In this prospective study, the prevalence and incidence of coronary artery disease, hypertension, and other cardiovascular diseases were compared using standardized endpoint criteria. The prevalence of cardiovascular risk factors in midlife were compared between cohorts, and included smoking, diabetes, family history, dietary factors, and lipoprotein cholesterol levels. The youthful predictors of midlife cardiovascular risk factors were determined using baseline data collected by identical protocols in the two cohorts between 1957 and 1965. The youthful risk factors were related to the incidence of disease in midlife in two cohorts to identify differences in significance, independence, and relative importance of risk factors in Blacks versus whites.