That is the question researchers at the University of Wisconsin studied in a recent paper in the Wisconsin Medical Journal: Socioeconomic Disparity in the Prevalence of Autism Spectrum Disorder in Wisconsin.
The brief report looked at the data used in the 2002 CDC prevalence study that reported 1 in 150 children are diagnosed with autism in the U.S.. The data are collected through the Autism and Developmental Disabilities Monitoring (ADDM) Network. Here is one of the tables:
What’s it say? Basically, if you are wealthy or have a high level of education, your kid is much more likely to be diagnosed autistic.
The authors are pretty limited in what they can say. They didn’t look into the “why”. That they did say was this:
Although the positive association with SES reported here is consistent with early observations of autism and some previous epidemiologic studies,2-3,5 the reason for this association and the potential role of SES differences in access to health and educational services for ASD cannot be determined from the data available.
Further research is also needed to examine whether the association reported in this paper is a result of differential access to health services, other sources of ascertainment bias, or SES differences in the risk of developing ASD.
Do I think that kids of wealthy parents are really 2.5 times more likely to be autistic? No. But, are they more likely to get a diagnosis? It sure looks like it.
I am not surprised. There are very large disparities by geography (state to state, rural vs. urban) and by ethnicity in much of the CDC ’s ADDM network data. I was surprised that the disparity by socio-economic-status was so large.