Autism in Utah 8-year-olds far more prevalent than previously reported

Autism prevalence among 8-year-old Utah children has risen by nearly 30% in less than a decade, according to a study of 11 communities nationwide, including Salt Lake City and surrounding counties, led by the Centers for Disease Control and Prevention (CDC). Autism prevalence among 8-year-olds in the state rose from 1 in 58 children in 2012, when the last survey was conducted here, to about 1 in 46 in 2018, as reported in the current study.

The study and a companion report on the prevalence of autism spectrum disorder (ASD) among 4-year-olds appears in Mortality and Morbidity Weekly Report.

The researchers, including University of Utah Health scientists, attribute much of the increase to greater awareness of the disorder, better diagnostic tools used to detect it, and improved access to medical care.

"Utah's autism prevalence is significantly higher now than when we last measured it," says Deborah Bilder, M.D., a co-author of the study and a professor of child and adolescent psychiatry and pediatrics at Huntsman Mental Health Institute (HMHI) at University of Utah Health. The CDC considers 8 years old the optimal age to determine the prevalence of ASD in communities. By that age, Bilder explains, children are most likely to exhibit recognizable symptoms of the disorder.

"I believe Utah legislation passed over the last decade has had a substantial positive impact on children's access to autism diagnostic and treatment services," Bilder says. "This is particularly true for those children in the lower and middle household income range."

In Utah and several other sites nationwide, the percentage of Hispanic children with ASD was lower compared to White or Black children. This finding suggests that disparities in getting an ASD diagnosis, based on ethnicity, could be a problem, says Amanda Bakian, Ph.D. a co-author of the study, associate professor of psychiatry at HMHI, and principal investigator of the Utah ADDM study.

ASD prevalence also rising elsewhere in U.S.

Overall, the CDC's Autism and Developmental Disabilities Monitoring (ADDM) Network concluded that about 1 in 44 8-year-old children living in 11 communities nationwide had some form of ASD in 2018 compared to 1 in 54 in 2016. Utah did not participate in the 2016 assessment.

Estimates in the current study varied widely by locale, ranging from 1 in 60 children in Missouri to 1 in 26 in California. The researchers suspect these variations might be due to geographic differences in early detection and evaluation, diagnostic practices, and other differences in documentation of ASD symptoms.

Early detection, early treatment key to treating ASD

The scientists conclude that practices that improve equitable access to early ASD identification and services are a vital step forward.

"Early autism diagnosis and treatment optimizes children's ability to learn, engage with others, and develop independence," Bilder says.

"That's why these studies are so important," Bakian says. "They not only help us get a better idea of the growing prevalence of autism but can also help us improve policies, services, and research directed toward helping children and their families affected by autism."

In addition to Salt Lake County, Davis and Tooele Counties were included in the Utah portion of the study. Other participating communities were in Arizona, Arkansas, California, Georgia, Maryland, Minnesota, Missouri, New Jersey, Tennessee, and Wisconsin. Although the study spanned the country, the researchers stress that their findings are a snapshot of ASD in these communities and not a national estimate of autism prevalence in the United States.