SEXUAL-MATURATION AND RACIAL-DIFFERENCES IN BLOOD-PRESSURE IN GIRLS -THE NATIONAL-HEART-LUNG-AND-BLOOD-INSTITUTE GROWTH AND HEALTH STUDY

Objective: To evaluate racial differences in blood pressure in girls a ged 9 to 10 years in the National Heart, Lung, and Blood Institute Gro wth and Health Study (NGHS) and to evaluate the extent to which racial differences in blood pressure are explained by other factors, includi ng sexual maturation and body size. Methods: The NGHS enrolled 539 bla ck and 616 white girls aged 9 years, and 674 black and 550 white girls aged 10 years. Racial differences in blood pressure were examined. Re lationships of stage of sexual maturation, height, and skinfold thickn ess with systolic and diastolic blood pressure were evaluated by multi ple regression analysis. Results: The black girls had significantly hi gher systolic (102.0 +/- 8.90 vs 100.5 +/- 9.42 mm Hg, p<0.001) and di astolic (58.0 +/- 12.0 vs 56.5 +/- 12.51 mm Hg, p<0.01) blood pressure s than the white girls. The black girls were also more advanced in sex ual maturation and were taller (142.9 +/- 7.94 vs 139.6 +/- 7.05, p<0. 001) and heavier (39.6 +/- 11.24 vs 35.3 +/- 8.73 kg, p<0.001) than th e white girls. Both systolic and diastolic blood pressure were signifi cantly correlated with level of maturation, height, weight, and sum of skinfolds, Stage of maturation was found to account for the differenc e in blood pressure between black girls and white girls, In a multiple regression analysis, controlling for height (for diastolic blood pres sure) and for both height and sum of skinfolds (for systolic blood pre ssure) eliminated the effects of race and stage of maturation on blood pressure. Conclusion: Racial differences in blood pressure were obser ved for 9- and 10-year-old girls and are explained by the fact that bl ack girls were more mature than white girls. The effect of sexual matu ration on blood pressure appears to operate through height and body fa t. The effect of obesity may be more important for systolic than for d iastolic blood pressure. Continuation of racial differences in blood p ressure may result in a higher prevalence of hypertension for black wo men.