Gastrointestinal symptoms in autism spectrum disorder: A review of the literature on ascertainment and prevalence.
Calliope Holingue, Carol Newill, Li-Ching Lee and 2 others
PMID 28856868WHAT IT FOUND
Gut symptom rates in autism research vary wildly because studies ask different people using different questions.
No autism-specific gut questionnaire has been checked enough to be trusted as a symptom measure, so reported rates are unreliable.
Key findings
01Across the 144 reviewed studies, 83 used questionnaires administered only to parents or caregivers, and 68 of 119 questionnaire studies created their own instrument.
02Prevalence estimates were extremely wide: any GI symptom ranged from 4.2% to 96.8%, constipation from 4.3% to 45.5%, and diarrhea from 2.3% to 75.6%.
03Symptom estimates differed significantly by who reported them: diarrhea, abdominal pain/discomfort, nausea/vomiting, and bloating/flatulence/gas all differed by respondent type.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
This was not a formal systematic review, although it used some PRISMA-like steps. Only PubMed was searched, so studies published in journals not indexed there may be missing. Many studies did not report GI symptoms separately for people with intellectual disability or nonverbal people. None of the GI questionnaires designed for ASD had been formally validated. Many studies did not state who reported symptoms or whether the sample was clinic-based, population-based, or enriched-risk.
Declared interests
The authors reported no financial relationships or conflicts of interest. The article is listed as supported by NIH extramural research.
The easy way to misread this
Do not read the high prevalence estimates as proof that gut symptoms are common in autism. The estimates came from studies using different questions and different reporters, and none of the autism-specific gut questionnaires had been formally validated.