1. From Framingham Heart Study, National Heart, Lung, and Blood Institute, Framingham, Mass (K.A.P., M.G.L., J.C.E., P.A.S., P.W.F.W., D.L.); Institute for the Prevention of Cardiovascular Disease, Cardiovascular Division, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Mass (K.A.P., G.H.T., I.L., M.A.M., J.E.M.); National Heart, Lung and Blood Institute, Bethesda, Md (P.W.F.W., D.L.); and Department of Mathematics, Boston University, Boston, Mass (M.G.L., J.C.E., P.A.S., R.B.D.).