Global burden of autism spectrum disorders among population aged 70 years and older from 1990-2021, with projections to 2040: findings from the Global Burden of Disease Study 2021.

Autism spectrum disorders (ASD) is a lifelong neurodevelopmental condition that negatively affects older adults, yet it receives minimal priority and limited attention in research and healthcare services for this population. Using data from Global Burden of Diseases, Injuries, and Risk Factors Study 2021, we estimated the prevalence and disability-adjusted life-years (DALYs) of ASD among population aged ≥70 years globally from 1990-2021, with projections to 2040. Decomposition analysis was conducted. Globally, the number of ASD cases among individuals aged ≥70 years increased from 894.7 thousand in 1990 to 2478.9 thousand in 2021, corresponding to an increase of 177.1%, with population growth contributing to the largest increase, followed by increased age-specific prevalence rates. It is projected that by 2040, the number of cases will reach 5150.9 thousand worldwide, accounting for 864.7 thousand DALYs. Between 1990 and 2021, the prevalence rate of ASD among the older population increased by 13.2%, projecting to increase steadily by 2040. Males had a higher prevalence rate of ASD in 2021 (773.6 versus 287.8 per 100,000 people) than females. High sociodemographic index (SDI) countries had the highest rate and the greatest increase. Similar trend patterns were observed in the number of DALYs and DALY rates. To address this overlooked but increasingly severe challenge, more attention and timely development of effective interventions and management services are needed. High SDI countries should focus on developing effective intervention and treatment strategies, while middle and low SDI countries need to improve screening and diagnostic capacities and public awareness of ASD.