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."
Black Participants Are Sorely Absent from Medical Research
Black participants are under-represented in clinical research.
After years of suffering from mysterious symptoms, my mother Janice Thomas finally found a doctor who correctly diagnosed her with two autoimmune diseases, Lupus and Sjogren's. Both diseases are more prevalent in the black population than in other races and are often misdiagnosed.
The National Institutes of Health has found that minorities make up less than 10 percent of trial participants.
Like many chronic health conditions, a lack of understanding persists about their causes, individual manifestations, and best treatment strategies.
On the search for relief from chronic pain, my mother started researching options and decided to participate in clinical trials as a way to gain much-needed insights. In return, she received discounted medical testing and has played an active role in finding answers for all.
"When my doctor told me I could get financial or medical benefits from participating in clinical trials for the same test I was already doing, I figured it would be an easy way to get some answers at little to no cost," she says.
As a person of color, her presence in clinical studies is rare. The National Institutes of Health has found that minorities make up less than 10 percent of trial participants.
Without trial participation that is reflective of the general population, pharmaceutical companies and medical professionals are left guessing how various drugs work across racial lines. For example, albuterol, a widely used asthma treatment, was found to have decreased effectiveness for black American and Puerto Rican children. Many high mortality conditions, like cancer, also show different outcomes based on race.
Over the last decade, the pervasive lack of representation has left communities of color demanding higher levels of involvement in the research process. However, no consensus yet exists on how best to achieve this.
But experts suggest that before we can improve black participation in medical studies, key misconceptions must be addressed, such as the false assumption that such patients are unwilling to participate because they distrust scientists.
Jill A. Fisher, a professor in the Center for Bioethics at the University of North Carolina at Chapel Hill, learned in one study that mistrust wasn't the main barrier for black Americans. "There is a lot of evidence that researchers' recruitment of black Americans is generally poorly done, with many black patients simply not asked," Fisher says. "Moreover, the underrepresentation of black Americans is primarily true for efficacy trials - those testing whether an investigational drug might therapeutically benefit patients with specific illnesses."
Without increased minority participation, research will not accurately reflect the diversity of the general population.
Dr. Joyce Balls-Berry, a psychiatric epidemiologist and health educator, agrees that black Americans are often overlooked in the process. One study she conducted found that "enrollment of minorities in clinical trials meant using a variety of culturally appropriate strategies to engage participants," she explained.
To overcome this hurdle, The National Black Church Initiative (NBCI), a faith-based organization made up of 34,000 churches and over 15.7 million African Americans, last year urged the Food and Drug Administration to mandate diversity in all clinical trials before approving a drug or device. However, the FDA declined to implement the mandate, declaring that they don't have the authority to regulate diversity in clinical trials.
"African Americans have not been successfully incorporated into the advancement of medicine and research technologies as legitimate and natural born citizens of this country," admonishes NBCI's president Rev. Anthony Evans.
His words conjure a reminder of the medical system's insidious history for people of color. The most infamous incident is the Tuskegee syphilis scandal, in which white government doctors perpetrated harmful experiments on hundreds of unsuspecting black men for forty years, until the research was shut down in the early 1970s.
Today, in the second decade of twenty-first century, the pernicious narrative that blacks are outsiders in science and medicine must be challenged, says Dr. Danielle N. Lee, assistant professor of biological sciences at Southern Illinois University. And having majority white participants in clinical trials only furthers the notion that "whiteness" is the default.
According to Lee, black individuals often see themselves disconnected from scientific and medical processes. "One of the critiques with science and medical research is that communities of color, and black communities in particular, regard ourselves as outsiders of science," Lee says. "We are othered."
Without increased minority participation, research will not accurately reflect the diversity of the general population.
"We are all human, but we are different, and yes, even different populations of people require modified medical responses," she points out.
Another obstacle is that many trials have health requirements that exclude black Americans, like not wanting individuals who have high blood pressure or a history of stroke. Considering that this group faces health disparities at a higher rate than whites, this eliminates eligibility for millions of potential participants.
One way to increase the diversity in sample participation without an FDA mandate is to include more black Americans in both volunteer and clinical roles during the research process to increase accountability in treatment, education, and advocacy.
"When more of us participate in clinical trials, we help build out the basic data sets that account for health disparities from the start, not after the fact," Lee says. She also suggests that researchers involve black patient representatives throughout the clinical trial process, from the study design to the interpretation of results.
"This allows for the black community to give insight on how to increase trial enrollment and help reduce stigma," she explains.
Thankfully, partnerships are popping up like the one between The Howard University's Cancer Center and Driver, a platform that connects cancer patients to treatment and trials. These sorts of targeted and culturally tailored efforts allow black patients to receive assistance from well-respected organizations.
Some observers suggest that the federal government and pharmaceutical industries must step up to address the gap.
However, some experts say that the black community should not be held solely responsible for solving a problem it did not cause. Instead, some observers suggest that the federal government and pharmaceutical industries must step up to address the gap.
