1. From the National Heart, Lung, and Blood Institute’s Framingham (Mass) Heart Study (all authors); the Divisions of Cardiology and Clinical Epidemiology, Beth Israel Hospital, Harvard Medical School, Boston, Mass (D.L.); the Cardiology Section (E.J.B.) and Department of Preventive Medicine and Epidemiology (R.S.V., M.G.L., D.L., E.J.B.), Boston (Mass) University School of Medicine; and the National Heart, Lung, and Blood Institute, Bethesda, Md (D.L.).