Received: 13 February 2020
Accepted: 12 August 2020
First Online: 28 August 2020
Ethics approval and consent to participate
: The study protocol was approved by the Ethics Committee of Tokyo Metropolitan Institute of Gerontology (Approval No. 28; October 16, 2015). The committee waived the need for informed consent due to the use of anonymized claims data.
: Not applicable.
: The authors declare that they have no competing interests.