A study of the M235T variant of the angiotensinogen gene and hypertension in a sample population of Calabar and Uyo, Nigeria

Abstract

A common molecular variant of the angiotensinogen gene had been reported to predispose some ethnic groups to hypertension. This case–control study was designed to determine the frequency and association of the angiotensinogen M235T allele with hypertension in residents of Calabar and Uyo cities, south–south Nigeria. The study involved 1308 subjects, 612 patients and 696 controls. The M235T variant was investigated using an allele specific polymerase chain reaction and enzymatic digestion to determine allele frequencies. Hypertensinogenic factors such as dietary habits, physical activity, smoking and drinking
habits were assessed using questionnaires. Descriptive statistics,  chi-square and multiple regression analysis were used to analyze the data obtained. The M235T allele frequency was high (0.94 for hypertensives and 0.96 for controls) though it was not associated with hypertension status. The odds ratio for hypertension was 0.64 (95% confidence
interval: 0.39–1.06) there were no significant differences between the genotype frequency of hypertensives and controls. By multiple regression, Hypertension was observed to be associated with age and was a predictor for systolic blood pressure in both patient r2= 0.359; p< 0.05 and control
groups r2= 0.26. Age and body mass index were predictors for diastolic blood pressure in the control group, r2 =0.28.  Although the frequency of the M235T variant was high, it was not a significant risk factor for
hypertension in the study population.