1. From the School of Public Health and School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC (KH and EM-D); the Feinberg School of Medicine, Northwestern University, Chicago, IL (KL and MLD); the University of Vermont College of Medicine, Colchester, VT (NSJ); the Columbia University Medical Center, New York, NY (RJ and RGB); the Johns Hopkins University School of Medicin