1 Division of Respiratory Medicine, Institute of Clinical Medicine, School of Medicine, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland.
2 Center of Medicine and Clinical Research, Division of Respiratory Medicine, Kuopio University Hospital, Kuopio, Finland.
3 Research Unit of Internal Medicine, University of Oulu & Medical Research Center (MRC) Oulu, Oulu University Hospital, Oulu, Finland.