1. Division of Community Medicine Department of Medical and Health Sciences Faculty of Health Sciences Linköping University Pain and Rehabilitation Center Anaesthetics, Operations and Speciality Surgery Center Region Östergötland Linkoping Sweden
2. Occupational and Environmental Medicine Div of Neuro and Inflammation Science, Department of Clinical and Experimental Medicine Linköping University Linköping Sweden
3. Clinic of Otorhinolaryngology County Hospital Ryhov Jönköping Sweden
4. Division of Neuro and Inflammation Science Department of Clinical and Experimental Medicine Linköping University Occupational and Environmental Medicine Center Heart and Medicine Center Region Östergötland Linkoping Sweden
5. Department of Occupational and Environmental Medicine Faculty of Medicine and Health Örebro University Örebro Sweden