Zhang, Yaru
Li, Jiajia
Fang, Feng
Fu, Wenhao
Article History
Received: 26 March 2021
Accepted: 14 September 2021
First Online: 27 September 2021
Declarations
:
: All methods were performed in accordance with the relevant guidelines and regulations. The study was approved by the Ethics Committee of School of Public Health in Shandong University, P. R. China. Each participant and his/her parental/guardian gave written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.