1. Office of Dietary Supplements (C.T.S., E.A.Y., R.L.B., J.T.D., P.M.C., M.F.P.), National Institutes of Health, Bethesda, Maryland 20816;
2. Department of Preventive Medicine and Epidemiology (R.A.D.-A., G.C., H.K.), Loyola University Chicago Stritch School of Medicine, Maywood, Illinois 60153;
3. Bone Metabolism Laboratory (B.D.-H.), Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts 02111;
4. National Center for Health Statistics (A.C.L., V.B., X.Z., J.G.), Centers for Disease Control and Prevention, Hyattsville, Maryland 20782;
5. National Center for Environmental Health (R.L.S.), Centers for Disease Control and Prevention, Atlanta, Georgia 30341