Several studies suggest that endothelial nitric oxide synthase (eNOS) Glu298Asp polymorphism is associated with coronary heart disease. We evaluated the relation between eNOS Glu298Asp polymorphism and the risk factors for myocardial infarction.

We selected 102 acute myocardial infarction (AMI) male patients younger than 65 years old and 112 healthy men as age matched controls. The eNOS genotypes were determined from blood lymphocyte DNA samples by using PCR-RFLP method.

There was no difference in frequency of eNOs Glu298Asp polymorphism between the AMI and control groups. eNOS Glu298Asp polymorphism was not an independent risk factor for AMI. However smoking, smoking amount, hypertension, hypercholesterolemia, high fasting sugar and low HDL-cholesterol were independent risk factors (p<0.01). Among the subjects having the eNOS GG genotype, the smokers had 3 times higher risk of AMI compared with nonsmokers (p=0.0413). Among the subjects having the eNOS TT or GT genotype, the smokers had 15 times higher risk of AMI compared with nonsmokers (p=0.0271). Among the subjects having the eNOS GG genotype, the high risk group had 21.9 times higher risk of AMI compared with the low risk group (p=0.0001). Among the subjects having eNOS TT or GT genotype, the high risk group had 31.9 times higher risk of AMI compared with the low risk group (p=0.0089).

eNOS TT or GT genotype demonstrated a synergistic effect with smoking and high risk group on the risk of AMI.