title: An incidence study of diagnosed autism-spectrum disorders among immigrants to the Netherlands.
abstract: OBJECTIVE
  To estimate the risk of developing autism-spectrum disorder (ASD) in children born to immigrants as compared with children of Dutch-born parents.
  
  
  METHODS
  Retrospective, population-based cohort study of all live births (n = 106 953) between 1998 and 2007 in a circumscribed geographical region in the Netherlands. Cohort members were linked to the Psychiatric Case Register to identify diagnosed cases.
  
  
  RESULTS
  A total of 518 cases of ASD were identified, including 150 children with autism and 368 children with Asperger syndrome or Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS). Children born to migrants from developing countries were at significantly lower risk of ASD [rate ratio (RR) = 0.6, 95% confidence interval (CI) 0.5-0.9] than children of Dutch-born parents. Within the ASD group, the risk for the subgroup with Asperger syndrome and PDD-NOS was reduced (RR = 0.4, 95% CI 0.3-0.6), whereas that for narrowly defined autism was non-significantly increased (RR = 1.4, 95% CI 0.9-2.4). Migrant groups did not differ in age at diagnosis.
  
  
  CONCLUSIONS
  The results echo Swedish findings indicating a reversal of risk gradient in children of parents from developing countries, specifically a decreased risk for high-functioning and increased risk for low-functioning autism.
authors.affiliation: Rivierduinen Foundation, GGZ Leiden, Leiden; Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, the Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: van der Ven
authors.forename: F
authors.initials: F
authors.lastname: Termorshuizen
authors.forename: W
authors.initials: W
authors.lastname: Laan
authors.forename: E J
authors.initials: EJ
authors.lastname: Breetvelt
authors.forename: J
authors.initials: J
authors.lastname: van Os
authors.forename: J P
authors.initials: JP
authors.lastname: Selten
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology; D001321:Autistic Disorder / Q000453:epidemiology; D002648:Child; D002659:Child Development Disorders, Pervasive / Q000175:diagnosis* / Q000453:epidemiology*; D015331:Cohort Studies; D015897:Comorbidity; D054242:Emigrants and Immigrants / Q000706:statistics & numerical data*; D005192:Family Health / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D012042:Registries / Q000706:statistics & numerical data; D012307:Risk Factors; D017678:Sex Distribution