Confused, angry parents push junk science vaccine/autism link

[Pangloss]

Sure they do, just ask any parent or journalist. Aren't they the ones who write science policy now?

 

Besides, my best friend's mother's hairdresser says it's so, and she's the one who put me on to The Secret, so it must be true.

[swansont]

Three people have commented here that rising autism rates are because we're just "finding" more people with autism, not because more people are actually born with autism. This seems to be more of a myth then anything else. Although we are better at diagnosing people with autism, according to experts, this cannot explain the increasing rates by any significant extent.

 

It was not presented that way. The comments were to the point that this needs to be addressed as a possible source of systematic bias, and not just assumed.

 

 

http://www.ucdmc.ucdavis.edu/mindinstitute/newsroom/study_final.pdf

 

"There is no evidence that a loosening in the diagnostic criteria has

contributed to increased number of autism clients served by the Regional Centers...

Without evidence for an artificial increase in autism cases, we conclude that some, if not all, of the observed increase represents a true increase in cases of autism in California, and the number of cases presenting to the Regional Center system is not an overestimation of the number of children with autism in California." They also say that rise in the state's population can explain only "a small portion."

 

And they also say, regarding an autism vs retardation diagnosis:

 

"However, these numbers cannot be used to make reliable estimates of the number of children with autism not being counted (and not being treated), because 1) we had a relatively low response rate by families with mentally retarded children, and 2) families were more likely to agree to enroll if their mentally retarded child also had an autism spectrum disorder."

 

IOW, there is no way to know from this survey if autistic children who would have been diagnosed as retarded in the past are now being properly diagnosed.

 

later on,

"Parents of the older group were more likely to report that their autistic child also had mental retardation (41% vs. 21%). This is consistent with the review of Regional Center records that found a decrease in diagnosed mental retardation in the younger group (50% in the 1983-85 group vs. 22% in the 1993-95 group)."

 

would seem to bear out the notion that the diagnosis of autism as mental retardation was more prevalent in the past.

 

And

 

"Recent data suggest that the increase in cases of autism matches a decrease in cases of mental retardation.³⁵ Changes in how both autism and mental retardation are classified could cause an artificial increase in autism cases. It is possible that children with both mental retardation and autism could be classified as having mental retardation with autistic features. This might have been recorded as something other than CDER Status 1 in the past, but now similarly affected children may be entered into the data as autistic (CDER status 1 autism) with mental retardation. Presumably, this misclassification occurred more in the past, when the imperative for early diagnosis of autism to allow for early intensive therapies was not as great." (from p13)

 

Also, "Hispanic children are more likely to be included in the younger autistic group (28% in the 1983-85 group and 39% in the 1993-95 group)" begs the question of whether autism rates are equal for different ethnicities, and what contribution this might have.

 

 

Lastly, note that this was a small-sample study. The largest indivdual group comprised 232 people, which has a statistical error of ~6.5%, and would be larger for smaller groups.

[swansont]

Sure they do, just ask any parent or journalist. Aren't they the ones who write science policy now?

 

Besides, my best friend's mother's hairdresser says it's so, and she's the one who put me on to The Secret, so it must be true.

 

Sarcasm aside (enjoyable though it is) science [math]\neq[/math] science policy

[1veedo]

The story cant be explained by any single factor. Rising population in just California for example contributes some, classification can explain some of it, etc, but the question "do more people have autism or are more people just being diagnosed with it" is a rather misinformed question. More people do have autism and whether, as the leading theory suggests, genetics are causing this or something else is we don't know.