Autism rates continue to climb, and experts don't exactly know why

Karen Weintraub | Special for USA TODAY

Show Caption Hide Caption CDC report: Autism diagnoses are rising More school children are being diagnosed with autism and experts haven’t been able to figure out why.

Autism rates in schoolchildren jumped 15% between 2012 and 2014, continuing a two-decade rise, according to the latest data from the Centers for Disease Control and Prevention, which does not detail the reasons for the increase.

In a count of 11 communities across the United States, about one in 59 8-year-olds had autism in 2014, up from one in 68 in 2012. Overall, autism rates have climbed 150% since 2000, when the figure was one in 150 children.

The rise is partly driven by increasing diagnoses among African-American and Hispanic children, who are narrowing the diagnostic gap with their white classmates.

In the 2012 report, white children were diagnosed 50% more often than Hispanic children and 20% more than African-American children. In the latest report, that gap shrunk to 20% among Hispanics and 10% among blacks.

Autism is a developmental disorder characterized by a range of communication and social challenges, as well as repetitive behaviors like rocking, hand-flapping or obsessions.

The report is published every two years by the Autism and Developmental Disabilities Monitoring Network, a CDC-funded tracking system that assesses more than 300,000 8-year-old children for the disorder.

Craig Newschaffer, director of the AJ Drexel Autism Institute at Drexel University in Philadelphia, said he understands why people find it frustrating to see the autism rates continually climbing with no explanation. But, as genetic studies are increasingly revealing, autism is extremely complex, he said.

There are no obvious environmental causes for the rising rates, and without data on adults, it remains unclear whether more people have autism, or the condition has always been this common, just unrecognized or called by other names, he said.

The Autistic Self Advocacy Network, a nonprofit run by and for individuals on the spectrum, has long called for a study to examine rates in adults.

“Autism is not a bad thing, and autistic people — of all ages, races, and genders — have always been here,” Zoe Gross, director of operations for the group, said. “What the CDC's research shows is that our data is catching up to that fact.”

The latest report found there are still large variations in autism rates across states, with New Jersey diagnosing nearly 3% of its schoolchildren with autism while Arkansas is closer to 1%.

Much of that variation can be explained by differences in who is counted in each state. In Arkansas, for example, a lot of the children counted are from rural areas, where fewer autism specialists may be located, compared to largely urban populations in New Jersey and other states, said Daisy Christensen, an epidemiologist with the CDC.

Walter Zahorodny, who tracks the autism rate in New Jersey as an associate professor of pediatrics at Rutgers New Jersey Medical School, said he’s seen no changes in New Jersey’s politics or diagnostic procedures to explain the huge increase in his state. In 2000, about 10 children out of 1,000 were considered to have autism, compared with nearly 30 out of 1,000 in 2014.

New Jersey, he noted, has more resources devoted to autism detection and treatment than most other states, and its population is well off and highly urbanized, both of which have been associated with higher autism rates.

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Although signs of autism usually appear between a child’s first and second birthday, the report highlighted the average age of diagnosis remains around 4 1/2 years old.

Out of every 20 children eventually determined to have autism, concerns were raised about 17 of them before age 3, but only eight received full developmental evaluations by that age, said Stuart Shapira, chief medical officer with the National Center on Birth Defects and Developmental Disabilities, part of the CDC.

“There’s a big gap between first developmental concern and when the child has a developmental evaluation that would be useful in order to get the child into services to improve their outcome and health,” Shapira said.

Pediatricians are now supposed to screen every child several times in the first three years to look for signs of autism. The younger a child receives autism services, the more likely they are to improve, research shows.

Shapira said parents can play a key role in raising concerns about their toddler’s development with their doctor. “It’s really important for parents to have a role in this and act quickly if there is a concern. Not to wait,” he said.

Advocates and researchers were not surprised by the unrelenting rise in autism rates.

Among others, Alison Singer, president of the Autism Science Foundation, which supports autism research, said the closing racial gap is good news, because it means more minority children will have access to services.

Gross said she expects the diagnosis rate to continue to climb until all communities are equally represented.

“We still have work to do to ensure equal access to culturally competent diagnosis and get rid of the disparities that remain,” Gross said.