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. This evidence concerns the gene ACAN and intervertebral disk degenerative disorder.