The Causal Relationship Between Acne Vulgaris and BMI: A Mendelian Randomization Study

As an inflammatory skin condition, acne usually presents with a complex pathogenesis. Recent studies suggest that BMI may relate to the incidence of acne. Mendelian randomization is a statistical method that is used to evaluate the causal effects of exposure factors on outcome variables.

We applied the inverse-variance weighted (IVW) method to evaluate the causal effect as the primary analysis between BMI and acne in our two-sample Mendelian randomization study. We included 58 SNPs accounting for 2.5% (R²) of the BMI variation as instrumental variables (IVs) for BMI-acne causal estimations.

The F-statistic obtained from the first stage of the MR regression model was 61. Importantly, the results from all three methods consistently indicated that an increase in BMI did not elevate the risk of acne, with each result reaching statistical significance. Cochran's Q test revealed no evidence of heterogeneity among the IV estimates for individual variants. Our I² values suggested low heterogeneity, thereby reinforcing the reliability of the MR estimates. Additionally, the "leave-one-out" analysis confirmed that no single SNP disproportionately affected the IVW point estimate.

Our findings suggested that there is no causal relationship between BMI and acne.