1. Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
2. Department of Epidemiology, Merck Research Laboratories, Rahway, New Jersey
3. Department of Medicine, Johns Hopkins University School of Medicine and Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland
4. Graduate Studies Program in Epidemiology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
5. Department of Medicine, University of Mississippi Medical Center, Jackson, Mississippi
6. Methodist DeBakey Heart Center and Department of Medicine, Baylor College of Medicine, Houston, Texas