1. Division of Cardiology, Johns Hopkins School of Medicine, Baltimore, Maryland.
2. Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
3. Division of General Internal Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland.
4. Section on Cardiovascular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina.
5. David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California.