Document is current

Article History

Received: 13 June 2025

Accepted: 12 November 2025

First Online: 25 November 2025

Declarations

:

: The CLASS database was approved by academic committee of school of population and health of Renmin University of China (L20250106). The survey was conducted within the articles 38, 39, and 40 of the Constitution of the People’s Republic of China and the legal framework governed by Chapter I, Article 9 of the Statistics Law of the People’s Republic of China. Verbal informed consent was obtained from all individual participants included in the study. Moreover, the interviewer also had documented more details information on the process of obtaining informed consent, which included whether agreed to attend this study, the time of agreed to attend this study, the reasons for disagreeing to attend this study, and so on. Our study was conducted in accordance with the Declaration of Helsinki. According to Article 32, Items 1 and 2 of the “Ethical Review Measures for Life Science and Medical Research Involving Human Subjects” issued on February 18, 2023, in China: Item 1: Research involving human subjects that only uses de-identified data from public databases and does not involve direct information related to individuals may generally be exempt from ethical review. Item 2: If the research data come from a project that has obtained informed consent and the use of the data conforms to the scope of the original informed consent, it may also be considered exempt from ethical review. Therefore, our research meets the criteria outlined above and can be exempt from further ethical review.

: Not applicable.

: The authors declare no competing interests.