Impact of the polymorphism in vitamin D receptor gene BsmI and the risk of systemic lupus erythematosus: an updated meta-analysis.

The etiology of system lupus erythematosus (SLE) still remains unclear, and vitamin D is associated with immune response. Although a few studies are conducted to investigate the association between polymorphism in vitamin D receptor (VDR) genes and SLE risk, their results are conflicting. Following the guideline of PRISMA, we conducted a systematic search and meta-analysis of the BsmI polymorphism rs1544410 and the risk of SLE. The pooled odds ratios (OR) and its 95 % confidential interval (CI) were calculated by using Stata Version 10 with dominant and recessive model and allele analyses. Nine studies were included in our meta-analysis with a total of 1247 SLE cases and 1687 controls. No significant association was found in both models in the overall population. Only Bb + BB genotypes showed a significantly elevated SLE risk in Asian subgroup with an OR of 3.26 (95 % CI = 1.30-8.17) while no significance was observed in Caucasian population. Notably, B allele significantly increased the SLE risk among Asian population with an OR of 2.29 (95 % CI = 1.14-4.61). No positive findings were reported in Caucasian population and in the overall analysis. In Asian population, Bb + BB genotype and B allele can significantly increase the SLE risk.