1. Department of Epidemiology UCLA Fielding School of Public Health Los Angeles California USA
2. Program in Epidemiology, Division of Public Health Sciences Fred Hutchinson Cancer Center Seattle Washington USA
3. Department of Head and Neck Surgery, Division of Surgery University of Texas M. D. Anderson Cancer Center Houston Texas USA
4. Division of Public Health, Department of Family and Preventive Medicine University of Utah School of Medicine, and Huntsman Cancer Institute Salt Lake City Utah USA
5. Departments of Epidemiology and Environmental Health Sciences, School of Public Health and Department of Urology, Medical School University of Michigan Ann Arbor Michigan USA
6. Department of Otolaryngology‐Head and Neck Surgery Baylor College of Medicine Houston Texas USA
7. Stony Brook Cancer Center, Department of Family, Population and Preventive Medicine Stony Brook University Stony Brook New York USA
8. Department of Medical and Surgical Sciences University of Bologna Bologna Italy