1. Department of Public Health and Clinical Medicine, Epidemiology and Global Health Umeå University Umeå Sweden
2. Department of Public Health and Clinical Medicine, Family Medicine Umeå University Umeå Sweden
3. Department of Paediatrics and Department of Clinical and Experimental Medicine Linköping University Norrköping Sweden
4. Department of Clinical Science and Education Karolinska Institutet and Paediatric Clinic Södersjukhuset Stockholm Sweden
5. Department of Paediatrics Uppsala University Hospital Uppsala Sweden
6. Department of Paediatrics Centre for Clinical Research Västmanland Hospital, Västerås and Karolinska Institutet Stockholm Sweden
7. Department of Paediatric Gastroenterology Queen Silvia Children′s Hospital Sahlgrenska University Hospital Gothenburg Sweden