The age group followed was infants aged 6 months to 3 years and the study compared gut symptoms in children with autism versus typical development.
The forward-looking study - that is, one designed in advance to test associations, as opposed to a retrospective study that would look back over data for links - is published online by JAMA Psychiatry.
Gastrointestinal (GI) symptoms reported by mothers were more common and more frequently persistent in the babies and small children with autism spectrum disorder than either in those with "typical" development for the age group, or in those with developmental delay.
The authors believe their study is the first examination of a population to prospectively report GI symptoms and disorders in a comparison between children with autism spectrum disorder (ASD) and those with typical development (TD) or developmental delay (DD).
Their aim was to "address the specific question of whether children with ASD are at greater risk of experiencing GI disturbances" than the other two groups in the large birth cohort of over 41,000 children followed from the age of 6 months through 36 months.
The research - by Michaeline Bresnahan, PhD, of Columbia University, New York, and co-authors - found that children with ASD, most of whom had been diagnosed in a research clinic, were, compared with children with TD:
- More likely to have constipation and food allergy/intolerance reported by their mothers in the 6- to 18-months age range
- More likely to have diarrhea, constipation and food allergy/intolerance in the 18- to 36-months range.
The paper concludes:
"Even though GI symptoms are common in early childhood, physicians should be mindful that children with ASD may be experiencing more GI difficulties in the first 3 years of life than children with TD and DD."
In total, 195 children in the cohort had autism spectrum disorder, 4,636 had developmental delay and delayed language and/or motor development, and 40,295 had typical development.
For the 6- to 18-month-olds, the chance of constipation being reported in the children with ASD approached three times the likelihood of these reports in the children with typical development (an odds ratio of 2.7, adjusted for other risk factors). The result for food allergy/intolerance in the same group approached twice the odds (adjusted OR of 1.7). The difference between the children for diarrhea was smaller (aOR, 1.2).
For the 18- to 36-month-olds, the odds of diarrhea being reported with ASD were over double the odds for those with typical development (an adjusted odds ratio of 2.3) - similar to the result for food allergy/intolerance in this age group (aOR, 2.0). Constipation for these children was increased but not by as much (aOR, 1.6).
The chances of any of the gastrointestinal symptoms overall being reported were higher in the ASD children compared with TD, especially in the older group of infants (adjusted OR of 2.1 for the older group, 1.4 for 6-18 months).
GI difficulties not only more frequent but 'more stubborn' among children with ASD
The authors, in addition to concluding that gastrointestinal difficulties were more frequent, conclude that they were more stubborn:
"Furthermore, the GI symptoms may be more persistent in children with ASD.
The potential for under-recognition and undertreatment of GI dysfunction in the context of a complicated developmental picture is real."
"Treatments that address GI symptoms," the authors say, "may significantly contribute to the wellbeing of children with ASD and may be useful in reducing difficult behaviors."
Young infants were also the subject of research into autism published in January, which found that video-based treatment may improve behaviors in children at risk.
And there was news in December that a number of different pet animals may be helpful to social skills in children with autism.
Finally, in more recent news about autism, a father of a boy with autism - who has established a foundation (N of One) to research what he believes may be "several mechanisms underlying autism" but with a particular interest in bacteria - has published a description of the improvements he observed in his son following a course of antibiotics for an unrelated condition.
By its own admission, the study report published this week relates to a trial of one person looking for clues about autism's causes, but the link made retrospectively by the father has been popular reading.