1. Department of Respiratory Medicine and Allergology, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden;
2. COPD Center Sahlgrenska University Hospital, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden;
3. Department of Public Health and Caring Sciences, Family Medicine and Preventive Medicine Section, Uppsala University, Uppsala, Sweden