Funding for this research was provided by:
National Natural Science Foundation of China (81301532/H0603)
Shanxi Scholarship Council of China (2017-119)
Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province-2017
the Shanxi Science and Technology Research Projects of China (201603D321074)
Text and Data Mining valid from 2018-10-24
First Online: 24 October 2018
Compliance with ethical standards
: The study was approved by the Research Ethics Committee of the Second Hospital of Shanxi Medical University and conducted in accordance with the Declaration of Helsinki (approval number 2013ky007).
: The authors declare that they have no conflicts of interest.