Possible Consequences of Court Ruling on Safety of Water Fluoridation

Lilian White, MD
Posted on October 21, 2024

Fluoride has been added to drinking water in various regions of the United States since 1945 for the purpose of preventing tooth decay. Currently, concern arises for the negative health effects of a chemical, individuals may petition the Environmental and Protection Agency (EPA) to act. If the petitioner disagrees with the EPA’s assessment, they may go to court for another opinion.

The practice of supplementing drinking water with fluoride has come under scrutiny recently when a court ruling on September 27, 2024, declared the currently recommended water level of fluoridation in the United States (0.7 mg per L) an unreasonable risk to health. Under the Toxic Substances Control Act, the EPA is now compelled to respond through regulatory action such as banning fluoridation or simply requiring a warning label on fluoridated water; however, the specific regulatory action is left to the EPA’s discretion.

Organizations such as the American Dental Association and American Academy of Pediatrics have voiced opposition to the ruling and continue to stand by recommendations for widespread drinking water fluoridation. In 1999, the Centers for Disease Control and Prevention (CDC) noted water fluoridation to be one of the top 10 great public health Achievements of the 20th Century, making a reversal of this accomplishment particularly controversial among some public health advocates. The AAFP has not commented on the case, but its current policy is in support of water fluoridation.

A systematic review conducted by the National Toxicology Program of the U.S. Department of Health and Human Services reported a 1-point drop in the IQ of children per 0.28 mg per L of fluoride in a pregnant mother’s urine. This was similarly corroborated by a cohort study published in JAMA earlier this year, raising concern for exposure to fluoridated water and clinical neurobehavioral problems among children.

A meta-analysis conducted in 2024 assessing the effect of high-fluoride drinking water exposure and thyroid health demonstrated an increase in the risk of thyroid diseases. Additionally, excess fluoride exposure may cause dental fluorosis in children with developing teeth (discoloration of teeth, among other adverse dental effects), which may be due to excessive fluoride exposure or low-level exposure over time. Fluorosis is primarily a cosmetic concern; however, as with other cosmetic diseases, it has the potential to negatively affect the self-esteem of children.

Interestingly, the association between tooth mottling due to fluorosis (incidentally caused by fluoride exposure) and reduced dental decay was the finding that eventually led to the movement to fluoridate drinking water in the United States. By 1989, 70% of the U.S. had fluoridated drinking water. Some states have even added water-fluoridation requirements to their laws, and most states have some degree of drinking water fluoridation.

People in the United States are primarily exposed to fluoride through supplemented drinking water, topical dental products, and foods and beverages to which fluoride has been added. The CDC recommends a fluoride level of 0.7 mg per L of drinking water to prevent tooth decay. The Community Preventive Services Task Force recommends fluoridation based on an older systematic review.

Real-world epidemiologic studies on the cost:benefit ratio of drinking water fluoridation are lacking. It has been theoretically estimated that fluoridated drinking water may result in savings of $32 per person per year with an estimated cost of $0.12 to $0.60 per person per year. The cost of harm from fluoridated drinking water has yet to be studied outside of theoretical models. 

For patients concerned about their personal exposure to fluoridated drinking water, physicians can direct patients to My Water’s Fluoride, a CDC directory for local water fluoridation; however, not all states participate in this program, and the directory does not provide quantitative exposure measures. The Environmental Working Group’s Tap Water Database provides more detailed information on a large number of possible water contaminants in addition to fluoride as well as information on specific filters that will remove relevant chemicals, offering a more practical resource for patients.

It will be interesting to see how the EPA responds to this court order to address fluoridated water as an unreasonable risk to health. With the current widespread use of fluoridated water, any regulatory action will likely be slow to implement. Additional research is needed on whether the potential adverse effects of fluoridation outweigh the established benefits for preventing caries in children.