The divergent effects of population aging: comparative analysis of the burden of Alzheimer's disease and other dementias in China and G20 countries, 1990-2050

OBJECTIVES: Alzheimer's disease and other dementias (ADOD) pose a serious and escalating public health challenge globally, particularly in China. This study aimed to compare the ADOD burden between China and Group of 20 (G20) countries to inform targeted policy development. METHODS: We assessed the burden of ADOD among adults aged 40 years and older in China and G20 countries during 1990-2021, using data from Global Burden of Disease 2021. Significant temporal trends were observed by joinpoint regression. Decomposition analyses estimated the effects of aging, population increase, and epidemiologic changes. Projections through the mid-century (2050) were derived using the autoregressive integrated moving average (ARIMA) models. RESULTS: In 2021, China exhibited the highest age-standardized prevalence (900.82 per 100,000), incidence (151.47 per 100,000), and Disability-Adjusted Life Years (DALYs) (562.39 per 100,000) of ADOD among all G20 countries. During 1990-2021, China also experienced the most pronounced increases in these metrics (322.18%, 314.42%, and 272.71%). Aging was the primary driver of the ADOD burden growth in China. In contrast, aging played a dual role in G20 countries, with an adverse effect on the prevalence and incidence while remaining a contributory factor to deaths and DALYs. CONCLUSION: Despite recent improvements, China faces a growing ADOD burden, largely propelled by population aging. This contrasts with the more complex role of aging in G20 countries, where aging shows a substantially mitigating effect on prevalence and incidence yet a persistent driving effect on deaths and DALYs. This underscores an urgent need for China to develop tailored strategies informed by experience from the G20.