Funding for this research was provided by:
Ministry of Health, Labour and Welfare (Gan-taisaku-ippan-012)
Received: 19 March 2020
Accepted: 5 January 2021
First Online: 14 January 2021
Ethics approval and consent to participate
: This study was approved by the Juntendo University Ethics Review Committee (Approval No. 2018042). The medical ethics committee of Juntendo University informed us that informed consent was not required because the previously existing data were anonymous and impossible to concatenate; therefore, no associated correspondence table is provided, in accordance with national guidelines [CitationRef removed].
: Not applicable.
: The authors declare that they have no conflicts of interest.