A nested case-control study was conducted using the stored blood serum. Laboratory measurements were done blindly without knowledge of whether the specimen was from a case or a control. Insulin was measured in all 600 specimens. DHEAS was measured in 200 cases and 100 controls. The means and distribution of insulin or DHEAS levels were compared between cases and controls. The analysis was done separately for the coronary heart disease deaths and surviving myocardial infarction cases and, if there were no differences between the case groups, they were pooled for comparison with the controls. The relationships were determined among the potential confounders, coronary heart disease morbidity and mortality and serum insulin or DHEAS levels. This analysis also included data on baseline serum cholesterol, systolic and diastolic blood pressure, cigarette smoking, serum thiocyanate, HDL and LDL cholesterol, triglycerides, basal metabolic index, fasting and one-hour blood glucose. Alcohol intake, physical activity, pulmonary function, and education were also evaluated. The relationships among insulin or DHEAS and coronary heart disease morbidity and mortality were evaluated after adjusting for possible confounders.