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. 2021 Nov 23;13(4):1044–1062. doi: 10.1093/advances/nmab142

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© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.

This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

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Venn diagram of meta-analyses of observational studies, meta-analyses of RCTs, and MR studies. The plot was performed by R package “VennDiagram.” The number of disease outcomes for overlapping and distinct study types is shown. Ⅰ, only reported in MR studies; ⅠI, reported in MR studies and meta-analyses of RCTs; ⅠII, only reported in meta-analyses of RCTs; ⅠV, reported in all 3 study types; V, reported in MR studies and meta-analyses of observational studies; VI, reported in meta-analyses of RCTs and meta-analyses of observational studies; VII, only reported in meta-analyses of observational studies. MR, Mendelian randomization; RCT, randomized controlled trial.