Association between the endothelial nitric oxide synthase gene Glu298Asp polymorphism and coronary heart disease: A meta-analysis of 39 case-control studies

Numerous studies have indicated that the human endothelial nitric oxide synthase (eNOS) gene Glu298Asp polymorphism is associated with coronary heart disease (CHD) susceptibility, however, their conclusions are inconsistent. The present meta-analysis aimed to evaluate the precise result by searching the PubMed database and using 39 case-control studies comprising 7489 cases and 7051 controls. Each study tested the association between the eNOS Glu298Asp polymorphism and CHD. A meta-analysis was then conducted using the Comprehensive Meta Analysis 2.2 software to calculate the pooled odds ratios (ORs) of five genetic models with 95% confidence intervals (CIs). Publication bias was also explored. The meta-analysis showed a significant association between the eNOS Glu298Asp polymorphism and CHD susceptibility for all the genetic models [Asp vs. Glu, OR 1.26, 95% CI 1.14-1.40, P<0.001; Asp/Asp vs. Glu/Glu, OR 1.58, 95% CI 1.23-2.02, P<0.001; Glu/Asp vs. Glu/Glu, OR 1.12, 95% CI 1.03-1.22, P=0.001; (Glu/Asp+Asp/Asp) vs. Glu/Glu, OR 1.17, 95% CI 1.07-1.27, P<0.001; Asp/Asp vs. (Glu/Glu+Glu/Asp), OR 1.59, 95% CI 1.25-2.03, P<0.001]. Subgroup and sensitivity analyses indicated that the result was robust. A weak publication bias was detected. The results indicated that the eNOS Glu298Asp polymorphism is a risk factor for developing CHD, particularly in the Asian population.