Peoples Gas Company: All data on the two cohorts were collected as part of the periodic medical examination program for all employees in the Medical Department of the Company by its full-time staff of physicians. Data were collected on age, race, height, weight, blood pressure, serum cholesterol, smoking history, heart rate, resting ECG, medical and family history, alcohol and coffee and tea consumption, education, military service, occupation, physical activity, diet, and glucose and serum uric acid levels. Repeat exams were scheduled yearly for men 50-59, every two years for men 40-49, and every four years for men 25-39.