Sp1 polymorphism was correlated with increased risk of disc degeneration under allelic model (T vs. G: OR = 1.28, 95% CI 1.00–1.64, P = 0.047, Fig. 4A), recessive model (TT vs. GG + GT: OR = 3.66, 95% CI 1.96–6.85, P < 0.001, Fig. 4C), and homozygote model (TT vs. GG: OR = 3.40, 95% CI 1.80–6.40, P < 0.001, Fig. 4D). The gene discussed is SP1; the disease is intervertebral disk degenerative disorder.