1. Research Unit of Biomedicine and Internal Medicine, University of Oulu, Oulu, Finland
2. Center of Internal and Respiratory Medicine and Medical Research Center (MRC) Oulu, Oulu University Hospital, Oulu, Finland
3. Center of Medicine and Clinical Research, Division of Respiratory Medicine, Kuopio University Hospital, Kuopio, Finland
4. Division of Respiratory Medicine, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
5. Heart and Lung Center, Helsinki University Hospital, Helsinki, Finland
6. Social Insurance Institution of Finland, Helsinki, Finland
7. Department of Respiratory Medicine, Tampere University Hospital, Tampere, Finland
8. Division of Medicine, Department of Pulmonary Diseases, Turku University Hospital, Turku, Finland
9. Department of Pulmonary Diseases and Clinical Allergology, University of Turku, Turku, Finland