VDR and osteoporosis: Also, Wang et al. [25] and Zhang et al. [22] conducted meta-analyses of 18 studies of VDR TaqI polymorphism and reported no significant relationship between TaqI polymorphism and osteoporosis incidence, while in Yadav et al. [26] meta-analysis, a total of 65 (14929 samples), 31 (7697 samples), 18 (3617 samples), and 26 (5353 samples) were studied.