The longitudinal study was ancillary to the National Growth and Health Study (NGHS), a multicenter study which investigated the occurrence of obesity in Black and white adolescent girls, predictors of the transition to the obese state, the correlates of the transition, and the relationship of the transition to other coronary heart disease risk factors. As part of the NGHS, participants from the Cincinnati, Ohio and Washington, D.C. public and parochial schools received physical examinations with attention to pubertal staging and anthropometric measurements including weight, height, and skinfold thickness. Along with NGHS blood samples, additional blood was obtained in years 1, 3, and 5 for measurements of lipids, lipoprotein cholesterols, apolipoproteins A1, A2, and B, and sex steroid hormones including plasma total and free testosterone, dehydroepiandrosterone sulfate, estradiol, and testosterone estrogen binding globulin.