Received: 3 November 2020
Accepted: 7 December 2021
First Online: 3 January 2022
: The data adopted was from a publicly available survey dataset whose ethical approval was obtained from the institutional review board at Shanghai Municipal Center for Disease Control & Prevention. All methods were carried out in accordance with relevant guidelines and regulations. Written informed consent was obtained from all participants before they agreed to participate in the study. Participants were informed that they could leave the study at any time without penalty, and all personal information was kept confidential. Thus, it was not necessary to obtain ethical approval from the institutional review board at the author’s institution.
: Not applicable.
: The author declares that he has no competing interests regarding the publication of this paper.