<\/a><\/p>\n\n\n\n <\/a><\/p>\n\n\n\n Related article<\/strong>What to know about fluoride in drinking water<\/a><\/p>\n\n\n\n The full review was finally published as a lengthy monograph<\/a> in August, and in September, the study became the basis<\/a> of a federal judge\u2019s ruling ordering the US Environmental Protection Agency to further regulate fluoride to protect children\u2019s intellectual development.<\/p>\n\n\n\n \u201cSimply put, the risk to health at exposure levels in United States drinking water is sufficiently high to trigger regulatory response by the EPA\u201d under federal law, US District Judge Edward Chen wrote in the ruling.<\/p>\n\n\n\n In November, Robert F. Kennedy Jr., President-elect Donald Trump\u2019s pick for US Health and Human Services secretary, made headlines after he called fluoride \u201can industrial waste\u201d and pledged<\/a> that the Trump administration would advise utilities to stop adding to public water supplies.<\/p>\n\n\n\n Fluoride is a naturally occurring mineral<\/a> that\u2019s found in soil, rocks and water to varying degrees. It is also a byproduct of fertilizer production<\/a>. On the recommendation of the US Centers for Disease Control and Prevention and the World Health Organization, many cities have added fluoride to their treated drinking water for decades to protect teeth from cavities.<\/p>\n\n\n\n As it washes over teeth, fluoride can stop early decay by putting minerals back into tooth enamel. It also makes teeth more resistant to acid<\/a> and interferes with bacteria\u2019s ability erode teeth.<\/p>\n\n\n\n In some places, including areas that have well water that\u2019s naturally high in fluoride, children were getting so much fluoride that it left streaks and spots on their teeth, a condition called dental fluorosis. In 2015, HHS <\/strong>lowered its recommended levels<\/a> for fluoride in drinking water from a range of 0.7 parts per million to 1.2 parts per million to 0.7 parts per million, to prevent fluorosis.<\/p>\n\n\n\n The CDC reiterated its faith<\/a> in the health benefits of fluoride in 2015, naming water fluoridation one of the \u201c10 Greatest Public Health Achievements of the 21st Century.\u201d<\/p>\n\n\n\n Now, though, environmental health experts say health agencies need to reassess the risks and benefits of fluoride, because of its potential neurotoxicity.<\/p>\n\n\n\n \u201cThe evidence is sufficient. It\u2019s not definitive,\u201d says Dr. Bruce Lanphear, an epidemiologist and professor at Simon Fraser University in Canada. Lanphear wrote a commentary on the new paper, and one of his studies was included in the review, but he was not involved in the report\u2019s conclusions.<\/p>\n\n\n\n \u201cWe need to pause,\u201d he said. \u201cWe need to review the evidence, rather than just stick their head in the sand.\u201d<\/p>\n\n\n\n In a separate commentary on the study, Dr. Steven Levy, a professor of preventive and community dentistry at the University of Iowa, questions the conclusions of the research and the way JAMA Pediatrics is presenting them, since the study itself doesn\u2019t talk about the rounds of reviews and the delay in its public release.<\/p>\n\n\n\n Levy says that just publishing the meta-analysis of human studies doesn\u2019t give readers important context about animal studies conducted by the National Toxicology Program, which found no apparent decrease in learning and memory in rodents exposed to low to moderate fluoride levels. He points out that all of the human <\/strong>studies included in the review were from countries outside the US and that the majority are classified by the study authors as having a high risk of bias.<\/p>\n\n\n\n \u201cThus, despite the presentation of some evidence of a possible association between IQ and high fluoride levels in water, there is no evidence of an adverse effect at the lower fluoride levels commonly used in [community water fluoridation] systems,\u201d he wrote.<\/p>\n\n\n\n The study authors agree with him on that point.<\/p>\n\n\n\n In a statement, they say they didn\u2019t have enough data to know whether the level of fluoride that\u2019s recommended for drinking water has any effect on children\u2019s IQ.