Fluoridation exposure misinformation spreads due to circulation of a flawed study

June 3, 2024
QUICK SUMMARY:  A MADRES study published in the journal JAMA Network Open analyzed the possible association between maternal urinary fluoride data from a small cohort and the reported behavior of their 3-year-old children. Due to the study's small scope and limitations, the impacts of fluoride exposure are being misrepresented. Read how organizations and publications have responded and find trusted resources to support discussions about the importance of community water fluoridation.

While dissemination of clinical studies can help enlighten researchers, health care providers and patients, the circulation of flawed studies can cause significant harm. 

A MADRES study that was recently published in the journal JAMA Network Open analyzed the possible association between maternal urinary fluoride data from a small cohort of mainly Latino pregnant persons from Los Angeles and the reported behavior of their 3-year-old children.  

Unfortunately, due to the small scope and limitations of the study, the impacts of fluoride exposure are being misrepresented. Leading publications that have picked up the MADRES study have amplified the misinformation. 

What does the MADRES study assert?

This study reports an association between mothers’ prenatal fluoride exposure and behavioral problems in children. Yet, the methods and data sample had significant limitations. 

How does the research compare with other studies?

In contrast to the MADRES study, a  2023 study in Australia  examined whether there was a link between exposure to fluoridated water and 5-year-old children’s executive function and emotional and behavioral development. It found no association. The 2023 research yielded higher-quality results due to multiple factors: 

  1. The Australian study did not use the unreliable modified ultrafiltration method to measure individual fluoride exposure. Instead, the Australian researchers used water fluoridation status.  
  2. The Australian study analyzed data from a much larger sample of 2,682 children. This sample is more than 10 times higher than the 229 children who were the focus of the MADRES study.  

Do scientists have concerns with the MADRES study? 

The reliability of fluoride-related studies is a very important issue. Experts have shared that spot samples of urinary fluoride are not a valid measure of an individual’s exposure to fluoride. The measurement of the children’s IQs was also viewed as unreliable.  

Where is the MADRES journal article circulating?

The article has already been picked up by the Los Angeles Times,  NBC, the New York Times and the Keck School of Medicine of USC. 

Of great concern is that health care providers and the public will only read about potential concerns while ignoring the fact that the authors of the MADRES study themselves acknowledged several limitations and described the study as exploratory. 

Howard Pollick, BDS, MPH, a professor at the University of California, San Francisco School of Dentistry, said that while new research is always welcome, the MADRES study is flawed. 

“Eight of 12 measures of mother-reported behaviors in the MADRES study were not statistically significant, and it is irresponsible of the authors, based on this study, to suggest that recommendations be changed on the beneficial use of fluoride to prevent dental problems,” Pollick said. 

How is the misinformation being addressed?

The American Fluoridation Society, American Dental Association, American Academy of Pediatrics, Cosmos, Medscape and other publications have issued responses about the study’s limitations. 

What should dentists know?

Community water fluoridation has been proven to safely prevent disease. The International Association for Dental, Oral, and Craniofacial Research issued a position statement that supports community water fluoridation as a safe and effective evidence-based intervention for the prevention of dental caries. 

Trusted resources are available to support discussions about the importance of fluoridation within the practice team and with patients. 

Properly designed research is essential to informing sound policies, clinical decisions and trusted dialogues between the health care community and the public. When reviewing new studies, dentists are encouraged to consider whether the data sets are sufficient, the scope is significant and that all contributing factors are properly measured. 

Find more fluoride and fluoridation resources at cda.org, peer-reviewed research through the CDA Journal and updates through the CDA newsroom. 


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