Press release from Rutgers, the State University of New Jersey. Adapted for space. See full report here.
According to the U.S. Centers for Disease Control and Prevention (CDC), about 4 percent of 8-year-old boys and 1 percent of 8-year-old girls in the U.S. have autism. The first study, the CDC’s 2020 autism prevalence report, found that California set new records, diagnosing 45 percent more boys with autism than any other state in the network.
Nearly 7 percent of all 8-year-old boys in the San Diego region are estimated to have autism spectrum disorder (ASD), according to the report.
In New Jersey, the combined rate of 8-year-old boys and girls with ASD was 28.7 per 1,000 children (2.9 percent), the third highest behind Minnesota (3 percent) and California (4.5 percent).
Maryland recorded the lowest rate (2.3 percent) across the 11 states in the network (which includes Arizona, Arkansas, California, Georgia, Maryland, Minnesota, Missouri, New Jersey, Tennessee, Utah and Wisconsin).
“For California in particular, the data are surprising and represent the highest autism prevalence estimates from a region by an epidemiologic study,” Dr. Walter Zahorodny said, director of the study.
There may be several reasons for the disparity between California’s numbers and the rest of the country, he said. For one, California’s figures were drawn from an area in metro San Diego that is leading national efforts to diagnose autism as early as possible, translating into more accurate – and higher – numbers than other states.
State-funded centers also provide evaluations and service coordination for children with disabilities and their families. Other states may be undercounting because they don’t have as many diagnostic resources, he said.
“The true rate may not be substantially different between California and other ADDM states, including New Jersey,” Zahorodny said. “What’s different is that California implemented some wide-ranging screening and intervention programs, which may have resulted in a higher estimated prevalence than elsewhere in the network.”
“Once considered a rare disorder, these figures suggest that autism may be one of the most common disabilities,” Zahorodny said. “The trouble is we don’t understand what the primary drivers of the increase are.”
Zahorodny said other states should consider expanding screening programs to echo what California has done. “Consistent universal screening of young children coordinated through multiple pediatric practices may be the way to make a difference in autism detection and intervention,” he said.
More difficult to ascertain is why ASD prevalence continues to climb. While there are known risk factors for autism, including age of parents, multiple-gestation birth, prematurity, C-section delivery and care in the intensive care unit after delivery, these perinatal factors have remained relatively stable even as the rate of ASD has continued to surge.
A common misconception is that better awareness and more availability of services is largely responsible for the rise, but Zahorodny said this was “impossible” because the scope and breadth of increase has been extensive across all subtypes of ASD, from mild to severe, and across all demographic groups.
“This is not just a phenomenon of becoming more sensitive to subtly impaired kids,” he said.