CDC study identifies prevalence of intellectual disabilities


Researchers from the Centers for Disease Control and Prevention (CDC) have reported new estimates of the number of American children with intellectual disability (ID). In a study looking at 8-year-olds in several communities across the U.S., researchers found that 1.2% had IQ scores of 70 or below qualifying them for an ID diagnosis.


The findings published late last year in the Disability Health Journal are based on data collected through the CDC’s Autism and Developmental Disabilities Monitoring Network, which regularly reviews health and educational records for 8-year-olds in selected communities. The CDC uses the same methods to determine its autism prevalence estimates, which are generally updated every two years.


Researchers looked at records for over 215,000 children in nine states in 2014, identifying children as having ID if they had an IQ score of 70 or less or if there was a written statement from a qualified professional indicating that the child’s intellectual functioning fell within that range.

The majority of children identified — 78% — had mild ID while 12% were classified in the moderate category and 1% were considered severe or profound. The study also discovered that 39% of children diagnosed also had autism.


Even though most cases of ID can be reliably diagnosed before age 5, the researchers noted that almost a quarter of the children studied did not undergo an IQ test until after age 6. They also said their findings are largely consistent with previous estimates of ID prevalence, which were based on surveys, administrative records or data from single states, but those prior studies lacked details on subpopulations.


The study authors indicated that given the “substantial disparities” seen across racial, ethnic and socioeconomic groups, the “results could be used to help inform strategies to enhance early access to intervention services to improve quality of life for children with ID.”


For more information about developmental disabilities in general, please visit the CDC’s Fact Page. For more information ongoing research in ID and developmental disabilities, click here.



Sources: CDC and Disability Scoop