1. From the Epidemiology, Demography, and Biometry Program, National Institute on Aging, Bethesda, Md (S.V., J.M.G., L.F., J.B., T.B.H.); the Geriatric Department, I Fraticini, Italian National Institute for Research and Care on Aging (INRCA), Florence, Italy (L.F.); and the Departments of Medicine and Epidemiology, The Johns Hopkins Medical Institutions, Baltimore, Md (P.C., L.P.F.).