Funding for this research was provided by:
Japan Agency for Medical Research and Development
Received: 27 December 2016
Accepted: 8 August 2017
First Online: 22 August 2017
Ethics approval and consent to participate
: The study was approved by the Internal Review Board of the Graduate School of Health Management, Keio University. We obtained written and oral informed consent from all the participants.
: Not applicable.
: The authors declare that they have no competing interests.
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