Unscientific Americans

25 Aug

In Saturday’s Los Angeles Times, Lori Kozlowski talked to Chris Mooney in an article headed ‘Bringing science back into America’s sphere.’ The piece is about a book that Chris has co-authored with Sheril Kirshenbaum “Unscientific America: How Scientific Illiteracy Threatens Our Future.” It provoked such a lot of comments that they set up a blog so everyone could have their say.

Needless to say, as one of the book’s targets is the vaccine/autism camp and Chris mentions Age of Autism, that nest of anti-vaxers has dominated the comments with an orchestrated campaign. Here is my own attempt to stem the tide.

Those who have argued for a link between vaccines and autism adopt two contradictory positions. On the one hand we have those who point to the epidemiological studies as evidence of an autism epidemic whose growth is supposed to coincide with changes in the United States schedule for early childhood vaccinations. But when population studies fail to find a connection between vaccines and autism we get a different argument. Apparently there is a subset of genetically susceptible children that is too small to show up in population studies of vaccine safety. We have yet to hear a convincing explanation for this alleged genetic susceptibility to vaccine induced autism. But the parents who subscribe to this view are all convinced that, whatever it is, their child must have it.

It is difficult to see how this latter group could be persuaded to abandon their belief that that in their individual cases correlation does indeed equal causation. But I am at a loss to understand why they are willing to make common cause with the autism epidemicists, who are clearly and demonstrably wrong.

Regarding prevalence we have a very good idea why prevalence used to be 4 in 10000 and is now approaching 100 in 10000. In 1966 Victor Lotter carried out one of the earliest epidemiological studies in the county of Middlesex in the UK. He used a very narrow definition of autism in which only children who actively avoided human contact and engaged in elaborate repetitive behaviour qualified for diagnosis. When his students Lorna Wing and Judith Gould repeated the study in 1979 they found a similar rate of between 4 and 5 in 10000. However they also discovered a larger group who also engaged in repetitive behaviour but did not avoid human contact. However they did show difficulties in social communication and interaction. Wing and Gould defined ther problems within the triad of impairments, which also explained the aloof behaviour of the more typical Kanner type autistics. The newly identified members of the autistic spectrum numbered around 15 in 10000. Thus a simple broadening of the criteria lifted the numbers from 4 to 20 in 10000.

Lotter, Wing and Gould had all studied children excluded from mainstream education. In 1993 Stephan Ehlers and Christopher Gillberg went looking for children with the triad of impairments in mainstream education in the Swedish city of Gothenburg. They found a rate of 71 in 10000 for children with an IQ greater than 70. The children who were identified were known by their teachers to be having social and/or educational problems but the nature of their difficulties had not been recognised prior to the study.

So, as early as 1994, on the basis of epidemiological studies by Wing and Gould (1979) and Ehlers and Gillberg (1993) it was apparent that autism in all its manifestations including the classic Kanner type and the Asperger type affected at least 91 in 10000. The National Autistic Society in the UK issued a fact sheet to that effect. The modern version is available on our website.

In 15 years the figure for all autistic spectrum disorders in the UK has moved from 91 in 10000 to 116 in 10000 (Baird et al 2006). Thus it has remained flat at around 1 per cent for the whole period of the so-called autism epidemic. And that 1 percent represents the whole spectrum with perhaps a fifth to a quarter consisting of people with recognizable learning difficulties that are moderate or severe. The rest are more able.

I see no reason to doubt that the CDC estimate of 1 in 150 and the figures from recent studies that more closely approach the overall prevalence figures from the UK contain within them similar proportions of more and less able individuals. It is a shame that it has taken health and education services on both sides of the Atlantic so long to catch up with the true prevalence of autism amongst our children and begin to tailor services to meet their needs.

That still leaves those more able adults, often living a life less ordinary without the benefit of diagnosis and support, but still experiencing difficulties in their daily lives. The recent I Exist campaign by the National Autistic Society in the UK has influenced our government to take adult issues seriously

Comments are still open. Please visit and counter the collective lunacy of the anti-vaxers.

4 Responses to “Unscientific Americans”

  1. Ed August 26, 2009 at 03:34 #

    I do enjoy these statistical proofs of the non-existence of an autism epidemic, of the lack of a link between autism and vaccines that have never looked at the autism rate among the unvaccinated

  2. Mike Stanton August 26, 2009 at 09:26 #

    Ed,
    the only reason we had a vaccine controversy is because autism rates appeared to be rising in California coincident with a change in the vaccine schedule.It was supposed to be the mercury – that’s what Generation Rescue, Safe Minds, NAA, TACA all said.

    But prior to the onset of this so called “epidemic” in countries which never adopted the US schedule and whose exposure to Thiomersal Containing Vaccines was always much lower than in the USA, we have hard epidemiological evidence for a prevalence rate of around 1 in a 100 for all autistic spectrum disorders. And this figure has barely changed.

    When you break the figures down and just look at people with an ASD and low IQ there is no significant change between Wing and Gould’s finding of 20 in 10000 in 1979 and Chakrabarti and Fombonne’s results in 2002 and 2005 based on the study of consecutive birth cohorts (1992-95,1996-1998) in the same health authority using identical methods of case finding and diagnosis in both studies.

    The bottom line is that there is no epidenic and hence no reason to suspect vaccines of causing an epidemic.

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