Early Autism and Developmental Disabilities Monitoring says autism prevalence is still rising...

"The overall ASD [autism spectrum disorder] prevalence was 13.4 per 1,000 children aged 4 years in 2010, 15.3 in 2012, and 17.0 in 2014 for Early ADDM [Autism and Developmental Disabilities Monitoring] sites with data for the specific years."

So said the surveillance summary published by Deborah Christensen and colleagues [1]. Those of you who follow the US ADDM initiative (see here) will already know about the aims of this "group of programs funded by the CDC" looking at the (estimated) autism numbers, changes to the numbers and the impact of the numbers on various communities. Through initiatives like the ADDM, we already know that the estimated prevalence of autism in 8-year olds living in the United States is round about 1 in 59 (see here) and that the estimate continues to grow for pretty much every surveillance year examined. We are also starting to find out about how the change to DSM-5 from DSM-IV is likely to/not to impact on future figures (see here). And hopefully, at some point, we might have some further data on what happens to autism past childhood (see here) from such an initiative.

The Christensen paper adds another tier to the knowledge being acquired as per their analysis of the (estimated) prevalence rate of autism in 4 year olds "whose parents or guardians lived within designated sites." Those sites were: Arizona, Colorado, Missouri, New Jersey, North Carolina, Utah, and Wisconsin. The Early ADDM initiative does not cover the same area as its big brother/sister ADDM but "is conducted in two phases using the same methods and project staff members as the ADDM Network." Those phases include first "reviewing and abstracting data from children’s records, including comprehensive evaluations performed by community professionals" and then a second phase involving "a review of the abstracted evaluations by trained clinicians using a standardized case definition and method." DSM-IV criteria covers most of the time points examined but: "For 2014 only, prevalence estimates based on surveillance case definitions according to DSM-IV-TR and the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) were compared."

Results: as per the opening sentence of this post, the overall (estimated) autism prevalence across all sites for autism in 4 year olds was on the increase between 2010 and 2014. That's not to say that there weren't differences between the various sites - New Jersey, a favourite autism prevalence site (see here) showed the highest prevalence: 19.7, 22.1, and 28.4 per 1,000 for 2010, 2012 and 2014 respectively - but overall the prevalence rate was increasing not decreasing.

There were a number of other important points raised in the Christensen findings. So: "Among four sites with ≥60% data on cognitive test scores (Arizona, New Jersey, North Carolina, and Utah), the frequency of co-occurring intellectual disabilities was significantly higher among children aged 4 years than among those aged 8 years for each site in each surveillance year except Arizona in 2010." I don't think I need to say much more about that. Also: "The overall prevalence estimate using a DSM-IV-TR case definition was approximately 20% higher than the prevalence estimate based on DSM-5 criteria." Again, I don't think too much more discussion is needed on this point aside from saying that for 4-year olds, the switch to DSM-5 might have made more of a difference than for 8-year olds. Indeed in comparison to the Wiggins data [2] based on 8-year olds where "46.0% children met both DSM-IV-TR and DSM-5 surveillance status, 44.0% met neither the DSM-IV-TR nor DSM-5 surveillance status, 4.0% met DSM-IV-TR status, but not DSM-5 status, and 6.0% met DSM-5 status, but not DSM-IV-TR status of ASD" the Christensen data showed something a little different: "Among 1,237 children who met the surveillance case definition for either DSM-IV-TR or DSM-5, 974 (78.7%) met both case definitions, 234 (18.9%) met the DSM-IV-TR but not the DSM-5 case definition, and 29 (2.3%) met the DSM-5 but not the DSM-IV-TR case definition." Perhaps more study is required on the diagnostic changes?

What's more to say? Well, one of the authors - Walter Zahorodny - kinda said it all in a media comment: "There’s no letup. I really don’t understand why the rate is going up in this way." So maybe the next question, a question that really should have been examined a long, long time ago, needs to be 'Why?' rather than just a continual chain of studies saying autism prevalence is increasing...

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[1] Christensen DL. et al. Prevalence and Characteristics of Autism Spectrum Disorder Among Children Aged 4 Years - Early Autism and Developmental Disabilities Monitoring Network, Seven Sites, United States, 2010, 2012, and 2014. MMWR Surveill Summ. 2019 Apr 12;68(2):1-19.

[2] Wiggins L. et al. Comparison of autism spectrum disorder surveillance status based on two different diagnostic schemes: Findings from the Metropolitan Atlanta Developmental Disabilities Surveillance Program, 2012. PLoS ONE. 2018; 13(11): e0208079.

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DSM-5 autism is "largely comparable to" to DSM-IV-TR autism

"Merry New Year". Welcome back to Questioning Answers in 2019. So let's continue.

