1. Beth Israel Deaconess Medical Center Harvard Medical School Boston Massachusetts
2. The Johns Hopkins School of Medicine Department of Medicine, The Johns Hopkins Bloomberg School of Public Health Department of Epidemiology The Welch Center for Prevention, Epidemiology and Clinical Research, and Johns Hopkins Medical Institutions Baltimore Maryland
3. Department of Medicine and Center of Biostatistics University of Mississippi Medical Center Jackson Mississippi
4. Section of Cardiovascular Research, Department of Medicine Baylor College of Medicine and Houston Methodist DeBakey Heart and Vascular Center Houston Texas