Text and Data Mining valid from 2019-05-16
Received: 31 March 2019
Accepted: 29 April 2019
First Online: 16 May 2019
Ethics approval and consent to participate
: This study was approved by the Sapporo Medical University Research Ethics Board (2015: No. 262-149) and registered with UMIN Clinical Trial Registry (UMIN trial ID: UMIN000016802, registered March 15, 2015).
: Not applicable
: The authors declare that they have no competing interests.
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