March 2014, VOLUME /ISSUE

Autism prevalence now 1 in 68, varies by sex, race/ethnic group

The prevalence of autism spectrum disorders (ASD) has risen to one in 68 children — a 30% increase over previous rates, according to data released today by the Centers for Disease Control and Prevention (CDC). Estimates reported in 2012 showed that one in 88 children had been identified with autism.

The most recent data on the prevalence of ASDs among 8-year-old children were gathered in 2010 through the active surveillance system, Autism and Developmental Disabilities Monitoring Network, from 11 U.S. sites using DSM-IV-TR criteria. The results are published in Morbidity and Mortality Weekly Report (MMWR. 2014;63(No. SS6302):1-24).

“The epidemiologic data doesn’t speak to reasons (for the increase),” said Susan L. Hyman, M.D., FAAP, chair of the Autism Subcommittee of the AAP Council on Children with Disabilities. “It is certainly plausible that we’re getting better at identifying symptoms, and we are getting closer to the true prevalence in the population and our ability to identify it.”

The surveillance found:

  • Intellectual ability of children with ASD varies greatly. About half of the children have average or above-average intellectual ability (i.e., IQ above 85) compared to only one-third 10 years ago.

  • Boys remain more likely to be identified with ASD with one in 42 diagnosed compared with one in 189 girls.

  • Prevalence also varied by racial/ethnic group, with non-Hispanic white children 30% more likely to be identified than non-Hispanic black children and 50% more likely than Hispanic children.

  • A greater number of black children (48%) were classified within the range of intellectual disability vs. 38% of Hispanic and 25% of non-Hispanic white children.

  • Median age at diagnosis remains 4 years of age, although resources enable diagnosis for some patients as young as 2 years old.

The report notes that the combined prevalence cannot be generalized to all U.S. 8-year-olds.

“The AAP is working to help make pediatric practices better equipped to provide ongoing care to the many children with autism. These rising rates certainly underscore the need to improve our understanding of the causes of autism and to work on prevention,” said AAP President James M. Perrin, M.D., FAAP.

Recommendations in the report call for efforts to enhance strategies to address standardized widely adopted measures to document ASD severity and functional limitations; improve recognition and documentation of symptoms that distinguish sex, intellectual disability and race/ethnic group; and lower the evaluation age and community support system enrollment age.

Better tools, such as the Modified Checklist for Autism in Toddlers (M-CHAT), have improved pediatricians’ ability to screen better and earlier, but only half of pediatricians use formal screening regularly, Dr. Hyman said.

“Tools only work if we believe the results and refer children who screen positive,” she said. “Even the children who are false positive on the M-CHAT have something that requires further evaluation. It may not be autism, but there are lots of developmental disorders that benefit from early intervention.”

Embedded Image