Gastrointestinal pathologies in children with autism or other ASDs

Teresa Binstock
Researcher in Developmental & Behavioral Neuroanatomy
July 29, 2009

Do children with autism or other autism-spectrum disorders have more gastrointestinal pathology? The answer depends. Indeed,  choose your favorite flavor, choose your science.

In the increasingly politicized arena of autism, a group of Mayo Clinic researchers recently concluded that "No significant associations were found between autism case status and overall incidence of gastrointestinal symptoms or any other gastrointestinal symptom category." (2)  Not surprisingly, a New York Times science writer jumped onto the Mayo bandwagon and presented a ramification rooted in medical orthodoxy, "Restrictive Diets May Not Be Appropriate for Children With Autism".

In stark contrast, a different research group recently concluded, our "...study confirms previously reported findings of an increase in bowel symptoms in children with autism" (1), thus reinforcing a previous observation that "Constipation is a frequent finding in children with gastrointestinal symptoms and autism, particularly in the rectosigmoid colon, often with acquired megarectum." (4)

Perhaps doctrinaire preference for an ancient paradigm enthralled the Mayo Clinic group whose personnel found no increased prevalence of gastrointestinal pathology in autism. Note their conclusion: "As constipation and feeding issues/food selectivity often have a behavioral etiology, data suggest that a neurobehavioral rather than a primary organic gastrointestinal etiology may account for the higher incidence of these gastrointestinal symptoms in children with autism." (2)

Perhaps their conclusion's rhetoric -- Constipation "often" has a "behavioral etiology" -- reflects a belief system. Are we to believe that chronic diarrhea (as reported by many parents of autistic children) or persistent constipation in autism (eg, 4) has a "behavioral etiology"?  To borrow from popular psychology, is the child's chronic diarrhea an acting out?

Alternatively, reactivity to gluten affects more individuals than had been previously recognized and occurs in individuals having none of the overt symptoms which previously defined celiac disease (5). Furthermore, in an ongoing data-collection project by Autism Research Institute, more than 60% among >2500 autism parents have reported improvements when their autistic child is on a gluten-free (GF) and/or casein-free (CF) diet (6).

Given prior, peer-reviewed findings of gastrointestinal pathology in autistic children, a question arises, "How did Mayo personnel achieve their finding? Among various factors, the researchers relied upon cumulative incidence and seemed to avoid comparing chronic vs rarely occurring gastro pathology.
        As a physician who is an autism-specialist noted: "It is very common to have one or two bouts with constipation or diarrhea over your entire childhood.  The important difference is how chronic it is, not if you’ve ever had it.  So [in the newly published study (2)] having a viral illness with diarrhea that lasts for a week or two was counted the same as children who may have had chronic loose stools every day of their life.  They do not distinguish these issues in their study data." (name withheld, personal communication).

Strikingly, a case study recently reported that one autistic child's gastrointestinal pathology and autism were alleviated by a gluten free diet (7-8).

References
:

1. Are there more bowel symptoms in children with autism compared to normal children and children with other developmental and neurological disorders? A case control study
Smith RA et al.
Autism 2009 13(4) 343–355.

There is considerable controversy as to whether there is an association between bowel disorders and autism. Using a bowel symptom questionnaire we compared 51 children with autism spectrum disorder with control groups of 35 children from special school and 112 from mainstream school.There was a significant difference in the reporting of certain bowel symptoms (constipation, diarrhoea, flatulence) and food faddiness between the autism group and the mainstream school control group. There was no significant difference between the autism group and children in the special schools except for faddiness, which is an autism specific symptom and not a bowel symptom. This study confirms previously reported findings of an increase in bowel symptoms in children with autism. It would appear, however, that this is not specifically associated with autism as bowel symptoms were reported in similar frequency to a comparison group of children with other developmental and neurological disorders.


2. Incidence of Gastrointestinal Symptoms in Children With Autism: A Population-Based Study
Ibrahim SH et al.
Pediatrics 2009;124:680–686.

