Investigators have examined the consistency of blood pressure levels in children to determine whether "tracking" occurs into the teenage years. The results of these studies have raised other interesting and important questions. Is there evidence for "tracking" of other coronary risk factors? Does "tracking" persist into young adult life, a time during which dramatic changes in life style are often taking place? The study will contribute to our understanding of the development of atherosclerosis and will help to determine an optimal strategy for prevention before individual life style patterns become well established. The Working Group on Heart Disease Epidemiology in 1978 recommended the study with highest priority. The study was approved by the National Heart, Lung, and Blood Advisory Council in November 1982. The Request for Proposals was released in December 1982.