VDR and intervertebral disk degenerative disorder: Similarly, no significant association was found between VDR ApaI polymorphism and IDD risk (a vs. A: OR = 0.914, 95%CI 0.649–1.288; aa vs. AA: OR = 0.757, 95%CI 0.477–1.202; aa vs. Aa/AA: OR = 0.924, 95%CI 0.516–1.653).