1. Department of Clinical Sciences and Community Health; Universitá degli Studi di Milano; Milan 20133 Italy
2. Department of Epidemiology; IRCCS-Istituto di Ricerche Farmacologiche ‘Mario Negri’; Milan 20156 Italy
3. Department of Otorhinolaryngology; Head and Neck Surgery, Nagoya City University, Graduate School of Medical Sciences; Nagoya Japan
4. Division of Molecular Medicine; Aichi Cancer Center Research Institute; Nagoya Japan
5. Department of Otorhinolaryngology; School of Medicine and Surgery, University of Milano-Bicocca; Milan Italy