Liu, Yu
Liu, Chunjie
Guo, Dongmei
Wang, Ning
Zhao, Ying
Li, Dan
Article History
Received: 15 January 2021
Accepted: 3 March 2021
First Online: 10 March 2021
Declarations
:
: The ethics committee of the Tangshan Workers Hospital approved this research and waived the informed consent because this was a retrospective observational study and all data were collected and analyzed anonymously.
: Consent for publication was obtained from every individual whose data are included in this manuscript.
: The authors declare that they have no competing interests.