Funding for this research was provided by:
JOA-Subsidized Science Project Research from the Japanese Orthopedic Association (2015-2)
the Center of Innovation Program from Japan Science and Technology Agency, JST (2014-377)
a Japanese Health Labor Sciences Research Grant
Received: 29 July 2017
Accepted: 23 April 2018
First Online: 17 May 2018
Ethics approval and consent to participate
: For this cross-sectional survey, the ethics committee of Hirosaki University, Graduate School of Medicine approved the study (2014–377), and all participants provided written informed consent before participation.
: The authors declare that they have no competing interests.
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