I/D polymorphism of the angiotensin-converting enzyme gene does not predict isolated systolic or systolic-diastolic hypertension in the elderly

To determine whether insertion/deletion (I/D) polymorphism (intron 16) of the angiotensin converting-enzyme (ACE) gene is associated with isolated systolic hypertension (ISH: systolic blood pressure (BP) ≥160, diastolic BP <90 mm Hg) or systolic-diastolic hypertension (S-D hypertension: diastolic BP ≥90 ± systolic BP ≥ 160 mm Hg) compared with normotensive controls (systolic BP <160, diastolic BP <90 mm Hg), we conducted a case-control study of 733 non-institutionalised, elderly (≥60 years) residents of Dubbo, NSW. Individuals were classified as: ISH (n = 167), S-D hypertension (n = 207) and normotensive control (n = 359) with age and sex matching. II, DD and ID genotypes were determined by a nested PCR strategy using DNA extracted from serum. The frequencies of D and I alleles in the control population (0.70 and 0.30 respectively) were not significantly different in the ISH group or the S-D hypertension group (χ²: 1.7, P = 0.42). After adjustment for several potential confounders, neither genotype nor allele predicted ISH (II vs DD: odds ratio (OR): 1.06, 95% confidence interval (CI): 0.55-2.03; I vs D: 1.09, 0.82-1.46) or S-D hypertension (II vs DD: 1.19, 0.67-2.10; I vs D: 1.16, 0.89-1.52) in this elderly cohort. The I/D polymorphism of the ACE gene is not a marker for either form of hypertension in this large elderly sample.