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Review: Evidence linking RA and autism is limited
According to a recently published systematic review, there is limited evidence children born to mothers with rheumatoid arthritis are at an increased risk for autism.
“Concern exists that children born to women with [rheumatoid arthritis] RA may have an increased risk for [autism spectrum disorders] ASD compared to children born to healthy women,” Sophie Wojcik, MD, in the Division of Rheumatology at McGill University Health Centre in Canada, and colleagues wrote. “However, the evidence is limited in RA, as shown by our systematic literature review, which identified only three studies with methodological limitations assessing the issue.”
Using PubMed, Embase and Web of Science, Wojcik and colleagues identified 70 articles. Of these, 67 were excluded either due to lack of relevance or that investigators did not report original data. In the first of the remaining three studies — a case-control of 2,095 controls and 407 children diagnosed by International Classification of Disease Ninth Revision (ICD-9) between 1995 and 1999 at the Kaiser Permanente Medical Care Program — there was no difference in the prevalence of RA in mothers of children who had ASD compared with controls (10.3% vs. 8.2%). In the second study — a case-control of 61 families recruited through the East Tennessee Chapter of the Autism Society of America — mothers of children with ASD had an eight-fold increased risk for having autoimmune disorders, which included RA, compared with control mothers (ratio = 8.8). In addition, the study reported 46% of children with ASD had a first-degree relative with RA compared with 26% of controls. In the third study — a population-based cohort of 689,196 controls and 3,325 children diagnosed by ICD-10 code between 1993 and 2004 in Denmark — there was an increased risk of ASD in children with mothers who had a history of RA compared with control mothers (ratio = 1.7).
However, these studies had methodologic limitations. Investigators noted none of the studies controlled for medication exposures and one controlled for obstetrical complications and considered timing of RA diagnosis in relation to pregnancy.
“Further studies are needed to better assess the risk of ASD in children exposed in utero to maternal RA, determining the strength of association (if any), evaluating consistency across studies, and assessing disease-related factors, such as disease activity, cytokine levels and autoantibody status, which might mediate the risk,” the researchers wrote. – by Will Offit
Disclosure s : Researchers report funding from a Canadian Institutes for Health Research Operating Grant. Please see the full study for a list of all other relevant financial disclosures.