Association between angiotensin II type I receptor polymorphism and resting hemodynamics in black and white youth.

OBJECTIVES

An angiotensin II type I receptor polymorphism (AGTR1/A1166C) was previously found to be associated with hypertension. The purpose of this study was to investigate the relationship between this polymorphism and resting measures of hemodynamics in normotensive youth.

DESIGN

Subjects were 41 Whites (mean +/- SD: 18 +/- 3 y old, 26 males) and 73 Blacks (19 +/- 2 y old, 55 males) with a positive family history of hypertension.

METHODS

Hemodynamic measures included resting systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR).

RESULTS

Allele frequencies were significantly different (chi2 = 14.10, P < or = .001) between Whites and Blacks (.23 vs .06 for the C allele, respectively). For all subsequent analyses, subjects were categorized into two genotype groups, carriers and non-carriers of the C allele, because only two Whites and no Blacks were homozygous for the C allele. Genotype frequencies were significantly different (chi2 = 12.66, P < or = .0011) between Whites and Blacks (.41 vs .12 for the carriers, respectively). Among Whites, univariate analyses of covariance, using body mass index and age as covariates, indicated that carriers of the C allele compared to non-carriers, had a higher DBP (61.6 +/- 6.7 vs 57.8 +/- 6.2 mm Hg, P < or = .05) and HR (68.0 +/- 10.5 vs 61.1 +/- 8.1, P < or = .05). Genotype was not associated with resting hemodynamic measures in Blacks (all P values > .05).

CONCLUSIONS

These results are consistent with findings that have typically involved White adults, and demonstrate that the renin system does not seem to play as great a role in BP control in Blacks as it does in Whites.