Analysis of Disease Burden Trends and Forecast of Alzheimer's Disease and Other Dementias among the Elderly in China from 1992 to 2021

Background In the context of an aging society, the number of elderly Alzheimer's disease and related dementia (ADRD) patients in China has been increasing year by year, placing a heavy caregiving burden on their primary family caregivers and garnering extensive attention both domestically and internationally. Objective This study aims to analyze the burden of ADRD among Chinese elderly individuals, explore the influence of age, period, and cohort factors on its incidence and prevalence, and predict its incidence post-2021, providing a basis for the development of preventive and curative measures by relevant authorities. Methods Using ADRD data from the Global Burden of Disease Study 2021 (GBD 2021), we extracted the crude incidence rate, crude prevalence rate, crude mortality rate, and crude DALY rate of ADRD among Chinese elderly individuals from 1992 to 2021. After age standardization, we analyzed trends using the Joinpoint regression model and calculated the annual percentage change (APC) and average annual percentage change (AAPC). Age-period-cohort models were used to analyze the effects of age, period, and cohort factors on the incidence and prevalence of ADRD, while Bayesian age-period-cohort models were employed to predict incidence rates from 2022 to 2030. Results The age-standardized incidence and prevalence of ADRD among China's elderly population from 1992 to 2021 showed an overall increasing trend (incidence: AAPC=0.57%, 95%CI=0.41%-0.72%; prevalence: AAPC=0.64%, 95%CI=0.60%-0.68%). The growth rate of standardized incidence was higher in men than in women (AAPC: 0.63% vs. 0.60%), while the growth in standardized prevalence was higher in women than in men (AAPC: 0.68% vs. 0.66%). The standardized mortality rate decreased across three intervals (1992-2019: APC of -0.11%, -0.41%, and -0.08%) but increased from 2019 to 2021 (APC=1.96%, 95%CI=0.78%-3.15%). The effects of age, period, and cohort factors on ADRD incidence and prevalence were significant. Specifically, the risk of incidence and prevalence increased with age in both men and women over 60 years old, with individuals aged 95 years and older having 13.24 and 13.53 times higher risk of incidence in men and women, respectively, compared to the 60-64 age group. The corresponding prevalence risks were 13.55 and 16.05 times higher. Over time, the risk increased, peaking during 2017-2021. In contrast, cohort effects revealed a progressive decrease in risk with later birth cohorts. By 2030, the standardized incidence rate is projected to increase by approximately 43.62% in women (from 1 267.77 to 1 820.80 per 100 000) and by 36.52% in men (from 920.22 to 1 256.30 per 100 000). Additionally, the number of ADRD cases among men and women was expected to rise significantly, with increases of 89.74% and 105.06%, respectively, between 2021 and 2030. Conclusion The increasing burden of ADRD in China's elderly population highlights the need for effective measures, particularly to protect elderly women.