1. Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
2. Respiratory Research unit, Department of Respiratory Medicine, Bispebjerg Hospital, Copenhagen, Denmark
3. Department of Respiratory Medicine, Hvidovre Hospital, Hvidovre, Denmark
4. Dept of Respiratory Medicine, Aarhus University Hospital, Aarhus C, Denmark
5. LHL-klinikkene Bergen, Nesttun, Norway
6. Department of Clinical Science, University of Bergen, Bergen, Norway
7. Department of Thoracic Medicine, Haukeland University Hospital, Bergen, Norway
8. Department of Medical Sciences: Respiratory, Allergy & Sleep Research, Uppsala University, Uppsala, Sweden
9. Department of Public Health and Clinical Medicine, Division of Medicine, Umeå University, Umeå, Sweden
10. Department of Respiratory Medicine & Allergology, Skåne University Hospital, Lund, Sweden
11. Division of Respiratory Medicine and Allergy, Karolinska University Hospital, Stockholm, Sweden
12. Institute of Medicine/Krefting Research Centre University of Gothenburg, Gothenburg, Sweden
13. Dept. of Allergy, Respiratory Medicine and Sleep Landspitali University Hospital Reykjavik Iceland, University of Iceland, Reykjavik, Iceland
14. Faculty of Medicine, University of Iceland, Reykjavik, Iceland
15. Department of Pulmonary Medicine, University of Tartu and Department of Pulmponary Medicine, Tartu University Hospital, Tartu, Estonia
16. Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland
17. Allergy Centre, Tampere University Hospital, Tampere, Finland
18. Department of Allergy, Respiratory Diseases and Allergology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
19. Department of Respiratory Medicine, Seinäjoki Central Hospital, Seinäjoki, Finland