1. From the Channing Laboratory (J.P.F., H.A.B.-F., W.C.W., M.J.S., G.C.C.), Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Renal Division (J.P.F., G.C.C.), Brigham and Women’s Hospital, Departments of Epidemiology (J.P.F., H.A.B.-F., W.C.W., G.C.C.) and Nutrition (W.C.W., M.J.S.), Harvard School of Public Health, Boston, Mass.