I don't have the full-text paper yet but the abstract does provide some interesting snippets of information. The main findings:
- Based on administrative records, the prevalence of autism in Utah changed from 2002 to 2008 to the order of a 100% increase in the numbers of cases. Note that this was prevalence not incidence.
- In 2008, 1 in 77 children aged 8 were identified with an autism spectrum disorder (ASD).
- For many, diagnosis as identified by health records didn't necessarily mean that children held a 'special education classification'. Indeed, most diagnoses were detected from health records.
I will perhaps need to look at the contents of this latest paper in more detail before any firm conclusions are drawn.