The global, regional, and national burden and attributable risk factors of Alzheimer's disease and other dementias, 1990-2021: A systematic analysis for the Global Burden of Disease Study

Background Dementia is a syndrome characterized by a decline in cognitive function, with Alzheimer's disease (AD) being the most common type. Updated global statistics on the burden of AD and other dementias provide critical insights for guiding prevention and treatment strategies. Objective To estimate the global, regional, and national burden and attributable risk factors of AD and other dementias from 1990 to 2021. Methods This cross-sectional study utilized the 2021 Global Burden of Disease (GBD) dataset from 204 countries and territories. The analysis focused on individuals aged 40 years and older with AD and other dementias and included data on incidence, all-cause and cause-specific mortality, disability-adjusted life years (DALYs), and estimated annual percentage changes (EAPCs). These trends were stratified by region, country, age, sex, and Socio-Demographic Index (SDI). Results From 1990 to 2021, global DALYs attributable to AD and other dementias rose from 3.83 million to 9.84 million. Age-standardized rates (ASRs) of incidence and DALYs increased for both sexes, with a more pronounced rise in males. ASRs for incidence, prevalence, and DALYs were positively correlated with SDI. Smoking was identified as the primary risk factor for dementia burden among males, whereas obesity was the leading risk factor for females. Conclusions The global burden of AD and other dementias has significantly increased from 1990 to 2021, especially in high-SDI regions. While females have a higher overall risk, the burden has grown more rapidly in males. These findings highlight the need for targeted interventions to address aging populations and reduce dementia risk factors.