Why Are Autism Rates Steadily Rising?
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."
How exactly does your DNA make you who you are?
It's because of epigenetics that identical twins can actually look different and develop different diseases.
Just as software developers don't write apps out of ones and zeros, the interesting parts of the human genome aren't written merely in As, Ts, Cs and Gs. Yes, these are the fundamental letters that make up our DNA and encode the proteins that make our cells function, but the story doesn't end there.
Our cells possess amazing abilities, like eating invading bacteria or patching over a wound, and these abilities require the coordinated action of hundreds, if not thousands, of proteins. Epigenetics, the study of gene expression, examines how multiple genes work at once to make these biological processes happen.
It's because of epigenetics that identical twins – who possess identical DNA -- can actually look different and develop different diseases. Their environments may influence the expression of their genes in unique ways. For example, a research study in mice found that maternal exposure to a chemical called bisphenol A (BPA) resulted in drastic differences between genetically identical offspring. BPA exposure increased the likelihood that a certain gene was turned on, which led to the birth of yellow mice who were prone to obesity. Their genetically identical siblings who were not exposed to BPA were thinner and born with brown fur.
These three mice are genetically identical. Epigenetic differences, however, result in vastly different phenotypes.
(© 1994 Nature Publishing Group, Duhl, D.)
This famous mouse experiment is just one example of how epigenetics may transform medicine in the coming years. By studying the way genes are turned on and off, and maybe even making those changes ourselves, scientists are beginning to approach diseases like cancer in a completely new way.
With few exceptions, most of the 1 trillion cells that make up your body contain the same DNA instructions as all the others. How does each cell in your body know what it is and what it has to do? One of the answers appears to lie in epigenetic regulation. Just as everyone at a company may have access to all the same files on the office Dropbox, the accountants will put different files on their desktop than the lawyers do.
Our cells prioritize DNA sequences in the same way, even storing entire chromosomes that aren't needed along the wall of the nucleus, while keeping important pieces of DNA in the center, where it is most accessible to be read and used. One of the ways our cells prioritize certain DNA sequences is through methylation, a process that inactivates large regions of genes without editing the underlying "file" itself.
As we learn more about epigenetics, we gain more opportunities to develop therapeutics for a broad range of human conditions, from cancer to metabolic disorders. Though there have not been any clinical applications of epigenetics to immune or metabolic diseases yet, cancer is one of the leading areas, with promising initial successes.
One of the challenges of cancer treatments is that different patients may respond positively or negatively to the same treatment. With knowledge of epigenetics, however, doctors could conduct diagnostic tests to identify a patient's specific epigenetic profile and determine the best treatment for him or her. Already, commercial kits are available that help doctors screen glioma patients for an epigenetic biomarker called MGMT, because patients with this biomarker have shown high rates of success with certain kinds of treatments.
Other epigenetic advances go beyond personalized screening to treatments targeting the mechanism of disease. Some epigenetic drugs turn on genes that help suppress tumors, while others turn on genes that reveal the identity of tumor cells to the immune system, allowing it to attack cancerous cells.
Direct, targeted control of your epigenome could allow doctors to reprogram cancerous or aging cells.
The study of epigenetics has also been fundamental to the field of aging research. The older you get, the more methylation marks your DNA carries, and this has led to the distinction between biological aging, or the state of your cells, and chronological aging, or how old you actually are.
Just as our DNA can get miscopied and accumulate mutations, errors in DNA methylation can lead to so-called "epimutations". One of the big hypotheses in aging research today is that the accumulation of these random epimutations over time is responsible for what we perceive as aging.
Studies thus far have been correlative - looking at several hundred sites of epigenetic modifications in a person's cell, scientists can now roughly discern the age of that person. The next set of advances in the field will come from learning what these epigenetic changes individually do by themselves, and if certain methylations are correlated with cellular aging. General diagnostic terms like "aging" could be replaced with "abnormal methylation at these specific locations," which would also open the door to new therapeutic targets.
