1 Division of General Surgery, McMaster University, Hamilton, Ontario, Canada; Harvard T.H. Chan School of Public Health, Harvard University, Boston, Massachusetts.
2 Department of Surgery, Brigham and Women's Hospital, Boston, Massachusetts.
3 Division of General Surgery, McMaster University, Hamilton, Ontario, Canada.
4 Division of Vascular Surgery, University of Toronto, Toronto, Ontario, Canada.
5 Division of General Surgery, Duke University, Durham, North Carolina.
6 Digestive Disease Institute, Cleveland Clinic, Cleveland, Ohio.