VDR and intervertebral disk degenerative disorder: Among them, a total of 9 studies [10]–[14], [21], [30]–[32], 5 studies [11], [21], [30], [33], [34], 3 studies [13], [14], [31], and 7 studies [11], [16]–[19], [35], [36], were finally included in the meta-analyses for the associations between the VDR TaqI, FokI, ApaI or aggrecan VNTR polymorphisms and the risk of IDD, respectively.