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

Abstract

It has been hypothesized that the role of obesity in the pathogenesis of coronary heart disease (CHD) may be mediated in part through its inverse relationship with high-density lipoprotein cholesterol (HDL-C). Obesity is inversely correlated with HDL-C, and HDL-C has been shown to 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 adiposity. Using baseline lipid and anthropometric data from the National Heart, Lung, and Blood Institute Growth and Health Study, cross-sectional associations among body mass, adiposity, HDL-C, and related lipid parameters (apolipoprotein [apo] AI and triglycerides [TGs]) were assessed in 821 white and 763 black 9- and 10-year-old girls, using multivariate linear regression models. Equations predicting HDL-C, apo AI, and TGs from age, race, race, sexual maturation stage, adiposity (sum of truncal--subscapular and suprailiac--skinfolds), and ponderosity (a ratio of weight to height) revealed that adiposity, not ponderosity, was the significant body composition variable to explain the variability of each of the lipids assessed. The amount of variance explained in each of the models was small (R2 <or= .10). When apo AI and TGs were added to the HDL-C model, R2 increased to 0.44 and race differences were no longer significant. These finding suggest that adiposity, not ponderosity, explains the effects of obesity on HDL-C, the effects are mediated through apo AI and TGs, and that black-white differences in HDL-C are a result of apo AI and TG-metabolic differences between the races.