The quote heading this post comes from the findings reported by Lisa Wiggins and colleagues [1] and their research aiming to "replicate agreement between surveillance status based on DSM-IV-TR criteria and DSM-5 criteria for ASD [autism spectrum disorder]." This authorship group have some interest in the description of autism across the DSMs (Diagnostic and Statistical Manual of Mental Disorders) as a function of their involvement with the United States CDC and their other, quite recent publication, talking about the national US autism prevalence estimates in 8-year olds for 2014 (see here).

As well as arriving at the conclusion that 1 in 59 children aged 8-year old in the United States *might* have autism [2] (still potentially an underestimate according to other recent figures), their latest prevalence paper also, for the first time, introduced the DSM-5 to the Autism and Developmental Disabilities Monitoring (ADDM) Network. Previously, the DSM-IV was top (diagnostic) dog, but with the publication of the DSM-5 (see here) there was a new sheriff in town. And as the DSM-5 started to be utilised more and more widely in diagnostic circles, so the CDC autism estimating teams had to start taking this into account in their musings...

Wiggins et al relied on data for "8-year-old children who had health and education records reviewed for ASD surveillance in metropolitan Atlanta, GA in the 2012 surveillance year as a part of the Metropolitan Atlanta Developmental Disabilities Surveillance Program (MADDSP)." As per the aims and objectives of the MADDSP - "estimates the number of children with selected developmental disabilities in metropolitan Atlanta" - autism is one of the diagnoses included in the surveillance program. DSM-IV-TR criteria for autism were applied to the health and education records of a cohort of children to see if diagnostic thresholds were met. Importantly too we are told that: "a previous ASD diagnosis was not sufficient evidence to confirm DSM-IV-TR surveillance case status." Alongside: "A DSM-5 coding scheme for ASD surveillance was developed by an independent body of ADDM-affiliated experts and then adapted and refined by a CDC-led clinical workgroup." Application of this DSM-5 coding scheme was similarly used on those education and health records data and results were collected and compared.

"Similar to ADDM data reported for the 2014 surveillance period, we found substantial agreement between DSM-IV-TR and DSM-5 surveillance status of ASD in a sample of records reviewed for the 2012 surveillance period." The figures in a little more detail: "46.0% children met both DSM-IV-TR and DSM-5 surveillance status, 44.0% met neither the DSM-IV-TR nor DSM-5 surveillance status, 4.0% met DSM-IV-TR status, but not DSM-5 status, and 6.0% met DSM-5 status, but not DSM-IV-TR status of ASD." The importance of this data is what the quote heading this post talked about: DSM-5 autism is "largely comparable to" to DSM-IV-TR autism. So when the ADDM eventually makes the transition over to DSM-5 derived autism data only, it means that all those years of DSM-IV diagnosed autism are still very much relevant (and can be used as a comparator) in a historical context.

But... the authors do mention about how some other studies have observed that: "fewer children meet DSM-5 criteria for ASD than DSM-IV-TR criteria for ASD in similar service settings" (see here and see here). This requires quite a bit more investigation; in particular how "record-review surveillance [such as that utilised by Wiggins et al] relies on information contained in surveillance records and does not include an in-person evaluation of the child." As I've indicated in my very critical musings on armchair diagnosis of historical persons (see here for an extreme example), there is absolutely no substitute for talking to and directly observing a person who has been referred for a diagnostic assessment. None. I've also previously suggested that another related label that crops up near to the DSM-5 description of autism - social (pragmatic) communication disorder (SCD) - might also need some research attention too. Indeed, I wonder if the ADDM might eventually start reporting on autism and SCD separately...

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[1] Wiggins L. et al. Comparison of autism spectrum disorder surveillance status based on two different diagnostic schemes: Findings from the Metropolitan Atlanta Developmental Disabilities Surveillance Program, 2012. PLoS ONE. 2018; 13(11): e0208079.

[2] Baio J. et al. Prevalence of Autism Spectrum Disorder Among Children Aged 8 Years — Autism and Developmental Disabilities Monitoring Network, 11 Sites, United States, 2014. Morbidity and Mortality Weekly Report (MMWR). 2018; 67(6): 1-23.

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An extremely low prevalence of autism in Quito, Ecuador

The title of this post is taken from the paper by Laura Dekkers and colleagues [1] (open-access) who sought to "get an estimate of ASD [autism spectrum disorder] diagnoses in children and adolescents aged between of five and fifteen at regular schools in Quito."

So, the starting point: "Ecuador has more than 14 million inhabitants... of which over 1.6 million are estimated to live in the capital city of Quito." As part of the "law requiring inclusive education", the authors decided to survey for "cases of ASD in regular schools" in Quito. Said schools were identified via the databanks of the Ministry of Education, of which 161 schools were eventually selected for analysis including just over 51,000 pupils aged 5-15 years. Cases of ASD within that population were "identified by the school administration" and included both autism spectrum diagnoses via DSM-III and DSM-IV criteria.

