1. Department of Medicine and Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina
2. Departments of Medicine and Epidemiology, Johns Hopkins University, Baltimore, Maryland
3. Division of Epidemiology and Community Health, University of Minnesota, Minneapolis
4. Department of Medicine, University of Mississippi Medical Center, Jackson
5. Departments of Medicine and Epidemiology, University of North Carolina at Chapel Hill
6. National Heart, Lung, and Blood Institute, Bethesda, Maryland