1. From Boston University, Department of Mathematics and Statistics (R.B.D., M.J.P.), School of Medicine (R.S.V., P.A.W., W.B.K.), and Department of Biostatistics (J.M.M.), Boston, Mass; Framingham Heart Study, Framingham, Mass (R.B.D., R.S.V., M.J.P., P.A.W., J.M.M., W.B.K.); and Unilever Research, Corporate Biology, Colworth Park, UK (M.C.).