A family history of rheumatoid arthritis, type 1 diabetes mellitus, or
celiac disease is associated with a higher risk of developing autism spectrum
disorders in children, a recent study found.
A group of Danish and U.S. researchers collected medical data on all
children born in Denmark to Danish mothers between 1993 and 2004 and matched
these children with their parents' and siblings' hospital records. Any
diagnoses of autoimmune diseases identified before the children were diagnosed
with an autism spectrum disorder were analyzed for possible correlations with
the children's risk for such a disorder.
Among 689,196 children, 3,325 had a diagnosis of an autism spectrum
disorder. Rheumatoid arthritis in mothers was associated with a 70 percent
increase in the risk of autism spectrum disorders in children (risk ratio
1.70, 95 percent confidence interval [CI] 1.07 to 2.54). Mothers' celiac
disease was associated with nearly three times the risk of autism spectrum
disorders compared with children of mothers who did not have celiac disease
(risk ratio 2.97, 95 percent CI 1.27 to 5.75). Family history of type 1
diabetes, with parents and siblings included, was associated with a
statistically significant increase in the risk of the childhood autism
diagnosis (risk ratio 1.78, 1.16 to 2.61), but not the risk of the overall
class of autism spectrum disorders.
These risk associations remained statistically significant even after the
authors limited the analyses to children who were born neither pre-term nor
underweight and who had no obvious distress at birth (Apgar score above 6).
This suggests that the observations cannot be entirely explained by
detrimental effects on the fetus due to the mother's autoimmune disease.
Combined with other research evidence, the authors speculated that certain
autoimmune diseases may share a common genetic root with autism.
Other autoimmune diseases, such as multiple sclerosis, psoriasis, and
Crohn's disease, in parents and siblings were not significantly associated
with autism spectrum disorders in the study children. Furthermore, a family
history of thyrotoxicosis was the only autoimmune disease studied that was
associated with a lower risk of autism spectrum disorder.
The study was published in the August Pediatrics and was funded by
grants from the U.S. National Institute of Mental Health and the Aarhus
University Research Foundation in Denmark.
Because of the nationalized health care and central medical registries in
Denmark, decades of complete medical data of all Danish citizens in the
databases provide a valuable resource for epidemiologic research. In a study
published in the February 21, 2004, British Medical Journal, Eaton
and colleagues found that a parental history of celiac disease was associated
with increased risk of schizophrenia in offspring, also using the Danish
national health care registries.
Celiac disease is an often-undiagnosed autoimmune disease triggered by
gluten in wheat-containing foods. Patients usually suffer from
gastrointestinal symptoms and nutritional deficiencies because the intestinal
linings are attacked and damaged by immune responses to even a minute amount
of gluten intake. According to a recent Mayo Clinic study, the prevalence of
celiac disease has increased fourfold from the 1950s. The study was published
in the July Gastroenterology. The reason for the trend remains
An abstract of "Association of Family History of Autoimmune
Diseases and Autism Spectrum Disorders" is posted at<http://pediatrics.aappublications.org/cgi/content/abstract/124/2/687>.▪