Autism: A True Increase Or Semantics
The jump in autism cases has spawned not only alarm but also debate about whether the number of children with autism could have increased that much in a relatively brief time.
“There’s a lot of controversy about that,” says Jeff Milunsky, MD, director of clinical genetics and associate director of the Center for Human Genetics at Boston University.
Two researchers who tracked the rate of autism in children born in the same area of England from 1992 to 1995 and then from 1996 to 1998 found that the rates were comparable, and concluded that the incidence of autism was stable. The study was published in the American Journal of Psychiatry in 2005.
But, Milunsky says, several studies have documented an increase in the U.S.
In a recent report in the journal Archives of Disease in Childhood, Milunsky and his colleagues point to several studies finding an increase in autism rates. In 2003, for instance, a large study conducted in Atlanta found that one in 166 to one in 250 children had autism, according to a report published in the Journal of the American Medical Association.
Another study conducted by the CDC in 14 states found an overall prevalence of one in 152, which Milunsky and others say is the generally accepted figure today.
“A kid labeled autistic today could have been labeled mentally retarded 10 years ago in the same school system,” Shattuck says. It wasn’t until 1992 that schools began to include autism as a special education classification.
Is Autism Actually On The Rise It’s Not As Straightforward As You Might Think
31 verified experts answered this question on independent fact-checking platform Metafact.io. 17 answered ‘likely’ or higher, this is one of them.
The prevalence of autism the number of cases diagnosed at any age, has increased hugely.
But prevalence is not the same as incidence – the number of cases born with autism. There is no reason to believe that the incidence of autism has increased.
An increase in the prevalence of cases was inevitable given the recognition that the classic definition of autism was too narrow and there was a whole spectrum of autism .
The historic factors in the increase in diagnosed cases was the widening of the criteria, to fit them also to adults, and to be able to apply them to cases previously diagnosed merely with learning disability, where this meant less access to special support.
For instance, a study found that the average administrative prevalence of autism among children in the US had increased from 0.6 to 3.1 per 1000 from 1994 to 2003. But this increase was accounted for by a .
This was not the only factor that drove up prevalence figures: Cases with only very mild symptoms previously not clinically diagnosed at all, were now also included in the autism category. It turns out that it is these cases which are the most likely cause of the increase in prevalence since 2000.
These figures were reported at the International Society for Autism Research 2018.
Screening Guidelines For Autism
Continued awareness of autism has resulted in increased routine screening by pediatricians, another contributing factor to a rise in cases. The American Academy of Pediatricians recommends that all children be screened for ASD at ages 18 and 24 months, along with regular developmental surveillance.
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Will Diagnoses Of Autism Continue To Increase
There is no way to know for sure if autism rates will continue to rise. As diagnostic criteria evolve, it could lead to either more or fewer children being qualified for an autism diagnosis.
Some experts, for example, expected a decline in autism diagnoses once Asperger’s syndrome and PDD-NOS were eliminated as catch-all options. Others expected an increase as awareness and services improve. For now, the number and rate of children diagnosed with autism continue to rise.
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The soonest that a child can get into services, the better the outcomes for the child and more likely to achieve their developmental potential, he noted.
Shapira cited the CDCs Learn the Signs. Act Early program, which offers free resources for parents to monitor their childs developmental milestones. Last year, the CDC also produced the Milestone Tracker mobile app for smartphones and tablets that parents can use to monitor their childs development in fun and interactive ways.
Clarification: A previous version of this story reported that the 2016 report was based on 2010 data.
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Why Autism Diagnoses Have Soared
The number of children diagnosed with autism spectrum disorder has risen consistently and dramatically since the 1990s. According to the Centers for Disease Control and Prevention , as of 2016, approximately 1 in 54 children in the United States was diagnosed with autism. In 2000, the corresponding rate was approximately 1 in 150 children. The rate is notably higher in boys than in girls .
There’s no way to pinpoint an exact reason for this increase, but it’s likely that significant changes in diagnostic criteria and reporting practices, in addition to greater awareness and possibly environmental factors, are responsible.
Here’s a look at some of the main theories about why autism is on the rise.
The Sooner The Better
Frazier agreed that diagnostic changes and increasing awareness have contributed to the increase in autism diagnoses. For example, people who used to be only diagnosed with mental retardation or an intellectual disability are now also getting an autism diagnosis, he said.
Were waiting longer to have kids, and older parents are more likely to have a child with autism, and premature babies are living at rates that they didnt use to live at, so those babies are at risk for autism, he said, adding that there are probably other unknown risk factors.
He noted that the male to female ratio decreased in the new report. It was 4.5 boys for every girl, and now its 4 boys to every girl. The decrease in those disparity gaps is a good thing, Frazier said. We have data to suggest that the ratio is probably closer to 2- or 3-to-1 as opposed to 4-to-1.
