Background: Studies in several populations have indicated that genetic variation at the apolipoprotein E structural locus influences atherosclerosis leading to cardiovascular diseases. The possible role of apolipoprotein E polymorphism in the development of essential hypertension has not been sufficiently investigated. In this case-control study, we aimed to determine the significance of association between essential hypertension and apolipoprotein E genotypes. In addition, apolipoprotein E genotypes were correlated with serum lipid levels in order to understand the possible interaction between the specific genotype and the lipid profiles that can contribute to hypertension.
Methods and results: The apolipoprotein E genotypes were assayed in 185 patients and 200 controls by polymerase chain reaction followed by enzymatic digestion with Hha I. Using logistic regression analysis, the multivariate-adjusted odds of hypertension were calculated. The incidence of epsilon4 allele was found to be significantly higher in patients (12.16%) than in controls (5.75%, chi2=10.87; p<0.05) and also in patients with positive family history (16.7%) as compared to negative family history (8.87%, chi2 = 8.45; p<0.1). Further, it was observed that carriers of epsilon4 allele have twice as much risk (p<0.05) for developing hypertension as compared to carriers of other alleles. Patients with epsilon4 allele had significantly higher levels of total cholesterol and low-density lipoprotein- cholesterol as compared to epsilon4 allele non-carriers (p<0.05). The adjusted odds ratios for epsilon4 and epsilon2 alleles versus epsilon3 allele were 2.2 (95% confidence interval 1.2 to 3.8, p<0.05) and 1.2 (95% CI, 0.75 to 1.77, p<0.514), respectively.
Conclusions: Our study revealed a strong association of apolipoprotein E locus with hypertension and lipid profile. However, large population-based studies are needed to understand the exact role played by the locus in causing the condition.