Ishida, Shiori http://orcid.org/0000-0002-1709-0562
Okuno, Hiromi
Igarashi, Hisato
Takahashi, Hiroko
Article History
Received: 20 August 2021
Accepted: 18 December 2021
First Online: 7 January 2022
Competing interests
: No authors reported any financial or other conflicts of interest in relation to the work described. The authors declare no competing interests.
: This study was approved by the Ethics Committee of Shinshu University (no. 4642) and was conducted in accordance with the Declaration of Helsinki.
: Informed consent from the parents in this investigation was obtained by an opt-in method via the distribution of an explanatory letter (including the study’s significance, purpose, methods, and expected results) and a questionnaire, which was voluntarily completed by each participant. Due to their young age, informed consent was not obtained from the children in this study.