To determine whether adiposity in children predicts adiposity, insulin resistance, and abnormal lipid levels in young adults. Children (n = 31) were recruited into an epidemiologic study at age 13.3 +/- 0.3 years and had blood pressure, weight, and height measured. They were reevaluated at age 21.8 +/- 0.3 years at which time the measurements were repeated, a euglycemic insulin clamp was performed, and fasting lipid levels were measured. All values are expressed as mean +/- SEM. Data were analyzed by analysis of variance and linear regression analysis. Body mass index (BMI) in childhood (22.6 +/- 0.6) was highly correlated with BMI in young adulthood (26.9 +/- 0.9). Childhood BMI was also inversely correlated with young adult glucose utilization (r = -0.5, P = .006) and positively correlated with total cholesterol (r = 0.37, P = .05), and low-density lipoprotein (LDL) cholesterol (r = 0.48, P = .01). These data confirm that adiposity in childhood is a strong predictor of young adult adiposity. In addition, these results demonstrate that cardiovascular risk in young adulthood is highly related to the degree of adiposity as early as age 13.