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Article History

Received: 3 July 2018

Accepted: 13 November 2018

First Online: 29 November 2018

Ethics approval and consent to participate

: This study was conducted with the approval of the Ethics Review Committee of Tokyo-Hokuto Health Co-operative Association (approval number: 71). Written informed consent was obtained from all the participants before the enrolment.

: Not applicable.

: The authors declare that they have no competing interests.

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