Body composition and blood pressure in children based on age, race, and sex.

We evaluated 675 nine- and twelve-year-old children for body composition and circulatory differences based on age, race, and sex. The specific variables measured included height, weight, triceps and subscapula skinfolds, body mass index, percentage fat, fat-free weight, and systolic, diastolic, and mean arterial blood pressures. A 2 x 2 x 2 factorial multiple analysis of variance (MANOVA) test of significance showed body composition and blood pressure differences (P < .01) for race, age, and sex. The univariate test of the specific variables within the factors showed that black children had higher fat-free weights and lower fat levels but higher blood pressure values (P < .05) than white children. Boys had lower fat levels than girls, and the older children had higher values on the body composition variables but not on blood pressure. Zero order correlations between body composition and blood pressure ranged from 0.14 to 0.55; systolic blood pressure and body weight shared the highest correlation. These data show that, although black children have less body fat than white children, they are heavier and have higher blood pressure. We hypothesize that some aspect of fat-free body weight may contribute to hypertension in black individuals.