1. Division of Pediatric Endocrinology, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts 02114 , USA
2. Endocrine Unit, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts 02114 , USA
3. Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts 02114 , USA
4. Weight Center, Massachusetts General Hospital , Boston, Massachusetts 02114 , USA
5. Department of Surgery, Boston University Medical Center , Boston, Massachusetts 02118 , USA
6. Department of Pediatric Surgery, Children's Hospital Colorado , Aurora, Colorado 80045 , USA
7. Department of Pediatrics, University of Colorado School of Medicine , Aurora, Colorado 80045 , USA
8. Biostatistics Center, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts 02114 , USA
9. Department of Radiology, Massachusetts General Hospital and Harvard Medical School , Boston, Massachusetts 02114 , USA