A new study suggests that the prevalence of autism spectrum disorders (ASDs) has surged in recent years, but questions remain as to whether the rise reflects an actual increase in the number of individuals with the condition, changing definitions of diagnosis or awareness, or a combination of such factors.
The study, released in December by the US Centers for Disease Control and Prevention (CDC), found that 1 8-year-old in 110 was classified in 2006 as having an ASD vs 1 in 153 estimated in 2002 (http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5810a1.htm). The study was a systematic retrospective review of evaluation records from 11 sites participating in the Autism and Developmental Disabilities Monitoring Network. It compared results with those from its 2002 analysis, which involved 10 of the same sites; for these sites, prevalence increased 57% from 2002 to 2006 (http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5601a2.htm). The researchers selected 8 years of age as a reasonable index age for monitoring peak prevalence.
Mitka M. Rising Autism Rates Still Pose a Mystery. JAMA. 2010;303(7):602. doi:10.1001/jama.2010.113