Study Finds No Link Between Autism, Celiac Disease
Research casts doubt on practice of placing children with autism on a gluten-free diet, experts say
"An increased risk doesn't mean it causes it in everybody," said Coury, who was not involved in the study. "I think that's important to note."
One finding from the study that can't be easily explained involved children who had immune reactions to wheat proteins that were picked up by a blood test, but no signs of intestinal damage. In other words, their blood tests for celiac disease were positive, but their biopsies were not.
The study found that those children were about three times more likely to be diagnosed with autism later in life than children who had negative blood test results.
Coury said it could be an important clue to the biology behind autism.
"We don't know what causes autism. So the question is, what's going on there?" he said. "We do know there are some inflammatory markers or immune issues involved with autism and this might help explain some cases of autism."
The study authors, however, said that the finding should be interpreted with caution.
It is possible, Murray said, that these children were just sick from an early age. Sick children are probably more likely to have blood tests ordered for them. And he noted that the blood tests for celiac disease are sometimes falsely positive, so that might have muddied the results.
Another explanation may be that children with autism simply have more allergies than those who don't. Or they might have disease where the same underlying defect causes both an immune disturbance and behavioral problems, as Coury speculated.
"I don't think our study was really addressing that," Murray said.
Other experts agreed.
"This study shows that autism is not related to celiac disease," said Dr. Peter Green, director of the celiac disease center at Columbia University Medical School.
"All these kids are on a gluten-free diet," Green said, even though "there's no evidence it's a causal relationship."