TRAIL gene 1595C/T polymorphisms contribute to the susceptibility and severity of intervertebral disc degeneration: a data synthesis

Abstract Background Studies have investigated the correlation between tumor necrosis factor related apoptosis-inducing ligand (TRAIL) gene polymorphisms and the susceptibility and severity of intervertebral disc degeneration (IDD), but the results were inconsistent. To evaluate the specific relationship, we performed a meta-analysis to clarify the controversies. Methods Four databases were searched, and the pooled results were presented as odds ratios (ORs) with 95% confidence intervals (CIs). Results Three case-control studies from Han Chinese were included (565 cases and 427 controls). All the included studies reported TRAIL 1595C/T gene polymorphisms. The recessive model (CC vs. CT + TT) was the optimal model, which demonstrated a significant relationship between 1595C/T polymorphisms and increased IDD risk (OR = 2.18, 1.45 to 3.27, P = 0.000). No significant heterogeneity was found in the recessive model (I2 = 48.6%, P = 0.143). Patients with lower grade IDD had more genotypes or alleles including 1595TT genotype (grade II vs. grade III: OR = 2.12, 1.18 to 3.83, P = 0.012; grade III vs. grade IV: OR = 2.59, 1.29 to 5.22, P = 0.007) and 1595 T allele (grade II vs. grade III: OR = 1.91, 1.43 to 2.55, P = 0.000; grade II vs. grade IV: OR = 2.46, 0.94 to 1.76, P = 0.000). Conclusions There is a significant relationship between 1595C/T polymorphisms and the susceptibility and severity of IDD in Han Chinese. Patients with lower grade IDD had higher frequency of the 1595TT genotype and 1595 T allele