Background: Autism spectrum disorders are often idiopathic. Studies have suggested associations between immune response and these disorders. We explored associations between parental autoimmune disorders and children's diagnosis of autism by linking Swedish registries.
Methods: Data for each participant were linked across 3 Swedish registries. The study includes 1227 cases and 25 matched controls for each case (30,693 controls with parental linkage). Parental diagnoses comprised 19 autoimmune disorders. We estimated odds ratios (ORs) using multivariable conditional logistic regression.
Results: Parental autoimmune disorder was weakly associated with autism spectrum disorders in offspring (maternal OR = 1.6 [95% confidence interval = 1.1–2.2]; paternal OR = 1.4 [1.0–2.0]). Several maternal autoimmune diseases were correlated with autism. For both parents, rheumatic fever was associated with autism spectrum disorders.
Conclusions: These data support previously reported associations between parental autoimmune disorders and autism spectrum disorders. Parental autoimmune disorders may represent a critical pathway that warrants more detailed investigation.
From the Departments of aEpidemiology and bMaternal and Child Health, University of North Carolina, Chapel Hill, NC; cWorldwide Epidemiology, GlaxoSmithKline R&D, Collegeville, PA; dInstitute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden; eDepartment of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden; fClinical Epidemiology Unit, Department of Medicine, Karolinska Institutet, Stockholm, Sweden; and gDivision of Clinical Pharmacology, Karolinska University Hospital Huddinge, Karolinska Institutet, Stockholm, Sweden.
Submitted 13 November 2009; accepted 2 June 2010; posted 26 August 2010.
Supported partially by the US Centers for Disease Control and Prevention (Grant # U50/CCU422345–04) and the US National Institute of Health Sciences (Grant # T32 ES007018).
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Correspondence: Alexander Keil, Department of Epidemiology, CB 7435, University of North Carolina, Chapel Hill, NC 27599–7435. E-mail: firstname.lastname@example.org.