1. Paediatric Department, Ostfold Hospital Trust, Grålum, Norway
2. NICU, Clinic of Pediatric and Adolescent Medicine
3. Neonatal Clinical and Epidemiological Research Group, Oslo University Hospital, Oslo, Norway
4. Institute of Clinical Medicine
5. Paediatric Research Group, Faculty of Health Sciences, University of Tromsø-The Arctic University of Norway, Tromsø, Norway
6. Department of Paediatrics, University Hospital of North Norway, Tromsø, Norway
7. Pediatric Research Institute, Faculty of Medicine, University of Oslo, Oslo, Norway