the risk of airflow obstruction: National Health and Nutrition Examination Survey (NHANES) 2007–2012. COPD J Chronic Obstr Pulm Dis. 2022;19:99–108.

Chen Y, Rennie D, Cormier Y, Dosman JA. Waist circumference associated with pulmonary function in children. Pediatr Pulmonol. 2009;44:216–21.

Molani Gol R, Rafraf M. Association between abdominal obesity and pulmonary function in apparently healthy adults: a systematic review. Obes Res Clin Pract. 2021;15:415–24.

Littleton SW. Impact of obesity on respiratory function. Respirol Carlton Vic. 2012;17:43–9.

Chapman DG, Berend N, King GG, Salome CM. Increased airway closure is a determinant of airway hyperresponsiveness. Eur Respir J. 2008;32:1563–9.

Littleton SW, Tulaimat A. The effects of obesity on lung volumes and oxygenation. Respir Med. 2017;124:15–20.

Agudelo CW, Samaha G, Garcia-Arcos I. Alveolar lipids in pulmonary disease. A review. Lipids Health Dis. 2020;19:122.

Grassi L, Kacmarek R, Berra L. Ventilatory mechanics in the patient with obesity. Anesthesiology. 2020;132:1246–56.

Chen Y, Rennie D, Cormier YF, Dosman J. Waist circumference is associated with pulmonary function in normal-weight, overweight, and obese subjects. Am J Clin Nutr. 2007;85:35–9.

Kwon H, Kim D, Kim JS. Body Fat distribution and the risk of Incident Metabolic Syndrome: a longitudinal cohort study. Sci Rep. 2017;7:10955.

Mu G, Zhou Y, Ma J, Guo Y, Xiao L, Zhou M, et al. Combined effect of central obesity and urinary PAH metabolites on lung function: a cross-sectional study in urban adults. Respir Med. 2019;152:67–73.

Arteaga-Solis E, Zee T, Emala CW, Vinson C, Wess J, Karsenty G. Inhibition of leptin regulation of parasympathetic signaling as a cause of extreme body weight-associated asthma. Cell Metab. 2013;17:35–48.

Saltiel AR, Olefsky JM. Inflammatory mechanisms linking obesity and metabolic disease. J Clin Invest. 2017;127:1–4.

Mancuso P. Obesity and lung inflammation. J Appl Physiol Bethesda Md 1985. 2010;108:722–8.

Google Scholar  

Ren Z, Zhao A, Wang Y, Meng L, Szeto IM-Y, Li T, et al. Association between Dietary Inflammatory Index, C-Reactive protein and metabolic syndrome: a cross-sectional study. Nutrients. 2018;10:831.

Gould JM, Weiser JN. Expression of C-reactive protein in the human respiratory tract. Infect Immun. 2001;69:1747–54.

Määttä AM, Kotaniemi-Syrjänen A, Malmström K, Malmberg LP, Sundvall J, Pelkonen AS, et al. Vitamin D, high-sensitivity C-reactive protein, and airway hyperresponsiveness in infants with recurrent respiratory symptoms. Ann Allergy Asthma Immunol off Publ Am Coll Allergy Asthma Immunol. 2017;119:227–31.

Sunyer J, Pistelli R, Plana E, Andreani M, Baldari F, Kolz M, et al. Systemic inflammation, genetic susceptibility and lung function. Eur Respir J. 2008;32:92–7.

Download references

Acknowledgements

Not applicable.

This study was supported by the Natural Science Foundation of Education Department of Anhui Province (No. 2022AH051221), Anhui Province Key Laboratory of Biological Macromolecules Research of Wannan Medical College (No. LAB202204) and Anhui Province Key Clinical Specialist Construction Programs.

Author information

Authors and affiliations.

Department of Laboratory Medicine, The First Affiliated Hospital of Wannan Medical College, 2 Zheshan West Road, Wuhu, Anhui Province, China

Zichen Xu, Lingdan Zhuang, Lei Li, Luqing Jiang, Jianjun Huang & Qiwen Wu

Department of Kidney Medicine, The First Affiliated Hospital of Wannan Medical College, 2 Zheshan West Road, Wuhu, Anhui Province, China

You can also search for this author in PubMed   Google Scholar

Contributions

ZXC and QWW designed the study and wrote the manuscript. LDZ, LL, LQJ, DQL, and JJH performed the statistical analysis and prepared Figs. 1 and 2. All authors reviewed and approved the final manuscript.

Corresponding authors

Correspondence to Daoqin Liu or Qiwen Wu .

Ethics declarations

Ethics approval and consent to participate.

The National Center for Health Statistics (NCHS) conducted the survey and received approval from the NCHS Institutional Review Board (IRB). Before data collection and NHANES health examinations, informed consent was obtained from all eligible subjects. ( https://www.cdc.gov/nchs/nhanes/irba98.htm ).

Furthermore, all authors affirmed that the methods employed in the study adhered to the relevant NHANES Analytic Guidelines. ( https://wwwn.cdc.gov/nchs/nhanes/analyticguidelines.aspx#analytic-guidelines ).

Consent for publication

Conflict of interest.

The authors declare that they have no conflicts of interest.

Additional information

Publisher’s note.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplementary Material 1

Rights and permissions.

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ . The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/ ) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Cite this article.

Xu, Z., Zhuang, L., Li, L. et al. Association between waist circumference and lung function in American middle-aged and older adults: findings from NHANES 2007–2012. J Health Popul Nutr 43 , 98 (2024). https://doi.org/10.1186/s41043-024-00592-6

Download citation

Received : 29 November 2023

Accepted : 22 June 2024

Published : 26 June 2024

DOI : https://doi.org/10.1186/s41043-024-00592-6

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Abdominal obesity
• Waist circumference
• Lung function
• National health and Nutrition examination survey

Journal of Health, Population and Nutrition

ISSN: 2072-1315

• Submission enquiries: [email protected]
• General enquiries: [email protected]