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.
The Latest News
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 crime scene photograph.
This past April, an alleged serial rapist and murderer, who had remained unidentified for over 40 years, was located by comparing a crime scene DNA profile to a public genetic genealogy database designed to identify biological relatives and reconstruct family trees. The so-called "Golden State Killer" had not placed his own profile in the database.
Forensic use of genetic genealogy data is possible thanks to widening public participation in direct-to-consumer recreational genetic testing.
Instead, a number of his distant genetic cousins had, resulting in partial matches between themselves and the forensic profile. Investigators then traced the shared heritage of the relatives to great-great-great-grandparents and using these connections, as well as other public records, narrowed their search to just a handful of individuals, one of whom was found to be an exact genetic match to the crime scene sample.
Forensic use of genetic genealogy data is possible thanks to widening public participation in direct-to-consumer recreational genetic testing. The Federal Bureau of Investigation maintains a national forensic genetic database (which currently contains over 16 million unique profiles, over-representing individuals of non-European ancestry); each profile holds genetic information from only 13 to 20 variable gene regions, just enough to identify a suspect. However, since this database and related forensic databases were established, the nature of genetic profiling has significantly changed: direct-to-consumer genetic tests routinely use whole genome scans involving simultaneous analysis of hundreds of thousands of variants.
With such comprehensive genetic information, it becomes possible to discern more distant genetic relatives. Thus, even though public DNA collections are smaller than most law enforcement databases, the potential to connect a crime scene sample to biological relatives is enhanced. The successful use of one genealogy database (GEDMatch) in the GSK case demonstrates the power of the approach, so much so that the genetic profiles of over 100 similar cold cases are now being run through the same resource. Indeed, in the two months since the GSK case was first reported, 5 other cold cases have been solved using similar methods.
Autonomy in the Genomic Age
While few would disagree with the importance of finally bringing to justice those who commit serious violent offenses, this new forensic genetic application has sparked broad discussion of privacy-related and ethical concerns. Before, the main genetic databases accessible to the police were those containing the profiles of accused or convicted criminals, but now the DNA of many more "innocent bystanders," across multiple generations, are in play.
The genetic services that provide a venue for data sharing typically warn participants that their information can be used for purposes beyond those they intend, but there is no legal prohibition on the use of crowd-sourced public collections for forensic investigation. Some services, such as GEDMatch, now explicitly welcome possible law enforcement use.
The decisions of individuals to contribute their own genetic information inadvertently exposes many others across their family tree.
The implication is that consumers must choose for themselves whether they are willing to bring their genetic information into the public sphere. Many have no problem doing so, seeing value in law enforcement access to such data. But the decisions of individuals to contribute their own genetic information inadvertently exposes many others across their family tree who may not be aware of or interested in their genetic relationships going public.
As one well-known statistical geneticist who predicted forensic uses of public genetic data noted: "You are a beacon who illuminates 300 people around you." By the same token, 300 people, most of whom you do not know and have probably never met, can illuminate your genetic information; indeed a recent analysis has suggested that most in the U.S. are identifiable in this way. There is nothing that you can do about it, no way to opt out. Thus, police interaction with such databases must be addressed as a public policy issue, not left to the informed consent of individual consumers.
When Consent Will Not Suffice
For those concerned by the broader implications of such practices, the simplest solution might be to discourage open access sharing of detailed genetic information. But let's say that we are willing to continue to allow those with an interest in genealogy to make their data readily searchable. What safeguards should we implement to ensure that the family members who don't want to opt in, or who don't have the ability to make that choice, remain unharmed? Their autonomy counts, too.
We might consider regulation similar to the kind that limit law enforcement use of forensic genetic databases of convicted and arrested individuals. For example, in California, familial searches can only be performed using the database of convicted individuals in cases of serious crimes with public safety implications where all other investigatory methods have been exhausted, and where single-source high-quality DNA is available for analysis. Further, California policy separates the genealogical investigative team from local detectives, so as to minimize the impact of incidental findings (such as unexpected non-paternity).
Importantly, the individual apprehended was not the first, or even second, but the third person subjected to enhanced police scrutiny.
No such regulations currently govern law enforcement searches of public genealogical databases, and we know relatively little about the specifics of the GSK investigation. We do not know the methods used to infer genetic relationships, or their likelihood of mistakenly suggesting a relationship where none exists. Nor do we know the level of genetic identity considered relevant for subsequent follow-up. It is also unclear how law enforcement investigators combined the genetic information they received with other public records data. Together, this leaves room for an unknown degree of investigation into an unknown number of individuals.
Why This Matters
What has been revealed is that the GSK search resulted in the identification of 10 to 20 potential distant genetic relatives, which led to the investigation of 25 different family trees, 24 of which did not contain the alleged serial rapist and murderer. While some sources described a pool of 100 possible male suspects identified from this exercise, others imply that the total number of relatives encompassed by the investigation was far larger. One account, for example, suggests that there were roughly 1000 family members in just the one branch of the genealogy that included the alleged perpetrator. Importantly, the individual apprehended was not the first, or even second, but the third person subjected to enhanced police scrutiny: reports describe at least two false leads, including one where a warrant was issued to obtain a DNA sample.
