This study has three central aims, all building upon our previous work in which we have assembled one of the most complete existing data sets tracking a black population from birth through childhood, and then adolescence and into young adulthood. The aims are: 1) to continue and undertake analyses aimed principally at tracking blood pressure (BP) and to perform longitudinal studies through periods of growth and development 2) to conduct a cycle of examinations to characterize cardiovascular disease risk factors more completely and estimate intrapopulation variability in our young black adults, and 3) to undertake stratified cross-sectional and longitudinal analyses of BP and its concomitants in young adulthood, using patterns of known risk factors and measures of intrapopulation variability. In previous studies, we have follwed: 1) samples totalling over 1000 black adolescents, originally ages 11-15 years, who were drawn from the Philadelphia Collaborative Perinatal Project population, longitudinally for three years (1976-1979), and 2) a sample of over 650 of these adolescents, at ages 17-21 years, for three years in young adulthood. The proposed additional examination will include measures not ascertained previously, and continue the basic assessment of BP status, body size and composition. We will measure, as correlates and risk factors for elevated BP, serum lipids, uric acid, and dehydroepiandrosterone sulfate. We will determine the intrapopulation genetic and phenotypic variability, using erythrocyte (glucose-6-phosphate dehydrogenase activity and variants), blood group markers and skin reflectance, because of their potential association with BP variation and risk for elevated BP. Following the examination cycle, we will undertake analyses in two areas. One will relate BP variation to patterns of known cardiovascular disease risk factors, including serum lipids and uric acid, and indices of body size and composition. The second will relate intrapopulation genetic variability (blood group markers, skin reflectance, and presence of red blood cell variants) to BP variation, BP tracking, and the interactions among BP and body size, proportion, and composition.