Xi, Yunfeng
Niu, Liwei
Cao, Ning
Bao, Han
Xu, Xiaoqian
Zhu, Hao
Yan, Tao
Zhang, Nan
Qiao, Liying
Han, Ke
Hang, Gai
Wang, Wenrui
Zhang, Xingguang
Funding for this research was provided by:
the Ministry of Finance of China and National Health and Family Planning Commission of China
the Inner Mongolia Autonomous Region Health and Family Planning Commission Research Project (201701041)
the Inner Mongolia Medical University talent training and innovation team building project
Article History
Received: 20 January 2020
Accepted: 26 June 2020
First Online: 6 July 2020
Ethics approval and consent to participate
: The study was approved by the ethics committee of Fuwai Hospital Chinese Academy of Medical Sciences (approval number: 2014–574). Written informed consent was obtained from each enrolled participant.
: Not applicable.
: The authors declare that they have no competing interests.