Received: 4 October 2018
Accepted: 11 February 2019
First Online: 6 March 2019
Ethics approval and consent to participate
: The study protocol in this paper was approved by the Waseda University Ethics Review Committee on research with human subjects (No. 2016–086) and the Tokyo Women’s Medical University Institutional Review Board (No. 4276), and the need for patient consent was waived.
: Not applicable.
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