Trends in type 2 diabetes burden in rapidly aging East Asian populations: Age-period-cohort analysis of disability-adjusted life years, 1994-2023.

AIMS: Despite the rising type 2 diabetes (T2D) burden in rapidly aging populations, the contributions of age, period, and cohort effects remain unclear. We aimed to quantify the contributions of age-period-cohort modeling to T2D-related disability-adjusted life years (DALYs) in rapidly aging East Asian societies to interpret trends in T2D burden and inform public health efforts. METHODS: Age- and sex-specific DALYs and population data for Japan, South Korea, and Taiwan (1994-2023) were extracted from the Global Burden of Disease Study 2023. Adults aged 20-79 years were grouped into five-year intervals, and age-period-cohort (APC) models were fitted to separate age, period, and cohort effects. RESULTS: T2D-related DALY rates declined significantly across all three societies, with South Korea showing the steepest decline and Japan the smallest. Period effects indicated consistent declines in South Korea and gradual reductions in Taiwan and Japan since 2009. Cohort patterns diverged: steady gains in South Korea, modest improvements in Japan among those born after 1960, and a plateau in Taiwan, where DALY rates showed no improvement among adults younger than 40 years. CONCLUSIONS: Declines in South Korea and Taiwan occurred alongside universal health coverage, which may have strengthened secondary prevention. Taiwan's stalled cohort improvements before age 40 suggest that gaps in primary prevention, alongside rising obesity prevalence and other lifestyle factors, may have constrained gains among younger generations. Sustained T2D burden reduction in aging societies will likely require effective secondary prevention and population-level primary prevention.