Cao, Junyan
Qiu, Weihong
Yu, Yong
Li, Na
Wu, Huixiang
Chen, Zhaocong
Article History
Received: 31 July 2021
Accepted: 6 December 2021
First Online: 4 January 2022
Declarations
:
: The datasets analyzed during the current study was derived from the survey of National Center for Health Statistics at the Centers for Disease Control, which was approved by the ethics review board of the National Center for Health Statistics. All methods of this study were performed in accordance with the Declaration of Helsinki and relevant guidelines and regulations.
: Not applicable.
: The authors declared that they have no competing interests.