title: Prevalence of non-febrile seizures in children with idiopathic autism spectrum disorder and their unaffected siblings: a retrospective cohort study.
abstract: BACKGROUND
  Autism spectrum disorder (ASD) is a heterogeneous disorder characterized not only by deficits in communication and social interactions but also a high rate of co-occurring disorders, including metabolic abnormalities, gastrointestinal and sleep disorders, and seizures. Seizures, when present, interfere with cognitive development and are associated with a higher mortality rate in the ASD population.
  
  
  METHODS
  To determine the relative prevalence of non-febrile seizures in children with idiopathic ASD from multiplex and simplex families compared with the unaffected siblings in a cohort of 610 children with idiopathic ASD and their 160 unaffected siblings, participating in the Autism Genetic Resource Exchange project, the secondary analysis was performed comparing the life-time prevalence of non-febrile seizures. Statistical models to account for non-independence of observations, inherent with the data from multiplex families, were used in assessing potential confounding effects of age, gender, and history of febrile seizures on odds of having non-febrile seizures.
  
  
  RESULTS
  The life-time prevalence of non-febrile seizures was 8.2% among children with ASD and 2.5% among their unaffected siblings. In a logistic regression analysis that adjusted for familial clustering, children with ASD had 5.27 (95%CI: 1.51-18.35) times higher odds of having non-febrile seizures compared to their unaffected siblings. In this comparison, age, presence of gastrointestinal dysfunction, and history of febrile seizures were significantly associated with the prevalence of non-febrile seizures.
  
  
  CONCLUSIONS
  Children with idiopathic ASD are significantly more likely to have non-febrile seizures than their unaffected siblings, suggesting that non-febrile seizures may be ASD-specific. Further studies are needed to determine modifiable risk factors for non-febrile seizures in ASD.
authors.affiliation: Division of Biostatistics, Washington University in St. Louis, School of Medicine, 660 Euclid Ave., St. Louis, MO, 63110, USA. mccuel@wustl.edu.
authors.forename: Lena M
authors.initials: LM
authors.lastname: McCue
authors.affiliation: Epidemiology Department, Saint Louis University, College for Public Health and Social Justice, 3545 Lafayette Ave., St. Louis, MO, 63104, USA.
authors.forename: Louise H
authors.initials: LH
authors.lastname: Flick
authors.affiliation: Department of Pediatrics, Saint Louis University School of Medicine, 1465 S Grand Blvd., St Louis, MO, 63104, USA.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Twyman
authors.affiliation: Department of Biostatistics, Saint Louis University, College for Public Health and Social Justice, 3545 Lafayette Ave., St. Louis, MO, 63104, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Xian
authors.affiliation: Department of Radiology, Washington University School of Medicine, 4525 Scott Ave., St Louis, MO, 63110, USA.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Conturo
mesh_terms: D000293:Adolescent; D000067877:Autism Spectrum Disorder / Q000453:epidemiology* / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D012042:Registries; D012189:Retrospective Studies; D012640:Seizures / Q000453:epidemiology* / Q000235:genetics; D035781:Siblings
keywords: AGRE; Autism; Epilepsy; Familial; Genetic; Idiopathic; Prevalence; Seizures; Siblings