Racial Differences in the Prevalence of Autism Spectrum Disorder: A Systematic Review

Purpose: Racial differences in prevalence rates of autism spectrum disorder (ASD) have shifted in the United States (US) since the 1990s. This review addresses the nature and context of this shift and discusses potential contributing factors and areas for future research. Methods: Seventeen population-based epidemiological birth cohort studies on ASD prevalence in the US that included race as a variable are included in the review. Studies were identified via a keyword search on PubMed. To be included, studies were required to include race or ethnicity as a variable in the prevalence estimates, include at least 1000 cases with autism, and be published in English by June 3rd, 2023. Results: Results suggest that in nearly all birth cohorts prior to 2010, ASD prevalence rates were highest among White children. ASD prevalence rates among Black, Hispanic, and Asian/Pacific Islander (API) children (22.3, 22.5, and 22.2 per 1000, respectively) surpassed prevalence rates among White children (21.2 per 1000) in the 2010 birth cohort and continued to increase in the 2012 birth cohorts. Conclusions: There are persistent racial differences in ASD prevalence in the US, and these differences were inverted after 2010, when ASD prevalence among Black, Hispanic, & API children surpassed ASD prevalence among White children. Possible drivers of this racial repatterning of ASD prevalence include changes in ASD screening and diagnosis, changes to health insurance policy, changes to immigration policy, and increased education attainment by minority groups.