A bombshell study published Wednesday in BMC Pediatrics confirms that water fluoridation, while reducing tooth decay, significantly increases the risk of autism in children exposed during their first 10 years of life. This peer-reviewed research highlights a disturbing trade-off between dental health and serious neurodevelopmental harm.
The study also found elevated rates of other disorders, including attention-deficit/hyperactivity disorder (ADHD), intellectual disability, and specific developmental delays, among children exposed to fluoride in their early years. These findings raise urgent questions about the safety of fluoridated water and its long-term impact on young minds.
“It appears from this study that the public health intervention of fluoridated water may have traded brain health for tooth health,” Children’s Health Defense Senior Research Scientist Karl Jablonowski said in a statement.
The Defender reports: The authors concluded that given both the benefits and harms they determined to be associated with water fluoridation, and in the context of growing evidence of fluoride’s serious neurodevelopmental risks, “new risk/benefit analyses should be undertaken regarding water fluoridation programs.”
Researchers David and Mark Geier analyzed data from the Independent Healthcare Research Database, composed of de-identified healthcare records from the Florida Medicaid System from 1990-2012. This allowed them to study a large population across a significant amount of time.
Because Florida has counties that are fluoridated and others that aren’t, they were able to compare outcomes among children exposed to water fluoridation for their whole lives — 25,662 children — to those who weren’t — 2,509 children.
Once they determined children’s fluoride exposure, they identified healthcare claims among those children for dental cavities and neurodevelopmental issues.
They examined fluoride exposure and outcomes during the first year of life and the first 10 years of life.
The researchers found that in the first year of life, there was a statistically significant slight decrease in the risk of tooth decay with increased water fluoride exposure and a statistically significant slight increase in the risk of neurodevelopmental disorders.
After 10 years of fluoride exposure, the risk of tooth decay was significantly lower — 3.6-fold — in exposed children, but the children had a significantly higher risk of developmental disorders — 6.26-fold greater for autism, 2.02-fold greater for intellectual disability and 1.24 greater for specific delays in development.
Dr. Hardy Limeback, former head of preventive dentistry at the University of Toronto, said the methods and findings of the study were valid and that they raised several questions.
The methodology didn’t allow the researchers to quantify the severity of the diagnoses, Limeback said. “What does ‘threefold’ likelihood of more cavities in non-fluoridated areas mean? Does it mean there was a massive difference in total cavities or was the average difference only 0.25 dmfs (decayed missing filled surfaces) in baby teeth, as reported by the latest Cochrane Review?”
The Cochrane Review, published in October 2024, concluded that water fluoridation might lead to a very small reduction — about one-quarter of one tooth — in cavities in children’s baby teeth.
Limeback said:
“Conversely, how many IQ points were lost in Medicaid kids living in fluoridated communities? How many more autistic kids can be blamed on fluoride exposure from birth to age 10?
“This study is one of four recently published studies that have looked at postnatal neurological harm from fluoride in drinking water. More well-done studies are needed to find out the extent of harm that fluoridation has been posing to developing children ever since its inception in 1945.
“Promoters of dental public health and medical public health must now work together to decide if saving even one cavity in Medicaid children (which is repairable) using fluoridation is worth irreversibly damaging their brains.”
Jablonowski said the latest research findings raised questions for research and public health interventions. “The authors present compelling evidence that something widely considered as safe may actually be harmful.”
He added:
“In terms of absolute risk, if this study is correct, out of every thousand children, water fluoridation prevents tooth decay in 58 of them and induces autism in 11, intellectual disability in 5 and specific developmental delay in 49.
“That is a trade-off no parent would make, no doctor would recommend and no society would allow.
“If this study is even close to correct in reflecting true adverse outcomes, the autism epidemic and the accelerated neurodivergence in America was hastened by a short-sighted so-called public health practice.”
Failure to assess safety of water fluoridation has been official public policy for decades
The authors said their methods and results overlap with a previous study by the Centers for Disease Control and Prevention (CDC), which analyzed water fluoridation and Medicaid dental reimbursements in Louisiana from July 1995 to June 1996.
That study found similar rates of claims for tooth decay, providing epidemiological support for the findings in the BMC Pediatrics study, Geier and Geier noted.
“Unfortunately, the Louisiana Medicaid study investigators undertook no safety assessments,” they wrote.
Studies assessing water fluoridation’s effect on tooth decay have consistently failed to assess fluoride for safety. Failure to assess fluoride’s safety has also been the official public policy in the U.S. for decades.
The U.S. Environmental Protection Agency’s (EPA) current enforceable drinking water standard for fluoride is 4.0 milligrams/liter (mg/L) and its “non-enforceable secondary standard” is 2.0 mg/L, which the EPA set lower to protect children from dental fluorosis — tooth discoloration or pitting that can be caused by excess fluoride exposure.
Dental fluorosis is the only harm from fluoride the EPA considers, despite extensive evidence that fluoride exposure causes neurodevelopmental harm.
Recent epidemiological studies in Canada, Mexico and the U.S. showed significant associations between higher fluoride exposure and worse neurocognitive outcomes for children.
A meta-analysis published in January showed that fluoride exposure was associated with significant reductions in IQ scores.
Meanwhile, the public health agencies that make recommendations about the levels at which communities should fluoridate their water have, in recent years, lowered the recommended dosage from 0.7-1.2 mg/L to 0.7 mg/L without publicly acknowledging that there are legitimate safety concerns beyond dental fluorosis.
However, emails and other documents show it is precisely the concerns about fluoride’s neurotoxic effects driving these changes — and moving officials as high up as the U.S. surgeon general to quietly withdraw their support for the practice.
Consumer and environmental advocacy groups sued the EPA over its failure to regulate fluoride in drinking water, despite evidence that exposure to the chemical lowers IQ in children.
In a landmark judgment, a federal judge ruled that fluoride poses an unreasonable risk to children’s health and must be regulated by the agency. The EPA said it will appeal the decision.
The American Academy of Pediatrics, the American Dental Association and other pro-fluoridation groups continue to confirm their staunch support for community water fluoridation, touting the alleged benefits of fluoride and declaring it safe.
They also claim there is “no scientific basis” to change that endorsement, despite the mounting evidence about fluoride’s neurological effects.
The CDC similarly maintains that water fluoridation safety is reevaluated frequently and there is no evidence of a connection between fluoridation and adverse health effects.
The authors of the BMC Pediatrics study acknowledged that the study has limitations — they couldn’t measure actual fluoride exposure on an individual basis or independently verify the diagnoses. They also said that developmental disorders tend to have multiple causes and so the outcomes must be viewed in that context.
They recommended that future similar studies be undertaken in other large population databases.
