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
The result: Researchers say they found no convincing evidence that autism and celiac disease are linked.
"If there was a connection between these two diseases -- either hidden celiac disease causing autism or autism causing celiac disease, it should have shown up in the study of this size. So, I think that's the big message," said Murray. "This brings some finality to that debate."
When researchers restricted their results to a smaller subset of children who were diagnosed with celiac disease before their autism was spotted, they found that a prior diagnosis of celiac disease boosted the odds that child would be diagnosed with autism down the road by roughly 40 percent.
"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.