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 (ASD). 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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Indeed, the CDC's latest autism report, released last week, which uses 2016 data, found that the prevalence of ASD in four-year-old children was one in 64 children, or 15.6 affected children per 1,000. That's more than the 14.1 rate they found in 2014, for the 11 states included in the study. New Jersey, as in years past, was the highest, with 25.3 per 1,000, compared to Missouri, which had just 8.8 per 1,000.
The rate for eight-year-olds had risen as well. Researchers found the ASD prevalence nationwide was 18.5 per 1,000, or one in 54, about 10 percent higher than the 16.8 rate found in 2014. New Jersey, again, was the highest, at one in 32 kids, compared to Colorado, which had the lowest rate, at one in 76 kids. For New Jersey, that's a 175 percent rise from the baseline number taken in 2000, when the state had just one in 101 kids.
"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.
The study echoed the findings of a surprising 2011 study in South Korea that found 1 in every 38 students had ASD. That was the the first comprehensive study of autism prevalence using a total population sample: A team of investigators from the U.S., South Korea, and Canada looked at 55,000 children ages 7 to 12 living in a community in South Korea and found that 2.64 percent of them had some level of autism.
Searching for Answers
Scientists can't put their finger on why rates are rising. Some say it's better diagnosis. That is, it's not that more people have autism. It's that we're better at detecting it. Others attribute it to changes in the diagnostic criteria. Specifically, the May 2013 update of the Diagnostic and Statistical Manual of Mental Disorders-5 -- the standard classification of mental disorders -- removed the communication deficit from the autism definition, which made more children fall under that category. Cynical observers believe physicians and therapists are handing out the diagnosis more freely to allow access to services available only to children with autism, but that are also effective for other children.
Alycia Halladay, chief science officer for the Autism Science Foundation in New York, said she wishes there were just one answer, but there's not. While she believes the rising ASD numbers are due in part to factors like better diagnosis and a change in the definition, she does not believe that accounts for the entire rise in prevalence. As for the high numbers in New Jersey, she said the state has always had a higher prevalence of autism compared to other states. It is also one of the few states that does a good job at recording cases of autism in its educational records, meaning that children in New Jersey are more likely to be counted compared to kids in other states.
"Not every state is as good as New Jersey," she said. "That accounts for some of the difference compared to elsewhere, but we don't know if it's all of the difference in prevalence, or most of it, or what."
"What we do know is that vaccinations do not cause autism."
There is simply no defined proven reason for these increases, said Scott Badesch, outgoing president and CEO of the Autism Society of America.
"There are suggestions that it is based on better diagnosis, but there are also suggestions that the incidence of autism is in fact increasing due to reasons that have yet been determined," he said, adding, "What we do know is that vaccinations do not cause autism."
Zahorodny, the pediatrics professor, believes something is going on beyond better detection or evolving definitions.
"Changes in awareness and shifts in how children are identified or diagnosed are relevant, but they only take you so far in accounting for an increase of this magnitude," he said. "We don't know what is driving the surge in autism recorded by the ADDM Network and others."
He suggested that the increase in prevalence could be due to non-genetic environmental triggers or risk factors we do not yet know about, citing possibilities including parental age, prematurity, low birth rate, multiplicity, breech presentation, or C-section delivery. It may not be one, but rather several factors combined, he said.
"Increases in ASD prevalence have affected the whole population, so the triggers or risks must be very widely dispersed across all strata," he added.
There are studies that find new risk factors for ASD almost on a daily basis, said Idan Menashe, assistant professor in the Department of Health at Ben-Gurion University of the Negev, the fastest growing research university in Israel.
"There are plenty of studies that find new genetic variants (and new genes)," he said. In addition, various prenatal and perinatal risk factors are associated with a risk of ASD. He cited a study his university conducted last year on the relationship between C-section births and ASD, which found that exposure to general anesthesia may explain the association.
Whatever the cause, health practitioners are seeing the consequences in real time.
