A study revealed the impact of gut microbiota on acne vulgaris: Evidence based on Mendelian randomization

Cumulative evidence has demonstrated an association between gut microbiota and acne vulgaris. However, previous studies have yielded mixed results, and despite extensive investigations, the causal relationship between them remains unclear. The genome-wide association studies summary data of 196 gut microbiota and acne vulgaris was obtained from the most extensive available genome-wide association studies database. A 2-sample Mendelian randomization (MR) study, which utilizes genetic variants as instrumental variables in 2 independent datasets to assess causal relationships between an exposure and an outcome, was used to test the causal relationship between the gut microbiota and acne vulgaris. The MR analysis was primarily performed with the inverse variance weighted method, and MR-Egger, Cochran Q test and Mendelian randomization pleiotropic residuals and outliers were performed as sensitivity analyses. The inverse variance weighted analysis revealed that the risk of acne formation was correlated with a total of 14 gut microbiota taxa that predicted the composition of intestinal flora. Among them, class Coriobacteriia (odds ratio [OR] = 0.588, 95% confidence interval [CI]: 0.357-0.966, P = .036), class Erysipelotrichia (OR = 0.559, 95% CI: 0.357-0.966, P = .036), family Coriobacteriaceae (OR = 0.599, 95% CI: 0.357-0.966, P = .036), family Erysipelotrichaceae (OR = 0.559, 95% CI: 0.325-0.963, P = .036), genus Candidatus Soleaferrea (OR = 0.576, 95% CI: 0.355-0.934, P = .025), genus Fusicatenibacter (OR = 0.533, 95% CI: 0.306-0.927, P = .026), genus Lactobacillus (OR = 0.658, 95% CI: 0.450-0.963, P = .031), order Erysipelotrichales (OR = 0.559, 95% CI: 0.325-0.963, P = .036) abundance was negatively correlated with acne vulgaris incidence. Family Bacteroidaceae (OR = 2.579, 95% CI: 1.237-5.378, P = .011), family Family XIII (OR = 1.456, 95% CI: 1.173-4.288, P = .015), genus Allisonella (OR = 1.385, 95% CI: 1.003-4.288, P = .015), genus Bacteroides (OR = 2.444, 95% CI: 1.053-5.671, P = .037), genus Coprococcus3 (OR = 2.122, 95% CI: 1.095-4.111, P = .026), genus Romboutsia (OR = 1.677, 95% CI: 1.064-2.645, P = .026) abundance had a positive correlation with acne vulgaris development. The reliability and robustness of the findings were confirmed using a variety of sensitivity analyses, including MR-Egger regression, Cochran Q test, and Mendelian randomization pleiotropic residuals and outliers, which revealed no indication of horizontal pleiotropy or significant heterogeneity among single nucleotide polymorphisms. The MR study has validated the potential causal relationship between gut microbiota and acne vulgaris, providing some insights into potential therapeutic targets and interventions for this dermatological concern. Nevertheless, further investigation is warranted to understand the underlying mechanisms.