Received: 13 July 2020
Accepted: 29 March 2021
First Online: 9 April 2021
: This study was approved by the Research Ethics Committee of Division for the Prevention and Control of Chronic Noncommunicable Diseases, China Center for Disease Control and Prevention and the Ethics Committee of Department of Public Health in Fudan University, Shanghai, China. All participants or their legally acceptable representatives provided written informed consent.
: Not applicable.
: The authors declare no conflicts of interest.