Endothelial Nitric Oxide Synthase Gene Polymorphisms and the Risk of Hypertension in an Indian Population

Genetic variants of eNOS gene play a significant role in the pathogenesis of hypertension. Many environmental factors have, also, been implicated in the aetiology of hypertension. We carried out an age-matched case-control study among adults. Hypertension was defined according to JNC-VII criteria and eNOS gene polymorphisms were determined by PCR and PCR followed by PCR-RFLP. eNOS intron 4 aa genotype (adjusted OR 6.81; 95% CI 2.29-20.25) and eNOS 894TT genotype (adjusted OR 7.84; 95% CI 2.57-23.96) were associated with the risk of hypertension. Tobacco users (either smoking/chewing or both) with eNOS intron 4 aa genotype (OR 14.00: 95% CI 1.20-163.37), eNOS 894GG genotype (OR 5.56: 95% CI 3.72-8.31), and eNOS T-786C CC genotype (OR 9.00: 95% CI 1.14-71.04) were at an increased risk of hypertension. Similarly a significant gene-environment interaction was observed between individuals consuming alcohol with eNOS intron 4 aa genotype (OR 12.00: 95% CI 1.20-143.73) and eNOS 894GG genotype (OR 1.95: 95% CI 1.35-2.81). The present study identified few susceptible genotypes of the eNOS gene with the risk of hypertension. Moreover, the interactive effects between the environmental factors and the risk of hypertension were dependent on the eNOS genotypes.