Received: 8 October 2020
Accepted: 3 December 2020
First Online: 6 January 2021
Ethics approval and consent to participate
: The study was in accordance with the Declaration of Helsinki and International Ethical Guidelines for Health-related Research Involving Humans. The Ethics Committee at Xinhua Hospital approved the study. The children’s legal guardians signed written informed consent before the research began.
: Not applicable.
: The authors declare that there is no conflict of interests.