These details, many of which only came to light after intense press coverage, raise a host of concerns about the methods employed and the degree to which they exposed otherwise innocent individuals to harms associated with unjustified privacy intrusions. Only with greater transparency and oversight will we be able to ensure that the interests of people curious about their family tree do not unfairly impinge on those of their mostly law-abiding near and distant genetic relatives.
Eric Kandel.
Eric Kandel, 88, is a living legend. A specialist in the neurobiology of learning and memory, he received a Nobel Prize in 2000 for his work on the physiological basis of memory storage. Kandel is the Director of the Kavli Institute for Brain Science and Co-Director of the Mortimer B. Zuckerman Mind Brain Behavior Institute at Columbia University, where he has taught and conducted research for 44 years.
"If you walk two or three miles a day, you will release sufficient osteocalcin from your bones to combat non-Alzheimer's age-related memory loss."
And he's still going strong. Leapsmag Editor-in-Chief Kira Peikoff recently caught up with Dr. Kandel about his latest research, his advice for fellow seniors, and his opinions on some of the biggest challenges in neuroscience today.
What are working on these days?
I'm working on three problems: one is age-related memory loss, the second is post-traumatic stress disorder, and the third is the beholder's share: how a viewer responds to works of art. The beholder's share is a term that Alois Riegl created. He said there are two shares to a painting: the painter creates it, but it's not meaningful until somebody responds to it: the viewer, the beholder.
That's fascinating. As far as age-related memory loss, what are you learning in that area?
I'm learning that there are two forms of age-related memory loss. One is Alzheimer's disease, which we've known about for a long time. But the second is a more benign form which I call just age-related memory loss, which begins actually somewhat earlier and has a very different anatomical locus in the brain. It is caused by a different anatomical defect and responds to different therapeutic measures. It critically involves an area in the hippocampus called the dentate gyrus and it responds to a hormone released by bone called osteocalcin.
It therefore seems likely that one very effective way of combatting age-related memory loss is walking. If you walk two or three miles a day, you are likely to release sufficient osteocalcin from your bones to combat non-Alzheimer's age-related memory loss. In collaboration with Gerard Karsenty at Columbia, my lab at Columbia has been exploring this over the last year and a half.
Have you published anything about this yet?
We are just getting ready to do so.
"I think at the moment we should stick with trying to just reverse abnormalities."
Another question I have is about brain-computer interfaces to help cure disease or even provide cognitive enhancements. What do you think of companies like Kernel and Neuralink that are trying to push this new technology?
I think if it works it would be very nice. We have to see some direct evidence first, but it's certainly an encouraging approach. I think there are a number of directions we could take. The one I think at the moment is most profitable is to try to use the brain as it is and try to enhance it, restore it, refurbish it, make it function better from its age-related condition.
You mean, without some kind of machine interface?
Without necessarily introducing anything from the outside world. Although I have no objection whatsoever to introducing ancillary aids if they're beneficial and not harmful.
Do you have any opinion on whether neuroscience and technology should aim to provide an enhancement to the brain or just return it to baseline and cure disease?
I would be perfectly satisfied if we just cured diseases. I think at the moment we should stick with trying to just reverse abnormalities, but certainly … having the capability of becoming more intelligent, more attentive, capable of remembering things better than normal, that would be nice.
What do you think is the most important challenge facing the field of neuroscience today?
It's hard to say. I think the biology of consciousness is one fantastic problem. Trying to understand and successfully reverse some of the abnormalities of the brain, like age-related memory loss, schizophrenia, depression, manic depressive illness would be wonderful.
To be able to reverse memory loss, to allow people in their 70s, 80s, and 90s to live free and independent lives, is a major challenge for brain science.
Absolutely. Is there anything else you'd like to share with our readers about your research or the field more broadly?
I'd emphasize that brain science is a relatively young discipline but it's moving ahead in a very responsible and a very effective fashion, making progress in a number of areas, and is clearly sensitive to, and responsive to, the demands of the social situation. Right now, number one, the population is aging dramatically. In 1900, the average life expectancy was 50, and now the average life expectancy is 78 for men, and 82 for women.
So people are living longer and therefore are having age-related diseases, including memory loss. To be able to reverse it, to allow people in their 70s, 80s, and 90s to live free and independent lives, is a major challenge for brain science in both its basic and its clinically applied fashion. I think this is very important and serious effort should be put into this.
Kira Peikoff was the editor-in-chief of Leaps.org from 2017 to 2021. As a journalist, her work has appeared in The New York Times, Newsweek, Nautilus, Popular Mechanics, The New York Academy of Sciences, and other outlets. She is also the author of four suspense novels that explore controversial issues arising from scientific innovation: Living Proof, No Time to Die, Die Again Tomorrow, and Mother Knows Best. Peikoff holds a B.A. in Journalism from New York University and an M.S. in Bioethics from Columbia University. She lives in New Jersey with her husband and two young sons. Follow her on Twitter @KiraPeikoff.