Text and Data Mining valid from 2018-08-29
Received: 29 March 2018
Accepted: 15 August 2018
First Online: 29 August 2018
Ethics approval and consent to participate
: Written informed consent was obtained from all subjects. The study protocol was approved by the Ethics Committee in Shikoku Central Hospital of the Mutual Aid Association of Public School teachers and this study was performed in accordance with the Declaration of Helsinki. This trial was registered in the University Hospital Medical Information Network (UMIN) Clinical Trials Registry as UMIN000022801.
: Not applicable.
: The authors declare that they have no competing interests.
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