Children with autism spectrum disorders (ASD) are 3.5 times more likely to suffer chronic diarrhea or constipation than their normally developing peers. Now a new study from Columbia University supports and expands on these findings. For kids with autism, gastrointestinal troubles are more common and more persistent in the first three years of life than they are for peers who are developing normally or even for peers with developmental delays.

"There is increasing interest and research on the topic of the gut-brain axis," Dr. Michaeline Bresnahan, assistant professor at Columbia University and first author of the study, told Medical Daily; yet because "this is beyond the scope of the data we presented," she is not suggesting her results might be evidence of or linked to this axis.

Characterized by difficulty with social interactions, communication, and repetitive behaviors, autism is a select group of brain development disorders. It is widely known that gastrointestinal (GI) symptoms are among the most common health conditions associated with autism. What is not known, though, is the prevalence of GI troubles among patients with autism, the age at which such tummy troubles commonly start, and whether they occur more frequently with ASD than other neurodevelopmental disorders.

To answer these questions, the researchers sorted through data from the Norwegian Mother and Child Cohort Study (MoBa), which recruited more than 90,000 pregnant women between the years 1999 and 2008. During that time, a total of 114,516 children became enrolled in MoBa. The researchers of the current study, then, based their analyses on medical data concerning these children and released from MoBa through Oct. 1, 2013.

“We defined three groups of children,” the authors wrote, noting 195 children had ASD and 4,636 children had developmental delays, while 40,295 children showed typical development. Next, the researchers searched all the mother’s reports of constipation, diarrhea, and food allergy/intolerance and then they compared all three groups.

What they discovered will probably not surprise mothers who have compared their autistic children to same-age kids. Children with autism had higher odds of suffering from constipation and food allergy/intolerance between ages 6 and 18 months; and higher odds of diarrhea, constipation, and food allergy/intolerance between ages 18 and 36 months than their peers, whether those children showed typical developing or even developmental delays.

Some readers might wonder if the mother's experience impacted these results. "Additional analyses were conducted to investigate the influence of the number of prior live births to the mother," Bresnahan told Medical Daily. New mothers and experienced mothers reported similar incidents of GI symptoms. Overall, this is disheartening news, but still the study supports the observations of many anguished mothers.

“Treatments that address GI symptoms may significantly contribute to the well-being of children with ASD and may be useful in reducing difficult behaviors,” the researchers wrote at the conclusion of their study.

Source: Bresnahan M, Hornig M, Schultz AF, et al. Association of Maternal Report of Infant and Toddler Gastrointestinal Symptoms With AutismEvidence From a Prospective Birth Cohort. JAMA Psychiatry. 2015.