Received: 21 July 2018
Accepted: 8 November 2018
First Online: 19 November 2018
Ethics approval and consent to participate
: This study was approved by the ethics committee of the Yokohama City University Medical Center. The approved number is B171100008. The study protocol and contact address/telephone number were available on the website of the Yokohama City University Medical Center, so all participants had the opportunity to decline to participate in the study.
: Not applicable.
: The authors declare that they have no competing interests.
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