1. the Departments of Nutrition, Epidemiology, and Biostatistics (G.C.C., W.C.W., D.S., G.A.C., J.E.M., M.J.S.), Harvard School of Public Health; the Channing Laboratory (G.C.C., W.C.W., G.A.C., J.E.M., F.E.S., M.J.S.), Division of Preventive Medicine (J.E.M.), and the Renal Division (G.C.C., G.M.C.), Department of Medicine, Brigham and Women's Hospital; the Renal Section (G.C.C., G.M.C.), Medical Service, Brockton/West Roxbury Veterans Affairs Medical Center; and Harvard Medical School, Boston, Mass.