Funding for this research was provided by:
the Seed Funding, Army Medical University (Third Military Medical University),China (2016XYY04)
Text and Data Mining valid from 2018-08-16
Received: 25 October 2017
Accepted: 24 July 2018
First Online: 16 August 2018
Ethics approval and consent to participate
: The study was approved by the Institutional Review Board of Preventive Medicine College and Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, China. Written informed consent was obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.