An estimated 1 in 68 children have an autism spectrum disorder, a 30 percent spike in rates over two years, according to findings released today by the Centers for Disease Control and Prevention.
The latest findings are based on surveillance data collected between 2008 and 2010 as part of the Autism and Developmental Disabilities Monitoring Network, which looked at 8-year-olds identified to have autism in 11 communities across the US. The CDC previously estimated 1 in 88 children had the disorder.
The reason for the spike, however, is unclear. Colleen Boyle, director of the CDC’s National Center on Birth Defects and Developmental Disabilities said it may include better community awareness and better abilities by physicians to identify the range of symptoms.
“To better understand the why, there’s an urgent need to do more research,’’ Boyle said.
Older parenting and environmental factors may also contribute to the rise in autism.
According to the new data, New Jersey had one of the highest rates of children with the disorder. One in 45 children are diagnosed with autism in the state.
Boyle said the higher rates in some states may be due to better identification, diagnosis, and community resources.
“Those [states] that have the lower numbers of prevalence had less education resources in the community,’’ she said.
The latest data still found that boys are nearly 5 times more likely to have the disorder than girls.
Children who are on the spectrum vary in intellectual abilities. The data also found that nearly half of the children identified with autism had an above-average intelligence, compared to a third in 2002. Those findings suggested to the researchers that the spike in diagnoses may be due to the broad identification of the disorder.
“Autism is evolving [and so is] our clinical knowledge about it,’’ said Boyle. “There’s greater awareness in the community about autism.’’
Dr. Christopher McDougle, director of Massachusetts General Hospital’s Lurie Center for Autism, said he’s both surprised and concerned by the rise. The increase speaks to just how large the spectrum of disorder is becoming, he said.
“It’s fine to have a spectrum, but if you look at individuals on each end of the spectrum side by side, they are quite different,’’ he said. ’’As time goes on we’re going to learn more about subtypes that are linked to certain causes and be able to tailor treatments.’’
For now, identifying autism in those with higher IQs could lead to could help them get appropriate services, said McDougle.
“More social and communication disabilities are being identified in those with higher intellectual capabilities than ever before,’’ he said. “It’s important to diagnose higher functioning [children] because many times they’re overlooked.’’
Autism can be reliably detected in children by as early as age 2, but most children are not diagnosed with the disorder until after age 4.
Ongoing research has looked into detecting the disorder much earlier. One preliminary study, published Wednesday in the New England Journal of Medicine , suggests that autism can be detected as early as the second trimester of pregnancy. The researchers looked at postmortem brain tissue of 22 children ages 2 to 15, half of whom were diagnosed with autism before they died. They found that certain brain cells in those diagnosed with autism that were supposed to develop prior to birth failed to mature within the womb.
“It’s critical that we as a society do not become numb to these numbers,’’ Dr. Susan Hyman, chair of the American Academy of Pediatrics autism subcommittee said in a public statement. “They remind us of the work we need to do in educating clinicians and parents in effective interventions for all children, including those with developmental disabilities.’’
The CDC launched a new initiative Thursday aimed at educating families, educators, and professionals to watch for developmental milestones and identify signs of autism. The “Birth to 5: Watch Me Thrive’’ initiative advocates that all children are regularly screened for the disorder.