Ultimately, Frazier believes that more research is needed, because without that, we arent going to understand why autism has increased so dramatically over the decades. Weve also got to push on services, because look at the numbers.
The necessary services include not only educational but adult transition services, he said: We need to do more work to get kids identified earlier, we should be identifying kids closer to age 2.
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Zeroing In On The Genetics Of Autism
Some evidence that genetics plays a role in autism and ASD is provided by research on twins. According to the CDC, if one identical twin has autism, there’s a 75% chance the other twin will be affected, too. If a fraternal twin is affected, the other twin has a 3% chance of having autism.
Parents who give birth to a child with ASD have up to an 8% chance of having another child who is also affected, the CDC estimates.
Many U.S. couples have delayed childbearing, and the older ages of both the mother and the father have been linked with a higher risk of having children with ASD, according to a report in the journal Pediatrics. With age could come increased risk for genetic mutations or other genetic problems.
Specific genetic problems help explain only a small percentage of autism cases so far. “We know that major chromosomal abnormalities are identified in about 5% of ASD,” says Milunsky of Boston University. “We know that Fragile X syndrome is responsible for about 3%.” Fragile X syndrome, a family of genetic conditions, is the most common cause of inherited mental impairment, and also the most common known cause of autism or autism-like behaviors.
“Hot spots” of genetic instability may play a role, researchers say. For instance, a team of researchers reported in The New England Journal of Medicine that duplications and deletions on a specific chromosome seem to be associated with some cases of autism.
But genetics is not the whole story, he and other experts say.
Why Are Autism Rates Steadily Rising
Stefania Sterling with her son Charlie, who was diagnosed at age 3 with autism.
Stefania Sterling was just 21 when she had her son, Charlie. She was young and healthy, with no genetic issues apparent in either her or her husband’s family, so she expected Charlie to be typical.
“It is surprising that the prevalence of a significant disorder like autism has risen so consistently over a relatively brief period.”
It wasn’t until she went to a Mommy and Me music class when he was one, and she saw all the other one-year-olds walking, that she realized how different her son was. He could barely crawl, didn’t speak, and made no eye contact. By the time he was three, he was diagnosed as being on the lower functioning end of the autism spectrum.
She isn’t sure why it happened and researchers, too, are still trying to understand the basis of the complex condition. Studies suggest that genes can act together with influences from the environment to affect development in ways that lead to Autism Spectrum Disorder . But rates of ASD are rising dramatically, making the need to figure out why it’s happening all the more urgent.
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“It is surprising that the prevalence of a significant disorder like autism has risen so consistently over a relatively brief period,” said Walter Zahorodny, an associate professor of pediatrics at Rutgers New Jersey Medical School, who was involved in collecting the data.
Searching for Answers
A Polarizing Theory
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Broadening Of Diagnostic Criteria
There is no objective measure for diagnosing ASD, unlike body weight and blood pressure. When applied in the 1966 study, Scientific American explains, the definition of autism had not yet made it into the widely used DSM. The definition relied on Leo Kanner’s 1943 observations of “infantile autism,” a term he coined to identify children who had previously been described as “as feeble-minded, retarded, moronic, idiotic or schizoid,” Spectrum News writes. Therefore, most diagnosed cases were severe.
Today’s diagnostic criteria comes from the the DSM-5, which clinicians have continued to expand since 1980, and defines ASD as a developmental disorder that causes “Persistent deficits in social communication and social interaction across multiple contexts.” People with ASD also exhibit “restricted, repetitive patterns of behavior or interests,” which can include reactions of extreme sensitivity or indifference to sensory inputs such as pain and loud noises, intense interests, and inflexibility in routine.
This change is significant enough that a literature review in the journal Research in Autism Spectrum Disorders in 2011 concluded, “Unless researchers are able to control for previously used diagnostic criteria, comparisons to previous prevalence estimates hold little information. Miller’s study did just that and concluded that 59% of children diagnosed “not autistic” in a landmark study on autism from the 1980s would meet today’s criteria for ASD.
Do More Children Have Autism Now Than Before
This article was originally posted on The Conversation on 5 December, 2011.
273% Increase in Autism and We Dont Know Why! Thursday, April 15, 1999, Los Angeles Times.
The rising prevalence of autism is a story destined to achieve headlines, take up column inches and even bump MasterChef from the top of the water-cooler gossip list. The headline above, which appeared in the influential Los Angeles Times, is perhaps the one that started off the frenzy of intrigue.
So, is there a rise in the number of children with autism? And if so, what is causing it?
The first question is by far the easier. Yes, there has most certainly been a steady rise in the incidence and prevalence of autism during the past half-a-century.
The finding is well-replicated and has been observed in every country that has an appropriate data source to tap.
