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Article History

Received: 11 February 2025

Accepted: 27 April 2026

First Online: 6 May 2026

Competing interests

: The authors declare no competing interests.

: The study involved human participants. More specifically, it utilised data from the CLASS conducted by Renmin University of China, the procedures of which accorded with the ethical standards of the institutional research committee and with the Declaration of Helsinki 1964 and its later amendments or comparable ethical standards. Approval for the current study, a secondary analysis of publicly available data from CLASS, was granted by the Institutional Review Board of School of Social Development and Public Policy at Fudan University (Approval No.: FDU-SSDPP-IRB-2023-1-063) on June 28 th , 2023. All research was performed in accordance with institutional ethical guidelines and regulations.

: Informed consent was obtained from all human participants. Verbal informed consent was obtained by trained CLASS interviewers from all participants immediately prior to their face-to-face interview. Oral consent was obtained rather than written consent to ensure accessibility for the survey respondents, many of whom are older adults with limited literacy: the average years of schooling for the 2018 sample is 5.62 years, with 30% receiving no formal education. The consent process was conducted via tablet-based interviews where trained interviewers read a standardised script to participants. Verbal consent was recorded by the interviewer using a precise electronic timestamp (year-month-day-hour-minute). To ensure quality and ethical compliance, locally based supervisors randomly verified 30% of the surveys via telephone. A copy of the consent script is provided as a supplementary file (Supplementary Note S1 in the supporting information file). All data for the 2018 wave were collected between 2018 and 2019.