Funding for this research was provided by:
Social and Humanities Sciences Research Planning Fund Project from Ministry of Education (17YJA840015)
Article History
Received: 22 December 2019
Accepted: 12 June 2020
First Online: 19 June 2020
Ethics approval and consent to participate
: The study was approved by the Chongqing Medical University Committee. Written consent was obtained from every participant and the parents or guardians of minors involved in this study. The consent forms were approved by the Commission of QiJiang District.
: Not applicable.
: The authors declare that they have no competing interests.