Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) are associated with a significantly increased risk of all-cause mortality, suggests a systematic review and meta-analysis published in JAMA Pediatrics.

“Understanding the mechanisms of these associations may lead to targeted strategies to prevent avoidable deaths in high-risk groups of children and young people as an approach to improve public health,” researchers wrote. “For example, clinicians and health care professionals can be encouraged to routinely collect information on behavioral, medical conditions, and health outcomes related to ASD/ADHD, emphasizing the need to recognize and address modifiable vulnerability factors and prevent delays in health care provision.”

The investigation included 27 epidemiologic studies, 16 of which had a low risk of bias,  spanning a total 642,260 people.

All-cause mortality was higher for people with ASD as well as for people with ADHD compared with the general population, the analysis found.

Related: Several Genetic Variants Shared Between Autism and ADHD, Study Finds

Researchers also looked at causes of death, which they categorized as natural (such as neurologic-, respiratory system-, or cancer-related deaths) or unnatural (such as deaths due to injury, poisoning, or other external causes).

Both deaths from natural causes and deaths from unnatural causes were significantly increased among people with ASD. Researchers reported mortality rate ratios of 3.80 for death from natural causes and 2.50 for death from unnatural causes for people with ASD.

Meanwhile, only deaths from unnatural causes were significantly increased in people with ADHD. Mortality rate ratios were 1.62 for death from natural causes and 2.81 for death from unnatural causes in the ADHD population, according to the study.

The evidence behind mortality risk by natural vs unnatural causes, however, was considered low confidence for both groups.

“[W]e hope that these estimates can shed some light for future studies related to examining mortality-related health estimates in persons with ASD or ADHD,” researchers wrote.

Reference

Catalá-López F, Hutton B, Page MJ, et al. Mortality in persons with autism spectrum disorder or attention-deficit/hyperactivity disorder: a systematic review and meta-analysis. JAMA Pediatrics. Published online February 14, 2022. doi:10.1001/jamapediatrics.2021.6401