Migration and Risk of Autism and Intellectual Disability – Preliminary Findings from the Stockholm Youth Cohort

Poster Presentation
Saturday, May 12, 2018: 11:30 AM-1:30 PM
Hall Grote Zaal (de Doelen ICC Rotterdam)
C. Magnusson1, H. Heuvelman2, M. Morinaga1, A. C. Hollander1, C. Dalman3 and D. Rai4, (1)Karolinska Institutet, Stockholm, Sweden, (2)University of Bristol, Bristol, United Kingdom of Great Britain and Northern Ireland, (3)Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden, (4)Population Health Sciences, Bristol Medical School, Centre for Academic Mental Health, Bristol, United Kingdom
Background: Parental migration status is an emerging risk factor for autism spectrum disorder (ASD) and perhaps also for intellectual disability (ID). The foundation of any association is, however, not established.

Objectives: To elucidate whether migration status is universally linked to neurodevelopmental disorders or specifically to ASD or ID, and how any link varies with parental region of origin. In addition, to investigate how any relationships may be explained by migration-related by comparing risks between full siblings discordant for maternal migrant status (siblings being born in Sweden versus abroad).

Methods: Total population study based on linkages of health and administrative registers, including 545,648 individuals born in 1984-2007, who were resident in Stockholm County, Sweden for at least four years through 2011. Migration status was defined according to parental country of birth and timing of maternal immigration to Sweden in relation to the index persons’ birth. Odds ratios (ORs) from total cohort analyses were adjusted for age, sex, maternal and paternal age, using generalized estimating equation models to account for family clustering. Sibling comparisons were adjusted for sex.

Results: In all, 11,163 and 6,845 individuals were respectively identified with diagnoses of ASD and ID during follow-up. Children of migrant parents had an increased risk of autism with co-morbid ID (aOR 1.69, 95% CI 1.54 - 1.85) and of ID only (aOR 1.74, 95% CI 1.61 - 1.87), but a decreased risk of ASD without ID (aOR 0.56, 95% CI 0.52 - 0.60).These associations were particularly pronounced in children of parents from low-income countries. Timing of maternal migration in relation to birth of the index child appeared to influence the risk of ASD (but not ID only), such that the risk increased with increasing nearness of immigration to the timing of pregnancy. Individuals born in Sweden had a twofold increase in risk of ASD regardless of comorbid ID compared to their full siblings born abroad, while no such discrepancy for ID only was observed.

Conclusions: Parental origin in low-income countries is strongly associated with ID, with or without ASD in Stockholm County – but the explanatory mechanisms may differ between ASD with ID and ID only. ASD without ID is comparatively less often diagnosed in children of migrants to Sweden.

See more of: Epidemiology
See more of: Epidemiology