Exploring the link between gut microbiota and alopecia areata: a two-sample Mendelian randomization analysis

Abstract

Background: While observational studies have suggested a link between gut microbiota diversity and alopecia areata (AA), the causal relationship remains unclear. Methods: We leveraged data from the MiBioGen and FinnGen consortiums' Genome-wide association studies (GWAS) encompassing gut microbiota (n = 13,266) and AA (n = 211,428) datasets. A comprehensive Mendelian randomization (MR) and reverse MR approach were employed, utilizing five statistical methods to evaluate causality. Sensitivity analyses were also conducted to corroborate the MR results. Results: Inverse variance weighted (IVW) analysis indicated a protective effect against AA from Butyricimonas (OR = 0.37, 95% CI: 0.18–0.77, P = 0.01), Enterorhabdus (OR = 0.40, 95% CI: 0.16–0.95, P = 0.04), Eubacterium (xylanophilum group) (OR = 0.36, 95% CI: 0.15–0.84, P = 0.02), and Phascolarctobacterium (OR = 0.37, 95% CI: 0.15–0.91, P = 0.03), while Ruminococcaceae UCG003 posed as a risk factor (OR = 2.79, 95% CI: 1.27–6.14, P = 0.01). Reverse MR showed no significant causal link between AA and gut microbiota, with no significant heterogeneity or horizontal pleiotropy. Conclusions: Our analysis suggests probable causality between certain gut microbiota and AA, shedding light on its pathogenesis and potential intervention strategies.