Interaction between eNOS gene polymorphism and current smoking on susceptibility to coronary heart disease in Chinese people

OBJECTIVE: This study aims to explore the relation between endothelial nitric oxide synthase (eNOS) single-nucleotide polymorphisms (SNPs) and the risk of coronary heart disease (CHD). METHODS: SNPstats (online software: http://bioinfo.iconcologia.net/SNPstats) was performed to test Hardy-Weinberg equilibrium in controls. Generalized multifactor dimensionality reduction (GMDR) was adopted to screen the preferable interaction between eNOS SNPs and smoking. RESULTS: The frequency for the rs1799983-T allele was 31.1% in CHD patients, which was significantly higher than that of 19.8% in controls (P < 0.05). The frequency for the rs891512-A allele was 28.8% in cases, which was also significantly higher than that of 20.1% in controls (P < 0.05). Logistic regression analysis showed that both rs1799983-T and rs891512-A alleles were related with increased risk of CHD, and the odds ratios (ORs) [95% confidence interval (CI)] were 1.71 (1.31-2.15) and 1.57 (1.14-2.07), respectively. High-order interactions were investigated among SNPs and environmental factors using the GMDR method. The data showed that a two-locus model (rs1799983 × smoking) had a testing accuracy of 0.60 (P = 0.001). We found that current smokers with rs1799983-GT or TT within eNOS gene have the highest CHD risk, compared to never smokers with rs1799983-GG genotype, OR (95% CI) = 2.74 (1.78-3.85), after covariates adjustment for age, gender, BMI, and alcohol drinking. CONCLUSION: The rs1799983-T and rs891512-A alleles and interaction between rs1799983 and smoking were all risk factors of CHD.