1. Department of Medicine, Division of Endocrinology, Metabolism, and Molecular Medicine (F.M.-J.), and Comprehensive Center on Obesity (F.M.-J.), Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611;
2. Department of Internal Medicine (D.J.C.), University of Texas Southwestern Medical Center, Dallas, Texas 75390;
3. Department of Medicine (A.L.H.), Division of Endocrinology, Diabetes and Hypertension, David Geffen School of Medicine, University of California, Los Angeles, California 90095