Association between the - 786T>C 1polymorphism in the promoter region of endothelial nitric oxide synthase (eNOS) and risk of coronary artery disease: a systematic review and meta-analysis

Background: A variety of studies have evaluated the association between the -786T>C polymorphism in the promoter region of endothelial nitric oxide synthase (eNOS) and risk of coronary artery disease (CAD). However, the results remain conflicting. To better understand the role of eNOS -786T>C polymorphism in CAD risk, we conducted a comprehensive systematic review and meta-analysis.

Methods: Case-control, cohort or cross-sectional studies evaluating the association between eNOS -786T>C polymorphism and CAD risk were searched in electronic databases of PubMed, ISI Web of Knowledge, Medline, Embase and Google Scholar Search (up to January 2013). Overall and subgroup analyses were performed. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the association between eNOS -786T>C polymorphism and CAD risk. Statistical analysis was performed with Review Manager 5.0 and STATA12.0.

Results: Twenty-four studies were analyzed between 6192 CAD cases and 9281 healthy controls. The combined results of overall analysis showed significant positive associations between CAD risk and eNOS -786T>C polymorphism in dominant model (OR=1.45, 95% CI=1.27-1.65), recessive model (OR=1.37, 95% CI=1.20-1.56), homozygote comparison (OR=1.64, 95% CI=1.31-2.04), heterozygote comparison (TC vs. TT, OR=1.39, 95% CI=1.23-1.57; CC vs. TC, OR=1.20, 95% CI=1.04-1.37) and allele comparison (OR=1.35, 95% CI=1.21-1.50). On subgroup analysis based on the ethnicity of population (Caucasians, Asians and others), significant differences were found in all genetic models for Caucasians, similar associations existed in Asians except heterozygote comparison (CC vs. TC). However, the associations were only found in dominant model, heterozygote comparison (TC vs. TT) and allele comparison for the populations named others.

Conclusions: Our investigations demonstrate the significant associations between eNOS -786C>T polymorphism and CAD risk, and this polymorphism might become an early marker for the risk evaluation of CAD.