<\/p>\n\n\n\n The new review includes 74 studies from 10 countries. Most of the studies \u2013 45 \u2013 come from China, where researchers first noticed differences in intelligence between communities exposed to high fluoride levels and those that were not.<\/p>\n\n\n\n Researchers then picked apart the methods of each study, looking at factors like the age of the children who were involved, how they were tested for intelligence and how researchers measured their exposure to fluoride, whether they estimated it from less exact metrics like amount of fluoride in the water where they lived, or whether it came from more precise measures such as lab testing fluoride in urine.<\/p>\n\n\n\n Some of the strongest <\/strong>studies, from Canada and Mexico, looked at measures of fluoride in the urine of pregnant women and then tested the IQ of their children years later.<\/p>\n\n\n\n <\/a><\/p>\n\n\n\n <\/a><\/p>\n\n\n\n Related article<\/strong>RFK Jr. says fluoride is \u2018an industrial waste\u2019 linked to cancer, diseases and disorders. Here\u2019s what the science says<\/a><\/p>\n\n\n\n The researchers sliced the data in three meta-analyses, or studies of studies.<\/p>\n\n\n\n In their first study, which included nearly 21,000 children from 59 studies, they found significant differences in IQ between children with the highest and lowest fluoride exposures. Children exposed to the highest fluoride levels scored about 7 points lower on IQ tests than those exposed to the lowest fluoride. When researchers restricted their analysis to only the highest-quality studies, the difference remained, though it was not as large: about 3 IQ points.<\/p>\n\n\n\n In a second analysis of studies with group-level measurements of fluoride in urine and water, the researchers found a slightly more than 2-point drop in IQ between the highest and lowest fluoride levels. When they restricted their analysis to the four studies with the lowest risk of bias in their data, they found that children drinking water with 2 parts per million of fluoride had IQ scores that were almost 5 points lower, on average, compared with those who weren\u2019t exposed to lower levels. When the researchers looked at water below 1.5 parts per million, however, there were no significant differences in IQ.<\/p>\n\n\n\n In a group of four studies with a low risk of bias that reported group-level measures of fluoride in urine, they found that people with less than 1.5 parts per million in their urine \u2013 a measure of all the sources they consume, not just water \u2013 had IQ scores that were about 1 point lower on average than those exposed to lower levels.<\/p>\n\n\n\n In a final meta-analysis of studies that reported individual measures of fluoride in urine and IQ scores in nearly 4,500 children, they found that a 1 part per million increase in fluoride was linked to a 1.63 drop in IQ score.<\/p>\n\n\n\n Lanphear says the consistency of the finding is striking across all these analyses.<\/p>\n\n\n\n \u201cChildren who had higher fluoride exposure \u2013 whether that was measured with fluorosis, which is kind of a crude measure, or fluoride in water or fluoride in urine \u2013 they found consistent evidence that higher exposure was associated with diminished IQ,\u201d he said.<\/p>\n\n\n\n Lanphear was involved in a particularly influential study<\/a> from Canada that was published in JAMA Pediatrics in 2019. The conclusions were so surprising, the editors of the journal attached a note to the study<\/a> letting their readers know that they carefully considered whether to publish it.<\/p>\n\n\n\n![\"20241121-data-fluoride-FINAL.jpg\"\/](\"https:\/\/media.cnn.com\/api\/v1\/images\/stellar\/prod\/20241121-data-fluoride-final.jpg?c=16x9&q=h_144,w_256,c_fill\")
<\/a><\/figure>\n\n\n\nStudy findings<\/h2>\n\n\n\n
![\"Kennedy](\"https:\/\/media.cnn.com\/api\/v1\/images\/stellar\/prod\/2024-08-23t193953z-977736823-rc2ul9a8rv4w-rtrmadp-3-usa-election-kennedy.JPG?c=16x9&q=h_144,w_256,c_fill\")
<\/a><\/figure>\n\n\n\nA consistent link<\/h2>\n\n\n\n