IL1B and intervertebral disk degenerative disorder: Meta-analysis of the IL-1β (+3954C/T) polymorphism showed no significant association with risk of IDD in any genetic model, nor even a clear trend towards significance (TT versus CC: OR = 1.29, 95% CI: 0.60, 2.77; Pheterogeneity = 0.76; CT versus CC: OR = 0.83, 95% CI: 0.58, 1.19; Pheterogeneity = 0.81; CT/TT versus CC: OR = 0.90, 95% CI: 0.61, 1.34; Pheterogeneity = 0.97; TT versus CC/CT: OR = 1.71, 95% CI: 0.85, 3.46; Pheterogeneity = 0.51).