Data collected on the ARIC cohort at baseline included: a clinical history, a physical examination including blood pressure, height, weight, and anthropometry. A second history and physical examination were performed after three years, and annual telephone interviews were conducted in the intervening years. Laboratory studies at baseline and at three years included: electrocardiogram, pulmonary function tests, ultrasonographic examination of both carotids and one popliteal artery for direct visualization of the atherosclerotic process in peripheral large vessels, and numerous blood studies. Certain hemostatic and lipid tests were performed only in 'cases' with ultrasonographically determined carotid atherosclerosis and matched normal 'controls.'