1. From the Stroke Program (L.D.L., D.L.B., M.A.S., N.M.G., L.B.M.), University of Michigan Medical School, Ann Arbor, Mich.; the Stroke Program (J.K.I.), University of Texas Medical School at Houston; the Department of Epidemiology (J.M.H.R.), University of Texas School of Public Health at Houston; and the Department of Epidemiology (L.B.M.), University of Michigan School of Public Health, Ann Arbor, Mich.