Received: 5 December 2017
Accepted: 7 May 2018
First Online: 6 June 2018
Ethics approval and consent to participate
: This study was conducted according to the guidelines of the Declaration of Helsinki, and all procedures involving human subjects were approved by the ethics committee of National Hospital Organization Higashi-Hiroshima Medical Center (reference number: 28-59). We obtained verbal consent from each participant.
: The authors declare that they have no competing interests.
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