1. From Departments of Neurology (R.R.D., S.S., A.S.B., M.K.H., R.A., C.S.K., P.A.W.), Biostatistics (A.S.B., J.J.H.), Preventive Medicine (P.A.W.), Medicine (E.J.B.), and Mathematics (R.B.D.), Boston University, Boston, Mass; Department of Radiology (J.J.P.), Tufts University, Boston, Mass; The Framingham Heart Study and National Heart Lung and Blood Institute (S.S., A.S.B., M.K.H., R.A., C.S.K., E.J.B., C.J.O., R.B.D., P.A.W.), Framingham, Mass; and Department of Neurology (C.D., M.Y.), University of...