Genetic association between TNF-α −857 C/T polymorphism and ankylosing spondylitis susceptibility: evidence from a meta-analysis

Certain studies have suggested that the tumor necrosis factor-α (TNF-α) −857 C/T polymorphism is associated with risk of ankylosing spondylitis. However, the conclusions remain controversial. Therefore, we performed a meta-analysis to provide a more precise conclusion. Such databases as PubMed, Embase, CBM, CNKI, and Wanfang Data were searched to identify relevant studies up to August 26, 2015. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to estimate the association between TNF-α −857 C/T polymorphism and ankylosing spondylitis susceptibility. A total of 10 studies were included in the meta-analysis. Overall, an elevated risk between TNF-α −857 C/T polymorphism and ankylosing spondylitis was observed in three genetic model (T vs. C: OR 1.86, 95% CI 1.19–2.92; CT vs. CC: OR 2.51, 95% CI 1.49–4.23; TT + CT vs. CC: OR 2.46, 95% CI 1.40–4.30), except in homozygote model (TT vs. CC: OR 2.41, 95% CI 0.96–6.06) and recessive model (TT vs. CT + CC: OR 1.54, 95% CI 0.71–3.35). Sensitivity analysis showed the overall results were robust. Subgroup analyses according to Hardy–Weinberg equilibrium and ethnicity showed that the increased risk of ankylosing spondylitis were predominant in Asian population. This meta-analysis indicated that TNF-α −857 C/T polymorphism might increase the susceptibility of ankylosing spondylitis, especially in Asians. Further studies were needed to verify the conclusion.