Migration and Autism Spectrum Disorders

Thursday, May 17, 2012
Sheraton Hall (Sheraton Centre Toronto)
3:00 PM
C. Magnusson1, D. Rai1,2, A. Goodman3, M. Lundberg1, S. Idring1, A. Svensson1, I. Koupil4, E. Serlachius5 and C. Dalman1, (1)Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden, (2)School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom, (3)London School of Hygiene & Tropical Medicine, London, United Kingdom, (4)Stockholm University , Stockholm , Sweden, (5)Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
Background: Migration is associated with a range of biological, psychological and sociocultural stressors. Parental migration has been implicated as a risk factor for offspring autism, but the evidence is limited and inconsistent.

Objectives: To investigate the relationship between parental migration status and risk of autism spectrum disorders (ASD), taking into consideration the importance of region of origin, timing of migration and possible discrepancies in associations between autism subtypes.

Methods: The Stockholm Youth Cohort is a record-linkage study comprising all individuals aged 0-17 years, ever resident in Stockholm County in 2001-2007 (N=589,114). Cases (N=4,952) were identified using a multisource approach, involving registers covering all pathways to ASD diagnosis and care, and categorized according to presence of co-morbid intellectual disability. Extensive and prospectively recorded information on parental migration status and other potential risk factors were retrieved from national and regional health and administrative registers.

Results: Children of migrant parents were at increased risk of ASD with comorbid intellectual disability (odds ratio [OR] 1.5, 95% confidence interval [CI] 1.3-1.7); this risk was highest when parents migrated from regions of low human development, and peaked when migration occurred around pregnancy (OR 2.3, 95% CI 1.7-3.0). A decreased risk of ASD without intellectual disability was observed in children of migrant parents, regardless of area of origin or timing of migration. Parental age, income or obstetric complications did not fully explain any of these associations.

Conclusions: Environmental factors associated with migration may contribute to the development of autism presenting with comorbid intellectual disability, especially when acting during fetal life. ASD presenting with and without intellectual disability may have partly different etiologies, and should be studied separately.

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