The study was longitudinal in design. Physical examinations were conducted at baseline and information collected on behavioral risk factors, medical history, and medications. Evaluations included a maximal exercise tolerance test, four day supervised food recordings, a broad set of hematological and chemical tests from fasting venous blood and two 24-hour urine samples. Holter monitoring and ultrasonography of the carotid arteries were performed in Cohort II only. Psychosocial measures included social support and network participation, socioeconomic status, job strain, Type A behavior pattern, and John Henryism. All members of Cohort II were re-examined three years post-baseline. Cohort I members were not re-examined because they did not undergo Holter monitoring and ultrasonography. Prevalence and ischemic heart disease incidence analyses were performed using both cohorts. Baseline psychosocial factors were examined in relation to study endpoints which included extent of carotid atherosclerosis, presence of ischemia on exercise, presence of arrhythmias, tendency toward blood clotting, four year progression of atherosclerosis, and incidence of fatal and non-fatal ischemic heart disease.