VDR and Alzheimer disease: The overall pooled results manifested that VDR TaqI polymorphism was dramatically relevant to AD risk under homozygous model (tt vs. TT: OR = 0.67, 95% CI = 0.49–0.93, P = 0.017, Supplementary Figure 3), and the ApaI polymorphism was significantly correlated with AD risk under allelic, homozygous, and recessive models (A vs. a: OR = 0.85, 95% CI = 0.73–0.99, P = 0.033; AA vs. aa: OR = 0.68, 95% CI = 0.47–0.96, P = 0.030; AA vs. Aa/aa: OR = 0.72, 95% CI = 0.56–0.92, P = 0.009, Figure 2 and Table 3).