Abstract
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.