30 March 2023

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New report reinforces confidence in the safety of fluoride

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A newly drafted report by the National Toxicology Program (NTP) has removed the hazard classification of fluoride. This strengthens the broad consensus that fluoride in toothpaste and water safely reduces dental cavities. The NTP report was revised from previous versions that had failed to pass the peer review process.

According to a news release from the American Fluoridation Society, NTP has abandoned the peer review process that it had requested and entered into with the National Academies of Sciences, Engineering, and Medicine. During this review process, the National Academies voiced numerous concerns, including how NTP evaluated the quality of studies and NTP's inconsistency in assessing studies' risk of bias. Many of these concerns were not addressed in the latest draft. NTP also has ignored the National Academies' instruction that NTP "make it clear that the [draft report] cannot be used to draw any conclusions" about low fluoride exposures, "including those typically associated with drinking-water fluoridation."

Dr. Johnny Johnson, president of the American Fluoridation Society, said there was both good and bad news in the newly drafted report.

"NTP realized correctly that it should remove the hazard classification," said Johnson in the news release. "On the other hand, it is disturbing that NTP chose to abandon its peer review process. The National Academies is the most prestigious, independent scientific body in our nation. Walking away from that process suggests that the authors of the NTP draft report may be driven more by an agenda than by science."

It is telling that NTP removed the hazard classification for fluoride even without analyzing two recent studies from Australia and Spain. Both peer-reviewed studies showed no link between fluoride exposure and adverse cognitive effects. In fact, a study in Spain revealed that fluoride exposure was linked with higher cognitive performance scores for boys. In addition, the authors of a study in Sweden estimated "a zero effect on cognitive ability" from exposure to fluoride at or near the level used for water fluoridation.

Opponents of water fluoridation have claimed that officials outside of NTP "blocked" the program from releasing its report earlier. But this claim is contradicted by the NTP's own website, which explains that NTP's Director "decided to delay publication" of the report to allow more time for internal scientific review.

Additional review was important because there are serious concerns about the quality of many fluoride-related studies. A 2020 fluoride-IQ study was recently retracted after the journal BMC Public Health found "inconsistencies in methodology and major misinterpretation of the primary result." A just-published research review of fluoride-cognition studies, coauthored by Linda Birnbaum (former NTP Director), found that only one out of 30 studies was at low risk of bias. The only low-risk-of-bias study found no link between fluoride exposure and cognitive harms. Policymakers should be aware of the NTP draft report because anti-fluoride activists have cited this document to encourage communities to cease water fluoridation. Some cities have learned a tough lesson about the impact that cessation has on residents' dental health:

The city council in Calgary, one of Canada's largest cities, voted to reinstate fluoridation in 2021 after research showed a significant rise in dental cavities in the years after fluoridation had ended. After Alaska's capital city stopped fluoridation, researchers studied the impact on low-income children. Without fluoridation, the average preschool-age child needed one additional cavity-related treatment each year at a cost of about $300.

The leading medical, dental, and public health organizations recommend water fluoridation as a beneficial, safe way to reduce the number and severity of dental cavities. Like the issue of vaccinations, fluoride is the target of a variety of myths and conspiracy theories. The American Fluoridation Society offers fact sheets and other materials that distinguish the myths from the facts.

View the report at: https://ntp.niehs.nih.gov/whatwestudy/assessments/noncancer/ongoing/fluoride/index.html