Jessica Bradshaw and colleagues have an article at The Journal of Autism and Developmental Disorders titled "County-Level Prevalence Estimates of Autism Spectrum Disorder in Children in the United States"
Prevalence estimates of autism spectrum disorder (ASD) point to geographic and socioeconomic disparities in identification and diagnosis. Estimating national prevalence rates can limit understanding of local disparities, especially in rural areas where disproportionately higher rates of poverty and decreased healthcare access exist. Using a small area estimation approach from the 2016–2018 National Survey of Children’s Health (N = 70,913), we identified geographic differences in ASD prevalence, ranging from 4.38% in the Mid-Atlantic to 2.71% in the West South-Central region. Cluster analyses revealed “hot spots” in parts of the Southeast, East coast, and Northeast. This geographic clustering of prevalence estimates suggests that local or state-level differences in policies, service accessibility, and sociodemographics may play an important role in identification and diagnosis of ASD.
From the article:
States differ significantly in services covered by private insurance mandates, timing of adoption of insurance mandates, and availability of service providers, all unique factors that may impact whether and when parents seek an ASD diagnosis (Choi et al., 2020; Johnson et al., 2014). While statewide mandates certainly contribute to regional differences, county and neighborhood resource allocation and access play an important role in regional differences. Indeed, large variation exists even within small, relatively densely populated states (Shenouda et al., 2022). For example, regional hotspots observed in this study may be explained in part by clusters of high-resource areas within states, which can be examined using proximity to high-volume medical or autism centers. In the current study, this may be the case where some hotspots include areas with a high density of university-based medical research centers with autism diagnostic programs in the Northeast (including New York, NY, New Haven, CT, Providence, RI, Boston, MA), the Southeast (Atlanta, GA; Charleston, SC), and parts of Southern California (San Diego, Los Angeles). In addition, the observed contrast in ASD prevalence between hotspot regions in Southern California (San Diego/Los Angeles) and cold spot regions Northern California surrounding San Francisco (e.g., San Francisco, Marin) partially align with recent findings of increasing ASD diagnoses among white children in middle income counties, including San Diego, Los Angeles and decreasing ASD diagnoses among white children in wealthier counties surrounding San Francisco (e.g., Marin) (Nevison & Parker, 2020). These data highlight the importance of county- and region-specific examinations of ASD resources and suggest a combination of sociodemographic and geographic features that may serve as facilitators and barriers to ASD diagnosis. Future research should explore the intersection of ASD prevalence with neighborhood sociodemographics as well as the co-location of high or low ASD prevalence and the corresponding high or low density of healthcare providers (e.g., pediatricians, behavioral health providers, etc.) to determine the potential relationship with local access to care.