Affiliation: | 1. Department of Clinical Science, University of Bergen, Bergen, Norway;2. Department of Paediatrics, Landspítalinn University Hospital, Reykjavik, Iceland Faculty of Medicine, University of Iceland, Reykjavik, Iceland;3. Environment and Health/Youth health Care, Department of Public Health and Primary Care, University of Leuven, KU Leuven, Belgium;4. Department of Paediatrics, Landspítalinn University Hospital, Reykjavik, Iceland |