Funding for this research was provided by:
the Health Care Science Institute (iken2013-05)
Text and Data Mining valid from 2018-03-27
Received: 22 July 2016
Accepted: 8 March 2018
First Online: 27 March 2018
Ethics approval and consent to participate
: This study used a de-identified publicly-available dataset, and thus, approval from the institutional review board was exempted based on Ethical Guidelines for Medical and Health Research Involving Human Subjects by Japan’s Ministry of Education, Culture, Sports, Science and Technology (MEXT) & Ministry of Health, Labor and Welfare (MHLW) [CitationRef removed, CitationRef removed].
: Not applicable
: The authors declare that they have no competing interest.
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