1. From the Division of General Internal Medicine (S.T.C., N.M.M., L.J.A.), The Johns Hopkins University School of Medicine, Baltimore, Md; Welch Center for Prevention, Epidemiology, and Clinical Research (L.J.A.), The Johns Hopkins University School of Medicine, Baltimore, Md; and the Department of Epidemiology (L.J.A.), The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Md.