Funding for this research was provided by:
The National Key Research and Development Program of China (2016YFC0902000)
The National Natural Science Funds (81872464)
Received: 29 March 2019
Accepted: 15 May 2019
First Online: 22 May 2019
Ethics approval and consent to participate
: The present meta-analysis was based on previous published studies, and involved no experiments on humans and animal. Therefore, no ethical approval is required.
: Not applicable.
: The authors declare that they have no competing interests.