1. Department of Surgical Sciences, Otorhinolaryngology, Head and Neck Surgery, Uppsala University, Uppsala, Sweden
2. Division of Ear, Nose and Throat Diseases, Department of Clinical Sciences, Intervention and Technology, Karolinska University Hospital, Huddinge, Sweden
3. Department of Otorhinolaryngology, Head and Neck Surgery, Sahlgrenska Academy, Gothenburg, Institute of Clinical Science, University of Gothenburg, Sweden
4. Department of Surgical and Perioperative Sciences, Surgery, Umeå University, Umeå, Sweden
5. Department of Respiratory Medicine and Sleep, University of Iceland, Reykjavik, Iceland
6. Department of Occupational and Environmental Medicine, University of Gothenburg, Gothenburg, Sweden
7. Department of Global Public Health and Primary Care, Centre for International Health, University of Bergen, Bergen, Norway
8. Department of Occupational Medicine, Haukeland University Hospital, Bergen, Norway
9. Department of Pulmonology, Tartu University Hospital, Tartu, Estonia
10. Department of Public Health, Aarhus University, Aarhus, Denmark, National Research Centre for the Working Environment, Copenhagen, Denmark
11. Department of Medical Sciences, Respiratory, Allergy and Sleep Research, Uppsala University, Uppsala, Sweden