1. Department of Pharmacology and Therapeutics, Faculty of Medicine of the University of Porto, Porto, Portugal
2. Gastroenterology Department, Instituto Português de Oncologia de Lisboa, Lisboa, Portugal
3. Gastroenterology Department, Centro Hospitalar do Porto, Porto, Portugal
4. Department of Pediatrics, Centro Hospitalar São João, Porto, Portugal
5. Department of Gastroenterology and Hepatology, Hospital de Santa Maria, University of Lisbon, Lisbon, Portugal
6. Department of Community Medicine, Faculty of Medicine of the University of Porto, Porto, Portugal, and Centre for Health Technology and Services Research, Porto, Portugal
7. Department of Gastroenterology, Faculty of Medicine, Centro Hospitalar São João, Porto, Portugal