1 Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA; New Hampshire Colonoscopy Registry, Lebanon, New Hampshire, USA.
2 Department of Gastroenterology and Hepatology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA; New Hampshire Colonoscopy Registry, Lebanon, New Hampshire, USA.
3 Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA; Department of Gastroenterology and Hepatology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA; New Hampshire Colonoscopy Registry, Lebanon, New Hampshire, USA.