Association between the TNF-α G-308A polymorphism and risk of ischemic heart disease: a meta-analysis

Background: The role of the tumor necrosis factor-alpha (TNF-alpha) G-308A polymorphism in the risk of ischemic heart disease (IHD) has been controversial in recent decades. A substantial number of newly-published studies concerning the association between the TNF-alpha polymorphism and IHD risk have emerged after the publication of the latest meta-analysis. Therefore, we conducted an updated meta-analysis to further investigate the influence of this polymorphism on IHD. Methods: Electronic databases (PubMed, Embase, CNKI, and Wanfang) were systematically searched to identify all relevant papers published before September 25th, 2014. The quality of all eligible studies was assessed. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) of all studies and high-quality studies were assessed by the fixed/random-effects model in Review Manager 5.0.25 and STATA 10.0. Heterogeneity and publication bias were detected; sensitivity analysis was conducted. Results: Data from 36 studies were recorded after study selection and exclusion. Under the dominant model, the results of pooled analysis of high-quality studies suggested that the G-308A polymorphism was associated with an increased risk of IHD in total population (P = 0.02, OR = 1.13, 95% CI = 1.02-1.24, P-heterogeneity = 0.009, I-2 = 45%). No significant result was obtained in Asians, Caucasians, or Indians. Conclusion: The TNF-alpha -308A allele is probably associated with an increased risk of IHD in total population, but to further identify this association, more high quality studies in Indians and Africans are merited.