¹KU Leuven, Department of Human Genetics, Laboratory of Complex Genetics, Leuven, Belgium, ²University of Ulsan College of Medicine, Department of Biochemistry and Molecular Biology, Seoul, South Korea, ³Asan Medical Center, University of Ulsan College of Medicine, Department of Gastroenterology and Inflammatory Bowel Disease Center, Seoul, South Korea

¹University of Edinburgh, Child Life and Health, Edinburgh, UK, ²Royal Hospital for Sick Children, Paediatric Gastroenterology and Nutrition, Edinburgh, UK, ³Royal Aberdeen Children's Hospital, Paediatric Gastroenterology and Nutrition, Aberdeen, UK, ⁴Royal Hospital for Children, Paediatric Gastroenterology and Nutrition, Glasgow, UK

¹St George's Healthcare NHS Trust, Gastroenterology, London, UK, ²Imperial College London, School of Public Health, London, UK, ³University College London, Epidemiology and Health Informatics, London, UK, ⁴Aarhus University, Biostatistics, Aarhus, Denmark, ⁵King's College London, Institute of Psychiatry, London, UK

¹Medical University of Vienna, Medicine III, Division Gastroenterology and Hepatology, Vienna, Austria, ²Danish Centre for eHealth and Epidemiology, Department of Gastroenterology, Frederikssund, Denmark

¹Western General Hospital, Gastroenterology, Edinburgh, UK, ²University of Edinburgh, Gastroenterology, Edinburgh, UK, ³Department of Paediatric Gastroenterology and Nutrition, Royal Hospital for Sick Children, Edinburgh, UK

¹Copenhagen University Hospital Hvidovre, Gastrounit, Medical Division, Copenhagen, Denmark, ²Bispebjerg and Frederiksberg Hospital, Center for Clinical Research and Prevention, Copenhagen, Denmark

¹Schneider Children's Medical Center of Israel Hospital for Children, Petah Tikva, Israel, ²Tel Aviv Sourasky Medical Center, Tel Aviv, Israel, ³Shaare Zedek Medical Center, The Juliet Keidan Institute of Paediatric Gastroenterology and Nutrition, Jerusalem, Israel, ⁴Shaare Zedek Medical Center, Jerusalem, Jerusalem, Israel, ⁵Meuhedet Health Services, Tel Aviv, Israel, Tel Aviv, Israel, ⁶Leumit Health Services, Tel Aviv, Israel, Tel Aviv, Israel, ⁷Maccabi Healthcare Services, Tel Aviv, Israel, Tel Aviv, Israel, ⁸Clalit Research Institute, Chief’s Office, Clalit Health Services, Tel Aviv, Israel, Tel Aviv, Israel

¹Oslo University Hospital, Ullevaal, Gastroenterology, Oslo, Norway, ²University of Oslo, Faculty of Medicine, Oslo, Norway, ³Oslo University Hospital, Rikshospitalet, Rheumatology, Oslo, Norway, ⁴OsloMet, Faculty of Public Health, Oslo, Norway

¹Institute of Technology Tralee, Department of Nursing and Healthcare Sciences, Tralee, Ireland, ²Cork University Hospital, Department of Gastroenterology, Cork, Ireland, ³Beaumont Hopsital, Department of Gastroenterology, Dublin, Ireland, ⁴Mercy University Hospital, Department of Gastroenterology, Cork, Ireland

¹Henry Dunant Hospital Centre, Athens, Greece, ²‘Evangelismos-Ophthalmiatreion Athinon-Polykliniki’ Hospital of Athens, Athens, Greece, ³General Hospital of Pafos, Pafos, Cyprus, ⁴National Kapodistrian University of Athens, Athens, Greece

¹Royal London Hospital, GI Medicine, London, UK, ²University College London Hosptial, GI Services, London, UK, ³St Marks Hospital, GI Medicine, London, UK, ⁴Royal London Hosptial, GI Medicine, London, UK

¹Institute of Technology Tralee, Department of Nursing and Healthcare Sciences, Tralee, Ireland, ²University College Cork, School of Nursing and Midwifery, Cork, Ireland, ³King's College London, Florence Nightingale Faculty of Nursing, Midwifery and Pallative Care, London, UK, ⁴Øsfold University College, Health Sciences, Halden, Norway

¹Sunshine Coast University Hospital, Gastroenterology, Birtinya Queensland, Australia

¹IBD clinic, Imelda general hospital, Department of gastroenterology, Bonheiden, Belgium, ²Awell Health, Brussel, Belgium

¹King's College London, Faculty of Nursing, Midwifery and Palliative Care, London, UK, ²King's College London, Health Psychology Section, London, UK

¹Northern Trust, Gastroenterology, Antrim, UK

¹Rabin Medical Center, IBD Center, Division of Gastroenterology, Petah-Tikva, Israel, ²Tel Aviv University, Sackler Faculty of Medicine, Tel Aviv, Israel

¹University of Greenwich, Faculty of Education and Health, London, UK, ²King's College London, Florence Nightingale Faculty of Nursing and Midwifery, London, UK, ³King's College London, Institute of Psychiatry, London, UK, ⁴PPI Team Lead, London, UK

¹University College Cork, School of Nursing and Midwifery, Cork, Ireland, ²Cork University Hospital, Gastroenterology/Hepatology, Cork, Ireland

¹University Hospital of Linköping, Gastroenterology and Hepatology, Linköping, Sweden