Received: 19 September 2017
Accepted: 17 January 2018
First Online: 1 February 2018
Ethics approval and consent to participate
: This study was approved by the Ethics Committee of Shiga University of Medical Science, Shiga, Japan (approval number: 26–217), and written informed consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.
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