An estimated one in 59 U.S. children had autism spectrum disorder (ASD) in 2014—a rate that was 15% than previously projected, according to a CDC report released Friday.
The report revises an estimate from a previous CDC report based on 2012 data, which had projected that one in 68 U.S. children had ASD in 2012. The latest report is based on 2014 data collected through the Autism and Developmental Disabilities Monitoring (ADDM) Network—an active surveillance system that monitors and estimates the prevalence of ASD among more than 300,000 children who are eight-years-old and live in 11 U.S. communities in:
- New Jersey;
- North Carolina;
- Tennessee; and
Daisy Christensen, co-author of the report and the surveillance team lead in the developmental disabilities branch of CDC's National Center on Birth Defects and Developmental Disabilities, said, "[T]hese are diverse communities so that we can look at autism prevalence and characteristics in a number of different groups defined by race/ethnicity or by socioeconomic status."
While the sample is not representative of the entire U.S. population, it provides a glimpse of the prevalence of ASD in specific U.S. communities. According to CDC, the ADDM network is the largest population-based program in the United States to monitor autism and it is the only ASD tracking system that examines both education and health records.
According to the report, the prevalence rate of ASD was 1.7% in 2014—up from an estimated prevalence rate of 1.5% in 2012. The latest estimate represents a 15% increase in the prevalence of ASD from 2012 to 2014 and a 150% increase from 2000 to 2014. According to the researchers, it is unclear whether the higher prevalence rate is a result of more children having ASD or improvements in screening and diagnosis.
For instance, the researchers said the estimate might be higher because of improvement in the identification of ASD cases among Hispanics and blacks. Though CDC data show ASD is more prevalent among white children, it also shows a growing number of black and Hispanic children have ASD. In particular, CDC data show the prevalence of ASD was about 20% higher among white children than in black children in 2012, but in 2014, the rate disparity reduced to just 10%. The prevalence of ASD was 50% higher among white children than Hispanic children in 2012, but in 2014, that difference reduced to 20%.
The researchers also found a difference in the prevalence of ASD among sex. According to the report, the male to female ratio for ASD prevalence decreased from 4.5 males for every one female in 2012 to four males for every one female in 2014.
According to the report, the prevalence of ASD varied significantly across the 11 communities studied. The researchers found that five communities had ASD prevalence estimates of up to 1.4%. New Jersey had the highest estimated prevalence of ASD, at 2.9%.
The researchers found fewer than 50% of the children diagnosed with ASD had received their diagnosis by the age of four—which researchers said highlighted the need for earlier diagnoses to provide such children with access to earlier interventions. According to the report, 85% of children with ASD had notes in their health records that raised concerns about their development by the time the children were three, but only 42% of such children received a development evaluation by the age of three.
Stuart Shapira, associate director for science at CDC's National Center on Birth Defects and Developmental Disabilities, said although the findings show an increase in the prevalence of ASD, this is actually "good news," because it means that "[c]ommunities are doing a better job of identifying children and connecting them to services." Shapira added, "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." She continued, "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."
Christensen explained that "over the 80s and 90s, the diagnostic criteria expanded to include more children, so I think that's definitely a possibility for the increase that we've seen." She added that variations in the prevalence of ASD across the 11 communities studied stem from "differences in policies that affect access to services" and "differences in how children are screened and evaluated and diagnosed in those communities."
Thomas Frazier, chief science officer at Autism Speaks, said, the findings show "a significant increase." He continued, "Part of the increase is due to the fact that we have reduced disparities both in terms of identifying girls with autism and also African Americans and Hispanic children with autism. But also part of the increase we are just not sure exactly why that is happening." Frazier continued, "We know that if a child gets into early developmental behavior interventions that their outcome is going to be considerably better than children that don't get access to those interventions." He said additional research is needed, because "without that, we aren't going to understand why autism has increased so dramatically over the decades" (CBS News, 4/26; Scutti, CNN, 4/26; Shopp, ABC News, 4/26; Kaplan, Los Angeles Times, 4/26; Diamond, "Pulse," Politico, 4/27).
Your 10-minute cheat sheet on pediatric telehealth
Learn the emerging trends that are driving pediatric applications of telehealth, how reimbursement works, the business case for offering these services, and more—in this 10-minute read.