Fig. 1

Study design. The diagram provides an overview of our study design, which includes three stages. Firstly, we performed a two-sample Mendelian randomization (MR) analysis using the inverse variance weighted and Wald ratio method and several sensitivity analyses to identify potential causal gut microbial taxa of atrial fibrillation. Secondly, we validated the significant gut microbial taxa from stage one by utilizing three summary-level datasets of several atrial fibrillation and the individual-level from the UK Biobank. Finally, we performed a mediation MR analysis. We evaluated the causal relationship between gut microbial taxa and several atrial fibrillation risk factors, and further determined the extent to which gut microbial taxa influence on atrial fibrillation is mediated by these risk factors. DMP: Dutch microbiome project. MR-PRESSO: MR Pleiotropy Residual Sum and Outlier. HDL: high-density lipoprotein; LDL: low-density lipoprotein