Association of the C−344T aldosterone synthase gene variant with essential hypertension: a meta-analysis

BACKGROUND: The CYP11B2 gene (CYP11B2) encoding aldosterone synthase has been associated with essential hypertension and some, but not all, studies have reported that the C-344T variant may influence the risk of the disease. OBJECTIVE: We performed a systematic review of the literature by means of a meta-analysis to evaluate the influence of the C-344T CYP11B2 polymorphism on arterial hypertension and intermediate phenotypes. METHODS: From 485 reports, we included 42 observational studies, case-control and cohort at baseline. Fixed and random effect models were used to pool data from individual studies. RESULTS: From 19 heterogeneous studies including 5343 essential hypertensive and 5882 control subjects, we found a significant association between hypertension and the C-344T variant in fixed but not in random effect models for homozygous CC: odds ratio (OR), 0.834; 95% confidence interval (CI), 0.760-0.914; P < 0.0001, n = 11 225. Besides, homozygous CC subjects had lower plasma renin activity (D, -0.161; 95% CI, -0.279 to -0.043; P < 0.01, n = 1428) but no difference in plasma aldosterone levels (D, -0.006; 95% CI, -0.081 to 0.07; P = 0.88, n = 2872). Limiting the quantitative analysis of blood pressure to 13 studies including only untreated individuals, no significant association was found for systolic arterial blood pressure (D, 0.042; 95% CI, -0.057 to 0.141; P = 0.41, n = 1775) and diastolic arterial blood pressure (D, 0.026; 95% CI, -0.073 to 0.125; P = 0.61, n = 1775). CONCLUSION: Homozygous individuals for the -344C CYP11B2 allele are at 17% lower risk of hypertension with respect to homozygous TT subjects.