Affiliation:
1. State Key Laboratory of Traditional Chinese Medicine Syndrome, The First Clinical Medical College of Guangzhou University of Chinese Medicine Guangzhou China
2. Guangdong Clinical Research Academy of Chinese Medicine Guangzhou China
3. Department of Rheumatology The First Affiliated Hospital of Guangzhou University of Chinese Medicine Guangzhou China
Abstract
AbstractBackgroundPrevious studies have reported low serum 25‐hydroxyvitamin D [25(OH)D] levels in dermatomyositis (DM) patients, but the exact causal relationship between them remains elusive. Our aim is to confirm the causal relationship between 25(OH)D and DM risk through a Mendelian randomization study.MethodsRetrieve genome‐wide association study (GWAS) data on 25(OH)D (n = 441 291) and DM (n cases = 201, n controls = 172 834) from the GWAS database (https://gwas.mrcieu.ac.uk/). Select single‐nucleotide polymorphisms (SNPs) strongly correlated with 25(OH)D as instrumental variables (IVs). The primary analytical approach involves the use of the inverse‐variance weighted method (IVW), supplemented by MR‐Egger regression and weighted median methods to enhance the reliability of the results. Heterogeneity and sensitivity analyses were conducted using Cochran's Q and leave‐one‐out approaches, respectively.ResultsThe IVW analysis confirmed a positive causal relationship between genetic variation in 25(OH)D levels and DM (OR = 2.36, 95% CI = 1.01–5.52, p = .048). Although not statistically significant (all p > .05), the other methods also suggested a protective effect of 25(OH)D on DM. Based on MR‐Egger intercepts and Cochran's Q analysis, the selected SNPs showed no horizontal pleiotropy and heterogeneity. Sensitivity analysis demonstrated the robustness of the results against individual SNPs.ConclusionWe provide the first evidence of a causal relationship between 25(OH)D levels and DM. Our findings support the importance of measuring serum 25(OH)D levels and considering vitamin D supplementation in clinical practice for patients with DM.