(SALT LAKE CITY)—Following a decade of alarming increases, the overall prevalence of U.S. 8-year-olds diagnosed with autism spectrum disorder (ASD) remained unchanged from 2010 to 2012, while data for Utah showed that the prevalence dropped slightly in the state. Although the Utah ASD prevalence has not increased for two consecutive study years, this was the first study year in which the nationwide prevalence remained the same and the Centers for Disease Control and Prevention (CDC) isn't ready to declare that the nationwide surge in ASD has leveled off.
The study, released online on March 31, 2016, in the CDC's Morbidity and Mortality Weekly Report, looked at de-identified education and/or health care records of children living in the CDC's Autism and Developmental Disabilities Monitoring Network (ADDM) comprising 11 states: Utah, Arizona, Arkansas, Colorado, Georgia, Maryland, Missouri, New Jersey, North Carolina, South Carolina and Wisconsin.
Researchers examined records of children who were 8 years old in 2012 and compared them with records of 8-year-olds in 2010. They found that the average ASD prevalence among children across all 11 states was 14.6 per thousand, or one in 68, which is virtually unchanged from 2010. In Utah, researchers with the Utah Registry of Autism and Developmental Disabilities (URADD), a Utah Department of Health (UDOH) program run in cooperation with University of Utah Department of Psychiatry, found that the ASD prevalence among 8-year-olds was 17.3 per 1,000 8-year-olds in 2012, down from 18.6 per 1,000 in 2010. This slight decline is not considered statistically significant.
This study follows one in December 2015 showing that children are being evaluated for ASD at earlier ages, finding that kids who were 4 years old in 2010 were evaluated at a median age of 27 months compared with 32 months for those who were 4 years old in 2006. Identifying children with ASD at the youngest age possible is critical for getting them the right help and improving long-term outcomes. The American Academy of Pediatrics has recommended kids be screened at 18 months old and again at age 2.
Deborah Bilder, M.D., U associate professor of psychiatry and co-investigator of URADD, said the reason for Utah's slight drop in ASD prevalence is unclear. Despite the minor dip, Utah still ranked fourth highest in ASD prevalence among the ADDM states behind New Jersey, North Carolina, and part of Maryland.
"The national ASD prevalence is following the pattern that Utah started last study year of maintaining rather than increasing in number," Bilder says. "Now that the alarming increase in measured ASD prevalence has subsided, both in our state and nationally, we are shifting our focus to facilitate earlier recognition of ASD at the youngest age possible, so that children with ASD can access needed services at an age when they can benefit most."
Marc Babitz, M.D., director of the Division of Family Health and Preparedness at the UDOH, believes the ADDM studies are providing critical information to help families. "I greatly value the collaborative relationship that the UDOH has with the University of Utah's Department of Psychiatry that allows us to collect and analyze data on this condition that has such a profound impact on Utah families," he says. "I know that the more we understand about this disorder and the numbers of Utah children affected, the better we can prepare to address their needs."
The CDC set up the ADDM network in 2000 to track ASD prevalence among the nation's 8-year-olds. Findings from the consortium can give direction to local, state, and federal officials who set policies to help those with ASD.
The ASD prevalence ranged widely among the ADDM sites in the current study. In states where only de-identified health records indicating that a child had ASD were available, the prevalence estimates tended to be lower, 10.7 per 1,000 versus 17.5 per 1,000 in states where both education and health records were accessible. An area of Maryland, for example, where only health records could be analyzed, had an estimate prevalence of 8.2 per 1,000 8-year-olds, the lowest rate of any area in the study. In New Jersey, conversely, where both health care and education records were available, the prevalence estimate of 24.6 per 1,000 was the highest in the study.
Other findings of the 2012 study were consistent with previous research showing that ASD prevalence was almost 4.5 times higher among 8-year-old boys, 23.6 per 1,000, than girls, 5.3 per 1,000. Prevalence among non-Hispanic white children, 15.5 per 1,000, was significantly higher than that of non-Hispanic black children, 13.2 per 1,000, and Hispanic children, 10.1 per 1,000 8-year-olds. Among children identified with ASD by the ADDM network, 82 percent had a previous diagnosis or educational classification.