1. Department of PediatricsStavanger University Hospital Stavanger Norway
2. Department of Clinical ScienceUniversity of Bergen Norway
3. Department of Research, Section of BiostatisticsStavanger University Hospital Stavanger Norway
4. Department of Chronic Diseases and Aging, Division of Mental and Physical HealthNorwegian Institute of Public Health Oslo Norway
5. Centre for Clinical ResearchHaukeland University Hospital Bergen Norway
6. Department of Global Public Health and Primary CareUniversity of Bergen Bergen Norway
7. Centre for Fertility and HealthNorwegian Institute of Public Health Oslo Norway
8. MRC Integrative Epidemiology UnitUniversity of Bristol Bristol UK
9. Population Health SciencesBristol Medical School Bristol UK