Investigating the causal link between gut microbiota and dry age-related macular degeneration: a bidirectional Mendelian randomization study

AIM: To assess the causal link between 211 gut microbiota (GM) taxa and dry age-related macular degeneration (dAMD) risk. METHODS: Mendelian randomization using instrumental factors taken from a genome-wide association study (GWAS) were used. Inverse variance weighted (IVW) analysis and sensitivity analysis were performed on the FinnGen project, which included 5095 cases and 222 590 controls. RESULTS: The IVW analysis showed substantial genus-and family-level relationships between GM taxa and dAMD risk. Specifically, the family Peptococcaceae (P= 0.03), genus Bilophila (P=3.91x10(-3)), genus Faecalibacterium (P=6.55x10(-3)), and genus Roseburia (P=0.04) were linked to a higher risk of developing dAMD, while the genus Candidatus Soleaferrea (P=7.75x10(-4)), genus Desulfovibrio (P= 0.04) and genus Eubacterium ventriosum group (P= 0.04) exhibited a protective effect against dAMD. No significant causal relationships were observed at higher taxonomic levels. Additionally, in the reverse IVW analysis, no meaningful causal effects of the 7 GM taxa. CONCLUSION: These findings give support for the gut- retina axis participation in dAMD and shed light on putative underlying processes. Investigations on the connection between GM and dAMD have not yet revealed the underlying mechanism.