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  • The CDC says more children are being diagnosed with autism than ever before.
  • The rates may reflect growing awareness of autism spectrum disorder and a focus on getting more children into treatment.
  • Other factors including air pollution, low birth weight, and stress may also be behind the increase in diagnoses.

New data published this month from the U.S. Centers of Disease Control and Prevention (CDC) revealed that more children are being diagnosed with autism spectrum disorder (ASD) now than at any other point since the agency begin monitoring autism rates in 2000.

They also found that Black and Hispanic children are being diagnosed with autism at higher rates than white children.

According to the data, 1 in 36 eight-year-olds (2.8%) had autism in 2020 — a jump up from 1 in 44 (2.3%) in 2018.

Autism continues to be identified more frequently in boys but the report revealed that the prevalence of autism among girls has increased to over 1%.

A second CDC report evaluating autism rates in 4-year-olds similarly found that autism is now more common in Black, Hispanic and Asian and Pacific Islander children and is being diagnosed at younger ages.

Compared with white children, autism rates were 1.8 times as high among Hispanic kids, 1.6 times as high among Black kids, 1.4 times as high among Asian or Pacific Islander children, and 1.2 times as high among multiracial children.

Stephen M. Kanne, PhD, a clinical psychologist at NewYork-Presbyterian, professor of psychology and director of the Center for Autism and the Developing Brain at Weill Cornell Medical College, said the rising rates can be attributed to multiple factors including increased access to care, awareness, and screening.

“Diagnostic criteria have changed and broadened to accurately capture those individuals with autism that may have been missed prior to those changes,” Dr. Kanne said.

Researchers suspect that the rising rates of autism can be attributed, in part, to the growing awareness and advocacy of autism.

It’s possible that autism has always been a common condition and we are just beginning to capture the true prevalence due to better screening efforts, said Dr. Peter J. Chung, a developmental-behavioral pediatrician and Medical Director of The Center for Autism & Neurodevelopmental Disorders at University of California, Irvine.

On the other hand, some researchers suspect that certain environmental factors are contributing to the growing rates of autism, Chung added.

“Experts vary on their opinions regarding this phenomenon, but I personally believe it is probably a little bit of both,” Chung said.

Historically, rates of autism have been lower in non-white children, however, this report is the first to find that the rates of autism in Black and Hispanic children have exceeded rates of autism in white children.

Chung said rates of autism in Black and Hispanic kids have grown as more communities have worked to address racial and ethnic disparities in autism diagnosis.

“It is possible that these efforts in increasing screening and access to referrals has resulted in more non-white children getting evaluated,” Chung said.

Though access to autism screening and treatment has increased for Black and Hispanic kids, it hasn’t surpassed access in the white community, Chung noted, so it’s unclear why autism is being identified more frequently in Black and Hispanic kids.

Many factors are known to increase the likelihood of autism — like premature birth and low birth weight.

Other factors like exposure to air pollution and maternal stress may also play a role.

“It may be that Black and Hispanic children have greater exposure to those factors,” said Kanne.

Though it’s widely believed that autism is a neurobiological disorder, it’s unclear if genetics play a role, Kanne noted.

Autism rates varied significantly across the 11 states included in the analysis, which the researchers believe can be attributed to state differences in how autism is screened and treated.

Autism prevalence in eight-year-old kids ranged from 23.1 per 1,000 (2.3%) children in Maryland to 44.9 per 1,000 (4.5%) in California.

In 4-year-olds, prevalence ranged from 1.3% in Utah to 4.6% in California.

Certain states, like California, have programs in place to better identify and treat children who are suspected of having autism.

“This increased emphasis in early screening is likely contributing to the rise in prevalence as these children are identified early, intending to provide treatment and support as soon as possible,” Kanne said.

According to Chung, data consistently shows that early intervention for children with autism leads to the best possible outcomes in cognition, language, and behavior.

All pediatricians are encouraged to screen for autism at each child’s 18 and 24-month check-ups.

The CDC’s findings highlight the importance of high-quality surveillance, screening, and intervention efforts for the pediatric population, Chung said.

“The increase in Autism diagnoses speak to the need for more training and resources for professionals involved in identifying, diagnosing, and caring for autistic individuals and their families so we can provide treatment and support as early as possible,” Kanne said.

More children than ever before are being diagnosed for autism. Additionally, Black and Hispanic children are being diagnosed with autism at higher rates than white children, according to new data from the CDC. The increased prevalence of autism can be attributed, in part, to greater awareness and advocacy for autism. Some researchers believe environmental factors, like exposure to air pollution and maternal stress, are contributed to the rising rates, but more research is needed to understand why autism rates continue to rise.