Polymorphisms in the vitamin D receptor gene and multiple sclerosis risk: A meta-analysis of case–control studies

BackgroundThe vitamin D receptor (VDR) polymorphisms have been reported to be associated with multiple sclerosis (MS), however, evidence remains conflicting. A meta-analysis was conducted to investigate this association.MethodsWe searched Pubmed, Medline and Embase databases for case–control studies evaluating the association between the VDR Apa-I, Bsm-I, Fok-I, Taq-I polymorphisms and MS risk. Data were extracted using standardized forms and odds ratios (OR) with 95% confidence intervals (CI) were calculated.Results11 case–control studies involving a total of 2599 cases and 2816 controls were included in this meta-analysis. Available data did not suggest an association between any of the VDR polymorphisms and the risk for MS. For Taq-I, which is the most investigated VDR polymorphism with 8 studies (2472 cases and 2446 controls), the combined OR was 1.12 (95% CI: 1.00–1.26) for the dominant model (tt + Tt vs. TT), 1.03(95% CI: 0.88–1.20) for the recessive model (tt vs. Tt + TT), and 1.04 (95% CI: 0.78–1.38) for the homozygote model (tt vs. TT). ORs for other VDR polymorphisms were similar.ConclusionThe VDR Apa-I, Bsm-I, Fok-I and Taq-I polymorphisms are not associated with MS risk.