1. Department of Biosciences and Nutrition; Karolinska Institutet; Stockholm Sweden
2. Department of Otorhinolaryngology - Head and Neck Surgery; University of Helsinki and Helsinki University Hospital; Helsinki Finland
3. Department of Medical Epidemiology and Biostatistics; Karolinska Institutet; Stockholm Sweden
4. Department of Occupational and Environmental Medicine; School of Medicine, Ewha Womans University; Seoul South Korea
5. Division of Ear, Nose and Throat Diseases, Department of Clinical Sciences; Intervention and Technology, Karolinska Institutet and Karolinska University Hospital; Stockholm Sweden
6. Department of Surgery; University of California at San Francisco (UCSF); San Francisco CA