Socioeconomic Inequality in the Prevalence of Autism Spectrum Disorder: Evidence from a U.S. Cross-Sectional Study

Department of Population Health Sciences, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America.
PLoS ONE (Impact Factor: 3.23). 07/2010; 5(7):e11551. DOI: 10.1371/journal.pone.0011551
Source: PubMed


This study was designed to evaluate the hypothesis that the prevalence of autism spectrum disorder (ASD) among children in the United States is positively associated with socioeconomic status (SES).
A cross-sectional study was implemented with data from the Autism and Developmental Disabilities Monitoring Network, a multiple source surveillance system that incorporates data from educational and health care sources to determine the number of 8-year-old children with ASD among defined populations. For the years 2002 and 2004, there were 3,680 children with ASD among a population of 557,689 8-year-old children. Area-level census SES indicators were used to compute ASD prevalence by SES tertiles of the population.
Prevalence increased with increasing SES in a dose-response manner, with prevalence ratios relative to medium SES of 0.70 (95% confidence interval [CI] 0.64, 0.76) for low SES, and of 1.25 (95% CI 1.16, 1.35) for high SES, (P<0.001). Significant SES gradients were observed for children with and without a pre-existing ASD diagnosis, and in analyses stratified by gender, race/ethnicity, and surveillance data source. The SES gradient was significantly stronger in children with a pre-existing diagnosis than in those meeting criteria for ASD but with no previous record of an ASD diagnosis (p<0.001), and was not present in children with co-occurring ASD and intellectual disability.
The stronger SES gradient in ASD prevalence in children with versus without a pre-existing ASD diagnosis points to potential ascertainment or diagnostic bias and to the possibility of SES disparity in access to services for children with autism. Further research is needed to confirm and understand the sources of this disparity so that policy implications can be drawn. Consideration should also be given to the possibility that there may be causal mechanisms or confounding factors associated with both high SES and vulnerability to ASD.

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    • "In the U.S., children with autism spectrum disorder (ASD) have been found to live in spatial clusters (Mazumdar et al., 2010; Hoffman et al., 2012). From a public health perspective, these clusters mean that children in certain neighbourhoods—often overrepresented by Latinos, African Americans, and low socioeconomic status (SES) families (Durkin et al., 2010)—are less likely than others to receive important services that can improve life outcomes (Liptak et al., 2008). Identifying the causes of the clusters will inform public health officials on how to remediate these inequities and inform us on " contextual drivers " of the increasing prevalence of ASD (Mazumdar et al., 2013). "
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    ABSTRACT: In the U.S., children with autism spectrum disorder (ASD) have been found to live in spatial clusters. Studies have suggested that the clustering is caused by social or environmental factors, but determining the cause of the clustering is difficult in the U.S. setting because of unmeasured variation in healthcare access and diagnostic practices. The present study explores the diffusion of ASD in a small setting in which the diagnosis is not widely publicised and there is no variation in healthcare access or diagnostic practices. Costa Rica provides universal healthcare and only has one diagnosing clinic for young children, and the diagnosis is relatively new and little known among clinicians and parents. In addition, the potential for mercury exposure from the source that has been associated with ASD is absent, and areas with high levels of air pollution are spatially concentrated. Focusing on all young children who underwent an ASD assessment from 2010 to 2013, we identify spatial clusters that suggest a mechanism that does not depend on information about ASD, healthcare access, diagnostic practices, or environmental toxicants. These findings provide details of the "contextual drivers" of the increasing worldwide prevalence of ASD. Copyright © 2015 Elsevier Ltd. All rights reserved.
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    • "Diagnosis of ASD has historically been influenced by certain demographic variables . Children of privileged and/or Caucasian families have been overrepresented, and families of lower socioeconomic status (SES) and of minority racial and ethnic backgrounds have traditionally been underdiagnosed (Durkin et al. 2010; Fountain et al. 2011). Although community awareness of ASD has begun to reduce these racial and socioeconomic disparities, group differences remain (CDC 2014; Gourdine and Algood 2014; Pedersen et al. 2012; Zuckerman et al. 2013). "
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    ABSTRACT: Having a consistent source of medical care may facilitate diagnosis of autism spectrum disorders (ASD). This study examined predictors of age of ASD diagnosis using data from the 2011-2012 National Survey of Children's Health. Using multiple linear regression analysis, age of diagnosis was predicted by race, ASD severity, having a consistent source of care (CSC), and the interaction between these variables after controlling for birth cohort, birth order, poverty level, parental education, and health insurance. While African American children were diagnosed earlier than Caucasians, this effect was moderated by ASD severity and CSC. Having a CSC predicted earlier diagnosis for Caucasian but not African American children. Both physician and parent behaviors may contribute to diagnostic delays in minority children.
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    • "Thus, one would expect that representation of children from various racial and ethnic backgrounds diagnosed with ASD would be aligned with their proportional representation in the general population . Contrary to epidemiological research, discrepancies are evident in the rate of identification of ASD (i.e., disproportional representation) across race/ethnicity and socioeconomic status (SES) in the extant literature (e.g., Becerra et al. 2014; Durkin et al. 2010; Mandell et al. 2009; Sullivan 2013). "
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    ABSTRACT: Autism spectrum disorder (ASD) diagnoses are made based on a pattern of behavioral symptoms, yet a growing body of research indicates that when, and indeed whether, an individual receives a diagnosis of ASD is influenced by myriad demographic factors including race, ethnicity, socioeconomic status (SES), and parental education level. The current manuscript provides a focused review of a subset of existing literature chosen to demonstrate how demographic factors may be related to the identification of individuals with ASD within the United States. Several possible explanations for existing disparities are discussed, along with clinical implications for professionals working with children from diverse backgrounds who are suspected of having ASD. Additional research in this area is needed to facilitate development of effective means to eliminate the diagnostic disparities.
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