"People say rates are higher because of the changes in the diagnostic criteria," said Dr. Roseann Capanna-Hodge, a psychologist in Ridgefield, CT. "And they say it's easier for children to get identified. I say that's not the truth and that I've been doing this for 30 years, and that even 10 years ago, I did not see the level of autism that I do see today."
Sure, we're better at detecting autism, she added, but the detection improvements have largely occurred at the low- to mid- level part of the spectrum. The higher rates of autism are occurring at the more severe end, in her experience.
A Polarizing Theory
Among the more controversial risk factors scientists are exploring is the role environmental toxins may play in the development of autism. Some scientists, doctors and mental health experts suspect that toxins like heavy metals, pesticides, chemicals, or pollution may interrupt the way genes are expressed or the way endocrine systems function, manifesting in symptoms of autism. But others firmly resist such claims, at least until more evidence comes forth. To date, studies have been mixed and many have been more associative than causative.
"Today, scientists are still trying to figure out whether there are other environmental changes that can explain this rise, but studies of this question didn't provide any conclusive answer," said Menashe, who also serves as the scientific director of the National Autism Research Center at BGU.
"It's not everything that makes Charlie. He's just like any other kid."
That inconclusiveness has not dissuaded some doctors from taking the perspective that toxins do play a role. "Autism rates are rising because there is a mismatch between our genes and our environment," said Julia Getzelman, a pediatrician in San Francisco. "The majority of our evolution didn't include the kinds of toxic hits we are experiencing. The planet has changed drastically in just the last 75 years –- it has become more and more polluted with tens of thousands of unregulated chemicals being used by industry that are having effects on our most vulnerable."
She cites BPA, an industrial chemical that has been used since the 1960s to make certain plastics and resins. A large body of research, she says, has shown its impact on human health and the endocrine system. BPA binds to our own hormone receptors, so it may negatively impact the thyroid and brain. A study in 2015 was the first to identify a link between BPA and some children with autism, but the relationship was associative, not causative. Meanwhile, the Food and Drug Administration maintains that BPA is safe at the current levels occurring in food, based on its ongoing review of the available scientific evidence.
Michael Mooney, President of St. Louis-based Delta Genesis, a non-profit organization that treats children struggling with neurodevelopmental delays like autism, suspects a strong role for epigenetics, which refers to changes in how genes are expressed as a result of environmental influences, lifestyle behaviors, age, or disease states.
He believes some children are genetically predisposed to the disorder, and some unknown influence or combination of influences pushes them over the edge, triggering epigenetic changes that result in symptoms of autism.
For Stefania Sterling, it doesn't really matter how or why she had an autistic child. That's only one part of Charlie.
"It's not everything that makes Charlie," she said. "He's just like any other kid. He comes with happy moments. He comes with sad moments. Just like my other three kids."
A 3D rendering of an astronaut in outer space.
We all know the typical astronaut accessories—the EVA suit, the oxygen tanks, the radio assembly. But there's an invisible part of each space mission that's often overlooked: the trillions of microorganisms that hitch a ride.
Observing responses of pathogens in space could help scientists figure out how to outsmart them when they cause trouble on Earth.
Dr. Sarah Wallace is a NASA microbiologist who aims to keep microbes from causing problems for U.S. astronauts aboard the International Space Station. According to Wallace, research on microorganisms in space has more than cosmic importance. It can also reveal things about our health here on Earth:
1) Avoiding disease isn't all about maintaining a sterile environment.
NASA has a great track record of keeping the crew healthy on space missions. But surprisingly, it's not from having kept the space flight environment as sterile as possible.
Wallace says, "We [monitor] the environment but unless we find something that's medically significant, or [in] super high numbers, we're not going to do anything."
Not only is it impossible for astronauts to live in completely sterile quarters—crew members, after all, are microbe-shedding machines—but it may not even be desirable, given what we now know about the human microbiome. Scientists have found that the entire community of microorganisms (bacteria, archaea, fungi, and viruses) living in and on us likely have an active role in keeping us healthy. This means that down on the ground we need to let go of the germophobe idea that eradicating all microbes is always better for our health.
