Disease Burden and Risk Factors of Early-Onset Alzheimer’s Disease and other Dementias in China (1990–2021) with 20-Year Projections to 2041: A Global Burden of Disease Study Analysis

Background Early-onset Alzheimer’s disease and other Dementias (EOAD) have emerged as a major public-health challenge worldwide and in China. With the rapidly ageing population, especially in China, the burden of EOAD continues to rise. Using 2021 Global Burden of Disease (GBD) data, we analysed the EOAD burden and its principal risk factors among Chinese adults aged 40–64 years from 1990 to 2021, and projected trends for the ensuing 20 years. Methods Data from GBD 2021 were extracted to quantify the prevalence, incidence, mortality, and disability-adjusted life years (DALYs) of EOAD in China from 1990 to 2021, along with corresponding age-standardised rates (ASRs). Temporal trends were evaluated using the annual average percentage change (AAPC), and an autoregressive integrated moving average (ARIMA) model was applied to forecast the EOAD burden over the next 20 years. We also assessed the association between EOAD burden and the Socio-Demographic Index (SDI). Results From 1990 to 2021, the age-standardized prevalence rate (ASPR) of EOAD in China for the 40–64 age group increased from 703.1 to 900.8 per 100,000, with a percentage change (PC) of 28.1% (AAPC = 0.44%, 95% UI: 0.35%, 0.53%), significantly higher than the global increase of 3.2%. The age-standardised incidence rate (ASIR) increased from 100.3 to 126.5 per 100,000 in males and from 135.4 to 171.8 per 100,000 in females, representing rises of 26.2% (AAPC = 0.50%, 95% UI: 0.43%, 0.57%) and 26.9% (AAPC = 0.42%, 95% UI: 0.33%, 0.50%), respectively. The age-standardised mortality rate (ASMR) in males rose modestly from 25.1 to 25.9 per 100,000 (3.1% increase; AAPC = − 0.03%, 95% UI: −0.07%, 0.01%), whereas the female rate remained largely unchanged at 33.8 per 100,000 (AAPC = − 0.20%, 95% UI: −0.24%, − 0.17%). For age-standardized DALYs rate (ASDAR), males increased from 429.9 to 463.7 per 100,000, while females increased from 596.7 to 631.4 per 100,000, with increases of 7.9% (AAPC = 0.09%, 95% UI: 0.05%, 0.13%) and 5.8% (AAPC = -0.02%, 95% UI: -0.06%, 0.03%), respectively. ASRs for incidence and prevalence were positively correlated with SDI. Metabolic risk factors now constitute the principal drivers of EOAD burden, whereas smoking and other behavioural risks continue to exert a pronounced effect among men. Prevalence and incidence are projected to rise further over the next two decades, with the steepest increases anticipated in women. Although male mortality shows a slight decline, female mortality remains stable. Conclusion China’ s EOAD burden has risen markedly over the past three decades, with women disproportionately affected. In the future, public health interventions, early screening and clinical management measures for gender differences and metabolic health will be the key to reducing the burden of EOAD in China.