1. Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
2. Department of Epidemiology, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, Pennsylvania
3. Department of Epidemiology, Biostatistics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania
4. Columbia University, New York, New York
5. Department of Surgery, University of Washington, Seattle
6. University of North Dakota, Neuropsychiatric Research Institute, Grand Forks
7. National Institute of Diabetes and Digestive and Kidney Diseases, New York, New York
8. Neuropsychiatric Research Institute, Fargo, North Dakota
9. Weill Cornell Medical College, New York, New York
10. Department of Surgery, Brody School of Medicine, Greenville, North Carolina
11. Department of Medicine, Oregon Health and Science University, Portland
12. Department of Surgery, Oregon Health and Science University, Portland
13. National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland