Funding for this research was provided by:
Fujian Provincial Health Commission (2014-CXB-38)
Science and Technology Bureau of Xiamen City (3502Z20154005)
Received: 7 January 2018
Accepted: 9 July 2019
First Online: 24 July 2019
Ethics approval and consent to participate
: Not applicable.
: The manuscript is approved for publication by all the authors.
: The authors declare that they have no competing interests.