The Follow-up Study, initiated in 1977, was designed to relate the baseline observation made in 1972-1976 to total and cause-specific mortality. The study assessed the risk factor status of plasma triglycerides, HDL cholesterol and exercise electrocardiography for cardiovascular disease mortality in general, and coronary heart disease in particular. Follow-up baseline measurements included lipid and other clinical chemistries, one-day dietary recalls, medication histories and physical examinations. Assessments were also made of the relationships of estrogen use in women to subsequent cardiovascular disease, coronary heart disease, and cancer mortality and of the relationships of lipids and lipoprotein levels to site-specific cancer, as well as the relationship of retinol levels to cancer mortality.