Login
A novel biomonitoring study, published in Neurotoxicology and Teratology, analyzes levels of pesticides and plasticizers in baby teeth, collected by parents after they are shed, in children with and without autism.
In comparing teeth from the two groups of children, higher levels of pesticides are found in children with autism than in the control group.
“We investigated cumulative pesticide and plasticizer exposures in shed baby teeth from children with and without autism,” the authors state.
In highlighting the results, they continue:
“Sixty compounds were detected in more than 50% of participants (n = 38). Of these, 95% (57/60) were higher in cases compared to controls, and 19/60 were statistically significantly elevated.
“Thirty-nine of the 60 compounds detected are known developmental toxicants or endocrine-disrupting compounds. To date, 21/60 compounds lack Environmental Protection Agency (EPA) developmental toxicity data.”
The current body of biomonitoring studies primarily focuses on urine and blood, which provide insights into short-term exposure. Baby teeth, however, are able to capture long-term exposures from approximately 13-14 weeks in utero (time in the womb) through early childhood.
In analyzing shed baby teeth, this study showcases elevated levels of toxicants in children with autism from early life exposure.
Background
As shown in Beyond Pesticides’ Pesticide-Induced Diseases Database, there is a wide body of science connecting pesticide exposure to deleterious health effects, including brain/nervous system and learning/developmental disorders like autism.
As the current study authors state:
“Once a rare condition (Rutter, 2005), the prevalence of autism has sharply risen in the last 30 years to 1 in 31 children (Shaw et al., 2025), and over 5.4 million US adults live with autism (Dietz et al., 2020).
“Autism includes an array of developmental disorders characterized by social deficits with repetitive and restrictive interests and behaviors.”
Scientific literature shows that this disorder has both genetic and environmental determinants.
“However, the sharp rise in autism underscores the importance of investigating environmental triggers alongside genetic susceptibility,” the researchers point out.
Previous studies show that environmental factors play a large role in autism, with multiple classes of chemicals, including pesticides and plasticizers, as well as heavy metals, being implicated in the disorder. (See here and here.)
Research on prenatal pesticide exposures shows an association with a wide range of adverse developmental outcomes, including increased autism and attention deficit/hyperactivity disorder (ADHD) risk. (See here and here.)
Additional studies also find that increased autism risk is highest for organophosphate pesticides. (See here and here.)
As documented on the Beyond Pesticides’ Hazards of Pesticides for Children’s Health page, infants and children face much higher hazards than adults from pesticide exposure.
Their small size and developing organ systems, propensity to crawl and play near the ground, tendency for frequent hand-to-mouth motion, and greater intake of air and food relative to body weight make them particularly susceptible.
The hazards borne by children in the “windows of vulnerability” at a young age have critical implications for long-term health. For additional information, see Children and Pesticides Don’t Mix and Daily News coverage related to infants and children here.
Methodology and results
To assess pesticides and plasticizers in children, a study of shed deciduous teeth, commonly known as baby teeth or primary teeth, was conducted. Thirty-eight samples of teeth from children with autism came from The Autism Tooth Fairy Project, a case-control study at The University of Texas Health Science Center at San Antonio, and were analyzed alongside sixteen control samples.
As the researchers note, biomonitoring studies using other methods, such as with blood or urine, have limitations that “can be overcome by using deciduous teeth, which incorporate circulating chemicals into dentin layers as they form, thereby preserving a chronological record of early-life exposures.”
On average, over 300 toxicants are detected in each tooth sample. Specifically, 12 of the identified compounds are used in pesticide formulations, and 37 compounds are classified as both pesticides and plasticizers, “yielding a total of 49 pesticidal compounds with detection frequencies ranging [from] 50% to 100%.”
Many of these compounds are known developmental or endocrine-disrupting chemicals or have not been comprehensively analyzed by EPA for developmental toxicity.
“In conclusion, our study suggests that children are being chronically and repeatedly exposed to a wider range of developmental toxicants than previously identified in short-term exposure studies,” the authors state.
By capturing pesticide and plasticizer residues in samples of teeth in conjunction with autism diagnoses, this study highlights the impacts of prenatal and early-life exposure.
Previous coverage
The scientific evidence linking pesticide exposure to neurotoxicity continues to mount. A study in Discover Toxicology highlights neurotoxic pollutants as significant environmental threats, showcasing the adverse impacts on vertebrates’ neurological health from pesticides, including organophosphates, carbamates and organochlorines.
As the review points out:
“[T]he prevalence of autism has tripled between 2000 and 2016, coinciding with a more than 15-fold increase in chemical production since the 1940s, including neurotoxicants.
“Recent data indicate that the prevalence of autism continues to rise, with the CDC [Centers for Disease Control and Prevention] reporting 1 in 36 children diagnosed with ASD [autism spectrum disorder] in 2020, coinciding with sustained high levels of industrial chemical production.”
The researchers continue, saying, “Additionally, exposure to agricultural chemicals such as glyphosate has increased markedly, with usage rising to about 250 million pounds per year in the United States and animal models linking glyphosate to oxidative stress and depressive-like behaviours such as reduced mobility in the forced swim test and increased immobility time, which are indicative of behavioural despair and altered neurochemical signaling.” (See Daily News here.)
As documented in Daily News, titled Parent’s Toxic Chemical Exposure Linked to Autism in Offspring, exposure to chemical toxicants, molds and algae contributes to autism and attention disorders in children, according to research that bolsters earlier findings.
The exposures may be most relevant not in the children, but one generation back — in the parents, based on the study published in the Journal of Xenobiotics, “Assessing Chemical Intolerance in Parents Predicts the Risk of Autism and ADHD in Their Children.”
Led by Dr. Claudia S. Miller, an immunologist at the University of Texas at San Antonio noted for her work on chemical intolerance, the authors build on previous work published in 2015 establishing parental chemical intolerance as a risk factor for autism and ADHD. Miller participated in Beyond Pesticides’ 2022 Forum Series. Recordings of her presentation are available on YouTube here and here.
A study, published in Environmental Research, finds an association between adverse neurodevelopment (brain function and development) among infants and exposure to the herbicide glyphosate during pregnancy (gestational).
Moreover, neurodevelopmental effects become more pronounced at 24 months or two years. (See Daily News here and additional coverage in the Daily News archive on autism here.)
Moving forward
As the prevalence of autism and other neurological disorders continues to rise, it is imperative to eliminate exposure to pesticides and plasticizers, particularly in pregnant women and children facing disproportionate risks.
As documented in a previous Action of the Week, titled “Despite Escalating Pesticide Threats to Children’s Health, GOP Farm Bill Slashes Protections,” a multitude of studies make the connection between prenatal and postnatal exposure to pesticides and severe consequences for children, including childhood cancers and adverse neurodevelopmental outcomes, underscoring what are being called unnecessary dangers of agriculture that relies on toxic pesticides.
These outcomes are both shocking and deplorable, since organic agriculture can produce any product produced by chemical-intensive agriculture.
With future agriculture policy now under consideration, it is important that the Farm Bill not be used to prop up the chemical industry, but instead support organic agriculture that will not threaten vulnerable populations.
Originally published by Beyond Pesticides.
