And that led to the new study, published today in the journal PLOS ONE, which showed that children with autism who were fed soy formula had 2.6 times as many febrile seizures as the children fed non-soy formula in the database. That means 4.2 percent of the soy group had a seizure associated with a fever, compared to 1.6 percent of the others.
To put it another way, the vast majority of both groups did not have seizures. "This is not saying that all autistic children who eat soy-based formula are going to develop seizures," says Westmark.
And yet that increase is worrying, Westmark says. "The prevalence of autism is increasing and currently affects one American child in 88. Soy is a widespread ingredient in many food products and 25 percent of infant formulas are soy based, so this is something that needs to be studied. If the child is lactose intolerant, there are alternatives that a pediatrician can recommend."
The study, Westmark says, was not the kind of randomized clinical trial that can prove causation. "We can say that we have a potential association between the use of soy-based formula and seizures in autistic children; we can't say that this is cause and effect. We were fortunate to be granted access to the SFARI database, but it was not set up to answer the questions we were asking."
Although it's possible that seizures could also be more frequent among children who consume soy formula but do not have a developmental disability, "There is no data available at this time to support that," Westmark says. Still, the study raises concerns, since seizures cause neurological damage and repeated seizures epilepsy can develop into a lifelong problem.
"This needs to be studied more thoroughly," Westmark says. "If soy formula is lowering the threshold for seizures or increasing
|Contact: Cara Westmark|
University of Wisconsin-Madison