1. Paediatric Clinic II, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
2. Department of Biostatistics, University of Copenhagen, Copenhagen Denmark
3. Institute of Public Health, University of Southern Denmark, Odense, Denmark
4. State Social Services Agency, Department for Healthcare, Kiel, Germany
5. Department of Occupational Medicine and Public Health, Tórshavn, Faroe Islands
6. Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA