A new fluoride study confirms the results of other recent studies that have found an inverse association between fluoride exposure and IQ. This comes just before Robert F. Kennedy Jr. is set to be questioned in a confirmation hearing to become the HHS Secretary for the incoming Trump administration.

The National Toxicology Program (NTP) released the study in the Journal of the American Medical Association (JAMA) on Monday. The meta-analysis of 74 studies in 10 countries found that higher fluoride levels in urine are associated with lower IQ scores. A 1 ppm increase is associated roughly with a 1-point loss in IQ.

The EPA recommends fluoridated water levels of 0.7 ppm but has an enforceable standard of 4 ppm. If any water supply within the United States has fluoride levels below 4 ppm, the EPA cannot require the local government to correct the high fluoridation levels.

Of the data voluntarily shared by local governments across the U.S., two known water systems in South Carolina have fluoride levels exceeding the World Health Organization (WHO) guideline of 1.5 ppm. The CNN report shows that 940 water systems are within the recommended EPA guidelines, and 832 water systems are lower than the recommended guidelines. Some states have not publicly shared their data. If the water system exceeds 2.0 ppm, the local government must inform the public.

The Fluoride Action Network (FAN), the group that won the fluoride lawsuit against the EPA, responded to the recent study, which was an addition to the NTP report released in August. Chris Neurath, FAN’s science director, pointed out studies within the meta-analysis that found IQ loss at 0.3 ppm, half of the recommended levels of the EPA. There were seven studies in the analysis with levels below 1.5 ppm showing an average IQ loss of three points.

The NTP study authors stated, “Although the estimated decreases in IQ… may seem small… research on other neurotoxicants has shown that subtle shifts in IQ at the population level can affect people who fall within the high and low ranges of the population’s IQ distribution. For context, a 5-point decrease in a population’s IQ would nearly double the number of people classified as intellectually disabled.”

The HighWire reported about the landmark court decision that is forcing the EPA to take action on water fluoridation in the United States. The current recommended levels were deemed an “unreasonable risk” to human health. The attorney Michael Connett, from Siri and Glimstad, appeared on The HighWire last year and again this year to discuss the latest information regarding the potential harms of fluoride.

U.S. Senator Chris Murphy recently stated on MSNBC that he agrees with RFK Jr.’s push to stop pharmaceutical advertising but said he should not get a free pass. “He also wants to kill our kids by withdrawing vaccines from our schools and taking fluoride out of our drinking water.”  RFK Jr. has stated he has no intention of banning vaccines.

Dental groups have pushed against the notion that fluoridated water is a net harm to the public, and they say the oral health benefits outweigh any potential loss in IQ. There is, however, no evidence that fluoride consumption is preventing children from dying, as Senator Murphy suggests.

NBC News reported that RFK Jr. “previously said without credible evidence that fluoride is an industrial waste associated with arthritis, bone fractures, bone cancer, IQ loss,” and other problems.” Kennedy’s post links to The HighWire’s discussion between Jefferey Jaxen and Michael Connett in October.

Dr. Elise Bassin published a study in 2006 showing young boys aged 6-8 who drank fluoridated water below the recommended levels were more than five times more likely to develop osteosarcoma than boys who did not drink fluoridated water. Osteosarcoma is an aggressive form of bone cancer.

A 2021 study found postmenopausal women with “the highest third of fluoride consumption had a 59% increased risk of hip fractures.”

FAN breaks down the studies linking fluoride consumption to osteoarthritis and rheumatoid arthritis. FAN explains that U.S. health authorities claim arthritis can only occur from fluoride consumption when skeletal fluorosis is detectable by x-ray. They state, “Turkish researchers found that the most common x-ray finding among skeletal fluorosis patients was knee osteoarthritis. Of the 56 fluorosis patients examined, 66% had osteoarthritis in the knee, while only 3.6% had hyper-dense bone in the spine. Thus, many of the fluorosis patients had knee osteoarthritis without simultaneously showing the bone change in the spine that U.S. health authorities claim is necessary to make a diagnosis of skeletal fluorosis.”

The HighWire reported about the pushback from dental associations and their potential financial incentives for community water fluoridation advocacy. While the EPA must create a plan to address the “unreasonable risk” to human health, the process can take years before any real action is taken.

Connett explained on The HighWire that local communities do not have to wait for the EPA to act before deciding to stop fluoridating the water supply. FAN has reported about several communities that have taken the steps to stop water fluoridation. Most recently, Aberdeen, Washington, has discontinued the practice of water fluoridation, and Lakeland, Florida, is being pressured to act.

As the potential incoming secretary of HHS, Kennedy has stated his intent to stop community water fluoridation nationwide, but HHS does not have authority over the EPA. President-elect Donald Trump hasn’t explicitly stated whether he thinks fluoride should be removed from the water supply, but he said it “sounds ok” and he would talk to Kennedy about the topic. Lee Zeldin is set to become the next EPA administrator if he passes the confirmation process. Zeldin has not publicly made any statements in favor or against water fluoridation.