Migration and autism spectrum disorder: Population-based study

Department of Public Health Sciences, Karolinska Institutet, Norrbacka, Stockholm, Sweden.
The British journal of psychiatry: the journal of mental science (Impact Factor: 7.99). 02/2012; 201(2):109-15. DOI: 10.1192/bjp.bp.111.095125
Source: PubMed


Migration has been implicated as a risk factor for autism, but evidence is limited and inconsistent.
To investigate the relationship between parental migration status and risk of autism spectrum disorder, taking into consideration the importance of region of origin, timing of migration and possible discrepancies in associations between autism subtypes.
Record-linkage study within the total child population of Stockholm County between 2001 and 2007. Individuals with high- and low-functioning autism were defined as having autism spectrum disorder with and without comorbid intellectual disability, and ascertained via health and habilitation service registers.
In total, 4952 individuals with autism spectrum disorder were identified, comprising 2855 children with high-functioning autism and 2097 children with low-functioning autism. Children of migrant parents were at increased risk of low-functioning autism (odds ratio (OR) = 1.5, 95% CI 1.3-1.7); this risk was highest when parents migrated from regions with a low human development index, and peaked when migration occurred around pregnancy (OR = 2.3, 95% CI 1.7-3.0). A decreased risk of high-functioning autism 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.
Environmental factors associated with migration may contribute to the development of autism presenting with comorbid intellectual disability, especially when acting in utero. High- and low-functioning autism may have partly different aetiologies, and should be studied separately.

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Available from: Anna Goodman, Aug 02, 2014
    • "Several previous studies link maternal migration stressors with obstetric complications during pregnancy and labour (Binder et al., 2012aBinder et al., , 2012bBinder et al., , 2013 Essen et al., 2011). These include stressors linked with sociocultural conditions, beliefs and practices (Magnusson et al., 2012; Van der Ven et al., 2013), for example psychological and medical distress that can accompany common experiences, such as targeted discrimination, or culturally specifi c experiences , such as forced female circumcision. Mismatch expectations between migrant groups and healthcare providers (Warfa et al., 2006Warfa et al., , 2012), cultural or community misunderstandings of care procedures, inaccessible healthcare services, language and communication barriers (Bhui et al. , 2003Bhui et al. , , 2007 Warfa et al., 2006), and delayed help-seeking behaviour (Bhui et al., 2003; Binder et al, 2012a Binder et al, , 2012b Binder et al, ., 2013 Essen et al., 2011; Warfa et al., 2006 Warfa et al., , 2012) may all lead to stressors that induce epigenetic changes during pregnancy and delivery; with associated risk of AUT. "
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    • "After exclusion of observations with missing covariate data, the final sample consisted of 2,371,403 persons, with 24,414 identified ASD cases. The Stockholm Youth Cohort is a register-based study with continuous enrollment comprising all individuals who were ever resident in Stockholm County as children (Idring et al., 2012; Magnusson et al., 2012). All data are derived from linkages to national registers held by Statistics Sweden and the National Board of Health and Welfare, as well as regional registers held by the Stockholm County Council. "
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