Associations of four common VDR polymorphisms with rheumatoid arthritis and systemic lupus erythematosus: evidence from a meta-analysis

Associations of polymorphisms in vitamin D receptor (VDR) with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) have already been explored by many studies. The aim of this meta-analysis was to better clarify associations between polymorphisms in VDR and RA/SLE by combing the results of all relevant studies. Eligible studies were searched from Pubmed, Embase, WOS and CNKI. We used Review Manager to combine the results of eligible studies. Thirty-seven studies were included in this meta-analysis. VDR rs1544410 (recessive comparison: odds ratio (OR) = 1.36, 95% confidence interval (CI) 1.06-1.76; over-dominant comparison: OR = 0.81, 95% CI 0.71-0.93) and rs731236 (over-dominant comparison: OR = 0.77, 95% CI 0.63-0.94) polymorphisms were found to be significantly associated with RA in overall combined analyses. Besides, VDR rs1544410 (dominant comparison: OR = 0.61, 95% CI 0.46-0.82; over-dominant comparison: OR = 1.45, 95% CI 1.16-1.81; allele comparison: OR = 0.75, 95% CI 0.62-0.92), rs2228570 (dominant comparison: OR = 0.58, 95% CI 0.50-0.67; recessive comparison: OR = 1.57, 95% CI 1.21-2.03; allele comparison: OR = 0.69, 95% CI 0.60-0.80) and rs731236 (dominant comparison: OR = 0.69, 95% CI 0.50-0.96; allele comparison: OR = 0.80, 95% CI 0.70-0.90) polymorphisms were also found to be significantly associated with SLE in overall combined analyses. Subgroup analyses revealed that significant associations for VDR polymorphisms and RA/SLE were mainly driven by Asians. Collectively, this meta-analysis proved that VDR rs7975232, rs1544410, rs2228570 and rs731236 polymorphisms may confer susceptibility to RA and SLE, especially for Asians.