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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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