1. Department of Gastroenterology and Hepatology Nagasaki University Graduate School of Biomedical Sciences Nagasaki Japan
2. Department of Otolaryngology‐Head and Neck Surgery Nagasaki University Graduate School of Biomedical Sciences Nagasaki Japan
3. Department of Histology and Cell Biology Nagasaki University Graduate School of Biomedical Sciences Nagasaki Japan
4. Medical Education Development Center Nagasaki University Hospital Nagasaki Japan
5. Department of Rehabilitation Medicine Nagasaki University Hospital Nagasaki Japan
6. Biostatistics Section, Division of Scientific Data Registry, Atomic Bomb Disease Institute Nagasaki University Nagasaki Japan