The bowel habits of young children with Autistic Spectrum Disorders (ASD)

Background: There is evidence that a number of children with autism have chronic bowel disorders. It is unclear, however, how often children with ASD have such disorders or at what age they develop.

Objectives: To use the information collected by the Avon Longitudinal Study of Parents and Children (ALSPAC) to determine in what way the early bowel habits of the children diagnosed with ASD differed from the rest of the population.

Methods: Detailed information was collected from the ALSPAC mothers at 1, 6, 18, 30 and 42 months on the frequency with which they passed a motion, stool consistency (hard, soft, liquid, curdy) and colour (black, brown, green, yellow). Data were also available for bowel symptoms of colitis (diarrhoea, blood in stools and stomach pain).

Results: The 78 children with ASD were compared with the remainder of the cohort (N = 12,993). The only significant differences occurred at 30 and 42m. Children passing 2 stools per day were 50% more likely to have ASD compared to those passing stools once per day (P<0.001). Children who usually passed yellow stools were 70% more likely to have ASD than children who only sometimes had this colour (P<0.05). There were no strong differences earlier in the child’s life or with stool consistency, other stool colours or bowel symptoms.

Conclusions: There is some indication that children with ASD have more frequent bowel movements at 30 and 42 months of age. These differences are more likely to be associated with a restrictive or unusual diet than a precursor of ASD.