New data authored by researchers at the University of Utah in Salt Lake City shows there are far more children on the autism spectrum in the state than previously thought. Researchers say improvements in testing and diagnosing autism could be one reason for the increase.

Thousands of 8-year-olds and 4-year-olds from Salt Lake, Davis and Tooele counties took part in the Autism and Disabilities Monitoring study. Dr. Amanda Bakian, who co-authored the study, said health care officials used to believe 1 out of every 58 8-year-olds in Utah were on the autism spectrum. However, the latest data shows autism rates were actually much higher.

“The prevalence of autism in 2018, we found to be about 1 in 46 children,” she said.

Utah is slightly below the national average of 1 per 44 8-year-olds being diagnosed. Bakian said the data also shows there are more than three boys for every girl on the spectrum.

Why did the rate climb? Bakian believes it could be due to improvements in diagnosing and treating disorders related to autism, plus more families have access to testing. The study shows a high number of children in Utah’s low-income families are on the autism spectrum since lawmakers made it easier for children to be tested.

“Our community has been very good at identifying children with autism and getting them to services related to autism,” Bakian said.

Autism rates in other states varied wildly, according to the study. In Missouri, only 1 out of 60 children was diagnosed with autism. Meanwhile, in California, 1 out of every 26 children was placed on the spectrum. The study co-author Dr. Deborah Bilder said researchers should look at California’s numbers closely to see how doctors are able to diagnose and treat so many kids.

“There are aspects of the care in California that might be important for us to understand better in regards to how it may impact the identification of these children, particularly at a young age,” she said.

However, Bilder said the study shows major treatment gaps within certain communities. She said far fewer Hispanic children were diagnosed with autism than white or Black children, and they have no reason to believe autism impacts groups differently based on ethnicity.

“We feel this really reflects our need to step up our efforts even further on helping those children and those families,” Bilder said.

The study also found autism rates were lower among 4-year-olds, but the Centers for Disease Control and Prevention says symptoms are easier to spot among older children. Doctors said younger children were more likely to have other disorders diagnosed first.