Sex differences in the global burden of autism spectrum disorders: An analysis based on GBD 2021 data

Autism spectrum disorder (ASD) has become an increasingly serious global public health challenge, with a continuously rising disease burden and marked sex differences. This study aims to evaluate the long-term trends and global distribution patterns of sex differences in the burden of ASD and to project future changes, thereby providing evidence for ASD prevention and management.

Based on the Global Burden of Disease (GBD) 2021 data, disability-adjusted life years (DALYs) for ASD were extracted for 204 countries and territories. Combined with the sociodemographic index (SDI), the average annual percentage change (AAPC) was used to analyze sex differences in temporal trends and spatial distribution of ASD burden from 1990 to 2021, and to project trends from 2022 to 2050.

From 1990 to 2021, the global age-standardized DALY rate (ASDR) for ASD was significantly higher in males than in females, and this pattern is projected to persist through 2050. The absolute difference (AD) in ASDR ranged from 103.5 to 105.3 per 100 000, and the relative difference (RD) ranged from 1.0 to 1.1, with the most pronounced sex differences observed in East Asia and high-SDI regions. The male ASDR showed an increasing trend from 1990 to 2021, whereas the female ASDR is projected to increase after 2021, particularly in Africa. In 2021, global DALYs for ASD peaked among children under 5 years of age (221.9 per 100 000 in males and 112.8 per 100 000 in females), and the relative difference in DALYs increased with age. The absolute difference in DALYs during adulthood generally declined but increased among young adults and those aged ≥70 years, consistent with the pattern observed for relative differences. At the national level, sex differences were positively correlated with SDI and universal health coverage (UHC), and negatively correlated with the gender inequality index (GII) (all P<0.001). Spain, Japan, Singapore, South Korea, and China were identified as outliers to these associations.

Sex differences in the burden of ASD persist globally and increase with age. Targeted prevention and control strategies tailored to different sexes and age groups are warranted.