Results: 33 schools (~20%) reported having at least one pupil officially diagnosed on the autism spectrum. Interestingly the authors report that there was a possible relationship between school reporting one or more pupils on the autism spectrum and the size of the school - "the probability of reporting at least one pupil with an ASD diagnosis decreasing with the size of the school."

"Of the total number of pupils within all schools (N = 51,453) only 57 pupils had an official diagnosis of ASD. This brings the prevalence of ASD in Quito, as reported by schools for regular education, to 11.07 out of 10,000, which is 0.11 %." Most of those diagnosed were so with the label 'PDD-NOS' (Pervasive Developmental Disorder - Not Otherwise Specified). Bearing in mind the small numbers detected, the male: female ratio came in with a familiar statistic - "4.7 times more boys than girls" and mean age at diagnosis was a very poor 7-8 years of age.

Then another statistic: "Out of the 161 schools, 59 schools (36.6 %) mentioned that they thought that at their school there was at least one pupil who did not have an ASD diagnosis, but should have been diagnosed with ASD." In total there were 108 pupils falling into this 'maybe' category. And finally: "Out of all schools (N = 161), 14 schools (8.7 %) reported that they had at least once refused a boy or girl with ASD to their school, because of his or her behavior."

There are a few points to make about the Dekkers findings, some of which the authors already make themselves. First is the quite low prevalence rate estimated from their research. To quote (again): "We propose that the found percentage of 0.11 % reflects the current probability of receiving a diagnosis of ASD in Quito, Ecuador, rather than the proportion of the population that has ASD." Indeed, the authors provide a list of various factors that might have been contributory to the low prevalence rate estimated for autism in Ecuador including issues with accessibility to diagnostic services, the general lack of awareness of autism in the country and the stigma that still surrounds the label ("Autism is often not recognized as such and considered a punishment of God, leaving the family in shame hiding their child with problem behavior"). One might also entertain the notion that autism may not be as prevalent in Ecuador as other countries for genetic / biological or environmental reasons too; perhaps even learning some lessons from other labels (see here).

Second, we can expect more data from this group on this topic. "The ASD prevalence in special education was the second part of phase 1 of the PAE [Prevalence of Autism in Ecuador] project, including 11 special schools and centers, and a total of 1195 pupils; publication of the results is in preparation. We can expect a higher prevalence at these schools, because there is a trend for higher and increasing prevalence of autism in special education in areas with low prevalence of autism." I believe we have a few clues there as to what they found.

Finally, what is missing from the Dekkers data is information about the children themselves outside of just diagnosis and age. Things like whether comorbidity such as ADHD [attention-deficit hyperactivity disorder] is part of the clinical picture in light of what is known about a possible relationship (see here). Indeed, whether part of the low autism prevalence estimate suggested might also part of a wider trend in child psychiatry in Ecuador, and whether we can expect to see increasing rates as per other data from other countries [2]?

Music to close: Sash! - Ecuador.

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[1] Dekkers LMS. et al. Prevalence of Autism Spectrum Disorders in Ecuador: A Pilot Study in Quito. Journal of Autism and Developmental Disorders. 2015. Aug 30.

[2] van Bakel MME. et al. Low but Increasing Prevalence of Autism Spectrum Disorders in a French Area from Register-Based Data. JADD. 2015; 45: 3255-3261.

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Dekkers, L., Groot, N., Díaz Mosquera, E., Andrade Zúñiga, I., & Delfos, M. (2015). Prevalence of Autism Spectrum Disorders in Ecuador: A Pilot Study in Quito Journal of Autism and Developmental Disorders DOI: 10.1007/s10803-015-2559-6

1 in 50 children with parent-reported autism in the US

An estimated 1 in 50 US children aged between 6 - 17 years old present with an autism spectrum disorder (ASD). Attention-grabbing isn't it?

Today's post is based on the source of that soundbite, the publication by Stephen Blumberg and colleagues* (open-access) describing results from data mining of the 2007 and 2011-2012 US National Survey of Children's Health (NSCH) relevant to the numbers of cases of ASD.

Testing 1, 2, 3 @ Wikipedia  

The autism-numbers game is something that has been discussed previously on this blog; most recently with the CDC 1 in 88 estimate in mind (see here) and the even more recent data from New Jersey (see here). The direction of the figures seems only one way - up - but the reason(s) for the increase still remain the source of discussion.

