Stroke burden attributable to dietary risks in China and Japan from 1990 to 2023: a comprehensive comparative study

Background: Poor dietary habits are major modifiable risk factors for stroke. With population aging and shifts in dietary patterns, the stroke burden attributable to dietary risks has changed in both China and Japan; however, long-term cross-country comparisons remain limited. This study assessed and compared trends in dietary risk-attributable stroke burden in China and Japan from 1990 to 2023. Methods: Data were obtained from the Global Burden of Disease 2023 study. Stroke deaths, age-standardized mortality rates (ASMRs), age-standardized disability-adjusted life-year rates (ASDRs), and corresponding 95% uncertainty intervals attributable to dietary risks were analyzed. Estimates were stratified by age, sex, stroke subtype—ischemic stroke (IS), intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH)—and nine dietary risk factors. Temporal trends were evaluated using estimated annual percentage change (EAPC) and Joinpoint regression to calculate annual percentage changes (APCs) and average annual percentage changes (AAPCs). Results: From 1990 to 2023, dietary risk-attributable stroke burden declined in both countries but remained consistently higher in China across all demographic groups and stroke subtypes. ICH predominated in China, whereas IS accounted for the largest share in Japan. Burden increased with age and was higher in men. High sodium intake and low fruit intake were the leading contributors, followed by low whole grain and low fiber intake, while high red meat intake showed a protective association in both countries. ASMR attributable to dietary risks showed sustained declines (AAPC: –4.03% in China; –4.23% in Japan). All dietary risk–related burdens decreased except for sugar-sweetened beverage intake in China, which demonstrated an upward trend. Conclusions: Although declining, dietary risk-attributable stroke burden remains substantially higher in China than in Japan. Persistent high sodium intake and insufficient fruit and whole-grain consumption continue to drive the burden. Strengthening salt-reduction policies, improving dietary quality, and enhancing nutrition education are essential to further reduce diet-related stroke burden in both countries.