Huge increase in autism diagnoses. Measurement issue or environmental causes?

[astro]

@Spoleto

@astro

One out of 166 children will develop autism (via fark)

In my own research I learned that the increase has steadily increased since the mid 60’s. My older brother served in Nam and few months ago was invited to participate in an on-going Agent Orange study. Now I learned that his 3yr old grandson has been diagnosed as austistic… I guess I’m wondering if there might be a correlation between those exposed to Agent Orange decades ago and the rise in autism.

Agent Orange was used from 1961 to 1971

Kids of the agent orange era vets (ie those 20-40 YO between 1961 - 1971) would likely be in their mid 20s to early 40’s by now which does not appear to be the cohort that is showing the main increase in autism diagnoses. It’s more the grand kids of that Vietnam generation.

[Schuyler]

I am not a doctor, or even especially well-read yet on Asperger syndrome or autism spectrum disorders. Quoting from “A Parent’s Guide to Asperger Syndrome & High-Functioning Autism” page 19:

As recently as 10-15 years ago [meaning about 1990], we estimated only 2-4 of every 10,000 individuals had an autism-related condition. But a very recent (2001) study published in the prestigious Journal of the American Medical Association found a much higher rate. The research team of Dr. Eric Fombonne, a prominent French epidemiologist (a scientist who investigates the rate of diseases in the community), studied over 15,000 individuals in a region of England, identifying every case of autism spectrum disorders in the geographical area (verifying the diagnoses themselves). They found a rate of 63 people with autism spectrum disorders in every 10,000 individuals in the general population, making autism spectrum disorders more common than Down syndrome and many other childhood conditions.

The authors later say, on that same page:

Is autism increasing in frequency? Is it truly more common than it used to be, or do the rising prevalence figures simply reflect better diagnostic practices and increased awareness of the milder end of the continuum? The jury is still out. Two researchers, Dr. Lorna Wing (the same psychiastrist who first brought Asperger syndrome to the attention of the English-speaking world) and Dr. Eric Fombonne, the French epidemiologist, recently reviewed all studies of the prevalence of autism spectrum disorders ever conducted. Independently, both concluded that there is no evidence that autism is increasing in frequency; both suggested that the apparent increase comes from the fact that children with AS-HFA symptoms are more likely to be referred to a professional who can diagnose them accurately and from the fact that the criteria used to diagnose AS-HFA symptoms have been fine-tuned. … Some scientists still suspect that environmental factors increase the risk for autism and account for the increased prevalence rates, however. This in an active area of investigation at research centers around the world.

[Kent_Clark]

@Renee

Does this mean that more than 1/166 kids are mentally retarded? If not, what does it mean? Also, I was under the impression that sever autism and mental retardation kind of overlap. Is that true?

Mental retardation is commonly evaluated by a battery of tests (which include IQ tests) and judging how far the subject tests below the mean. If you score, for example, 50% below the mean it might be defined and mentally rearded. But 25% of the general population could be scoring 50% below the mean, and many of them would still be able to function in society.

Severe autism can bring such a host of issues that it might be impossible to successfully test an autistic’s mental skills, but by itself, that doesn’t mean the autistic is retarded. Only that they can’t adequately test it.

[Unix_Geek]

The link below is an CNN article dealing with older men having a much higher rate of autistic children. An important compenent in the rise of all genetic based problems is the fact that we are having children much later in life.

http://www.cnn.com/2006/HEALTH/09/04/autism.dads.age.ap/index.html?section=cnn_health

[Wendell_Wagner]

Unix Geek writes:

> An important compenent in the rise of all genetic based problems is the fact
> that we are having children much later in life.

Later, yes. Much later, no. The average age of the father of the average child born this year might be a year older than the average age of the father of the average child born twenty years ago. That’s not nearly enough to explain the increase by 5 or 10 times in the number of children diagnosed as autistic. It’s probably a matter of it being easier to diagnose children as autistic these days.