Air Date: Week of May 16, 2025

Autism spectrum disorder covers a range of presentations, characteristics, and support needs. Dr. Temple Grandin is a gifted animal communicator and a well-known autism rights advocate. (Photo: Steve Jurvetson, Flickr, CC BY 2.0)

Autism spectrum disorder is now diagnosed in about 1 in 31 children in the United States, a rise of 70 percent in just four years according to the CDC. In addition to better awareness and changing diagnostic tools, growing scientific evidence also points to the role of exposure to toxic chemicals especially during early development in the rising prevalence of autism. Dr. Philip Landrigan, a pediatrician, professor at Boston College, and one of the world’s leading experts on toxic exposure from plastics and pollution discusses with Host Steve Curwood.

Transcript

O’NEILL: It’s Living on Earth, I’m Aynsley O’Neill.

CURWOOD: And I’m Steve Curwood. Autism spectrum disorder is now diagnosed in about 1 in 31 children in the United States, based on a regional study by the Centers for Disease Control and Prevention released in April. That research showed a 70% increase in prevalence among children in just four years. Health and Human Services Secretary Robert F. Kennedy, Jr., who has previously tied the condition to vaccines, has instructed his department to determine the root causes of autism by this fall. Over the years, better awareness and changing diagnostic tools have contributed to rising cases of autism in adults and children. And growing scientific evidence points to the role of exposure to toxic chemicals especially during early development. Studies over the past few decades have shown that even low levels of exposure to substances like lead, mercury, PCBs, bisphenols and phthalates can alter brain development, reduce IQ, and increase the risk of conditions like autism. A 2025 report in the New England Journal of Medicine emphasizes that children are far more vulnerable than adults to these chemical exposures, especially in utero and early childhood. To help us understand the complicated factors that give rise to autism we’re joined by Dr. Philip Landrigan, a pediatrician, professor at Boston College, and one of the world’s leading experts on toxic exposure from plastics and pollution. Welcome back to Living on Earth, Dr. Landrigan!

LANDRIGAN: Steve, it's a pleasure to be with you.

CURWOOD: Dr. Landrigan, please briefly explain what Autism Spectrum Disorder is and what are the key differences within that spectrum.

LANDRIGAN: Autism Spectrum Disorder is a disorder of the brain. It's not a psychological condition. It's actually a brain disorder. It can range in severity from quite mild to profoundly severe. Two thirds of the children who have autism also have some degree of cognitive impairment, reduced IQ. Some have increased brain size. Some have epileptic seizures. Some have speech problems and motor problems. And yet, on the positive side, some have amazing, unique skills, like some children with what used to be called Asperger's syndrome can perform amazing feats of memory or mathematics. So it's really quite a range of conditions. Hence, the term spectrum.

CURWOOD: The Centers for Disease Control is reporting an increasing prevalence of autism being diagnosed. What does this increase mean, and what factors might be driving it, do you think?

LANDRIGAN: Well, it's probably driven by several things. To be sure, there's better recognition of autism at all levels of society, among health professionals teachers, but also among parents and those who care for children. And better recognition is certainly part of the story, but it by no means is it the whole story, and there is absolutely a rise in autism spectrum disorder among American children. The most recent statistic from CDC indicates that it occurs in one child in 31, that's up from one in 36 a year or two ago, and from one in 88 back in 2012 and one in 166 children back in 2004. So it is really, really going up, and that's far too rapid to be purely genetic explanation. When I was a pediatric resident at Boston Children's, which was in 1970, I think I may have seen one child with autism in in two years, and today, children with autism are ubiquitous at a place like Children's Hospital. So there is very definitely a real increase going on.

CURWOOD: Let me ask you about what scientific evidence, if any, that links endocrine disrupting chemicals to autism or broader neurodevelopmental issues in children.

LANDRIGAN: There have been a whole series of toxic chemicals that have been linked to problems with brain development. Going back 40 or 50 years, the first of these chemicals that we recognized were lead and methylmercury, and then PCBs, certain pesticides. And more recently, it's come to be understood that phthalates and bisphenol A's, both of which are endocrine disruptors, are among the chemicals that can disrupt children's brain development and can result in a range of conditions, autism among them.

CURWOOD: Now, where does this exposure take place? If it's related, is it in the parents? Is it in the child, him or herself?

LANDRIGAN: Well, the most worrisome exposures, the most dangerous exposures, are the ones that occur during the nine months of pregnancy, when a child's brain is still growing and developing, which is an incredibly rapid, complex and therefore easily disrupted process. And exposure can occur via various routes. If toxic chemicals such as insecticide or phthalates get into a mother, those chemicals can cross the placenta from the mother to the baby and get into the baby's brain and cause damage. And then, after the child is born, the child can become exposed to these chemicals through their food, their drinking water, through playing on the rug, hand to mouth behavior, and even through inhaling the chemicals, if they're volatile in the home environment.

