1. Loyola University Chicago Stritch School of Medicine, Department of Preventive Medicine and Epidemiology, Maywood, IL 60153
2. Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Bone Metabolism Laboratory, Boston, MA 02111
3. National Institutes of Health, Office of Dietary Supplements, Bethesda, MD 20816
4. Centers for Disease Control and Prevention, National Center for Health Statistics, Hyattsville, MD 20782
5. Iowa State University, Department of Statistics, Ames, IA 50011