1. Department of Respiratory Medicine and Infectious Diseases, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan;
2. Department of Otolaryngology Head and Neck Surgery, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan;
3. Division of Respiratory Medicine, Department of Internal Medicine, Nihon University of Medicine, Tokyo, Japan;
4. Department of General Medicine, Niigata University Medical and Dental Hospital, Japan, Niigata