1. From the Departments of Neurology, Boston University School of Medicine, Boston, Mass (R.E.P., A.S.B., S.S., M.K-.H., C.S.K., P.A.W.) and Biostatistics (A.S.B.), Boston University School of Public Health, Boston, Mass; and the National Heart, Lung, and Blood Institute’s Framingham Heart Study (A.S.B., S.S., M.K-.H., C.S.K., P.A.W.), Framingham, Mass.