Prevalence of ASD Increases in CDC's ADDM Network Report

Stuart Shapira, MD, PhD

Using data from its Autism and Developmental Disabilities Monitoring (ADDM) Network, the US Centers for Disease Control and Prevention (CDC) announced that among 8-year-old children in 11 US communities in the 2014 surveillance year, an estimated 1 in 59 (1.7%) was identified as having autism spectrum disorder (ASD), an increase from the 1 in 68 (1.5%) reported by the ADDM in 2016.

The data was collected from communities within Arizona, Arkansas, Colorado, Georgia, Maryland, Minnesota, Missouri, New Jersey, North Carolina, Tennessee, and Wisconsin, representing roughly 8% of 8-year-old children in the United States.

Overall, the prevalence of ASD varied among the sites from 13.1 to 29.3 per 1000 children aged 8 years, also varying by race/ethnicity and sex. Males were found to be 4-fold as likely to be identified with ASD as females. White children were more likely to have ASD compared to black children, and both were more likely to be identified with ASD than Hispanic children.

“Autism prevalence among black and Hispanic children is approaching that of white children,” Stuart Shapira, MD, PhD, the associate director for science at CDC’s National Center on Birth Defects and Developmental Disabilities, said in a statement. “The higher number of black and Hispanic children now being identified with autism could be due to more effective outreach in minority communities and increased efforts to have all children screened for autism, so they can get the services they need.”

The prevalence of ASD among white children exceeded that of black children by 30% in the surveillance years 2002, 2006, and 2010, but only by 20% in 2008 and 2012. Likewise, the prevalence of ASD among white children exceeded that of Hispanic children by almost 70% in 2002 and 2006 but was reduced to 50% in 2008, 2010, and 2012.

The CDC noted that this reduction in the ratio of white-to-black and white-to-Hispanic ASD prevalence may be partially due to improved rates of ASD identification in minority populations, an important aspect of ensuring these patients get access to services sooner.

Evaluation of these patients, according to the CDC, must improve. Less than 50% of those identified in the ADDM Network received their first ASD diagnosis by age 4, and despite 85% of children with ASD having concerns about development noted in their health records by age 3, only 42% of them received an evaluation by that time.

“This lag between first concern and first evaluation may affect when children with autism can begin getting the services they need,” according to the CDC.

“Parents can track their child’s development and act early if there is a concern. Health care providers can acknowledge and help parents act on those concerns. And those who work with or on behalf of children can join forces to ensure that all children with autism get identified and connected to the services they need as early as possible,” Shapira said in a statement. “Together we can improve a child’s future.”

To meet the definition for ASD for the CDC, the children needed to display behaviors that are consistent with the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) diagnostic criteria for autistic disorder; pervasive developmental disorder that is not otherwise specified (PDD-NOS, including atypical autism); or Asperger disorder. These behaviors must be described on ≥1 comprehensive evaluations completed by professional health care providers.

The CDC’s Learn the Signs. Act Early program is providing parents, childcare professionals, and health care providers resources in both English and Spanish for monitoring children’s development for children as young as 2 months of age. The CDC’s Milestone Tracker Mobile App can help parents track their child’s development and share the information with their healthcare providers. The CDC requests those seeking more information to visit www.cdc.gov/ActEarly.