1. Department of Otorhinolaryngology/Head and Neck Surgery; University of Groningen; University Medical Center Groningen; Groningen The Netherlands
2. Graduate School of Medical Sciences (Groningen University Institute for Drug Exploration); University of Groningen; The Netherlands
3. Department of Pathology; University of Groningen; University Medical Center Groningen; Groningen The Netherlands
4. Department of Epidemiology; University of Groningen, University Medical Center Groningen; Groningen The Netherlands