1. Division of Cardiology, Department of Internal Medicine, College of Medicine, Hanyang University, Seoul, Korea
2. Department of Otorhinolaryngology–Head and Neck Surgery, College of Medicine, Hanyang University, Seoul, Korea
3. Department of Dentistry, College of Medicine, Hanyang University, Seoul, Korea
4. Department of Occupational and Environmental Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea