Autism may be more common than previously thought, according to the CDC

Abstract

Problem/Condition: Autism spectrum disorder (ASD).

Period Covered: 2014.

Description of System: The Autism and Developmental Disabilities Monitoring (ADDM) Network is an active surveillance system that provides estimates of the prevalence of autism spectrum disorder (ASD) among children aged 8 years whose parents or guardians reside within 11 ADDM sites in the United States (Arizona, Arkansas, Colorado, Georgia, Maryland, Minnesota, Missouri, New Jersey, North Carolina, Tennessee, and Wisconsin). ADDM surveillance is conducted in two phases. The first phase involves review and abstraction of comprehensive evaluations that were completed by professional service providers in the community. Staff completing record review and abstraction receive extensive training and supervision and are evaluated according to strict reliability standards to certify effective initial training, identify ongoing training needs, and ensure adherence to the prescribed methodology. Record review and abstraction occurs in a variety of data sources ranging from general pediatric health clinics to specialized programs serving children with developmental disabilities. In addition, most of the ADDM sites also review records for children who have received special education services in public schools. In the second phase of the study, all abstracted information is reviewed systematically by experienced clinicians to determine ASD case status. A child is considered to meet the surveillance case definition for ASD if he or she displays behaviors, as described on one or more comprehensive evaluations completed by community-based professional providers, consistent with the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) diagnostic criteria for autistic disorder; pervasive developmental disorder–not otherwise specified (PDD-NOS, including atypical autism); or Asperger disorder. This report provides updated ASD prevalence estimates for children aged 8 years during the 2014 surveillance year, on the basis of DSM-IV-TR criteria, and describes characteristics of the population of children with ASD. In 2013, the American Psychiatric Association published the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), which made considerable changes to ASD diagnostic criteria. The change in ASD diagnostic criteria might influence ADDM ASD prevalence estimates; therefore, most (85%) of the records used to determine prevalence estimates based on DSM-IV-TR criteria underwent additional review under a newly operationalized surveillance case definition for ASD consistent with the DSM-5 diagnostic criteria. Children meeting this new surveillance case definition could qualify on the basis of one or both of the following criteria, as documented in abstracted comprehensive evaluations: 1) behaviors consistent with the DSM-5 diagnostic features; and/or 2) an ASD diagnosis, whether based on DSM-IV-TR or DSM-5 diagnostic criteria. Stratified comparisons of the number of children meeting either of these two case definitions also are reported.

Results: For 2014, the overall prevalence of ASD among the 11 ADDM sites was 16.8 per 1,000 (one in 59) children aged 8 years. Overall ASD prevalence estimates varied among sites, from 13.1–29.3 per 1,000 children aged 8 years. ASD prevalence estimates also varied by sex and race/ethnicity. Males were four times more likely than females to be identified with ASD. Prevalence estimates were higher for non-Hispanic white (henceforth, white) children compared with non-Hispanic black (henceforth, black) children, and both groups were more likely to be identified with ASD compared with Hispanic children. Among the nine sites with sufficient data on intellectual ability, 31% of children with ASD were classified in the range of intellectual disability (intelligence quotient [IQ] <70), 25% were in the borderline range (IQ 71–85), and 44% had IQ scores in the average to above average range (i.e., IQ >85). The distribution of intellectual ability varied by sex and race/ethnicity. Although mention of developmental concerns by age 36 months was documented for 85% of children with ASD, only 42% had a comprehensive evaluation on record by age 36 months. The median age of earliest known ASD diagnosis was 52 months and did not differ significantly by sex or race/ethnicity. For the targeted comparison of DSM-IV-TR and DSM-5 results, the number and characteristics of children meeting the newly operationalized DSM-5 case definition for ASD were similar to those meeting the DSM-IV-TR case definition, with DSM-IV-TR case counts exceeding DSM-5 counts by less than 5% and approximately 86% overlap between the two case definitions (kappa = 0.85).

Interpretation: Findings from the ADDM Network, on the basis of 2014 data reported from 11 sites, provide updated population-based estimates of the prevalence of ASD among children aged 8 years in multiple communities in the United States. The overall ASD prevalence estimate of 16.8 per 1,000 children aged 8 years in 2014 is higher than previously reported estimates from the ADDM Network. Because the ADDM sites do not provide a representative sample of the entire United States, the combined prevalence estimates presented in this report cannot be generalized to all children aged 8 years in the United States. Consistent with reports from previous ADDM surveillance years, findings from 2014 were marked by variation in ASD prevalence when stratified by geographic area, sex, and level of intellectual ability. Differences in prevalence estimates between black and white children have diminished in most sites, but remained notable for Hispanic children. For 2014, results from application of the DSM-IV-TR and DSM-5 case definitions were similar, overall and when stratified by sex, race/ethnicity, DSM-IV-TR diagnostic subtype, or level of intellectual ability.

