Funding for this research was provided by:
National Natural Science Foundation of China (81601952)
Tianjin Science and Technology Committee (16ZXMJSY00070)
Text and Data Mining valid from 2019-11-27
Received: 11 July 2019
Accepted: 28 October 2019
First Online: 27 November 2019
Ethics approval and consent to participate
: This study was approved by the Tianjin Medical University ethics committee (TJMU18052401). Every participant was fully informed of research nature. All participants signed an informed consent form to participate before data collection.
: Not applicable
: The authors declare that they have no competing interests.