1. Department of Epidemiology, University of North Carolina, Chapel Hill, North Carolina
2. Department of Medicine, University of North Carolina, Chapel Hill, North Carolina
3. Department of Medicine, University of Washington, Seattle, Washington
4. Epidemiologic Research and Information Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington
5. Department of Public Health Sciences, Wake Forest University, Winston-Salem, North Carolina
6. Department of Biostatistics, University of Michigan, Ann Arbor, Michigan
7. Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina
8. Kaiser Permanente, Portland, Oregon
9. Department of Epidemiology, University of Washington, Seattle, Washington