1. Inflammatory Bowel Disease Center, Department of Gastroenterology and Hepatology, University Medical Center Utrecht, Utrecht, the Netherlands
2. Inflammatory Bowel Disease Center, Department of Gastroenterology and Hepatology, Radboud University Medical Center, Nijmegen, the Netherlands
3. Department of Medical Psychology, Leiden University Medical Center, Leiden, the Netherlands
4. Department of Gastroenterology, Division of Medicine, University of Edmonton, Alberta, Canada
5. Department of Gastroenterology and Hepatology, Elisabeth-TweeSteden Hospital, Tilburg, the Netherlands