The Blumberg report is open-access, but a few pointers might be useful:

• Based on 91,642 telephone interviews in 2007 and 95,677 interviews between 2011-2012, parental reports of receipt of an ASD diagnosis (autism, Asperger syndrome, PDD) in offspring were noted, alongside other variables such as age of the child, severity of presentation (mild, moderate, severe) and aged when first diagnosed.
• Actually in the age range 6-17 years old, data were collected from 63,967 interviews (2007) and 65,556 (2011-2012).
• Results: "based on parental reports, the prevalence of diagnosed ASD in 2011-2012 was estimated to be 2.00% for children aged 6-17". This compared with 1.16% or 1 in 86 for 6-17 year olds in 2007.
• The increase in prevalence was noted across the age ranges when they were sub-categorised and perhaps not surprisingly, there was a greater increase in prevalence in boys (2007: 1.8% vs. 2011-2012: 3.23%) than girls (2007: 0.49% vs. 2011-2012: 0.70%). Reported severity also shifted between the various data points (and age ranges) indicating that there was a trend towards less severe presentation (milder ASD) post 2008 diagnosis.
• The authors were able to some degree, rule out "survey-based measurement error" as being a major contributor to the prevalence increase and there is some discussion about the data not necessarily reflecting "factors that exist prior to or occur just after birth". Indeed the authors very firmly suggest that the changes are a consequence of either "recognition of ASD by health professionals or survey-based measurement changes over time". They also conclude that increases in the prevalence of parent-reported ASD especially for children aged 6-13 "was the result of diagnoses of children with previously unrecognized ASD".
• As per the report on this story in USA Today "15% to 20% of children who were once diagnosed with autism no longer have the condition". Which raises similar questions as to that of the Fein study on 'outgrowing autism' and 'optimal outcomes' which created so many column inches recently (see here and here).

Bearing in mind that this was a prevalence study not an incidence study (see here for the difference) and issues with regards to response rates (2007: 46.7% vs. 2011-2012: 23.0%), and the sole reliance on parental judgement of variables like severity, the data being presented are indeed stark.

That the rates of autism have seen an inordinate shift from what was once considered a rare condition to something which theoretically should [almost] appear in every school classroom at least once is an eye-opener. As mentioned, the debates rumble on about factors such as better awareness of autism, better case ascertainment, diagnostic switching and broadening, etc. as being the source of the increase. A real increase in cases? Hardly a mention in this latest data. The implication that for example our screening methods and skilled professionals have been able to miss or mis-diagnoses a staggering number of children presenting with an ASD is truly mind-boggling and worthy of an inquiry or two in the US and beyond. Indeed better be quick with that investigation with the DSM-V revision deadline fast approaching and the potential impact that might have on the autism numbers game (including adult numbers**).

So 1 in 50 children with an ASD. What happens next? Sure, many children were described as falling into the mild and moderate ability ranges but as I've said before, terms like 'high-functioning' don't necessarily mean 'can function' with regards to daily living skills, quality of life and onwards translating into positive outcomes in adulthood. Certainly society has to play its role in helping people with autism reach their potential (I have a post scheduled on job interviews and autism coming up soon) and changes are indeed on-going (e.g. the implementation of the Autism Act here in the UK). But let's not be too proud of the achievements done in this area, as still many people on the autism spectrum, their families and concerned others have to fight daily for appropriate recognition, provisions and services.

Another important issue also springs to my mind on the basis of the new prevalence figure. Comorbidity, of which autism is by no means immune from, are not mentioned. The realisation that autism is often very much more than the sum of its triad - soon to be dyad - in terms of comorbidity must surely factor into the potential impact of the latest figures. Not least because of the quite startling health inequalities which seem to be present when an ASD is diagnosed and how as was very recently detailed in the CIPOLD report, such inequality can in some cases, have the most profound and far-reaching effects. I'm not trying to scare anyone; just sayin' that we need to be mindful of the whole person not just their autism.

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* Blumberg SJ. et al. Changes in prevalence of parent-reported autism spectrum disorder in school-aged U.S. children: 2007 to 2011–2012. National Health Statistics Reports. 2013: 65.

** Wilson CE. et al. Comparison of ICD-10R, DSM-IV-TR and DSM-5 in an adult autism spectrum disorder diagnostic clinic. J Autism Dev Disord. March 2013.

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Wilson, C., Gillan, N., Spain, D., Robertson, D., Roberts, G., Murphy, C., Maltezos, S., Zinkstok, J., Johnston, K., Dardani, C., Ohlsen, C., Deeley, P., Craig, M., Mendez, M., Happé, F., & Murphy, D. (2013). Comparison of ICD-10R, DSM-IV-TR and DSM-5 in an Adult Autism Spectrum Disorder Diagnostic Clinic Journal of Autism and Developmental Disorders DOI: 10.1007/s10803-013-1799-6