1. Jackson Heart Study, University of Mississippi Medical Center, Jackson State University, Jackson, Mississippi;
2. National Heart, Lung, and Blood Institute's Framingham Heart Study and Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts;
3. Department of Preventive Medicine, University of Mississippi Medical Center, Jackson State University, Jackson, Mississippi;
4. Department of Cardiology and Radiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina.