Attributable risk and time trend in hemorrhagic and ischemic stroke mortality due to high sodium intake in Zhenjiang City from 2010 to 2021: an Age-Period-Cohort (APC) analysis

Introduction: GBD studies have showed high sodium intake's attributable burden on stroke mortality, while existing risk data remain predominantly global, national, or provincial-level, lacking representativeness for specific cities or regional areas. By associating salt intake with elevated systolic blood pressure, it becomes feasible to conduct risk analysis attributing high sodium intake to specific population groups. Objective: To determine the attributable risk of stroke mortality due to high sodium intake in Zhenjiang City, Jiangsu Province, China, from 2010 to 2021, and analyze time trends in hemorrhagic and ischemic stroke mortality rates associated with high sodium intake, to provide a scientific basis for evaluating and improving the effectiveness of local dietary salt reduction policies. Methods: Using GBD data and Zhenjiang chronic disease surveillance records, this study calculated the attributable burden of hemorrhagic and ischemic stroke mortality caused by high sodium intake through a sodium intake-increase of SBP correlation method, referencing the death risk of elevated SBP leads to hemorrhagic and ischemic stroke. Joinpoint regression was employed to analyze mortality trend amplitude and direction, while an APC model evaluated age, period and cohort effects. Results: From 2010 to 2021, the PAFs for hemorrhagic and ischemic stroke death due to high sodium intake ranged between 12.0% and 19.3%, showing a yearly decreasing trend with higher amplitude observed in males than females. The AAPC of ASMR for hemorrhagic and ischemic stroke was -8.10% (95% CI: -12.00% to -3.90%), with hemorrhagic stroke was -11.10% (95% CI: -13.30% to -8.90%), and ischemic stroke ASMR demonstrated a downward trend after 2013, with its AAPC was -12.30% (95% CI: -14.80% to -9.70%). The overall net drift of mortality for hemorrhagic and ischemic stroke due to high sodium intake was below 0, with hemorrhagic stroke showing greater decline amplitude than ischemic stroke. The value of local drifts with age showed a trend that initially stabilizes and shifted to decreasing and then increasing. Although the age effects on female ischemic stroke mortality due to high sodium intake increased after age 85, both period and cohort effects show a downward trend in stroke mortality risks, the favorable and unfavorable cohort effects on different stroke mortality in different genders deserved more attention. Conclusion: In Zhenjiang City, the attributable risk of hemorrhagic and ischemic stroke mortality due to high sodium intake has shown a downward trend. Priority should be given to women and elderly populations, with continued implementation of salt-reduction-focused stroke prevention strategies to mitigate the health impacts of excessive sodium intake.