1. Department of Epidemiology & Prevention, Wake Forest School of Medicine, Winston-Salem, North Carolina
2. Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
3. Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
4. Department of Medicine, University of California San Diego, La Jolla, California
5. Department of Family Medicine and Public Health, University of California San Diego, La Jolla, California