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Congressional Hearing – Gender/Race Disparity in Autism

A topic of much debate was the disparity observed in autism spectrum disorder diagnosis rates between gender, race, and geographic locations. To account for these differences, several hypotheses were put forth by each panel in regards to the mechanisms that have prevented a diagnostic consistency all ASD populations. These include financial and geographic barriers, differences in screening procedures and diagnostic criteria in different populations, and differences in how different populations collect data on ASD. Below is a number of statistics discussed during the hearing that illustrate the incongruities detected amongst the different population.

Earlier in 2012, the CDC released their report from the Autism and Developmental Disabilities Monitoring (ADDM) Network, which aimed to determine the prevalence of autism in the United States through data collected from 14 states in 2008. The following are some of the major statistics released in their report:5

  • Overall prevalence of ASD is 1:88
  • 1 in 54 boys vs. 1 in 252 girls are diagnosed with an ASD
  • Racial Statistics:

  • White (non-Hispanic):12 per 1, 000

  • Black (non-Hispanic): 10.2 per 1,000

  • Hispanic: 7.9 per 1,000

  • Asian or Pacific Islander: 9.7 per 1,000

  • The prevalence rates varied by ADDM site, with Alabama exhibiting the lowest prevalence rate at 1 in 210 while New Jersey and Utah had an alarming prevalence rate of 1 in 49 and 1 in 47 respectively.

The data collected by the ADDM demonstrates that the estimated prevalence of ASD in the United States has risen 78% since 2002.5 It has been argued by many that a good portion of this substantial increase is caused by superior diagnostic evaluation and more accurate screening tools. Others have claimed that the inclusion of Asperger’s syndrome within the DSM-IV has led to an increase in the number of individuals diagnosed with autism. Dr. Guttmacher stated:1

Clearly we know for sure that some of the increase in terms of the rates the CDC cites…is due to increased and better diagnosis which is laudable. Whether that explains the whole thing I don’t think that we scientifically know for sure….regardless of the answer we know: A. That there are environmental factors at play here, and we need to identify them; B. We know it is a common public health problem, so we need to take it seriously. (1:54)

While Mr. Blaxill did not seem to disagree with the latter sentiments of Dr. Guttmacher’s statement, he did take exception to the belief that improved detection and screening tools are responsible for this substantial increase. Mr. Blaxill emphatically proclaimed that “some people claim [the rise of ASD prevalence] isn’t real. That we’re just doing better diagnosis, that’s just wrong…even in the CDC studies they are using the same methodology. So, when you see those numbers rising it’s not because the methods are changing, it is because there are more cases.”1 (2:39)

A study released in 2011 found that the estimated prevalence of autism spectrum disorders in South Korea is 1 in 38, which translates to 2.64% of the population.6 These numbers indicate a dramatic difference between the CDC’s domestic estimates of ASD prevalence vs. that of South Korea; however, these latter figures may be more accurate. The difference, according to Bob Wright, president of Autism Speaks, is caused by the unique methodology of the two studies. The ADDM study utilized systematic record review, which consists of reviewing health and educational records to identify children with autism behaviors.5 While the study that collected data in Seoul, South Korea, which was funded by a Pilot Research Grant from Autism Speaks to “support better detection, assessment and services…”, 6 gathered data from “those enrolled in special education and the disability registry, as well as children enrolled in general education schools. Children were systematically assessed using multiple clinical evaluations.”6 It has been suggested that if these types of screening procedures and diagnostic criteria were applied to our population, ASD prevalence could possibly exceed the CDC’s current estimates.6

Although issues may exist with the CDC’s screening process and diagnostic criteria, the consistency of data collection throughout the 14 ADDM sites raises questions concerning the incongruity of ASD prevalence numbers in the different states. Two theories proposed to account for these differences include environmental factors in specific to certain geographic areas are affecting the prevalence of ASD in certain populations and differences in the ways states collect records on children with ASD are contributing to the discrepancies observed in different parts of the country. Dr. Boyle believes the latter theory is more likely the cause of the disparity. When asked about this topic, Dr. Boyle stated that “our tracking program utilizes [state] record sources to identify children and that varies from state to state. Those numbers are in many ways a reflection of that. Some of our states don’t have access to education records, and since we are dealing with 8-year-old children or school-aged children and they’re served through IDEA and special education that makes a difference as well.”1 (2:11) Actions taken to investigate this matter further include a study funded by Autism Speaks, which is utilizing the South Carolina ADDM site to “enhance our understanding of ADDM prevalence estimates, identify barriers to identification, and characterize the needs of children across the entire spectrum.”7 The 3-year study is expected to conclude in 2014.

Methodological issues cannot account for the differences observed between race and gender observed in the most recent ADDM report however. The diagnostic rates between white and African-American children are “fairly comparable”,1 but the diagnostic rate for Hispanics is significantly lower. Moreover, research has demonstrated that “white kids may be diagnosed with autism as much as a year and a half earlier than black and other minority children.”8 This is alarming because participating in treatments and interventions as early as possible is a critical for individuals on the autism spectrum. Some of the barriers preventing minority children from receiving early and accurate diagnosis discussed at the congressional hearing include language, socioeconomic, and a general lack of awareness.1