Funding for this research was provided by:
Ministry of Health, Labour and Welfare (H29-Policy-Designated-009 and H29-ICT-General-004)
Ministry of Education, Culture, Sports, Science and Technology, Japan (17H04141 and 16K09254)
Japan Agency for Medical Research and Development
Received: 31 August 2019
Accepted: 9 December 2019
First Online: 13 January 2020
Ethics approval and consent to participate
: The study was approved by the Institutional Review Board of the University of Tokyo. Informed consent was waived because of the anonymous nature of the data.
: Not applicable
: The authors declare that they have no competing interests.