Trends in stroke incidence and mortality in China, Japan, and South Korea (1990–2021) with projections to 2035

Stroke incidence and mortality trends in China, Japan, and South Korea differ, with largely unknown underlying causes. This study analysed stroke incidence and mortality trends in China, Japan, and South Korea from 1990 to 2021 and projected trends to 2035, and compared these patterns with the U.S. and global trends in stroke burden and key determinants to inform prevention strategies. Global Burden of Disease data for stroke incidence and mortality in these countries and regions from 1990 to 2021 were used. Temporal trends were analysed using joinpoint regression; age-period-cohort analysis assessed age, period, and cohort effects; and a Bayesian age-period-cohort model predicted trends to 2035. From 1990 to 2021, the age-standardised incidence rates (ASIRs) and mortality rates (ASMRs) of stroke for both sexes in China, Japan, and South Korea declined. The average annual percentage declines in the stroke ASIR and ASMR were - 3.58% and - 5.52% in South Korea, - 1.55% and - 3.54% in Japan, and - 0.37% and - 1.79% in China, compared with - 1.29% and - 1.15% in the U.S., and - 0.81% and - 1.60% globally. Age and cohort effects were key determinants of stroke incidence and mortality trends, with older age groups having the highest incidence and mortality relative risks, which declined in later birth cohorts across China, Japan, and South Korea. Despite progress, only stroke deaths among females in Japan are projected to decline. Stroke ASIRs and ASMRs are projected to remain stable or decline in China and South Korea, whereas Japan's ASIR is projected to rise, despite a decline in the ASMR. This study, centred on China, Japan, and South Korea, provides a comprehensive comparison with U.S. and global trends, highlighting regional characteristics in the context of international standards, and emphasises the impact of ageing and cohort effects on differences, offering an evidence base for targeted stroke prevention strategies and an international reference in East Asia.