Funding for this research was provided by:
National Natural Science Foundation of China (81172680)
Received: 22 July 2020
Accepted: 25 September 2020
First Online: 2 October 2020
Ethics approval and consent to participate
: Ethical approval was obtained from the Ethics Committee of Xiangya School of Public Health, Central South University. Informed written consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.