Objectives: To assess whether the gender (primary) and geographical affiliation (post hoc) of the first and/or last authors of manuscripts is associated with publication decisions after controlling for known confounders. Design: Case-control (1:1) study. Setting: Two large general medical journals and 20 specialist journals. Participants: Original peer reviewed research manuscripts submitted between January 1, 2012, and December 31, 2019. Main outcomes measures and predictor: Manuscripts accepted (cases) and rejected (controls) were compared between women and men first authors (main predictor), and between women and men last authors (secondary predictor). Results: Of 7,000 included manuscripts 6,724 (96.1%) first and 6,768 (96.7%) last authors gender were identified; 3,056 (43.7%) and 2,214 (32.7%) were women, respectively. The proportion of women first and last authors were respectively 46.7% (n=1,571) and 32.3% (n=1,093) among cases and 44.2% (n=1,485) and 33.1% (n=1,121) among controls. In univariate analysis, being a woman first author increased the likelihood of acceptance for publication (odds ratio 1.11; 95% confidence interval 1.00 to 1.22). After adjustment for study attributes, then post-hoc variables, the association between the first author gender and acceptance for publication became non-significant 1.04 (0.94 to 1.16). The likelihood of acceptance for publication was significantly lower for first authors affiliated to Asia 0.58 (0.48 to 0.70) compared to Europe, and for first author affiliated to upper middle income 0.61 (0.47 to 0.78) and lower middle and low-income 0.65 (0.45 to 0.93) compared to high income countries. Compared to papers where both first and last authors were from the same country, acceptance for publication was significantly higher when both authors were affiliated to different countries from the same geographical and income groups 1.39 (1.09 to 1.77), to different countries, different geographical but same income groups 1.45 (1.14 to 1.84), or to different income groups 1.59 (1.20 to 2.11). The study attributes (design, and funding) were also independently associated with acceptance for publication. Conclusions: The absence of gender inequalities during the editorial decision-making process is reassuring. However, the underrepresentation of first authors affiliated to Asia and low-income countries in manuscripts accepted for publication indicates poor representation of global scientists opinion and supports growing demands for improving diversity in biomedical research.

The authors have declared no competing interest.

This study was supported by grant 10001A_192374 from the Swiss National Science Foundation (SNF) to Angele Gayet-Ageron and Angela Huttner. We thank Angela Huttner for her assistance with the grant application. The funders had no role in considering the study design or in the collection, analysis, or interpretation of data, the writing of the report, or the decision to submit the article for publication.

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Ethical approval was received from the Institutional Review Board of the Geneva Canton on April 16, 2018 for the ATHENA project (2019-00540).

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Data described in the manuscript, code book, and analytic code will be archived and preserved on Yareta, the research data repository for Geneva higher education institutions. Data will not be made publicly available, but relevant anonymised data are available on reasonable request from the corresponding author. The study was conducted under a confidentiality agreement between BMJ Publishing Group and the medical school of Geneva University represented by the Department of Health and Community Medicine and the Swiss Institute for Bioinformatics and the HES-SO/HEG Geneva.