RACIAL-DIFFERENCES IN THE AGE-RELATED INCREASE IN LEFT-VENTRICULAR MASS IN YOUTHS

We determined the factors related to left ventricular mass adjusted for body size in 60 black (mean age, 13+/-2 years) and 40 white (mean age, 14+/-2 years) normotensive youths. The factors examined included age, sex, systolic blood pressure, diastolic blood pressure, plasma renin activity, plasma aldosterone concentration, and sodium and potassium intake as determined by 24-hour excretion. Sex (beta=13.3, P<.003), age (beta=2.88, P<.001), and systolic blood pressure (beta=0.41, P<.02) were independent predictors in the sample as a whole, accounting for 37% of the variance of left ventricular mass adjusted for height. Separate analyses were performed for black and white subjects. In the black subjects, age (beta=4.4, P<.004) followed by sex (beta=11.85, P<.02) were independent factors, accounting for 43% of the variance of left ventricular mass adjusted for height. In contrast, in white subjects systolic blood pressure (beta=0.4, P<.003) followed by sodium excretion (beta=0.13, P<.05) were independent factors, with gender (beta=8.89, P<.07) tending to account for 36% of the variance. Similar results were observed for left ventricular mass adjusted for body surface area. In conclusion, the age-related increase in adjusted left ventricular mass in black but not white youths may in part account for the early development of cardiovascular disease among the black population.