Rate of Autism Spectrum Diagnoses Among Children Increasing, CDC Reports

The number of children diagnosed with autism is on the rise, with one in 59 children now on the spectrum, according to the findings of a new study. 

U.S. Centers for Disease Control and Prevention (CDC) researchers report that rates of reported cases of autism spectrum disorder (ASD) have increased nearly 150% since 2000. The findings were published in the April 27 issue of the CDC’s Morbidity and Mortality Weekly Report.

Researchers indicate that data collected from 2014 shows a 15% increase in prevalence of the diagnosis, compared to data collected in 2012.

Autism spectrum disorder is a developmental disability. Children with autism often experience problems with social interaction, communication, and complete repetitive and restrictive behaviors.

In the new report, researchers looked at data from 11 Autism and Developmental Disabilities Monitoring (ADDM) Network sites. The ADDM is an active surveillance system that provides estimates of the prevalence of autism spectrum disorder among children aged 8 years whose parents reside within 11 ADDM areas in the U.S.

The 11 ADDM sites are Arizona, Arkansas, Colorado, Georgia, Maryland, Minnesota, Missouri, New Jersey, North Carolina, Tennessee, and Wisconsin. The data from these sites represents about eight percent of all eight-year old children living in the United States.

In 2014, the prevalence of autism was 16.8 per 1,000, the equivalent of one in 59 children. Researchers indicate the prevalence of autism is higher than previously reported estimates from the ADDM network.

The rates varied from state to state. In New Jersey, one in 34 children is diagnosed with autism. However, in about five states that rate drops to one in 75 children.

While the rates also varied by sex and race/ethnicity, with males four times more likely than females to be diagnosed with autism. The prevalence of autism was higher for non-Hispanic white children compared to non-Hispanic black children. Both white and black children were more likely to have autism than hispanic children.

The increase in diagnoses may be because the criteria for diagnosis has expanded to include more children, researchers noted. Some children who would have previously been diagnosed with intellectual disability are now receiving an autism diagnosis instead.

More minority children are being diagnosed than in the past. This isn’t because the prevalence among Black and Hispanic children has increased, researchers said; it’s simply because minority children were less likely to be identified based on lack of medical care and services.

Additionally, awareness of autism has increased in recent years. This prompts more parent and caregivers to recognize certain behaviors and bring it to the attention of doctors.

Among children diagnosed with autism, 31% of children were classified as having an intellectual disability, with an IQ under 70. About 25% of children were classified at the borderline IQ range 71-85, and nearly half of children had IQ scores in the average to above average IQ range of 85.

Most children had some mention of developmental concerns by age 3. In fact, developmental concerns were documented for 85% of children diagnosed with autism by that age. The findings of one study linked lead exposure during early life to an increased risk.

About 42% of children had a comprehensive evaluation conducted by three years of age. However, the earliest autism diagnosis was 52 months, or 4 years old. Some researchers indicate certain exposures may be the key to autism.

One previous study, for example, linked Tylenol use during pregnancy to an increased risk of autism. Another recent study indicated the strength of ultrasounds may pose a potential risk.

The study’s authors warn that more research is needed to determine the cause of the increasing prevalence. However, because the prevalence is increasing, more funding is being directed toward autism studies.