Aspies For Freedom

Someone on another messageboard was skeptical of the figure and did some research. I'll copy and paste her post:

Quote:

I've posted the relevant studies below, but the short version is that the CDC, in their Atlanta study published in 2003 found a prevalence of 1/294 for ASDs, which they said was similar to prevalences found in other recent studies, listed below, which showed prevalences ranging from 1/81-1/172 for ASDs and 1/166-1/1000 for autistic disorder. The 1/166 number is based on the very smallest study, which found only 5 children with autism. Because of the small size 1/166 could reflect an actual prevalence of anywhere from 1/71-1/526, with 95% confidence that the actual prevalence falls somewhere within that interval. The larger studies show rates of autism around 1/250-1/500, and ASD around 1/150-1/200, consistent with the figures quoted by sources such as the ASA, CDC, NIH. The authors of all of the studies were in unanimous agreement (and it was specifically discussed in each publication) that since methodological differences have so much potential effect on results, it is impossible to tell whether the rates of autism have actually increased compared with old studies which clearly showed lower prevalences. Though in the future this will not be as much of a problem.

Anyway, here are summaries of the studies:

Publication year Authors Journal
Location Population screened
Definitions
Prevalences

2003 Yeargin-Allsopp et al JAMA
Atlanta USA 289,456 3-10 year olds
"Autism": Autism, AS or PDDNOS (DSM-IV)
1/294

2001 Chakrabarti, Fombonne JAMA
Staffordshire, England 15,500 2.5-6.5 year olds
PDDs: DSM-IV
1/159
Autistic Disorder: DSM-IV
1/595

2001 Bertrand et al Pediatrics
Brick Township, USA 8,896 3-10 year olds
ASD: Autistic disorder, AS, PDDNOS (DSM-IV)
1/149
Autistic disorder: DSM-IV
1/250

2000 Baird et al J Am Acad Child Adolesc Psychiatry
SEThames, Eng 16,235 7 year olds
ASD: atypical autism, autism, other PDD (ICD-10)
1/172
Childhood autism: ICD-10
1/324

1999 Kadesjo et al J Autism Dev Disord
Karlstad, Sweden 826 6.7-7.7 year olds
ASD: autistic disorder, autistic-like condition or AS (ICD-10 and DSM-3R)
1/83
Autistic Disorder: ICD-10 and DSM-3R
1/166 (95% confidence interval 1/71-1/526)

1997 Arvidsson et al Autism Int J Res Pract
Goteborg, Sweden
Autism
1/1000
(I haven't actually seen this paper yet)

The 1/166 represented in the Kadesjo study represented only 5 children. If you divide 826 by 4 or by 6, you can see how much only one child more or less changes the result. If you use the incorrect assumption that a study of 826 children can be used to make a valid estimate of prevalence, you could also conclude that autism occurs only in boys, as found in this study, or that 20% of people with autism also have Down syndrome, as was the case here.

Are you saying you disagree with the figures or you think there are more? I would think that if you look at those with AS who have not been formally diagnosed the ratio would surprise many. In one state in the USA studies showed that Autism had increased two hundred percent in three years so the true figures may never be known.

Debs

The figures are not clear, the problem I have is that I CAN'T form an opinion about them because of that. I am worried though that Epidemiology is having an effect on public policy that is disproportionate to it's relevance.

I agree with your point Lucas, there is too much publicity given to a so called current epidemic of autism diagnoses, I've even seen it be called a plague, which is infuriating. The media does love to sensationalise though, and obviously organisations like CAN profit from exaggeration of numbers, and cost of care.

I have to agree with you Amy, but the figures I mentioned I read about at Simon B-C's clinic. I don't give any consideration to the inflammatory rubbish dished out by CAN, I prefer to source my information from those who aren't simply looking for a cure.

Debs

With so little consesus on definitions anyway, how can any count be meanignfull? And when it comes specifically to "Aspies", an awful lot of those actually holding down a job are going to keep their heads down anyway! I suspect I'd do the same as the current situation stands; in the absence of any protective legislation the best protection is probably denial?

Lucas

davixen

Lucas

Amy

davixen

gwynfryn