All-Cause Mortality and Specific Causes of Death in Autism: A Nationwide Analysis.

Background: Western studies have reported a higher mortality risk in autistic individuals. However, the specific causes of death and the roles of age, sex, and concurrent intellectual disability (ID) remain unclear. This study aimed to analyze the causes of death in autism and the moderating effects of age, sex, and concurrent ID. Methods: This nationwide population-based study, conducted between 2008 and 2019, identified 64,685 autistic individuals and were age and sex matched with 1,279,174 nonautistic controls. All-cause mortality and specific causes of death were compared between autistic and nonautistic controls. The modifying effects of age, sex, and concurrent ID were also examined. Results: The risk of all-cause mortality (hazard ratio = 2.28) is higher in autistic individuals than in nonautistic controls. The elevated all-cause mortality in autistic individuals was consistent across sex, age, and the presence or absence of ID and was higher in autistic women, adults, and those with concurrent ID than in their counterparts. The mortality risks for most examined specific causes, except cancer, are higher in the autistic group than those in nonautistic controls. Although autistic individuals with concurrent ID showed higher mortality risks in neurological, respiratory, and gastrointestinal categories and accidents, the risk of suicide is lower. Autistic women had higher mortality risks in most categories, whereas autistic adults had a higher mortality risk in the neurological and respiratory categories. Conclusion: Autistic individuals face higher mortality risks across various disease categories, regardless of sex, age, or concurrent ID. Health care policies should prioritize the implementation of specific strategies for the early detection of diseases and health promotion, as well as accident and suicide prevention among autistic women and those without ID. Clinical Trial Registration number: NCT04010422.