Unravelling the causal link between gut microbiota and acne risk using a genetic approach

Background Acne is a common inflammatory dermatological condition that can have detrimental psychological consequences due to its visible lesions and scarring. Recent studies suggest a potential role of gut microbiota in acne development; however, the evidence remains inconclusive and might be subject to various confounders. Objectives To investigate the causal relationship between gut microbiota and acne. Methods This study investigated the causal relationship between gut microbiota and acne using a two-sample Mendelian randomization (MR) approach with large-scale genome-wide association study summary statistics. To ascertain the direction of causality and the independent effect of gut microbiota, reverse MR and multivariable MR accounting for dietary phenotypes were performed. Results Higher abundances of the Actinobacteria phylum and class, Bifidobacteriales order, Bifidobacteriaceae family and Bifidobacterium ­genus were associated with a reduced risk of acne [odds ratios (ORs) ranging from 0.54 to 0.63]. In contrast, higher levels of the Gastranaerophilales order, Streptococcaceae family and Streptococcus genus were positively associated with an increased risk of acne (OR 1.12–1.36). Notably, associations for Bifidobacterium and its upstream taxa remained robust even after accounting for dietary factors. Conclusions These findings provide further evidence of a causal relationship between gut microbial composition and acne, highlighting the role of gut microbiota in developing more targeted and possibly less harmful alternatives to current acne management strategies.