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

## TL;DR

This study finds that certain gut bacteria, like Bifidobacterium, are linked to lower acne risk, while others, like Streptococcus, are linked to higher risk, suggesting gut microbiota may play a causal role in acne.

## Contribution

The study uses Mendelian randomization to establish a causal link between specific gut microbes and acne risk, accounting for confounding factors like diet.

## Key findings

- Higher abundances of Bifidobacterium and related taxa are associated with reduced acne risk (ORs 0.54–0.63).
- Increased levels of Streptococcus and related taxa are linked to higher acne risk (ORs 1.12–1.36).
- The associations for Bifidobacterium remain robust even after adjusting for dietary factors.

## Abstract

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.

To investigate the causal relationship between gut microbiota and acne.

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.

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.

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.

We used Mendelian randomization to show that certain gut bacteria, including Bifidobacterium, are linked to reduced acne risk, while others like Streptococcus are associated with increased risk. These findings strengthen evidence for a causal role of gut microbiota in acne development and suggest potential new avenues for targeted treatment.