1. Department of General Medicine, Juntendo University Faculty of Medicine, Tokyo, Japan
2. Department of General Medicine, Juntendo Tokyo Koto Geriatric Medical Center, Tokyo, Japan
3. General Medicine Center, Shimane University Hospital, Izumo, Japan
4. Division of Respiratory Medicine, Juntendo Tokyo Koto Geriatric Medical Center, Tokyo, Japan
5. Department of Psychiatry, Juntendo Tokyo Koto Geriatric Medical Center, Tokyo, Japan