1. HUNT Research Centre, Department of Public Health and Nursing, Faculty of Medicine and Health Sciences Norwegian University of Science and Technology, NTNU Levanger Norway
2. Department of Medicine and Rehabilitation Levanger Hospital, Nord‐Trøndelag Hospital Trust Levanger Norway
3. Clinic of Thoracic and Occupational Medicine, St. Olav's Hospital Trondheim University Hospital Trondheim Norway
4. K.G. Jebsen Centre for Genetic Epidemiology, Department of Public Health and Nursing, Faculty of Medicine and Health Sciences Norwegian University of Science and Technology, NTNU Trondheim Norway
5. MRC Integrative Epidemiology Unit University of Bristol Bristol UK
6. Department of Public Health and Nursing, Faculty of Medicine and Health Sciences Norwegian University of Science and Technology, NTNU Trondheim Norway
7. Department of Clinical and Molecular Medicine Norwegian University of Science and Technology Trondheim Norway
8. COPD Centre, Sahlgrenska University, Hospital and Institute of Medicine Gothenburg University Gothenburg Sweden