Suggestive associations between genetically predicted gut microbiota and endometriosis: a two-sample Mendelian randomization study

Introduction. Endometriosis affects 10–20% of reproductive-age women. Emerging evidence links the gut microbiota to endometriosis pathogenesis, but observational studies are limited by confounding, reverse causation and uncertainty about whether reported microbial signals represent reproducible aetiological associations. Hypothesis/Gap Statement. Whether genetically predicted gut microbial genera are associated with endometriosis risk remains unclear, and available observational evidence does not establish robust causal effects after accounting for multiple testing. Aim. This study aimed to explore potential Mendelian randomization (MR)-based associations between genetically predicted gut microbiota composition and endometriosis using a two-sample MR framework. Methodology. Genome-wide association study (GWAS) summary statistics for 119 bacterial genera (MiBioGen consortium: n =18,340) and endometriosis (FinnGen: 8,288 cases, 68,969 controls) were used. Single nucleotide polymorphisms (SNPs) associated with each genus ( P