1. Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine (M.A.M., H.P., S.O.L., P.J.S.), Philadelphia, Pennsylvania 19104;
2. Laboratory of Structural NMR Imaging, Department of Radiology (C.S.R., Y.A.B., F.W.W.), Philadelphia, Pennsylvania 19104;
3. Department of Biostatistics and Epidemiology (W.G.), Philadelphia, Pennsylvania 19104;
4. the Division of Gastroenterology, Hepatology, and Nutrition (B.S.Z.), The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104;
5. Division of Endocrinology and Metabolism (C.W., R.S.S.), Harbor-University of California at Los Angeles Medical Center and Los Angeles Biomedical Research Institute, Torrance, California 90509
6. the Clinical and Translational Research Center (S.C.K.), Raymond and Ruth Perelman School of Medicine, University of Pennsylvania,Philadelphia, Pennsylvania 19104;