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Article History

Received: 3 November 2022

Accepted: 17 September 2024

First Online: 1 October 2024

Declarations

:

: Medical ethics approval of this study was approved by the Ethical Committee of School of Public Health, Shandong University (No. 20180225). Informed consent for the data collection and the use of the data was obtained from all subjects. All methods were carried out in accordance with relevant guidelines and regulations in the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For illiterate older people, in addition to obtaining their verbal consent, we also require their legally/kin authorized representative to provide a proxy written informed consent.

: Not applicable.

: The authors declare no competing interests.