1. Department of Surgery, St Joseph Mercy Ann Arbor, Ann Arbor, Michigan
2. Department of Surgery, East Carolina University, Greenville, North Carolina
3. Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill
4. Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill
5. Department of Surgery, University of Virginia, Charlottesville
6. Department of Surgery, Wake Forest Baptist Health, Winston-Salem, North Carolina