The first survey was conducted in the 1960s and produced a prevalence estimate of one individual with autism in every 2,500 people or 0.04% of the population. When I first started my research in this area in the early 2000s, the oft-quoted figure was one in every 250 people .
In the last decade, studies have seemed to continually outdo each other with higher and higher prevalence figures, ranging from the 2005 Australian figure of one in every 160 people , to a recent South Korean study, which found an astonishingly high rate of one in every 38 people .
Conceptual change
Diagnostic substitution
Methodological differences
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What Can Be Done
Throughout the workshop, ideas for building on existing infrastructure and for developing new initiatives to better understand ASD trends were discussed. In particular, efforts are needed to improve the specificity in quantifying and qualifying the multiple factors that might be influencing trends in ASD prevalence. These suggestions for improving our understanding of ASD trends are included below:
Collaboration: Collaboration among professionals and stakeholders is important, and the following points may assist collaborative efforts among those interested in understanding ASDs and supporting the ASD community through science:
Continue efforts to develop and enhance communication among families, individuals affected, researchers, service providers, advocates, and government entities about ASD prevalence, research, and service needs.
Seek publicprivate partnerships to support data collection, analyses, and usage.
Seek input from and collaboration with those in other fields, such as cancer epidemiology, to identify and utilize methodologies for evaluating changes in the prevalence of complex conditions.
Collaborate with other data systems to improve access to population-level environmental data.
Analytic Activities: Improve utilization of existing data to understand ASD prevalence trends:
Provide funding opportunities to encourage analyses and dissemination of findings from existing datasets.
Conduct simulation studies to predict the anticipated course of ASD prevalence.
One In 44 Us Children Diagnosed With Autism New Data Suggests
New autism numbers released Thursday suggest more U.S. children are being diagnosed with the developmental condition and at younger ages.
In an analysis of 2018 data from nearly a dozen states, researchers at the Centers for Disease Control and Prevention found that among 8-year-olds, 1 in 44 had been diagnosed with autism. That rate compares with 1 in 54 identified with autism in 2016.
U.S. autism numbers have been on the rise for several years, but experts believe that reflects more awareness and wider availability of services to treat the condition rather than a true increase in the number of affected children.
A separate CDC report released Thursday said that children were 50 percent more likely to be diagnosed with autism by age 4 in 2018 than in 2014.
There is some progress being made and the earlier kids get identified, the earlier they can access services that they might need to improve their developmental outcome, said CDC researcher and co-author Kelly Shaw.
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Autism Rate Has Increased
One in 68 children in the United States have now been identified with an autism spectrum disorder, according to new Centers for Disease Control and Prevention numbers released Thursday.
The latest estimate is roughly 30 percent higher than the CDC’s previous measure, released in 2012, which found that 1 in 88 children had autism, based on health and education records.
According to the new report, among 8-year-olds living in one of 11 CDC surveillance areas across the country in 2010, roughly 14.7 in every 1,000 had autism, though there were some regional differences in rates — many of them pronounced. In New Jersey, for example, 1 in 45 children had been identified with autism, compared to just 1 in 175 in Alabama.
Overall, the new report mirrors earlier estimates, finding that autism is roughly five times more common in boys than in girls. One in 42 boys were affected, compared to just 1 in 189 girls. White children were more likely to be identified with autism than black or Hispanic children.
The global prevalence of autism has increased twenty- to thirtyfold since the first population studies were conducted in Europe in the late 1960s and ’70s, according to background information provided in the new report. At that time, research suggested that only 1 in 2,500 children in Europe were affected by autism.
It’s still not precisely known what is causing the steady rise in autism diagnosis.
Lessons From Other Conditions And Analytic Methods
There are other complex conditions, such as cancer, Parkinsons disease, asthma, and schizophrenia, where evaluating prevalence changes and understanding biologic and environmental contributions has been a challenge. They provide some examples of how analytic models may be used to understand condition trends.
Changes in cancer trends can be seen from changes in: 1) diagnosis or detection classification and 3) exposures ., Examining patterns of change among a population might explain disease trends due to changes in factors such as the annual frequencies of exposures, availability of screenings, use of new diagnostic technologies, and changes in disease coding. It is important to have data on the occurrence of a condition before and after the change factor being evaluated. In the case of cancer surveillance, there are some well-established sources of data . It is also helpful if there is a clear change factor that has occurred as is seen in the similar slopes of reductions in lung cancer following reductions in smoking., Peaks in prostate cancer prevalence were correlated with the introduction of the first Prostate-specific antigen screening and when follow-up biopsies became more routine.
Modeling change is an integral part of cancer surveillance. There are several important lessons learned from this modeling that can be useful when examining changes in ASD prevalence. The basic steps of modeling change are:
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