1. Department of Gastroenterology and Hepatology; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands
2. Department of Otorhinolaryngology - Head and Neck Surgery; University Medical Center Utrecht; Utrecht The Netherlands
3. Department of Gastroenterology and Hepatology; Erasmus MC University Medical Center; Rotterdam The Netherlands
4. Department of Epidemiology and Biostatistics; Academic Medical Center; University of Amsterdam; Amsterdam The Netherlands