Vitamin D receptor polymorphisms and susceptibility to Parkinson's disease and Alzheimer's disease: a meta-analysis

The goal of this study was to examine whether vitamin D receptor (VDR) polymorphisms are associated with susceptibility to Parkinson's disease (PD) and Alzheimer's disease (AD). A meta-analysis was performed to investigate the association between VDR FokI, BsmI, TaqI, ApaI, rs4334089, or rs11568820 polymorphism and susceptibility to PD or AD. Thirteen studies, including seven on PD and six on AD, were included in this meta-analysis. The meta-analysis revealed an association between the BB + Bb genotype and PD in the Asian population (OR 0.478, 95 % CI 0.259-0.884, p = 0.018). We also observed a significant association between PD and the FokI F allele (OR 1.413, 95 % CI 1.144-1.746, p = 0.001). Meta-analysis of the A allele, the AA vs. Aa + aa, and the AA vs. aa for the ApaI polymorphism revealed significant associations with AD (OR 0.729, 95 % CI 0.0.591-0.900, p = 0.034; OR 0.591, 95 % CI 0.431-0.810, p = 0.001; OR 0.580, 95 % CI 0.361-0.931, p = 0.024, respectively). This meta-analysis demonstrates that the VDR BsmI polymorphism is associated with PD susceptibility in Asians, and the FokI polymorphism is associated with PD. Furthermore, we identified associations between the VDR TaqI and ApaI polymorphisms and AD susceptibility.