Funding for this research was provided by:
a Grant-in-Aid for Scientific Research (15K01643, 15H04754)
Text and Data Mining valid from 2019-07-17
Received: 4 January 2019
Accepted: 2 July 2019
First Online: 17 July 2019
Ethics approval and consent to participate
: Ethical approval was obtained from the ethics committee of the Graduate School of Medicine, Hirosaki University, Ref. 2015-002. The study purpose was explained to the participants. Written informed consent was provided by the respondents, based on their willingness to participate in the study. The parents or guardians of the minors provided written, informed consent for the minors to participate in the study.
: Not applicable.
: Norio Yasui-Furukori has been a speaker for Dainippon-Sumitomo Pharmaceutical, Mochida Pharmaceutical, and MSD. The funders had no role in the study design, data collection and analysis, the decision to publish, or the preparation of the manuscript. The remaining authors declare that they have no competing interests.