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Laying the Foundation for Policy: Measuring Local Prevalence for Autism Spectrum Disorder
Autism spectrum disorder (ASD) is a neurodevelopmental condition that is characterized by lifelong impairments in social relationships and communication, and repetitive, rigid behaviours, and is the most commonly diagnosed neurological disorder in children. Prevalence estimates are of vital importance for policy makers, particularly for the planning of a variety of support resources. However, accurate prevalence readings are difficult to acquire, and such an undertaking is financially burdensome. Currently suggested prevalence levels have had their accuracy levels questioned, and tend to focus on a national scope. This is problematic in that these reports can mask regional variation. National rates are also less preferred to more narrowed readings, such as on a regional or municipal level. Currently, Canada lacks a national surveillance system that can provide estimates for geographic locales. A better understanding of the rates in more narrow locales is important for policy makers, especially given that individuals may migrate to the province of Alberta to access more funding.
Objectives:
This study sought to ascertain an accurate measure of the number of students with ASD living in the Calgary, Alberta region.
Methods:
With the support of local school boards, student records for children enrolled in grades 1 through 12 in the 2012/2013 school year were accessed and analyzed, with all cases of ASD pulled according to criteria outlined in the DSM-IV. We estimate that 91 per cent of all children enrolled in Calgary and area schools were included as part of this study.
Results:
A total of 160,904 children were included as part of the sample. 1,711 children has an ASD diagnosis on their school record, leading to an overall prevalence of 1 in 94 children across all school boards, which differs significantly from the commonly cited Centers for Disease Control and Prevention rate. This study’s rate ranged between the individual boards from 1 in 11 in the “other” school board (likely due to some of the schools in this jurisdiction being tailored to children with ASD) to 1 in 97 for the Catholic Board of Education, 1 in 116 for the Calgary Catholic School District, and 1 in 120 for Rocky View Schools. Across all school boards, the ratio of boys to girls with an ASD diagnosis was 5.2:1. Additionally, 89% of children with ASD were reportedly severe in an educational setting. Interestingly, one school board in the study showed a drop of prevalence in senior grades as compared to younger grades, and no other school showed a coincidental increase in numbers, making it unclear where these students are going.
Conclusions:
Through the analysis of school records, this study provides important information to policy makers that are reflective of geographic variables. The discovered prevalence rate is similar to that identified in national surveillance reports. Important steps forward include regularly updating this data, and conducting this process across the province. Ideally, administrative records could also be used to track individuals beyond Grade 12. This study demonstrated a cost-effective and alternative approach to estimated regional prevalence of ASD.