Abstract
STUDY DESIGN: Meta-analysis to collect all the relevant studies to further investigate whether or not the FAS ligand (FASL) and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) genetic polymorphisms are associated with susceptibility to intervertebral disc degeneration (IDD) in Chinese Han population. OBJECTIVE: To investigate whether or not the FASL and TRAIL genetic polymorphisms are associated with susceptibility to IDD in Chinese Han population. SUMMARY OF BACKGROUND DATA: FASL and TRAIL are both apoptotic gene. Several studies have assessed the associations of FASL and TRAIL gene with risk of IDD in Chinese Han population, but the results are inconsistent. METHODS: We systematically searched the PubMed, EMBASE, Medline, Scopus, Web of Science, CBM, and the Cochrane Library databases. Eligible studies assessing the polymorphisms in the FASL and TRAIL gene and risk of IDD were incorporated. The pooled odds ratio (OR) with its 95% confidence intervals (95% CI) was used. RESULTS: Six studies with a total of 1766 IDD cases and 1533 controls were finally included in the meta-analysis. Meta-analysis of FASL-844C/T (rs763110) polymorphism was statistically associated with decreased IDD risk under all genetic models (allele model: OR = 0.68, 95% CI 0.59-0.80, P = 0.000; homozygote model: OR = 0.35, 95% CI 0.25-0.53, P = 0.000; dominant model: OR = 0.38, 95% CI 0.25-0.58, P = 0.000; recessive model: OR = 0.69, 95% CI 0.58-0.84, P = 0.000). There was a significant association between TRAIL-1595C/T (rs1131580) polymorphism with increased IDD risk under each genetic model (allele model: OR = 1.77, 95% CI 1.47-2.13, P = 0.000; homozygote model: OR = 2.44, 95% CI 1.70-3.51, P = 0.000; dominant model: OR = 1.67, 95% CI 1.22-2.29, P = 0.002; recessive model: OR = 3.13, 95% CI 2.40-4.08, P = 0.000). In addition, the association between TRAIL-1525G/A (rs1131568) polymorphism and the susceptibility of IDD was statistically significant under all genetic models. CONCLUSION: The present meta-analysis demonstrated that FASL and TRAIL polymorphisms were significantly associated with susceptibility to IDD in Chinese Han population. LEVEL OF EVIDENCE: 1.