Public Health Action: Beginning with surveillance year 2016, the DSM-5 case definition will serve as the basis for ADDM estimates of ASD prevalence in future surveillance reports. Although the DSM-IV-TR case definition will eventually be phased out, it will be applied in a limited geographic area to offer additional data for comparison. Future analyses will examine trends in the continued use of DSM-IV-TR diagnoses, such as autistic disorder, PDD-NOS, and Asperger disorder in health and education records, documentation of symptoms consistent with DSM-5 terminology, and how these trends might influence estimates of ASD prevalence over time. The latest findings from the ADDM Network provide evidence that the prevalence of ASD is higher than previously reported estimates and continues to vary among certain racial/ethnic groups and communities. With prevalence of ASD ranging from 13.1 to 29.3 per 1,000 children aged 8 years in different communities throughout the United States, the need for behavioral, educational, residential, and occupational services remains high, as does the need for increased research on both genetic and nongenetic risk factors for ASD.

11 responses to “Autism may be more common than previously thought, according to the CDC

  1. I just want to make sure I am understanding the data. So the number of 1 in 59 is from 2014? I’m assuming the CDC needed time to crunch the numbers? It also appears as though there are fewer ADDM sites than when they reported in the past. Last time there were 14. I’m wondering why the number of sites declined.

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    • Yes, they collect the data and take some time in analyzing the same. Just to say we always get a cross sectional analysis of prior years. However, if you go to meeting and talk to the individual center directors you can obtain information on how they are doing before the same is published. Thanks for the comment. Presently going to an autism think tank where I can imagine what will be discussed first.

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  2. though I despise the neurodiversity movement, they aren’t saying the prevalence has not changed, only that more people are being diagnosed for some reason and there is nothing in the environment that would cause the numbers to rise, but more people are being diagnosed because of shifting diagnosis criteria. This will be even more true and a greater prevalence if the ND movement gets its way and has an entirely new diagnostic definition for females versus males. They are helping researchers like Allison Ratto get financing to show there is a camouflaging effect among females, though there’s no real evidence of it. The ADDM numbers have no credibility with me. They keep changing sites, and counties within the actual site, so the prevalence from one report to another does not really show any true increase if they stuck to the same sites or better yet, examined the whole USA if that were feasible. The ADDM spends 5 million dollars a year on these reports, yet the money could be better spent on brain research, job training programs, residential facilities and what not. I believe the ADDM and their reports are a complete waste of taxpayer money and should be abolished.

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    • Yes, Neurodiversity tried to explain away the numbers by shifting diagnosis. This has already been studied, and accounts for some but not all of the increase. Irva Hertz-Picciotto has been influential in this regard. I agree that they over spend in these studies, and that they have faults.

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      • I think Irva’s study has been useful in this debate, but I beg to suggest that the most telling data is in Figures 3.1 to 3.4 in Chapter 3 at http://www.pseudoexpertise.com You can see that the increase of diagnoses (Fig 3.3) occurs exactly concurrently with the change of ratio data (Fig 2). This is impossible to credibly explain except in terms of the two being reflections of the same entirely real increase – and that chapter also provides more than a little evidence that it has been caused by the change to non-gamma-2 in 1976. From that data I predicted first that concurrently with the autism increase there would be an increase of (mercury poisoning) adult disability – as is confirmed in Figure 3.5, and then further predicted an earlier major increase 140 years earlier, again confirmed in Figure 3.7. Such confirmed predictions are the hallmark of the real best science, compared to which any number of doctorates amount to nothing of substance however much work was put into them. .

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    • It should firstly be noted that these stats are of cumulative (total current) autism (then divided by population), rather than in respect of birth-year cohorts years. This would make sense if the cause of autism were relatively instant, like your autism score depends on how much coffee you’ve recently drunk. But there is far more reason to reckon the cause to be more related to the situation pre and perinatally, for which birth-year cohorts makes far more sense.

      As for the environmental cause there is more than enough evidence that the autism increase has been caused by the change to non-gamma amalgams from 1976 – as detailed in Chapter 3 at http://www.pseudoexpertise.com . But don’t expect the “experts” at CDC etc to ever recognise it within the lifetimes of anyone alive today. The criticisms of the evidence can be summed up in less space than a full stop (or what the Trumplandians call a period).

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      • Oops major correction. I was getting mixed up with stats displayed on another site. The 1/59 prevalence stated in this study is effectively for the birth-year cohort of the year eight years before 2014 (about 2006). My other points appear to remain valid though. Note that this data tells us nothing of what’s happened in the past 12 years.

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    • I read females with a late diagnosis of ASD talking about unemployed adults as lazy and explaining “mimicry” as a sort of pretending to be empathic.

      Some of these women has high ability to manipulate and even get in trouble naive people with well stablished ASD diagnosis.

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    • I would say high functioning among females is underdiagnosed, the ratio is 1 to 8, but I believe there is a gender gap, 1 to 3-4 like severe which cannot be hidden. However to say it is 1 to 1 is absolute bullpoo. There is no evidence against what we have discovered, and for almost every condition be it heart disease or lung cancer, men get it more, so why deny any gender gap could exist? Or even be agnostic? But no, the ND movement keeps insisting it is 1 to 1.

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  3. “The CDC has reported an increased prevalence of autism spectrum disorder”
    Trust the brilliant CDC to report the number of cases of a “disorder” that doesn’t exist anyway – as explained in Chapter 2 at http://www.pseudoexpertise.com
    Such would-be expertise would be amusing if it were not so pathetic.
    By the way, a very real possibility is that any birth-year cohorts recent increase of autism behaviours could be merely the recognition catching up with the reality (which had increased previously), hence the real increase already ceased some years previously in terms of birth-year cohorts. .

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