1. Institute of Public Health, University of Southern Denmark, Odense, Denmark
2. Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA
3. Laboratory for Medical Allergology, Allergy Clinic and
4. Paediatric Clinic II, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
5. Department of Occupational Medicine and Public Health, Tórshavn, Faroe Islands