Peng, Zhekuan
Li, Liping
Su, Xuefen
Lu, Yaogui
Article History
Received: 24 October 2021
Accepted: 28 January 2022
First Online: 9 February 2022
Declarations
:
: All methods in this study were carried out in accordance with relevant guidelines and regulations. This study was approved by the Ethics Committee of the Shantou University Medical College (SUMC-2018-42). All the participants in the selected classes and their guardians agreed to participate in the study and provided signed informed consent on a voluntary basis.
: Not applicable.
: The authors declare that they have no competing interests.