Funding for this research was provided by:
fiftieth Scientific Research Foundation for the Returned Overseas Chinese Scholars State Education Ministry and science and technology basic and advanced research projects in Chongqing (cstc2014jcyjA10069, cstc2014jcyjA10069)
Received: 28 May 2019
Accepted: 13 January 2020
First Online: 17 March 2020
Ethics approval and consent to participate
: The study’s protocol and data collection procedure were approved by the Institutional Review Board of Preventive Medicine College, Army Medical University (Third Military Medical University), Chongqing, China. All participants had completed written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.