Funding for this research was provided by:
the Science and Technology Planning Project of Shenzhen City, Guangdong Province, China (SZGW2018002)
Sanming Project of Medicine in Shenzhen (SZSM201811093)
Article History
Received: 20 January 2020
Accepted: 3 June 2020
First Online: 26 June 2020
Ethics approval and consent to participate
: The study protocol was approved by the ethics committee of Shenzhen Center for Chronic Disease Control (SZCCC-201802). Consent to participate was obtained from each participant in written form.
: Not applicable.
: The authors declare that they have no competing interests.