Strengthening the Reporting of Observational Studies in Epidemiology Using Mendelian Randomization: The STROBE-MR Statement

Veronika W. Skrivankova, Rebecca C. Richmond, Benjamin A.R. Woolf, James Yarmolinsky, Neil M. Davies, Sonja A. Swanson, Tyler J. Vanderweele, Julian P.T. Higgins, Nicholas J. Timpson, Niki Dimou, Claudia Langenberg, Robert M. Golub, Elizabeth W. Loder, Valentina Gallo, Anne Tybjaerg-Hansen, George Davey Smith, Matthias Egger, J. Brent Richards*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

205 Citations (Scopus)
29 Downloads (Pure)


Importance: Mendelian randomization (MR) studies use genetic variation associated with modifiable exposures to assess their possible causal relationship with outcomes and aim to reduce potential bias from confounding and reverse causation. Objective: To develop the STROBE-MR Statement as a stand-alone extension to the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guideline for the reporting of MR studies. Design, Setting, and Participants: The development of the STROBE-MR Statement followed the Enhancing the Quality and Transparency of Health Research (EQUATOR) framework guidance and used the STROBE Statement as a starting point to draft a checklist tailored to MR studies. The project was initiated in 2018 by reviewing the literature on the reporting of instrumental variable and MR studies. A group of 17 experts, including MR methodologists, MR study design users, developers of previous reporting guidelines, and journal editors, participated in a workshop in May 2019 to define the scope of the Statement and draft the checklist. The draft checklist was published as a preprint in July 2019 and discussed on the preprint platform, in social media, and at the 4th Mendelian Randomization Conference. The checklist was then revised based on comments, further refined through 2020, and finalized in July 2021. Findings: The STROBE-MR checklist is organized into 6 sections (Title and Abstract, Introduction, Methods, Results, Discussion, and Other Information) and includes 20 main items and 30 subitems. It covers both 1-sample and 2-sample MR studies that assess 1 or multiple exposures and outcomes, and addresses MR studies that follow a genome-wide association study and are reported in the same article. The checklist asks authors to justify why MR is a helpful method to address the study question and state prespecified causal hypotheses. The measurement, quality, and selection of genetic variants must be described and attempts to assess validity of MR-specific assumptions should be well reported. An item on data sharing includes reporting when the data and statistical code required to replicate the analyses can be accessed. Conclusions and Relevance: STROBE-MR provides guidelines for reporting MR studies. Improved reporting of these studies could facilitate their evaluation by editors, peer reviewers, researchers, clinicians, and other readers, and enhance the interpretation of their results.

Original languageEnglish
Pages (from-to)1614-1621
Number of pages8
JournalJAMA - Journal of the American Medical Association
Issue number16
Publication statusPublished - 26 Oct 2021

Bibliographical note

Funding Information:
Funding/Support: The STROBE-MR meeting was funded through a Swiss National Science Foundation personal award (Dr Egger, grant No. 17481). Preparatory work was supported by the same award and by the Medical Research Council Integrative Epidemiology Unit (MC_UU_00011/1), University of Bristol, Bristol, United Kingdom, and the Institute of Social and Preventive Medicine, University of Bern, Switzerland.

Funding Information:
reported receiving grants from the National Cancer Institute (R01CA222147) during the conduct of the study. Dr Gallo reported reimbursement of travel expenses from the University of Bristol during the conduct of the study. Dr Tybjaerg-Hansen reported consultancies or talks for Akcea, AstraZeneca, Draupnir Bio, Novartis, Sanofi, Silence Therapeutics, and Regeneron. Dr Egger reported receiving grants from the Swiss National Science Foundation (189498) during the conduct of the study. Dr Egger convened the STROBE group and is a member of the CONSORT group. Dr Richards reported receiving personal fees from GlaxoSmithKline and Deerfield Capital and grants from GlaxoSmithKline, Eli Lilly, and Biogen outside the submitted work. No other disclosures were reported.

Publisher Copyright:
© 2021 American Medical Association. All rights reserved.


Dive into the research topics of 'Strengthening the Reporting of Observational Studies in Epidemiology Using Mendelian Randomization: The STROBE-MR Statement'. Together they form a unique fingerprint.

Cite this