CARDIA, which began recruitment in 1985, has completed 7 examinations over 20 years in a cohort of 5,115 men and women aged 18-30 years in four communities. Participants were initially sampled from the total population, selected census tracts or, in the case of one center, the membership of a large health plan. The original cohort had approximately equal representation by blacks and whites, men and women, those aged 18-24 and 25-30, and those with no more than a high school education and more than a high school education. The baseline examination (Year 0) was conducted over a 14-month period during 1985-86. The examination consisted of questionnaires on sociodemographic characteristics, health behaviors, and psychological factors; an exercise treadmill test; resting electrocardiography; a diet history assessment; anthropometry; pulmonary function testing; and resting blood pressure. Fasting blood measurements included total cholesterol and its subfractions, insulin, glucose, liver enzymes and other serum chemistry measurements, and hematology.