In the largest study of its kind, researchers have found that autism-related gut problems are already common in infancy – even before autism’s behavioral symptoms become obvious. The findings suggest that these GI issues – which include chronic constipation, diarrhea and food intolerances – are not simply a consequence of autism-related food aversions.
“While earlier studies have already shown that GI issues are common in children with autism, this study is important for being the largest and for looking earlier in life,” comments developmental pediatrician Paul Wang, Autism Speaks’ head of medical research. Dr. Wang was not directly involved in the study.
“It's hard to blame picky eating, when GI symptoms start so early,” Dr. Wang adds. “This is why it's so important that we understand what’s causing these issues.”
Read about Autism Speaks Gut-Brain Research Initiative here.
The researchers, led by Columbia University epidemiologist Michaeline Bresnahan, analyzed information on more than 45,000 children in the Norwegian Mother and Child Cohort Study. This included 195 children diagnosed with autism by age 3 and 4,636 children with delayed language or motor development. As part of the study, mothers filled out detailed health questionnaires when their children were 6, 18 and 36 months.
The analysis showed that children who were diagnosed with autism by 36 months were more than twice as likely as typically developing children to have had chronic GI problems at 6 months and 18 months, as reported by their mothers.
The children with autism were likewise more likely to have GI symptoms than were children with delays in language or motor development. This suggests that the GI disturbances were not simply related to the developmental delays that mark autism.
In addition, the researchers found that when typically developing children had GI symptoms in infancy, the problems tended to resolve by age 3. By contrast, the problems were more likely to persist among the children with autism.
While higher levels of GI symptoms are associated with autism, Dr. Bresnahan cautions that "the vast majority of children with these symptoms won't go on to develop autism, nor do all people with autism have GI problems as children."
"Factors that disrupt signaling along the gut-brain axis while the brain is still under development may ultimately provide a key to understanding how the disorder occurs in the subset of children with autism and GI complaints," adds study co-author Ian Lipkin, also of Columbia University, in New York City.
To learn more, also see “Office Hours with Dr. Buie: Exploring Autism’s Gut-Brain Connection.”