CURWOOD: So, looking at chemical exposure, how important do you think it is looking at these neurological, these neuro developmental issues for children, including autism spectrum disorder? I mean, how important are chemicals, do you think for this process?

LANDRIGAN: Chemicals are an important part of the story here. They're not the whole story. When I think of complex disorders like autism, I envision that there's always a mix of genetic factors and environmental factors in play. Kenneth Olden, the distinguished scientist who was the director of NIEHS for many years, used to say that genetics loads the gun and the environment pulls the trigger. Certainly, some children are genetically predisposed to conditions like autism, but autism may not develop unless there is some kind of a toxic environmental exposure that then triggers the disease. And I think the reason for the increase that we've seen over the past three or four decades is that children are being exposed to more and more external factors. Chemicals are one of them, not the only one, and these factors are interacting with children's genes and producing the condition that we call autism.

CURWOOD: Phthalates are an endocrine disruptor that's often found in fast food wrappers and such like that. How easy or hard is it to point a finger at something like the phthalates that you find in fast food as being part of this epidemic?

LANDRIGAN: Yeah, it's probably part of it. Phthalates damage the brain. Phthalates cause symptoms of autism in some small percentage of children who are exposed to them. So, I think it's part of the problem, the phthalates in food stuffs, fast food and others, mostly get there from plastics. Phthalates are used in formulating plastics, and they don't stay in the plastics. They escape from the plastics, and they get into the food. So one way to reduce our exposure to phthalates is try to avoid food that's packaged in plastics, which I know is not easy to do in today's world, but at least, make the effort minimize exposure. Try to avoid highly processed food, try to avoid fast food, and whenever possible, eat organic.

CURWOOD: Dr. Landrigan, to what extent is the rise in plastic production and distribution in our society over the last few decades linked to this rise in autism? What evidence might there be for that or not?

LANDRIGAN: Well, the two trends certainly line up with each other. Global plastic production has increased 250 times since 1955 and in fact, the global production of plastic is accelerating as we speak. It's on track to double by 2040 and triple by 2060 and the reason it's going up so fast is that the manufacturers of plastic have come to understand that there is great deal of money to be made in single use plastic, stuff that people use once and throw away, and many of those single use plastics contain the very chemicals that we're talking about here, such as phthalates and bisphenols.

CURWOOD: Some have advanced the argument that vaccines are behind autism. As an expert in pediatric environmental health, how do you respond to that claim?

LANDRIGAN: Well, that theory arose 25 years or so ago when it was observed from time to time that a child who had received a vaccine developed the symptoms of autism a week or two later. A doctor in England named Andrew Wakefield was the first who first proposed this theory. He had observed several children who developed autism in the weeks following vaccine. It turns out afterwards that he had fabricated a lot of his data, and that, in fact, he was trying to market a treatment for autism at the time, but nonetheless, Wakefield's theory took hold and became widespread on the internet. I think what's going on here is that most cases of autism, most clinical manifestations of autism, show up in children between the ages of one and three, and it's precisely in that same age range, one to three years old, that children receive so many vaccines to prevent their death from terrible diseases like measles and pertussis and tetanus and others. And so if you're vaccinating millions of children, some of whom are destined to develop autism at around that same time in life, it's inevitable that some of the children who get vaccinated are going to show up with autism in the weeks after vaccination. To address this issue, the scientific community has taken this issue very seriously and to address it, scientists in this country, in the UK, Scandinavia, Japan have launched major studies looking at the association between vaccines and autism and not one of them, none of them at all, have found a credible linkage between vaccines and autism. I think the most telling of these studies, most informative is a study that was undertaken in Yokohama, Japan, the province of Yokohama, the port city by Tokyo, and in that prefecture, the Japanese government decided to completely suspend MMR, measles, mumps, rubella vaccination for a period of about two years, because rates of autism were going up. They were concerned that MMR might be a driver, so they suspended all vaccination. What happened was that rates of autism continued to go up. A couple of kids got sick with measles. They said, enough is enough. They reinstated vaccines. Children were protected against measles, and yet autism continued to rise.

CURWOOD: What do you think is the most important message to take away from the ongoing scientific and public debate about autism and environmental toxins?

LANDRIGAN: The most important thing to understand here is that children in today's world are exposed to 1000s of chemicals in every aspect of their environment. Because of weakness in federal law in this country, fewer than 20% of those chemicals have ever been tested for toxicity. What this means is that American children are being exposed every day to chemicals of unknown hazard. We have to reduce children's exposure to these hazardous chemicals in food, in drinking water, in toys, in children's general environments.

CURWOOD: Dr. Philip Landrigan is Director of Global Program in Public Health and Common Good at Boston College. Thank you so much for taking the time with us.

LANDRIGAN: Thank you, Steve, a pleasure.

 

Links

Learn more about autism.

Explore ways you can reduce your exposure to endocrine disrupting chemicals.