(RxWiki News) Research on autism spectrum disorders has uncovered more and more information each year. One area that has often been studied is the relationship between autism and digestive problems.
A recent study found that there may be a link between celiac disease and autism spectrum disorders, but only celiac was identified through one testing method.
Celiac disease is a gastrointestinal disorder that prevents individuals from being able to process or handle gluten. Gluten is a protein found in many wheat products and is used as an additive in products such as soy sauce.
The link to autism was found in those who tested positive for gluten antibodies but not those who had a positive biopsy (tissue sample) for damage to their small intestine from celiac.
"See a pediatrician for your child's gastrointestinal problems."
This study, led by Jonas Ludvigsson, MD, PhD, of the Clinical Epidemiology Unit at Karolinska University Hospital in Sweden, looked for possible links between autism and celiac disease.
The researchers used 28 databases of biopsy findings to collect data on 26,995 individuals who had celiac disease.
A biopsy for someone with celiac disease looks at tissue from the individual's small intestine to see if it has been damaged by gluten.
The researchers also gathered data on 12,304 individuals who had inflammation indicating celiac disease symptoms and 3,719 individuals whose biopsy results were normal but who tested positive for celiac with a serologic test.
A serologic test looks for the antibodies that the body creates when it tries to fight off infection. The immune system of a person with celiac disease will create antibodies to fight off the gluten that it perceives to be a threat.
These combined 43,018 individuals with celiac symptoms were compared to 213,208 individuals who were matched to the celiac participants by age and sex.
The researchers then looked at the rates of autism spectrum disorders among all these individuals.
The researchers did not find that autistic individuals were any more or less likely to have full-fledged celiac disease (showing small intestine damage) than those without an autism spectrum disorder.
Autistic individuals were also no more or less likely to have gastrointestinal inflammation indicating celiac symptoms than those who were not autistic.
However, those with autism spectrum disorders were considerably more likely to have a normal biopsy but a positive serologic test for antibodies against gluten.
Autistic participants had about 4.6 times greater odds of having a positive serologic test result for gluten-fighting antibodies.
Then the researchers looked only at the individuals who did not have a diagnosed autism spectrum disorder at the time of their biopsy but were later diagnosed with one.
Those with biopsy-confirmed celiac disease had about 1.4 times greater odds of being later diagnosed with an autism spectrum disorder.
Those with inflammation shown in their biopsy were about twice as likely to later receive an autism spectrum disorder diagnosis.
Those who had normal biopsy results but a positive serologic test for celiac disease had three times greater odds for being later diagnosed with autism spectrum disorder.
The researchers concluded that there was no link between celiac disease or related inflammation and having an autism spectrum disorder.
However, there did appear to be an increased risk of being later diagnosed with autism spectrum disorder in those who had normal biopsy results but a positive serologic result.
“Interest in a possible causal relationship between disordered intestinal function and autism has persisted for many years, with individual anecdotes typically being much more positive than systematic studies," said Glen Elliott, MD, PhD, a clinical professor at the Stanford University Department of Psychiatry and Behavioral Sciences.
"These authors have provided data that, while unsatisfying to those convinced such a link exists, suggest that more research is needed to understand potentially subtler interactions between autism and disturbances in gut function," he said.
This study was published September 25 in the journal JAMA Psychiatry. The research was funded by Orebro University Hospital, the Karolinska Institutet, the Swedish Society of Medicine, the Swedish Research Council-Medicine, the Swedish Celiac Society, the Fulbright Commission and the National Institutes of Health.
One author has received grant funds from Alba Therapeutics and served on the advisory boards for Alvine Pharmaceuticals Inc. and Nexpep.
He has also consulted for Ironwood Inc, Flamentera, Actogenix, Ferring Research Institute Inc, Bayer Healthcare Pharmaceuticals, Vysera Biomedical, 2G Pharma, Inc., ImmunosanT, Inc., and Shire US, Inc.
Another author has received speakers' fees from AstaZeneca. No other conflicts of interest were reported.