Funding for this research was provided by:
Yunnan Provincial Science and Technology Department (2017FE468(-161))
Received: 13 May 2020
Accepted: 9 December 2020
First Online: 12 January 2021
Ethics approval and consent to participate
: This study was approved by the Ethics Committee of Kunming Medical University. Written informed consent was obtained from children’s legal guardians.
: Children’s individual person’s data were not contained in this article, and publication consent is not applicable.
: The authors declare that they have no competing interests.