Showing posts with label Prevalence. Show all posts
Showing posts with label Prevalence. Show all posts

Thursday, 30 August 2018

Éric Fombonne on Sloppy Autism Statistics

The reason I have a short list of talented researchers as my Dean’s List for this blog, is because of the generally low standard of much you can read about autism, even sometimes from governmental bodies like the CDC (Centers for Disease Control and Prevention) in the in the US and NICE (National Institute for Health and Care Excellence) in the UK.

I suppose these days it’s just called Fake News

My contribution is to highlight the researchers I think are worth paying attention to.
When it comes to the prevalence of autism, Éric Fombonne is a researcher who has more than his share of common sense.  Fombonne is a French psychiatrist and epidemiologist who also worked in the UK and Canada before moving to the US.
He recently gave the interview below, which highlights glaring errors/weaknesses in reports which are picked up by the mass media and put forward as facts. 

“… the CDC does not attempt to assess everybody in a population. Instead, it looks in the medical and special education records of each child in a certain region to determine whether a child meets criteria for its surveillance definition of autism. Children with no relevant notations of social problems in their records are assumed not to have autism.”
“In a study designed to validate these, researchers found that between 20 and 40 percent of children who met the CDC definition of autism did not actually have autism”
“Another issue is that of every 100 children the CDC researchers determine to have autism, only 80 have a reference to autism specifically in their medical or school records. So, one in five 8-year-old children the CDC decides has autism had never been picked up as autistic by any professional. At age 8, how is this likely?”
“I led a team that verified autism diagnoses prior to inclusion in a neuroimaging study. Trained researchers performed independent state-of-the-art assessments of over 200 children with an existing autism diagnosis. At least 30 percent of these children turned out to not have autism. It was mind-boggling.”
“In my clinics 25 years ago, I remember explaining to parents who had no clue about autism why their child qualified for the diagnosis. Things have now reversed. Nowadays, some parents and professionals push for that diagnosis and resist a ‘not autism’ conclusion because it may come with less support.”

I did a while back do my own review of autism prevalence, based on two studies carried out by Éric Fombonne.
My conclusion then was that prevalence is about 1% and that you can split it roughly into thirds.
·      One third has severe autism, which we can also call SDA (Strictly Defined Autism), or DSM3 autism.  DSM 3 autism is what medical professionals called autism 30 years ago, when it was rare. At that time it appears that many people with autism were only given a diagnosis of mental retardation (MR), which recently became intellectual disability (ID). The number of people diagnosed with MR/ID has fallen substantially as the number of people diagnosed with autism has increased, a clear case of substitution. 
·      One third have true Asperger’s, by which I mean above average IQ, no speech delay in childhood, but with substantial issues getting on with typical people.

·      The remaining third are people without MR/ID or a high IQ, may or may not have had a speech delay, but face significant challenges interacting with the wider world.  Surprisingly many people who today hold an Asperger’s diagnosis have below average IQ.

While someone with Down Syndrome (DS) will fit the diagnostic criteria of MR/ID and quite possibly autism, I think giving multiple diagnoses is unhelpful.
It is clear from the statistics that doctors stopped diagnosing people with MR/ID and instead switched many of these people to an autism diagnosis. 
Autism really should be seen as just a catch-all observational diagnosis, pending an accurate biological diagnosis, like Rett syndrome, Mitochondrial Disease etc.

The increase in prevalence of SDA
Due to the broadening of the definition of autism from DSM3 to DSM5 and, as Fombonne highlights, the very poor application of those ever moving diagnostic guidelines, we are left unable to draw any reliable conclusions about any increase in prevalence of SDA.
I certainly cannot prove it, but I believe the prevalence of SDA has increased substantially and most likely will continue to rise as society moves further from where it came from. This takes us back to the idea of the holobiont/hologenome.

The hologenome concept of evolution, considers a human as a community, or a holobiont - the host plus all of its symbiotic microbes. The collective genomes of the holobiont form a hologenome.

This becomes very relevant in human disease because in modern life humans have become separated from part of their evolutional holobiont (symbiotic microbes).  As a result all kinds on immune disease have become more prevalent.

To reduce the incidence of future SDA, steps could be taken now, just like public health tries to reduce the incidence of future heart disease.
You cannot stop random genetic mutations that lead to features diagnosed as autism, but you can influence many of the environmental factors and very likely you could take protective measures to increase the robustness of the mother and baby’s defensive mechanisms.