Relationship between bullous pemphigoid and metabolic syndrome and its relevant traits: a bidirectional two-sample Mendelian randomization study.

Bullous pemphigoid (BP) is a chronic autoimmune subepidermal blistering disease, affecting mostly the elderly. Metabolic syndrome (MetS) is a set of metabolic disorders including obesity, hypertension, glucose intolerance, and dyslipidemia. Observational studies have revealed a correlation between BP and MetS with controversial results and the causal relationship needs to be clarified. In the study of BP and MetS, observational investigations are prone to be biased by confounding factors such as the use of corticosteroids or age. However, Mendelian randomization (MR) is less susceptible to confounding factors and reverse causality. In this study, we aimed to use two-sample MR to investigate the causal correlation between BP and MetS from a genetic perspective. We used genome-wide association study (GWAS) data of BP, MetS, and its relevant traits to perform the analysis. The relevant traits consisted of four aspects, including central obesity, hypertension, impaired glucose tolerance, and dyslipidemia. In the results, it demonstrated no causal association of BP on the risk of MetS or its relevant traits and it revealed no significant linkage in the reverse procedure. This analysis enriched the research on the association of BP and MetS and provided evidence from a genetic perspective.