Funding for this research was provided by:
Zhejiang Medical Research Project (2018KY733)
Article History
Received: 27 January 2020
Accepted: 17 June 2020
First Online: 26 June 2020
Ethics approval and consent to participate
: The study was approved by the Research Ethics Committee of Ningbo Municipal Center for Disease Control and Prevention, China. All the participants read and signed the informed consent forms.
: Not applicable.
: The authors declare that they have no competing interests.