The overall goal of this study was to determine race/ethnic differences in the associations between renal ET-1 and indices of blood pressure-related target organ damage in healthy adolescents. The subjects ranged in age between 15-19 years, had no history of any disease, and were not on any prescription medications. The 92 subjects consisted of 48 Caucasians (CA) and 44 African-Americans (AA). The two groups were similar with respect to height, weight, body mass index, blood pressure, ET-1), albumin excretion rate (AER), and left ventricular mass).
Results:
The CA’s were slightly older 17±1 v 16±1 (p=.02). The protocol was preceded by a 3 day self-selected sodium controlled diet of 250 mEq/day day which the subject picked up each day. The test day began with an echocardiogram for the assessment of left ventricular mass. Next, the subjects were seated for 60 minutes of rest during which the subjects consumed 200 ml of water. This was followed by the collection of a urine sample for the measurement of ET-1 and AER. Overall, ET-1 excretion was correlated with AER (r=.278), LV mass/ht
2.7
(r=.341), and systolic blood pressure (SBP; r=.365; p=.01 for each). The significant overall correlations were the result of significant correlations in AAs for AER (r=.344; p=.05), LV mass/ht
2.7
(r=.520; p=.01), and SBP (r=.645; p=.01) which were not apparent in CA’s. These findings suggest urinary ET-1 contributes to the development of BP-related target organ damage in AA youths prior to the development of increases in blood pressure.
White coat hypertension and target organ involvement: the impact of different cut-off levels on albuminuria and left ventricular mass and geometry
