OBESITY AND HIGH-DENSITY-LIPOPROTEIN CHOLESTEROL IN BLACK-AND-WHITE 9- AND 10-YEAR-OLD GIRLS - THE NATIONAL-HEART-LUNG-AND-BLOOD-INSTITUTE GROWTH AND HEALTH STUDY

It has been hypothesized that the role of obesity in the pathogenesis of coronary heart disease (CHD) may be mediated in part through its in verse relationship with high-density lipoprotein cholesterol (HDL-C). Obesity is inversely correlated with HDL-C, and HDL-C has been shown t o be protective against CHD. Defining obesity as excess weight due to excess fat, the purpose of this analysis was to determine whether the effects of obesity are due to increased weight or to increased adiposi ty. Using baseline lipid and anthropometric data from the National Hea rt, Lung, and Blood Institute Growth and Health Study, cross-sectional associations among body mass, adiposity, HDL-C, and related lipid par ameters (apolipoprotein [ape] Al and triglycerides [TGs]) were assesse d in 821 white and 763 black 9- and 10-year-old girls, using multivari ate linear regression models. Equations predicting HDL-C, apo Al, and TGs from age, race, sexual maturation stage, adiposity (sum of truncal -subscapular and suprailiac-skinfolds), and ponderosity (a ratio of we ight to height) revealed that adiposity, not ponderosity, was the sign ificant body composition variable to explain the variability of each o f the lipids assessed. The amount of variance explained in each of the models was small (R(2) less than or equal to .10). When apo Al and TG s were added to the HDL-C model, R(2) increased to 0.44 and race diffe rences were no longer significant. These findings suggest that adiposi ty, not ponderosity, explains the effects of obesity on HDL-C, the eff ects are mediated through apo Al and TGs, and that black-white differe nces in HDL-C are a result of apo Al- and TG-metabolic differences bet ween the races. (C) 1996 by W.B. Saunders Company