Table 1. Characteristics of individual studies for associations between VDR, MMP-3 polymorphisms and IDD risks.
a, b, c, represent ff, Ff, FF for FokI (rs2228570), aa, Aa, AA, for ApaI (rs7975232), and 5A5A, 6A5A, 6A6A for MMP-3 (rs731236), respectively. VDR, vitamin D receptor; MMP-3, matrix metalloproteinase-3; IDD, intervertebral disc degeneration; NA, not available.