Article History
Received: 14 August 2020
Accepted: 16 December 2020
First Online: 7 January 2021
Ethics approval and consent to participate
: Ethical approval for the study was granted by the ethics committee of the Tokyo Metropolitan Institute of Gerontology (Acceptance no. 4, 2018). No administrative permissions or licenses were required to utilize the survey data in our research. The local government provided the data on the basis of research consent.
: Not applicable.
: The authors declare that they have no competing interests.