Geographic Differences Among Children with Autism Spectrum Disorders

Background:  There have been few nationally representative surveys that have explored geographic differences among children with autism spectrum disorder (ASD). Yet, regional differences may provide insight into what factors influence the likelihood that a child is diagnosed with ASD and whether the child is able to receive necessary services and treatments. In fact, previous studies have found varying rates of unmet needs and service utilization by geographic region (Chiri & Warfield, 2012; Lokhandwala, Khanna, & West-Strum, 2012). The current study expands the limited literature by analyzing regional differences in ASD prevalence and service utilization within a nationally representative sample of children.

Objectives: 1) Calculate the prevalence of ASD in four geographic regions (Northeast, Midwest, South, West), 2) Explore child and household demographic characteristics and the service utilization of children with ASD in each of these four geographic regions.

Methods:  Data were drawn from the 2014-2015 National Health Interview Survey (NHIS). NHIS is a nationally representative household survey of the noninstitutionalized US population. Respondents (usually parents) provided information on receipt of an ASD diagnosis and service utilization (among other topics) for one randomly selected child in each family. Children aged 3-17 years were included in this analysis.

Prevalence estimates were calculated using Stata 13.1 SE, which accounted for the complex survey design of the NHIS. Differences between geographic regions were compared using logistic and linear regressions with and without adjustment for child and household characteristics.

Results: The prevalence of ASD was highest in the Northeast (3.14%), followed by the Midwest (2.57%), South (2.15%) and West (1.86%). Without adjustment, children in the Northeast were significantly more likely to be diagnosed with ASD than children in the South and West. After adjusting for child and household demographics, children in the Northeast remained significantly more likely to be diagnosed with ASD than children in the West, but not the South.

Children with ASD living in the Northeast were the most likely to live in households with an annual income 400% or higher than the federal poverty level and live in two parent households. The majority of children with ASD in the Northeast lived in a large metropolitan statistical area (69.4%) and were non-Hispanic white (70.5%). Children with ASD located in the Northeast were younger than children with ASD in the Midwest.

Overall, the frequency of service utilization (number of office visits, ER visits, home visits) was highest among children with ASD in the Northeast, but this difference was not significant after adjusting for child and household demographics. However, even after adjustment, children with ASD in the Northeast were significantly more likely to have seen a specialist, therapist, or mental health professional in the past twelve months.

Conclusions: There were notable demographic differences among children with ASD between regions. These differences accounted for observed differences in the frequency of service use, but regional differences in specialized service use remained significant.