Funding for this research was provided by:
National Natural Science Foundation of China (81302406)
Basic Research Fund of Young Program of Higher Education of Liaoning Province (QNK201735)
Funds for Distinguished Young Scientists in School of Public Health, China Medical University.
Text and Data Mining valid from 2019-08-20
Received: 20 June 2019
Accepted: 14 August 2019
First Online: 20 August 2019
Ethics approval and consent to participate
: Not applicable.
: Written informed consent for publication was obtained from all participants.
: The authors declare that they have no competing interests.