1. Cardiology Division, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston (M.N., K.J.B.).
2. Sections of Preventive Medicine & Epidemiology, and Cardiology, Department of Medicine, Boston University School of Medicine, MA (R.S.V.).
3. Department of Epidemiology, Boston University School of Public Health; Boston University Center for Computing and Data Sciences (R.S.V.).