Affiliation: | 1. Department of Global Public Health and Primary Care, University of Bergen, , Bergen, Norway;2. Department of Pediatrics, Haukeland University Hospital, , Bergen, Norway;3. Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, , Durham, NC, USA;4. Medical Birth Registry of Norway, Norwegian Institute of Public Health, , Bergen, Norway;5. Department of Clinical Medicine, University of Bergen, , Bergen, Norway |