Funding for this research was provided by:
Japan Society for the Promotion of Science (26291100, 22370092, 24370101, 21657068)
Text and Data Mining valid from 2019-12-01
Received: 6 February 2019
Accepted: 19 November 2019
First Online: 5 December 2019
Ethics approval and consent to participate
: This study was performed in accordance with the ethical standards set forth in the Declaration of Helsinki and approved by the Ethics Committee of the Kindai University Faculty of Medicine. All parents and guardians received printed information regarding the study and signed a letter of consent.
: Not applicable.
: The authors declare that they have no competing interests.