According to Balls-Berry, socioeconomic barriers like transportation, time off work, and childcare related to trial participation must be removed. "These are real-world issues and yet many times researchers have not included these things in their budgets."
When asked to comment, a spokesperson for BIO, the world's largest biotech trade association, emailed the following statement:
"BIO believes that that our members' products and services should address the needs of a diverse population, and enhancing participation in clinical trials by a diverse patient population is a priority for BIO and our member companies. By investing in patient education to improve awareness of clinical trial opportunities, we can reduce disparities in clinical research to better reflect the country's changing demographics."
For my mother, the patient suffering from autoimmune disease, the need for broad participation in medical research is clear. "Without clinical trials, we would have less diagnosis and solutions to diseases," she says. "I think it's an underutilized resource."
Why You Can’t Blame Your Behavior On Your Gut Microbiome
People eating pizza; are they being influenced by their gut microbiome?
See a hot pizza sitting on a table. Count the missing pieces: three. They tasted delicious and yes, you've eaten enough—but you're still eyeing a fourth piece. Do you reach out and take it, or not?
"The difficulty comes in translating the animal data into the human situation."
Your behavior in that next moment is anything but simple: as far as scientists can tell, it comes down to a complex confluence of circumstances, genes, and personality characteristics. And the latest proposed addition to this list is the gut microbiome—the community of microorganisms, including bacteria, archaea, fungi, and viruses—that are full-time residents of your digestive tract.
It is entirely plausible that your gut microbiome might influence your behavior, scientists say: a well-known communication channel, called the gut-brain axis, runs both ways between your brain and your digestive tract. Gut bugs, which are close to the action, could amplify or dampen the messages, thereby shaping how you act. Messages about food-related behaviors could be particularly susceptible to interception by these microorganisms.
Perhaps it's convenient to imagine your resident microbes sitting greedily in your gut, crying for more pizza and tricking your brain into getting them what they want. The problem is, there's a distinct lack of scientific support for this actually happening in humans.
John Bienenstock, professor of pathology and molecular medicine at McMaster University (Canada), has worked on the gut microbiome-behavior connection for several decades. "There's a lot of evidence now in animals—particularly in mice," he says.
Indeed, his group and others have shown that, by eliminating or altering gut bugs, they can make mice exhibit different social behaviors or respond more coolly to stress; they can even make a shy mouse turn brave. But Bienenstock cautions: "The difficulty comes in translating the animal data into the human situation."
Animal behaviors are worlds apart from what we do on a daily basis—from brushing our teeth to navigating complex social situations.
Not that it's an easy task to figure out which aspects of animal research are relevant to people in everyday life. Animal behaviors are worlds apart from what we do on a daily basis—from brushing our teeth to navigating complex social situations.
Elaine Hsiao, assistant professor of integrative biology and physiology at UCLA, has also looked closely at the microbiome-gut-brain axis in mice and pondered how to translate the results into humans. She says, "Both the microbiome and behavior vary substantially [from person to person] and can be strongly influenced by environmental factors—which makes it difficult to run a well-controlled study on effects of the microbiome on human behavior."
She adds, "Human behaviors are very complex and the metrics used to quantify behavior are often not precise enough to derive clear interpretations." So the challenge is not only to figure out what people actually do, but also to give those actions numerical codes that allow them to be compared against other actions.
Hsiao and colleagues are nevertheless attempting to make connections: building on some animal research, their recent study found a three-way association in humans between molecules produced by their gut bacteria (that is, indole metabolites), the connectedness of different brain regions as measured through functional magnetic resonance imaging, and measures of behavior: questionnaires assessing food addiction and anxiety.
Meanwhile, other studies have found it may be possible to change a person's behavior through either probiotics or gut-localized antibiotics. Several probiotics even show promise for altering behavior in clinical conditions like depression. Yet how these phenomena occur is still unknown and, overall, scientists lack solid evidence on how bugs control behavior.
Bienenstock, however, is one of many continuing to investigate. He says, "Some of these observations are very striking. They're so striking that clearly something's up."
He says that after identifying a behavior-changing bug, or set of bugs, in mice: "The obvious next thing is: How [is it] occurring? Why is it occurring? What are the molecules involved?" Bienenstock favors the approach of nailing down a mechanism in animal models before starting to investigate its relevance to humans.
He explains, "[This preclinical work] should allow us to identify either target molecules or target pathways, which then can be translated."
Bienenstock also acknowledges the 'hype' that appears to surround this particular field of study. Despite the decidedly slow emergence of data linking the microbiome to human behavior, scientific reviews have appeared in brain-related scientific journals—for instance, Trends in Cognitive Sciences; CNS Drugs—with remarkable frequency. Not only this, but popular books and media articles have given the idea wings.
It might be compelling to blame our microbiomes for behaviors we don't prefer or can't explain—like reaching for another slice of pizza. But until the scientific observations yield stronger results, we still lack proof that we're doing what we do—or eating what we eat—exclusively at the behest of our resident microorganisms.