1. Department of Otolaryngology, Cathay General Hospital, Taipei; Fu Jen Catholic University School of Medicine, Taipei; and the Department of Public Health, China Medical University, Taichung, Taiwan (Dr Wang)
2. Department of Otolaryngology, Chang Gung Memorial Hospital and Chang Gung Institute of Technology, Taoyuan, Taiwan (Dr Li)
3. Institute of Occupational Safety and Health, Taipei and the Graduate Institute of Environmental Health, College of Public Health, China Medical University, Taichung, Taiwan (Dr Shih)
4. Department of Otolaryngology, Massachusetts Eye and Ear Infirmary and Department of Otology and Laryngology, Harvard Medical School, Boston, Massachusetts (Dr Gliklich)
5. Sleep Center, Department of Craniofacial Orthodontics and Faculty of Dentistry, Chang Gung Memorial Hospital, Taoyuan, Taiwan (Dr Liao).