Los Angeles, California (May 20, 2024) – A study published in the Journal of the American Medical Association (JAMA) on Monday found that in fluoridated Los Angeles, the children of mothers with higher fluoride exposures during pregnancy had double the odds of several neurobehavioral problems compared to mothers with lower exposures. Funding for the study was provided by the National Institutes of Health (NIH) and the US Environmental Protection Agency (EPA), reports the Fluoride Action Network.
Children exposed to more fluoride had significantly more problems with emotional reactivity, somatic complaints (such as headaches), anxiety, and symptoms linked to autism.
This represents the 10th consecutive NIH-funded study in humans finding adverse effects of fluoride on children’s developing brains. It supports and extends the findings of a study published two years ago that found increased somatic and anxiety problems in adolescents in fluoridated Cincinnati OH. The previous 8 studies were in Canada and Mexico and consistently found a lowering of IQ or an increased risk of behavioral problems like ADHD associated with early life exposure to fluoridated water or fluoridated salt.
One such study was by Green et. al. published in JAMA Pediatrics in 2019, linking exposure to “optimally” fluoridated water in Canada during pregnancy to a lowered IQ for the child. At the time, JAMA Pediatrics editor Dimitri Christakis, MD, MPH, remarked: “The effects of this study are comparable to the effects of lead, and if these findings are true, there should be as much concern about prenatal fluoride exposure. The question that needs to be asked of every pediatrician, scientist, and epidemiologist is what they’re going to tell pregnant women.” Christakis said he would advise his pregnant friends and family to avoid fluoridated water. “We can’t tell them to wait years for another study.”
FAN’s Executive Director, Stuart Cooper, said, “Scientists are sounding the alarm. NIH has only recently funded 10 studies investigating the effects of fluoride on the developing brain, and all 10 have found cognitive impairment and neurobehavioral side-effects. This is 100% consistency across multiple birth cohorts, with different study authors, studying children from different cultures, social economic backgrounds, and countries, all finding the same result.”
This latest study was conducted by researchers based at the University of Southern California on a cohort of mothers and children called the MADRES cohort. The stated goal of MADRES is to reduce the effects of environmental contaminants on the health and well-being of marginalized communities.
Fluoride exposures during pregnancy were assessed from measurements of urinary fluoride in the first and third trimesters. The study found that urinary fluoride levels were almost identical to those found in Canadian and Mexican studies where the main source of fluoride was artificial water fluoridation or salt fluoridation, respectively.
“This exposure can impact the developing fetus,” said Tracey Bastain, PhD, the study’s senior author. “Eliminating that from drinking water is probably a good practice.”
Behavioral problems in the children were assessed at 3 years of age with a widely-used method called the Child Behavior Checklist (CBCL). The types of behavioral problems assessed by the CBCL are classified into two types, “internalizing” and “externalizing”:
“Internalizing problems sums the Anxious/depressed, Withdrawn-depressed, and Somatic complaints scores; Externalizing problems combines Rule-breaking and Aggressive behavior. There also is a Total problems score, which is the sum of the scores of all the problem items.”
The MADRES cohort showed a significantly increased risk of total and internalizing problems as fluoride exposure increased. All seven of the CBCL problem sub-scales increased with increasing fluoride exposure, with somatic complaints and emotionally reactive classifications increasing the most, by 20% and 14%, respectively. None decreased.
Similarly, the study adapted CBCL scores to five subscales used in the American Psychiatric Association’s DSM-5 (Diagnostic & Statistical Manual of Mental Disorders) to assess behavioral problems and found all five types of behavior problems increased as fluoride increased. Autism and Anxiety symptom scores increased the most. An increase in maternal urine fluoride during pregnancy of 0.68 mg/L was associated with a significant 19% increase in autism spectrum problems.
FAN’s Science Director, Chris Neurath, noted, “This is the first rigorous study to look at fluoride and autism symptoms, so it is concerning that it suggests a link. Its findings bolster reports of individuals with autism whose symptoms are made worse when drinking fluoridated water or other sources of fluoride.”
The study controlled for many potentially confounding factors, thereby increasing confidence that fluoride was the cause of the increased behavioral problems. When controlling for prenatal lead exposure, the increased odds of behavior problems went from a doubling to as much as quadrupling.
In a press release from the Keck School of Medicine at USC, lead author Dr. Ashley Malin, said:
“Our findings are noteworthy, given that the women in this study were exposed to pretty low levels of fluoride—levels that are typical of those living in fluoridated regions within North America. There are no known benefits to the fetus from ingesting fluoride, and yet now we have several studies conducted in North America suggesting that there may be a pretty significant risk to the developing brain during that time.”
Malin’s comments are more relevant than ever after the publication of two large studies from England, the CATFISH study in children and the LOTUS study in adults, that found virtually no dental benefit from fluoridated water. Neither did they find any benefit for those in low socio-economic status groups.
The authors also emphasized that this is not an isolated study, but the most recent in a large number of studies consistently finding that fluoride harms the developing brain, including at exposures commonly found in people living in areas with fluoridation at 0.7 mg/L:
“Taken together, the weight of the scientific literature supports an association of prenatal fluoride exposure with adverse child cognitive and neurobehavioral development in North America.”
Dr. Howard Hu, Professor of Population and Public Health Sciences at USC and co-author of the study, further emphasized the importance of the large volume of research consistently finding that low levels of exposure to fluoride are harmful:
“When you add this to all the other studies that have been done on this subject in the last few years, it creates a body of evidence, which — in conjunction with the basic science looking at how fluoride may be toxicologically active on the brain — suggests that the impact of fluoride on neurobehavioral development problems is causal. It’s not just an epidemiological association.”
They cite the National Toxicology Program’s recent systematic review, which has identified over 70 human studies of fluoride and IQ, with 90% of them finding a significant reduction in IQ. Among the 19 highest quality studies—many with exposures in the range found in fluoridated communities—18 found reductions in IQ, a 95% consistency.
Cooper pointed out that “it’s shameful that it has taken this long for a study of fluoride’s effect on the brain of children to be done here in the US. In other countries, studies were being conducted decades ago, and they were consistently finding problems. The US is the birthplace of fluoridation and one of the few countries still practicing it, but our government avoided doing the research, perhaps out of fear of what would be found.”
Fluoridation proponents have even used the absence of a US study to dismiss the findings of studies from other countries. In FAN’s ongoing lawsuit against the EPA in federal court seeking to prohibit the addition of fluoride to drinking water, the EPA argued that extrapolating from other countries to the US was not possible.
Cooper says, “Clearly, this was never a valid argument, and this new study should put that misinformation to rest.” He added, “A federal ruling in our lawsuit is expected any day now. This new study further confirms that parents must not expose a child’s developing brain to fluoride, and the only way this is possible is if policymakers end water fluoridation immediately.”
In response to the neurotoxicity science, the NTP report, and the federal lawsuit, there has been a recent groundswell of citizens, water operators, local officials, and state legislators calling for an end to fluoridation. Bills to prohibit fluoridation have recently been introduced in Massachusetts, Pennsylvania, New Hampshire, Hawaii, and Oklahoma, and legislation to reverse state fluoridation mandates was introduced in Kentucky, Nebraska, and Georgia.
Large communities like State College, Pennsylvania, Collier County, Florida, Branson, Missouri, and Union County, North Carolina have recently ended their fluoridation programs after considerable research and debate. Over the past several months, more than a dozen additional towns have joined them in rejecting the practice.
One statement by a coauthor of the new study, made in the USC news release, requires correction. It was stated that most table-top water filters remove fluoride. That is not true. The large majority of water filters, including Brita-type filters, do not remove fluoride.