1. Department of Veterans Affairs Medical Center, White River Junction, VT and the Geisel School of Medicine at Dartmouth, Hanover, NH, USA
2. Division of Gastroenterology and Hepatology, University of Connecticut School of Medicine, Farmington, CT, USA
3. New Hampshire Colonoscopy Registry, Lebanon, NH, USA
4. Medicine, Geisel School of Medicine at Dartmouth, Hanover, NH, USA