1. National Heart, Lung, and Blood Institute's Framingham Heart Study; 73 Mount Wayte Avenue, Suite 2 Framingham MA USA
2. Division of Cardiology; Dartmouth Hitchcock Medical Center; Lebanon NH USA
3. Harvard School of Public Health; Boston MA USA
4. Department of Mathematics; Boston University; Boston MA USA
5. Cardiology Section (EJB, RSV), and the Department of Preventive Medicine and Epidemiology; Boston University School of Medicine; Boston MA USA
6. Division of Cardiology, Massachusetts General Hospital; Harvard Medical School; Boston MA USA
7. Veterans Affairs Hospital; West Roxbury MA USA