Bottom Line: Food and other types of allergies are more likely to be reported in children with autism spectrum disorder (ASD) than in children without ASD but the underlying reasons for this association aren't clear.
Why The Research Is Interesting: A diagnosis of ASD has become more common among U.S. children but it isn't clear why or what causes ASD. Some studies have suggested immune system dysfunction may potentially play a role. Allergies are common medical conditions of immune dysfunction in children.
Who and When: Data from 199,520 children (ages 3 to 17) who participated in the National Health Interview Survey between 1997 and 2016; food, respiratory and skin allergies were based on a response on a questionnaire by a parent or guardian
What (Study Measures): Parent or guardian response on a questionnaire about whether a child had received a diagnosis of ASD from a physician or other health professional
How (Study Design): This was an observational study using nationally representative data. Researchers were not intervening for purposes of the study and cannot control for all the natural differences that could explain the study results.
Authors: Wei Bao, M.D., Ph.D., of College of Public Health at the University of Iowa, Iowa City, and coauthors
Results: Children with ASD, compared to children without ASD, were more likely reported to have:
- Food allergy (11.25% vs. 4.25%)
- Respiratory allergy (18.7% vs. 12%)
- Skin allergy (16.8% vs. 9.8%)
Study Limitations: Parent or guardian reports about ASD or allergy diagnoses in children may have been incorrect. Some parents may over report or under report allergies in their children. Authors didn't know the timing of the onset of allergies or the ASD diagnosis. The study could not determine which diagnosis (ASD or allergic conditions) came first.
Study Conclusions: In a nationally representative sample of US children, a significant and positive association of common allergic conditions, in particular food allergy, with ASD was found. Further investigation is warranted to elucidate the causality and underlying mechanisms.
To Learn More: The full study is available on the For The Media website.
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.