1. Department of Otorhinolaryngology-Head and Neck Surgery, Korea Cancer Center Hospital, Seoul, Korea.
2. Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
3. Department of Internal Medicine, Healthcare Research Institute, Seoul National University Hospital Healthcare System Gangnam Center, Seoul National University College of Medicine, Seoul, Korea.
4. Department of Internal Medicine, Kangwon National University School of Medicine, Chuncheon, Korea.