Is There a Link Between Autism, Food Allergies? Study Offers Hint But No Answers

Researchers say they’ve found an association between autism spectrum disorder and allergic conditions in children—especially food allergies—in the largest study looking at the issue to date, but noted more research is needed before fully understanding any possible link between the 2 conditions.

A leading pediatric allergist also cautioned against drawing any conclusions from the study. Scott H. Sicherer, MD, director of the Elliot and Roslyn Jaffe Food Allergy Institute and the Elliot and Roslyn Jaffe Professor of pediatric allergy and immunology at the Icahn School of Medicine at Mount Sinai, said more studies are required in order to understand any possible biological pathways between the two conditions, both of which have been rising.

The observational study, published in JAMA Network Open, said that 11.25% of children with ASD had a food allergy, compared to the 4.25% of children without ASD who had a food allergy.

The data came from nearly 200,000 children from the National Health Interview Survey (NHIS), an annual conducted by the CDC. The children were between the ages of 3 and 17 and the data were gathered between 1997 and 2016.

However, the food allergy questions were based on self report. The question related to ASD asked if the child had ever received a diagnosis of ASD from a provider. Children with ASD were also more likely than children without ASD to report respiratory allergies (18.7% versus 12%) and skin allergies (16.8% versus 9.8%).

In an email with The American Journal of Managed Care^® (AJMC^®), study author Wei Bao, MD, PhD, of the College of Public Health at the University of Iowa, Iowa City, said he chose the study topic as the rate of autism rate is increasing, for reasons that are still unclear. “Previous studies indicated a possible link between immunologic dysfunction and autism,” he said. “We want to examine whether there is a relation between allergy, a condition relevant to immunologic dysfunction, and autism.”

Bao and his coauthors said one possible theory connecting the 2 conditions is the interaction of the gut-brain-behavior axis and the influence of the microbiome.

Rates of food allergy have also been rising, as are rates of other atopic disease and autoimmune diseases, said Sicherer, who was not involved in the study. He cautioned against overinterpreting the study. “I wouldn’t want people to misinterpret this to say that a food allergy is causing autism,” nor should children with ASD be routinely screened for food allergies.

While parents of children with autism may report their children have gastrointestinal difficulties or food allergies, it is unclear if they are true IgE-mediated food allergies or simply behavioral prefences, he said. The NHIS question asked if the child had “any kind” of food allergy or digestive issue, which is not the definition of food allergy, he noted. But the study raises interesting theories, he said.

Bao also agreed that they do not know which condition comes first.

“A future study that prospectively collect data on the timing of onset for food allergy and autism is needed to establish the temporal relationship between these two conditions,” said Bao.

ASD is a complex neurodevelopmental disorder characterized by deficits in social interaction, language, and communication, as well as the presence of restricted repetitive behaviors. The Autism and Developmental Disabilities Monitoring Network reported that the estimated prevalence of ASD increased from 0.67% in 2000 to 1.46% in 2012.

Reference

Guifeng X, Snetselaar LG, Jing J, Liu B, Strathearn L, Bao W. Association of food allergy and other allergic conditions with autism spectrum disorder in children. JAMA Network Open. 2018;1(2):e180279. doi:10.1001/jamanetworkopen.2018.0279