Tumor necrosis factor-alpha G-308A gene polymorphism and coronary heart disease susceptibility: An updated meta-analysis

Purpose: Several studies have reported apparently conflicting findings for the effects of tumor necrosis factor-alpha (TNF-alpha) G-308A polymorphism on coronary heart disease (CHD) susceptibility. We undertook a systematic review and meta-analysis to investigate the association between this gene variant and CHD predisposition. Methods: We systematically searched electronic databases (Medline, EMbase, Chinese BioMedical, BIOSIS, Global Health, PsycINFO, Allied and Complementary Medicine Database, Cochrane Library, HuGE Navigator, and British Nursing) for relevant studies published between 1947 and October, 2010. Summarized estimation of odds ratio (OR) and 95% confidence interval (CI) were calculated. Publication bias and heterogeneity among studies were explored. Results: We identified 24 studies providing data for 9 921 cases and 7 944 controls. Pooled analysis based on ORs adjusted by CHD risk factors showed that carrying the TNF-alpha gene A variant conferred a 1.5-fold increased risk of developing CHD (AG+AA vs. GG, OR=1.50, 95% CI: 1.23-1.77) in Caucasian population. No significant association between the gene polymorphism and CHD risk could be found in other ethnic groups. Conclusions: It is probable that carrying the A variant is associated with CHD risk in Caucasians but not in Asians, Indians, or Africans. Further studies are merited to assess the association in greater details, especially in Asians, Indians and Africans. (C) 2011 Elsevier Ltd. All rights reserved.