The present proposal is for continuation of a long-term serial study of levels of body fatness and its distribution as well as risk factors for cardiovascular disease. Measures of body fatness include anthropometry, underwater weighing, and dual energy X-ray absorptiometry. The risk factors for cardiovascular disease include blood pressure, cholesterol, triglycerides, high and low density lipoproteins, apolipoproteins, fasting glucose, insulin, and certain hormones. Important new serial data will be collected from over 800 juvenile and adult participants in the Fels Longitudinal Study to extend the serial records and collect additional variables. New and existing data from this unique study, which began in 1929, will be used to allow a better understanding of fat and fat-distribution in normal individuals. It will also allow a determination of which factors, in association with co-factors, predispose individuals as children and/or adults to high levels of body fatness, and to develop high levels of body fatness and risk for cardiovascular disease. There are three groups of specific aims for this project: 1) to study serial changes during childhood and adulthood in body composition, fat-related variables, and risk factors for cardiovascular disease and to study associations among patterns of change in these variables, 2) to examine associations among body composition, adipose tissue distribution risk factors for cardiovascular disease, and lifestyle variables, and 3) to develop, implement, and validate new methods for the study of body composition.