Direct, targeted control of your epigenome could allow doctors to reprogram cancerous or aging cells. While this type of genetic surgery is not feasible just yet, current research is bringing that possibility closer. The Cas9 protein of genome-editing CRISPR/Cas9 fame has been fused with epigenome modifying enzymes to target epigenetic modifications to specific DNA sequences.
A therapeutic of this type could theoretically undo a harmful DNA methylation, but would also be competing with the cell's native machinery responsible for controlling this process. One potential approach around this problem involves making beneficial synthetic changes to the epigenome that our cells do not have the capacity to undo.
Also fueling this frontier is a new approach to understanding disease itself. Scientists and doctors are now moving beyond the "one defective gene = one disease" paradigm. Because lots of diseases are caused by multiple genes going haywire, epigenetic therapies could hold the key to new types of treatments by targeting multiple defective genes at once.
Scientists are still discovering which epigenetic modifications are responsible for particular diseases, and engineers are building new tools for epigenome editing. Given the proliferation of work in these fields within the last 10 years, we may see epigenetic therapeutics emerging within the next couple of decades.
Goodnight, Moon. Goodnight, Sky Advertisement.
Imagine enjoying a romantic night stargazing, cozying up for the evening – and you catch a perfectly timed ad for Outback Steakhouse.
Countries have sovereignty over their airspace, but the night sky itself is pretty much an open field.
That's the vision of StartRocket, a Russian startup planning to put well-lit advertisements into outer space. According to a recent interview, StartRocket says its first client is PepsiCo.
The Lowdown
Launching at twilight during the early morning or early evening, the ads will be on cubesats – 10 cm square metallic boxes traditionally used in space. The attached Mylar sails will reflect light from the rising or setting sun, making the ad appear like an "orbital billboard."
The advertisements will need all the solar power they can get: According to a 2016 report, 80 percent of the world and 99 percent of America and Europe experience light pollution at night. Showing advertisements in, say, Wyoming will be much easier than attracting attention in Midtown Manhattan – and risks adding a considerable amount of light pollution to an already overburdened night sky.
Next Up
The StartRocket advertising program is set to begin in 2021. The most recent rate is $20,000 for eight hours of advertising space.
But first, StartRocket has to win over consumers, regulators and space activists.
"I don't see it taking off now," says TED Fellow and University of Texas, Austin Associate Professor Dr. Moriba Jah. Jah is the creator of Astriagraph, an interactive tool to help monitor space junk orbiting Earth. "In general, the space community is anathema to advertisements from orbit to people on the ground… The global astronomy community will be fighting it tooth and nail."
Jah notes SpaceX's launch of 60 satellites last month. "Astronomers were up in arms since they are so bright, you can see them with the naked eye." It got to the point where Elon Musk had to defend himself to the astronomy community on Twitter.
Open Questions
Startups come and go, especially those that are looking for funding. StartRocket is in both categories. Frankly, it's unclear if the ads will actually launch two years from now.
Space advertisements are more likely to be the future for less regulated and financially strapped areas.
The regulatory hurdles are just as unknown. According to Jah, countries have sovereignty over their airspace (think planes, balloons and drones), but the night sky itself is pretty much an open field. This doesn't remove the political ramifications, though, and any American-based launches would have to contend with the FCC, since it regulates advertisements, and the FAA, since it regulates flight.
Carbon credits-style redemptions may help balance out the potential environmental and political damage done by sky ads. It isn't a coincidence that space pioneers Musk, Jeff Bezos, and Richard Branson succeeded at other ventures first, giving them considerably deep pockets to survive red tape – something StartRocket's team doesn't have at the moment.
Space advertisements are more likely to be the future for less regulated, financially strapped areas. Depending on how ad companies negotiate with the local governments, it's easy to picture Kolkata with an "Enjoy Coke" advertisement blaring during a Ganges sunset.
"In rural places, it would be like having another moon," Jah says. "People would say the rich are now taking the sky away from us."