Funding for this research was provided by:
Ministry of Health, Labour and Welfare (H30-seisaku-shitei-003)
Ministry of Education, Culture, Sports, Science, and Technology (18H03031)
Received: 24 October 2019
Accepted: 12 March 2020
First Online: 3 April 2020
Ethics approval and consent to participate
: All procedures performed in studies involving human participants were in accordance with the Ethical Guidelines for Clinical Research of the Japanese Ministry of Health, Labour and Welfare, and with the 1964 Helsinki declaration and its later amendments. Written informed consent for responding to the surveys was obtained from all respondents after the aim of this study was explained to them. Ethics committee approval for this study was received from Niigata University of Health and Welfare (approval number: 17560–150205).
: Not applicable.
: The authors declare that they have no competing interests.