2) Disease-causing microbes change their behavior under different conditions.
Remember the recent E. coli O157:H7 outbreak linked to romaine lettuce? We're still grappling with a lot of pathogen problems here on Earth. One reason is that scientists are still learning which strategies these disease-causing microorganisms are capable of employing under different conditions.
Space missions are associated with a major shift in gut microbiome composition—as shown in NASA's twin study.
Wallace says experiments with Salmonella Typhimurium showed that the pathogen became more virulent in space. Yet curiously, the opposite seemed to happen to Staphylococcus aureus under space-flight-like conditions—it became more benign.
"The way these organisms have evolved, certain triggers [in the space flight environment] might be dictating how they're responding," Wallace says.
Observing these responses could help scientists figure out how to outsmart the pathogen when it causes trouble on Earth. "It's giving us some great insights into how we could target them differently in the future," she explains.
3) Major shifts in the gut microbiome could affect health in specific ways.
Scientists still have a lot to learn about which changes in an adult's gut microbiome actually cause a change in health status. In fact, microbiome-focused therapeutics companies are in hot pursuit of these connections.
Space missions are associated with a major shift in gut microbiome composition—as shown in NASA's twin study, which followed astronaut Scott Kelly during a year aboard the ISS while his identical twin brother Mark (a retired astronaut) stayed on the ground. Scott experienced simultaneous changes in telomere length and bone formation; were these related to the gut microbial differences?
Wallace says a soon-to-be-published study of nine additional astronauts could help answer this question. The research may reveal how closely gut microbiome shifts track health outcomes, and the reversibility of the changes.
She emphasizes the science from her lab isn't meant to help only the small minority of humans who will ever go to space: "That's always our goal—that our research is helping people on Earth."
A portrait of skepticism while reading information online.
Today's growing distrust of science is not an academic problem. It can be a matter of life and death.
Take, for example, the tragic incident in 2016 when at least 10 U.S. children died and over 400 were sickened after they tried homeopathic teething medicine laced with a poisonous herb called "deadly nightshade." Carried by CVS, Walgreens, and other major American pharmacies, the pills contained this poison based on the alternative medicine principle of homeopathy, the treatment of medical conditions by tiny doses of natural substances that produce symptoms of disease.
Such "alternative medicines" take advantage of the lack of government regulation and people's increasing hostility toward science.
These children did not have to die. Numerous research studies show that homeopathy does not work. Despite this research, homeopathy is a quickly-growing multi-billion dollar business.
Such "alternative medicines" take advantage of the lack of government regulation and people's increasing hostility toward science. Polling shows that the number of people who believe that science has "made life more difficult" increased by 50 percent from 2009 to 2015. According to a 2017 survey, only 35 percent of respondents have "a lot" of trust in scientists; the number of people who do "not at all" trust scientists increased by over 50 percent from a similar poll conducted in December 2013.
Children dying from deadly nightshade is only one consequence of this crisis of trust. For another example, consider the false claim that vaccines cause autism. This belief has spread widely across the US, and led to a host of problems. For instance, measles was practically eliminated in the US by 2000. However, in recent years outbreaks of measles have been on the rise, driven by parents failing to vaccinate their children in a number of communities.
The Internet Is for… Misinformation
The rise of the Internet, and more recently social media, is key to explaining the declining public confidence in science.
Before the Internet, the information accessible to the general public about any given topic usually came from experts. For instance, researchers on autism were invited to talk on mainstream media, they wrote encyclopedia articles, and they authored books distributed by large publishers.
