Association of hidradenitis suppurativa (HS) with waist circumference: A bidirectional two-sample Mendelian randomization study of HS with metabolic syndrome

Observational studies have suggested an associations between hidradenitis suppurativa (HS) and metabolic syndrome (MetS) and its components. However, it remains unclear whether the relationship is causal or not. Our study aimed to investigate the causal association of HS with MetS and its components. We performed a bidirectional, two-sample Mendelian randomization study using summary-level data from the most comprehensive genome-wide association studies of HS (n = 362 071), MetS (n = 291 107), waist circumference (n = 462 166), hypertension (n = 463 010) fasting blood glucose (FBG, n = 200 622), triglycerides (n = 441 016), and high-density lipoprotein cholesterol (HDL-C, n = 403 943). Genetic instrumental variables were constructed by identifying single nucleotide polymorphisms associated with the corresponding factors. The random-effects inverse-variance weighted method was applied as the primary method. The results showed that genetically predicted HS was positively associated with waist circumference risk in both directions. High waist circumference increased the risk of HS (odds ratio [OR] 4.147; 95% confidence interval [CI] 2.610–6.590; p = 1.746 × 10⁻⁹). In addition, HS was also affected by waist circumference (OR 1.009; 95% CI 1.006–1.012; p = 3.08 × 10⁻⁷). No causal relationships were found between HS and MetS or its components other than waist circumference. The findings highlight the importance of early intervention for obesity in HS patients. Further studies are needed to determine the pathophysiology of HS associated with MetS and its components.