Report: Autism Prevalence Has Increased

The prevalence of autism is higher than previously reported by the CDC’s Autism and Developmental Disabilities Monitoring (ADDM) Network and continues to vary among population groups and communities, according to a new report.

Published in the CDC’sMorbidity and Mortality Weekly Report(MMWR), the report estimates a prevalence of 1 in 59 (1.7%) children with autism in 2014, up from 1 in 68 (1.5%) children found in the ADDM estimate released 2 years ago. In the latest estimate, autism prevalence reached nearly 3% in some communities, indicating an overall 150% increase in prevalence since 2000.¹

The recent change in prevalence indicated by the study may be attributed to improved autism identification in minority populations, the authors theorized, though autism continues to be more likely identified in white children.¹The prevalence of autism among African-American and Latino children is approaching the levels shown in white children, Stuart Shapira, MD, PhD, associate director for science at the 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 faster,” she said.

The new data also demonstrate a decrease in the gender gap for those identified as children with autism. In 2014, boys were 4 times more likely to be identified than girls. In the previous report, with data from 2012, boys were 4.5 times more likely to be identified with autism.²

Dr. Thomas Frazier, a spokesman for the autism advocacy group Autism Speaks, said in a statement that the CDC’s evidence of improved identification of autism in girls and minority groups is encouraging.³“We must continue to narrow this gap, while greatly speeding up the time from first concerns about a child’s development to screening, diagnosis, and intervention,” he said. “If most children aren’t being diagnosed until after age 4, we’re losing months, if not years, of intervention that can deliver benefits throughout their lives.”

Identifying autism is important, because children who are identified early as having autism and connected to services are more likely to reach their fullest potential, according to the MMWR report. Data demonstrate that more work is needed to identify children with autism at younger ages and refer them to early intervention services. The report’s findings include:¹

• Fewer than half of the children identified in the ADDM received their first autism diagnosis by age 4.
• Just 42% of children with autism received a developmental evaluation by age 3, despite 85% of children with autism having developmental concerns noted in their health records by that time.
• The lag between the first concern and the first evaluation may affect when a child with autism can begin receiving needed services.

“Parents can track their child’s development and act early if there is a concern,” Shapira said. “Health care providers can acknowledge and help parents act on those concerns. And those who work with or on the 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.”

Eleven communities in 11 states were surveyed for the ADDM report, and they represent about 8% of children in the United States who are age 8. Autism prevalence estimates varied widely across the 11 communities, according to the report. The authors indicate that regional differences in how autism is being diagnosed and documented might play a role in differences between prevalence estimates.¹

In 5 of the communities surveyed, the prevalence of autism was similar, reported between 1.3% and 1.4%. A community in New Jersey reported the highest estimate, with a 2.9% prevalence of autism.¹

Frazier noted that in New Jersey, where the authors estimate the prevalence of children with autism to be 1 in 34, investigators had better access to education records used in the study. Meanwhile, an Arkansas community included in the study indicated the prevalence at 1 in 77 children.3 “This suggests that the new national prevalence estimate of 1 in 59 still reflects a significant undercount of autism’s true prevalence among our children,” Frazier said. “And without more and better research, we can’t know how much higher it really is.”

References

1. Autism prevalence slightly higher in CDC’s ADDM network [news release]. CDC website; April 26, 2018. cdc.gov/mmwr/volumes/67/ss/ss6706a1.htm?s_cid=ss6706a1_w. Accessed April 27, 2018.
2. Baio J, Wiggins L, Christensen DL, et al. Prevalence of autism spectrum disorder among children aged 8 years — autism and developmental disabilities monitoring network, 11 sites, United States, 2014.MMWR Surveill Summ. 2018;67(No. SS-6):1—23. DOI: http://dx.doi.org/10.15585/mmwr.ss6706a1
3. CDC increases estimate of autism’s prevalence by 15 percent, to 1 in 59 children. Autism Speaks website. autismspeaks.org/science/science-news/cdc-increases-estimate-autism%E2%80%99s-prevalence-15-percent-1-59-children. Published April 26, 2018. Accessed April 27, 2018.