Scientists from Columbia University's Mailman School of Public Health have discovered a link between autism and gastrointestinal issues. A new study found children with autism spectrum disorder (ASD) were two-and-a-half times more likely to experience persistent gastrointestinal (GI) symptoms as infants and toddlers than children without autism.

The study, published Wednesday in the journal JAMA Psychiatry, was based on data from a survey of mothers in Norway who were asked to report their children’s GI symptoms— constipation, diarrhea, and food allergy or intolerance— until age 3. More than 45,000 children were involved in the survey, including 195 children with ASD; 4,636 children with developmental delays in language and/or motor skills; and 40,295 children with standard development.

Results showed children with ASD had a higher instance of GI symptoms in both the 6- to 18-month-old age range and the 18- to 36-month-old age range than children with typical development.

"We not only learned that these symptoms appeared early in infancy; we also found that children with ASD were at (a) significantly increased risk for these symptoms to persist compared with typically developing children," study author Michaeline Bresnahan, assistant professor of epidemiology at Columbia University, told FoxNews.com.

According to the Centers for Disease Control and Prevention (CDC), one in 68 U.S. children has ASD, characterized by social communication difficulties and restrictive or repetitive behaviors. Autism is the most common ASD.

Researchers said the longitudinal nature of the study allowed them to uncover the presence of GI complaints in early life, before mothers knew their child would be diagnosed with autism.

Bresnahan added that although the study findings are significant in the field of ASD, GI symptoms alone shouldn’t be a cause for alarm for parents.

“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,” Bresnahan said.

The reason for the link between GI issues and autism is unknown, but suspicions include factors that disrupt signaling from the gut to the brain while the brain is still in development. Researchers hope the new findings, in combination with future studies, can help identify an underlying cause of the disorder.