Funding for this research was provided by:
ShanXi Science and Technology Department (201801D221414)
Received: 14 November 2019
Accepted: 20 January 2020
First Online: 5 February 2020
Ethics approval and consent to participate
: The study design was approved by the Ethical Committee of the Second Affiliated Hospital of Shanxi Medical University. All of the participants provided written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.