23 Association between Autism Spectrum Disorder and Parental Immigration among a Cohort of Preschool Children in Manitoba

Abstract

Abstract Background Recent data indicate that rates of autism spectrum disorder (ASD) are increasing and therefore, studies exploring risk factors for ASD that can further support early diagnosis and intervention are needed. A link between immigration and autism has been made by several international studies, but despite high rates of immigration, a Canadian study examining this association has not been conducted. Objectives To determine the proportion of children diagnosed with ASD at Manitoba’s primary autism referral site (the only publicly funded site for ASD evaluation of children <6 years of age) that were born to immigrant parents, and compare it with the known proportion of immigrants in Manitoba. Also, to compare demographic and clinical characteristics of children whose parents are immigrants with those whose parents were born in Canada. Design/Methods We conducted a retrospective chart review of >2000 electronic records that identified all children <6 years diagnosed with ASD at the referral site between May 2016 and September 2021. Data on parental immigration, demographics, diagnostic evaluation, and medical history was collected. Descriptive statistics were used to compare the relative proportion of children with ASD from immigrant parents with the proportion of immigrants in Manitoba based on 2016 census data. Results A total of 1865 children were diagnosed with ASD during the study period. The mean age at referral and diagnosis was 2.81 (SD 1.26) years and 3.88 (SD 2.90) years respectively; 78% were male and 13.5% were born preterm. The proportion of children with ASD from immigrant parents (36%) was greater than the expected proportion (18.3%) of immigrants based on Manitoba census data (p < 0.001). The most common countries of origin of immigration were the Philippines (30.7%), India (11.6%), Nigeria (8.6%), and Ethiopia (6.4%). Overall, children of immigrants were younger at referral (2.71 years, SD = 0.98 versus 2.91 years, SD = 1.43; p <0.001), less likely to have a family history of ASD (17.1% versus 35.6%; p = <0.001) and less likely to have comorbidities (46.8% versus 53.9%; p <0.001) including global developmental delay (18% versus 27.6%; p <0.001). Conclusion At Manitoba’s primary autism referral site, there was a greater proportion of children diagnosed with ASD born to immigrant parents than expected when compared to the Manitoba population. Overall, children of immigrants were younger, less likely to have comorbidities, developmental delay, and a family history of ASD. Future prospective studies are required to better understand the complex relationship between immigration and ASD diagnosis.