Vitamin D receptor gene polymorphisms and osteoarthritis: a meta-analysis

Objective To investigate the association of vitamin D receptor (VDR) gene polymorphisms with OA susceptibility. Methods Meta-analyses were performed using allelic contrast, contrast of homozygotes, and recessive and dominant models to clarify the association between OA and VDR ApaI, BsmI, TaqI and FokI polymorphisms. Odds ratio (OR) and the corresponding 95% CI were obtained, and subgroup analyses were performed based on the ethnicity and OA sites. Results A total of 18 studies with 2983 OA patients and 4177 controls were included in this meta-analysis. There were statistically significant associations in the spine between OA susceptibility and the VDR BsmI (B vs b: OR = 1.25, 95% CI: 1.03, 1.53, P = 0.026; BB vs bb: OR = 1.56, 95% CI: 1.02, 2.37, P = 0.038) and TaqI (T vs t: OR = 0.73, 95% CI: 0.54, 0.99, P = 0.044; TT vs Tt + tt: OR = 0.63, 95% CI: 0.42, 0.95, P = 0.028) polymorphisms, but not for the other polymorphisms. A statistically significant association was found between the VDR FokI polymorphism and OA susceptibility in the knee in the recessive model contrast (FF vs Ff + ff: OR = 0.63, 95% CI: 0.42, 0.95, P = 0.028), but this result was only pooled from one study. However, no significant associations were found between the VDR ApaI polymorphism and OA. Besides, ethnic stratification also indicated that there was no significant association between VDR gene polymorphism and OA in Caucasians or Asians. Conclusion Our meta-analysis suggests that the VDR BsmI and TaqI polymorphisms are associated with OA susceptibility in the spine. However, the VDR ApaI polymorphism is not a significant genetic risk factor for OA.