1. Department of Occupational and Environmental Health, Epidemiology, Bavarian Health and Food Safety Authority, Munich, Germany;
2. Institute for Medical Informatics, Biometry and Epidemiology, Ludwig-Maximilians-University, Munich, Germany;
3. Centre for Early Cancer Detection and Cancer Registration, Bavarian Health and Food Safety Authority, Nuremberg, Germany;
4. Department of Otorhinolaryngology, University Hospital Regensburg, Regensburg, Germany;
5. Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, Clinical Centre of the Ludwig-Maximilians-University, Munich, Germany