Associations between angiotensinogen gene variants and left ventricular mass and function in the HyperGEN study

Background The angiotensinogen M235T polymorphism is positively associated with plasma angiotensinogen, hypertension, and coronary heart disease. However, the association of M235T polymorphism with left ventricular (LV) mass and function is not well defined at the population level. We investigated whether 2 tightly linked polymorphisms of angiotensinogen gene, M235T and G-6A, are associated with LV mass and function in a large population-based sample, composed mostly of patients with hypertension. Methods Two-dimensional guided M-mode and pulsed Doppler scan echocardiograms were performed in 605 participants. The angiotensinogen M235T was analyzed with a standard polymerase chain reaction test, and the G-6A variant was measured with mass spectrophotometry. Results The association of angiotensinogen gene to LV mass and LV mass indexed to body surface area (LVMi) differed significantly between subjects with normotensive and hypertensive conditions with respect to the direction of association (P < .005). The methionine-threonine/threonine-threonine genotype was negatively associated with LV mass and LVM1 in patients with hypertension after adjustment for blood pressure, antihypertensive medication use, weight, and other covariates (P < .001), and patients with normotensive conditions with the methionine-threonine/threonine-threonine genotype had higher LV mass and LVM1 (P = .04, for LV mass; P = .14, for LVM1). The association in patients with normotensive conditions was not influenced by blood pressure but was partly confounded by weight. Conclusion Variation in the angiotensinogen gene was modestly associated with LV mass independently of covariates in patients with hypertensive conditions. The direction of the association was opposite to that observed in patients with normotensive conditions, probably because of the influence of other risk factors or antihypertensive medication use or both.