1. Departments of Otorhinolaryngology, Head and Neck Surgery; University of Helsinki; Helsinki University Hospital; Helsinki Finland
2. Department of Gastrointestinal Surgery; University of Helsinki; Helsinki University Hospital; Helsinki Finland
3. Division of Ear Nose and Throat Diseases; Department of Clinical Sciences, Intervention and Technology; Karolinska Institute and Karolinska Hospital; Stockholm Sweden
4. Department of Biosciences and Nutrition; Karolinska Institutet; Stockholm Sweden