New data analysis from the Centers for Disease Control and Prevention (CDC) finds that among 8-year-olds in the U.S., 1 in 36 has been diagnosed with autism spectrum disorder (ASD).

The new report was compiled from data in nearly a dozen states across the U.S. in 2020. That number is up from 1 in 44 8-year-olds in 2018 and 1 in 54 8-year-olds in 2016.

Experts believe this increase in diagnoses of ASD doesn’t mean an increase in the number of affected children; it’s more likely that the new number is more accurate due to awareness and a wider availability of healthcare and additional services for children with ASD.

A separate CDC report said that children were 50% more likely to be diagnosed with ASD by age 4 in 2018 than in 2014. The report also states that ASD can be detected as early as 1 year old and yet many of the children in the study were not diagnosed until they were much older.

“There is some progress being made and the earlier kids get identified, the earlier they can access services that they might need to improve their developmental outcome,” said CDC researcher and co-author of the data analysis, Kelly Shaw.

The AAP recommends developmental screenings at 9, 18 and 30 months and screening for autism at ages 18 and 24 months.

Related: AAP and CDC just changed developmental milestones guidelines for the first time in decades

The CDC data in question was gathered from counties and other communities in 11 states—some of these communities were more urban than others. ASD rates tend to be higher in more urban areas due to a more dense population, the authors said.

The CDC tracks the prevalence of ASD via their Autism and Developmental Disabilities Monitoring Network. This database consists of the medical and special education records of 4- to 8-year-olds living in one of the 11 regions outlined in the latest report.

The report shows varying rates of ASD diagnoses by state, too. In California, 1 in 22 children were diagnosed with ASD, compared to 1 in 43 children in Maryland. Eight-year-old boys were 4 times more likely to be diagnosed with ASD than girls of the same age. 

Overall, the latest data indicate that autism prevalence in 2020 was higher among Black and Hispanic children compared with white children, but that since 2000, ASD has increased steadily among all groups. “And while more research is needed to understand this difference, it could relate in part to less access to services that diagnose and support children with autism,” said Karen Remley, MD, MBA, MPH, FAAP, director of the CDC’s National Center on Birth Defects and Developmental Disabilities, in a press conference.

Related: I’m the mom of a child with autism. Here are 3 things I want other parents to know

The report’s authors noted that “These data indicate that ASD is common across all groups of children and underscore the considerable need for equitable and accessible screening, services, and supports for all children.”

A previous report from 2021 found that in 2018, children in Utah from lower-income families had higher rates of ASD diagnoses than those from wealthier families. Previously, experts determined that children from higher-income families had higher rates of ASD, but now they say Medicare and private insurance companies offer more coverage for ASD services than in previous years.

“We all need to work together to catch up to the progress we have been making to identify children with autism early, which is when we know interventions have the greatest likelihood of success,” said AAP President Sandy L. Chung, MD, FAAP.

Although early intervention is key, Dr. Chung urges parents to consult with their child’s pediatrician if they are concerned. “We also want parents to understand it’s never too late. If you are noticing something concerning with your child’s development at any stage, please reach out to your child’s doctor so we can begin that conversation.”

A version of this post was published December 6, 2021. It has been updated.