children's handsA new report from the Centers for Disease Control and Prevention (CDC) states that the prevalence of autism spectrum disorders (ASD) is now one in 68, a 30% increase since the last time the diagnostic rate of autism was measured. The findings are attributed largely to greater understanding of autism spectrum disorders, leading to more frequent and earlier recognition of its symptoms among children.

Data for the study came from the Autism and Developmental Disabilities Monitoring (ADDM) Network, which has measured the prevalence of people affected by ASD at intervals since the year 2000. The latest figures are based on school and medical records from 2010. Records were gathered for a sample of 5,338 eight-year-old children from 11 locations.

The results indicated that, as of 2010, 14.7 out of 1000, or one in 68, eight-year-olds were affected by an autism spectrum disorder. This represents a 30% increase from 2008, when one in 88 children had an ASD. When the CDC began tracking the rates of autism spectrum disorders in 2000, only one in 150 eight-year-olds were affected by autism.

The CDC estimates that 1.2 million people under 21 are affected by an autism spectrum disorder. The increase in ASD prevalence is likely due to greater awareness of ASD among parents, teachers, and clinicians.

Some demographics are not as frequently diagnosed with ASD as others. White children were 30% more likely to be identified as having an autism spectrum disorder than black children and they were 50% more likely to have an ASD than Hispanic children. Although detection of ASD has increased, it may be that not all children with an ASD are being identified.

Last year, changes were made to the diagnostic criteria for autism spectrum disorders; Asperger’s syndrome was subsumed by autism in the latest version of the DSM. However, the present data do not reflect this change since the records were compiled in 2010. The CDC will not know how the diagnostic rates will be affected by the criteria in the DSM-V until the analysis of 2014’s data is complete.

This research is reported in the Morbidity and Morality Weekly Report.

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