The Internet has enabled anyone to be a publisher of content, connecting people around the world with any and all sources of information. On the one hand, this freedom is empowering and liberating, with Wikipedia a great example of a highly-curated and accurate source on the vast majority of subjects. On the other, anyone can publish a blog piece making false claims about links between vaccines and autism or the effectiveness of homeopathic medicine. If they are skilled at search engine optimization, or have money to invest in advertising, they can get their message spread widely. Russia has done so extensively to influence elections outside of its borders, whether in the E.U. or the U.S.
Unfortunately, research shows that people lack the skills for differentiating misinformation from true information. This lack of skills has clear real-world effects: U.S. adults believed 75 percent of fake news stories about the 2016 US Presidential election. The more often someone sees a piece of misinformation, the more likely they are to believe it.
To make matters worse, we all suffer from a series of thinking errors such as the confirmation bias, our tendency to look for and interpret information in ways that conform to our intuitions.
Blogs with falsehoods are bad enough, but the rise of social media has made the situation even worse. Most people re-share news stories without reading the actual article, judging the quality of the story by the headline and image alone. No wonder research has indicated that misinformation spreads as much as 10 times faster and further on social media than true information. After all, creators of fake news are free to devise the most appealing headline and image, while credible sources of information have to stick to factual headlines and images.
To make matters worse, we all suffer from a series of thinking errors such as the confirmation bias, our tendency to look for and interpret information in ways that conform to our intuitions and preferences, as opposed to the facts. Our inherent thinking errors combined with the Internet's turbine power has exploded the prevalence of misinformation.
So it's no wonder we see troubling gaps between what scientists and the public believe about issues like climate change, evolution, genetically modified organisms, and vaccination.
What Can We Do?
Fortunately, there are proactive steps we can take to address the crisis of trust in science and academia. The Pro-Truth Pledge, founded by a group of behavioral science experts (including myself) and concerned citizens, calls on public figures, organizations, and private citizens to commit to 12 behaviors listed on the pledge website that research in behavioral science shows correlate with truthfulness.
Signers are held accountable through a crowdsourced reporting and evaluation mechanism while getting reputational rewards because of their commitment. The scientific consensus serves as a key measure of credibility, and the pledge encourages pledge-takers to recognize the opinions of experts - especially scientists - as more likely to be true when the facts are disputed.
The pledge "really does seem to change one's habits," encouraging signers to have attitudes "of honesty and moral sincerity."
Launched in December 2016, the pledge has surprising traction. Over 6200 private citizens took the pledge. So did more than 500 politicians, including members of US state legislatures Eric Nelson (PA), James White (TX), and Ogden Driskell (WY), and national politicians such as members of U.S. Congress Beto O'Rourke (TX), Matt Cartwright (PA), and Marcia Fudge (OH). Over 700 other public figures, such as globally-known public intellectuals Peter Singer, Steven Pinker, Michael Shermer, and Jonathan Haidt, took the pledge, as well as 70 organizations such as Media Bias/Fact Check, Fugitive Watch, Earth Organization for Sustainability, and One America Movement.
The pledge is effective in changing behaviors. A candidate for Congress, Michael Smith, took the Pro-Truth Pledge. He later posted on his Facebook wall a screenshot of a tweet by Donald Trump criticizing minority and disabled children. However, after being called out that the tweet was a fake, he went and searched Trump's feed. He could not find the original tweet, and while Trump may have deleted it, the candidate edited his own Facebook post to say, "Due to a Truth Pledge I have taken, I have to say I have not been able to verify this post." He indicated that he would be more careful with future postings.
U.S. Army veteran and pledge-taker John Kirbow described how the pledge "really does seem to change one's habits," helping push him both to correct his own mistakes with an "attitude of humility and skepticism, and of honesty and moral sincerity," and also to encourage "friends and peers to do so as well."
His experience is confirmed by research on the pledge. Two research studies at Ohio State University demonstrated the effectiveness of the pledge in changing the behavior of pledge-takers to be more truthful with a strong statistical significance.
Taking the pledge yourself, and encouraging people you know and your elected representatives to do the same, is an easy and effective way to fight misinformation and to promote a culture that values the truth.