Cardiovascular (CV) risk factors change over time with the emergence of clinically recognizable abnormalities (obesity, hypertension and hyperlipoproteinemia) in the second and third decades of life. A cohort of 286 subjects, aged 11-15 in 1973-74 were reexamined 6 years later to observe changes in height, weight, blood pressure, lipids and lipoproteins between adolescence and adulthood. During the 6 years of follow-up, 10-11 year-old males increased 30 cm in height and 32 kg in weight. Among 10-11 year-old girls, height increased 12-15 cm and weight increased 15 kg in whites and 20 kg in blacks. Mean systolic BP increased 16-23 mmHg in black males and 11-15 mmHg in white males. Mean serum total cholesterol levels increased with age such that levels in 20 year olds were 160-190 mg/dl, about 10 to 15 mg/dl higher than 18 year olds. In white males beta-lipoprotein cholesterol increased (13 mg/dl) with age; however, there was a simultaneous decrease in alpha-lipoprotein cholesterol (11 mg/dl), resulting in a dramatic rise in the beta-LPC/alpha-LPC ratio. These adverse changes in LPC may be related to the early development of atherosclerosis and risk for coronary heart disease of young white men. Early identification of hypertension and hyperlipoproteinemia should help to predict and prevent future CV disease.