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One in 59 children in the U.S. have autism spectrum disorder, based on a new estimate released Thursday by Centers for Disease Control and Prevention.
This finding indicates the prevalence of autism is slightly higher than previously thought, but does it mean autism is becoming more common? Here is what you need to know.
Where the new numbers came from: Since the turn of the century, the CDC and partner hospitals have measured the prevalence and evolution of autism spectrum disorder by using a massive group of 8-year-olds.
Known as the Autism and Developmental Disabilities Monitoring (ADDM) Network, this survey ranges in size — depending on the year — from 180,000 to 400,000 children. It is spread across 11 communities in Arizona, Arkansas, Colorado, Georgia, Maryland, Minnesota, Missouri, New Jersey, North Carolina, Tennessee and Wisconsin.
Every two years, the CDC compiles this health data into a report, but due to a lag, Thursday’s findings technically reflect how many autism cases existed in 2014.
The new rate, in context: The latest figure from the network represents a small — less than a quarter of a percentage point — increase compared to the autism rate released in 2016 (one in 68). CDC officials partially attribute this rise to improved surveillance and diagnosis in minority communities.
Socioeconomics factors into whether or not a child will receive access to autism screening, and prior research has found white and Asian children are more likely to be diagnosed than black and Hispanic kids. In 2012, the ADDM survey detected 20 percent more cases of autism in white versus black children. Compared to Latino children, the gap was even larger, at 50 percent.
“Autism prevalence among black and Hispanic children is approaching that of white children,” Stuart Shapira, associate director for science at CDC’s National Center on Birth Defects and Developmental Disabilities, said in a statement. “The higher number of black and Hispanic children now being identified with autism could be due to more effective outreach in minority communities and increased efforts to have all children screened for autism so they can get the services they need.”
But if it’s the case that the rate grew only because of better diagnosis, that would mean that autism spectrum disorder isn’t becoming more common among American children. Doctors are just better at spotting it.
Why it matters: There is huge room for improvement when it comes to diagnosing autism. Based on the latest survey, doctors had noted developmental concerns early on with 85 percent of the children with autism, typically by age 3. But physicians only referred them for specialized evaluation 42 percent of the time. The autism rate also varied dramatically by region, with New Jersey reporting a prevalence that is twice what is found in Arkansas.
Until screening becomes level across the nation, it will be difficult to fully determine the degree to which regional, environmental and socioeconomic factors contribute to autism.
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Meanwhile, any increase in the autism rate is met with a strong public scrutiny, as parents of children with the conditions continue to look, sometimes in alternative places, for a cause and cure. This year also marks two decades since The Lancet published a now retracted study by Dr. Andrew Wakefield that falsified a link between measles, mumps and rubella (MMR) vaccine and autism. Since its publication, dozens of studies have looked into any possible link between the measles vaccine and autism, and the evidence overwhelming shows no link.
After Wakefield’s study, the autism advocacy and medical communities endured a strained relationship, said Dr. Susan Hyman, division chief of developmental and behavioral pediatrics at the University of Rochester Medical Center. Just last autumn, a study found children whose older siblings have autism are about 14 percent less likely to be vaccinated than siblings of those without the disorder.
“Parents are still afraid because when you put that scary idea out there, it’s hard to put it back in,” said Alison Singer, president of the Autism Science Foundation (ASF). “So, there is still a legacy 20 years later from the Wakefield paper, and that legacy is disease and death.”
Since then, the anti-vaccination movement has survived both in the United States and Europe. In the United Kingdom, MMR immunization rates dropped about 4 percent after the Wakefield study’s publication. A measles outbreak at Disneyland in 2014 was attributed directly to misinformation about vaccines and autism.
“We tell parents all the time: when you withhold vaccines from your child, you are doing absolutely nothing to reduce the likelihood that they will be diagnosed with autism,” Singer said. “But you are absolutely increasing the likelihood that they will contract a disease from which they could potentially die.”
Nsikan Akpan is the digital science producer for PBS NewsHour and co-creator of the award-winning, NewsHour digital series ScienceScope.
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