1. Department of Pulmonary Medicine, Gentofte Hospital, Hellerup, Denmark
2. Respiratory Research Unit Zealand, Department of Respiratory Medicine, Naestved Hospital, Naestved, Denmark
3. Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
4. Department of Pulmonary Medicine, Hospital of Roskilde, Roskilde, Denmark
5. Department of Respiratory Medicine, University Hospital of Copenhagen, Bispebjerg Bakke, Denmark
6. Department of Respiratory Medicine, Hvidovre Hospital, Kettegård Alle, Denmark