Funding for this research was provided by:
National Natural Science Foundation of China (81773489)
Social Science and Technology Innovation Subject in Chongqing (cstc2015shmszx120070)
Technology Basic and Advanced Research Projects in Chongqing (cstc2014jcyjA10069)
Received: 22 October 2019
Accepted: 27 July 2020
First Online: 5 August 2020
Ethics approval and consent to participate
: The Ethics Committee of Institutional Review Board of Army Medical University ruled that no formal ethics approval was required in this particular case. The data used in this study was anonymised before its use. And the use of the raw data from this study were approved by the Chongqing Public Health Medical Center.
: Not applicable.
: The authors declare that they have no competing interests.