1. Department of Clinical Epidemiology, Aarhus University, Aarhus, Denmark;
2. Department of Surgery, Randers Regional Hospital, Randers, Denmark;
3. Center for Esophageal Diseases and Swallowing, Division of Gastroenterology and Hepatology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA;
4. Department of Epidemiology and Prevention, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA;
5. Gastroenterology Section, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA.