1. School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
2. Clinical Epidemiology and Biostatistics, Örebro University, Örebro, Sweden
3. Clinical Epidemiology Division, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
4. Department of Epidemiology and Public Health, University College, London, UK
5. Department of Public Health and Caring Sciences, Family Medicine and Preventive Medicine, Uppsala University, Uppsala, Sweden
6. Department of Medical Sciences, Respiratory, Allergy and Sleep Research, Uppsala University, Uppsala, Sweden
7. Department of Respiratory Medicine, School of Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden