Funding for this research was provided by:
Ministry of Education, Culture, Sports, Science and Technology (Basic Research (C), #17K09130, 2017-2019)
Text and Data Mining valid from 2019-12-01
Received: 15 February 2019
Accepted: 5 November 2019
First Online: 18 December 2019
Ethics approval and consent to participate
: The study protocol was approved by the Medical Ethics Committee of Showa University School of Medicine (Approval No. 2132) and the Ethics Committee of the All Japan Labor Welfare Foundation (Approval No. 3-1-0004). Informed consent for the use of personal information was obtained from each participant in this study.
: Not applicable.
: The authors declare that they have no competing interests.