Global Inequality and Future Burden of Autism Spectrum Disorders: A Frontier and Projection Analysis Based on GBD 2021

BACKGROUND: Autism spectrum disorder (ASD) comprises a group of persistent neurodevelopmental conditions characterized by impairments in communication, restricted behavioral patterns, and social dysfunction. In severe cases, ASD can lead to self-injury or suicide, imposing a significant burden on individuals, families, and society. This study aimed to comprehensively assess the temporal, demographic, and regional patterns of ASD burden from 1990 to 2021; project future trends; and provide insights into potential causes and public health strategies. METHODS: Data on the incidence, prevalence, and disability-adjusted life years (DALYs) of ASD were extracted from the Global Burden of Disease (GBD) Study 2021. Temporal trends were evaluated using estimated annual percentage change (EAPC) and Bayesian age-period-cohort (BAPC) modeling. We further examined burden distribution by age, sex, region, and sociodemographic index (SDI). RESULTS: In 2021, an estimated 61.82 million individuals were living with ASD globally, with 1.16 million new cases and 11.54 million DALYs. The global age-standardized point prevalence, incidence, and DALY rates were 788.3, 18.8, and 147.6 per 100,000 population, respectively-representing increases of 2.0%, 5.2%, and 2.1% since 1990. Regionally, the highest age-standardized prevalence rate was observed in the High-income Asia Pacific region, while tropical Latin America had the lowest. At the national level, Japan recorded the highest age-standardized prevalence, whereas the Republic of Mauritius had the lowest. CONCLUSION: ASD poses a rising global public health challenge, with persistent regional disparities and underrecognized burden in adults and females. Current gaps in epidemiological surveillance, etiological understanding, and treatment capacity highlight the urgent need for greater governmental investment in ASD-related research, early detection strategies, and inclusive care systems.