OBJECTIVE: To determine whether children with autism have an increased incidence of gastrointestinal symptoms compared with matched control subjects in a population-based sample.
DESIGN/METHODS: In a previous study including all of the residents of Olmsted County, Minnesota, aged <21 years between 1976 and 1997, we identified 124 children who fulfilled criteria on the basis of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, for a research diagnosis of autism. Two matched control subjects were identified for each case subject. Through the Rochester Epidemiology Project, all medical diagnoses, are indexed for computerized retrieval. Gastrointestinal diagnoses before 21 years of age were grouped into 5 categories: (1) constipation; (2) diarrhea; (3) abdominal bloating, discomfort,
or irritability; (4) gastroesophageal reflux or vomiting; and (5) feeding issues or food selectivity. The cumulative incidence of each
category was calculated by using the Kaplan-Meier method. Cox proportional hazards models were fit to estimate the risk ratios (case subjects versus control subjects) and corresponding 95% confidence intervals.
RESULTS: Subjects were followed to median ages of 18.2 (case subjects) and 18.7 (control subjects) years. Significant differences between autism case and control subjects were identified in the cumulative incidence of constipation (33.9% vs 17.6%) and feeding issues/food selectivity (24.5% vs 16.1). No significant associations were found between autism case status and overall incidence of gastrointestinal symptoms or any other gastrointestinal symptom category.
CONCLUSIONS: As constipation and feeding issues/food selectivity often have a behavioral etiology, data suggest that a neurobehavioral rather than a primary organic gastrointestinal etiology may account for the higher incidence of these gastrointestinal symptoms in children with autism.

3. {my comment: As usual, a NYTimes writer chose an ideologically correct position while ignoring methodological flaws in the Mayo "study" touted by a well known trade journal (2, above) and also ignoring contrary findings (1, above).

Regimens: Restrictive Diets May Not Be Appropriate for Children With Autism
By RONI CARYN RABIN
http://www.nytimes.com/2009/07/28/health/28autism.html

4. Constipation with acquired megarectum in children with autism
Afzal N et al.
Pediatrics. 2003 Oct;112(4):939-42.

OBJECTIVE: Recent evidence suggests that autistic children may have significant gastrointestinal symptoms. Although constipation occurs in 2% to 5% of healthy children, its clinical diagnosis is often difficult in children with behavioral disorders. We thus aimed to assess the prevalence of fecal loading in autistic children with gastrointestinal symptoms and to identify possible predictors of constipation. METHODS: We studied abdominal radiographs of 103 autistic children (87 boys) who were referred for gastroenterological assessment, in comparison with 29 control radiographs from children who were referred to the emergency department, most with abdominal pain. Radiographs were scored independently, in blinded manner, by 4 pediatric gastroenterologists and a radiologist. The severity of constipation was determined using a validated index. Details of stool habit, abdominal pain, dietary history, and laxative use were obtained from case notes. RESULTS: The incidence of constipation in the control subjects with abdominal pain was higher than reported for normal children. Despite this, moderate or severe constipation was more frequent in the autistic group than in the control subjects (36% vs 10%). Analysis of rectosigmoid loading showed more striking differences (54.4% of autistic children had moderate/severe loading or acquired megarectum compared with 24.1% of control subjects). Multivariate regression analysis showed consumption of milk to be the strongest predictor of constipation in the autistic group, whereas stool frequency, gluten consumption, soiling, and abdominal pain were not predictive of constipation. CONCLUSIONS: Constipation is a frequent finding in children with gastrointestinal symptoms and autism, particularly in the rectosigmoid colon, often with acquired megarectum. The absence of any correlation between the clinical history and the degree of fecal impaction in autistic children confirms the importance of an abdominal radiograph in the assessment of their degree of constipation.

5. Celiac Disease Insights: Clues to Solving Autoimmunity
Alessio Fasano     
Scientific American 2009
http://www.scientificamerican.com/article.cfm?id=celiac-disease-insights

6. Parent Ratings of Behavorial Effects of Biomedical Interventions
Autism Research Institute
http://www.autism.com/treatable/form34qr.htm

7. Celiac Disease Presenting as Autism
Genuis SJ, Bouchard TP.  J Child Neurol. 2009 Jun 29.
http://jcn.sagepub.com/cgi/rapidpdf/0883073809336127v1

Gluten-restricted diets have become increasingly popular among parents seeking treatment for children diagnosed with autism. Some of the reported response to celiac diets in children with autism may be related to amelioration of nutritional deficiency resulting from undiagnosed gluten sensitivity and consequent malabsorption. A case is presented of a 5-year-old boy diagnosed with severe autism at a specialty clinic for autistic spectrum disorders. After initial investigation suggested underlying celiac disease and varied nutrient deficiencies, a gluten-free diet was instituted along with dietary and supplemental measures to secure nutritional sufficiency. The patient's gastrointestinal symptoms rapidly resolved, and signs and symptoms suggestive of autism progressively abated. This case is an example of a common malabsorption syndrome associated with central nervous system dysfunction and suggests that in some contexts, nutritional deficiency may be a determinant of developmental delay. It is recommended that all children with neurodevelopmental problems be assessed for nutritional deficiency and malabsorption syndromes.

8. Gluten & autism: case study in Journal of Child Neurology
Teresa Binstock  Jul 02, 2009
http://www.generationrescue.org/binstock/090702-autism-gluten-jcn.htm

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