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Article History

Received: 4 February 2026

Accepted: 3 June 2026

First Online: 13 June 2026

Declarations

Competing interests: The authors declare no competing interests.

Ethical approval and consent to participate: This study was conducted in strict accordance with the Declaration of Helsinki and the relevant provisions of the Measures for the Ethical Review of Life Science and Medical Research Involving Human Subjects of China. This study is a retrospective, observational study using only mortality data of systemic ischemic heart disease from Health Hazard Factor Monitoring Subsystem of the China Disease Prevention and Control Information System. All data were fully anonymized without involving any sensitive personal information and posed no additional risk to the participants. According to Article 32 of the Measures for the Ethical Review of Life Science and Medical Research Involving Human Subjects, retrospective studies using fully anonymized data without personally identifiable information are exempt from ethical review and informed consent. Accordingly, the requirement for ethics approval and informed consent was formally waived, and this ethical waiver was verified and granted by the Ethical Review Committee of Shandong First Medical University.