Health Canada study found 'strong evidence' fluoridated water could lower children's IQ

A study commissioned by Health Canada that found "strong evidence" that water fluoridation could lower children's IQ has become a point of debate in a lawsuit to stop water fluoridation in the US.The peer-reviewed journal Critical Reviews in Toxicology published the study on February 6. According to Children's Health Defence, Health Canada commissioned a team of scientists who reviewed available literature on the effects of fluoride on human health. However, the agency only published a summary in June of 2023.The goal of the study was to "develop a point of departure (POD) for setting a health-based value (HBV) for fluoride in drinking water." The HBV would indicate at what concentrations fluoride would present a risk. The review identified 89 human studies, 199 animal studies and 10 major in vitro reviews. In all, 39 alleged health consequences were examined."In addition to dental fluorosis, evidence was considered strong for reduction in IQ scores in children, moderate for thyroid dysfunction, weak for kidney dysfunction and limited for sex hormone disruptions," the authors said."A POD of 1.56 mg fluoride per litre for moderate dental fluorosis may be preferred as a starting point for setting an HBV for fluoride in drinking water to protect against moderate and severe dental fluorosis. Although outside the scope of the current review, precautionary concerns for potential neurodevelopmental cognitive effects may warrant special consideration in the derivation of the HBV for fluoride in drinking water."Fluorosis is a condition where overexposure to fluoride during developmental years leaves white or brown stains on the teeth.The review found 17 studies from 2016 to 2022 of "of high or acceptable quality were identified, which reported a positive/possible association between reduced IQ scores and water fluoride.""The cumulative body of evidence suggests a positive association of reduced IQ scores for children and fluoride exposures relevant to current North American drinking water levels."The researchers calculated the hazard level or toxicological point of departure for observable effects of fluoride on IQ was 0.179 milligrams per litre (mg/L) in water. However, the authors said data at that low range had significant uncertainty and would benefit from further investigation.According to Children's Health Defence, levels of fluoride found in drinking water in the US and Canada typically are in the higher range of 0.7 mg/L.Following the study, Health Canada issued an expert panel summary report in June 2023. It reported a “growing body of evidence suggests that fluoride in drinking water may be associated with reduced IQ scores in children at fluoride levels that may be found in Canadian drinking water" but added, “questions remain regarding whether the weight of evidence supports a causal relationship.”The summary report and the full study were the subjects of submissions and testimony in a trial in the US Food & Water Watch, Fluoride Action Network, Moms Against Fluoridation and other groups and people are suing the Environmental Protection Agency to make them prohibit water fluoridation in the US due to fluoride’s toxic effects on children’s developing brains.The US National Toxicology Program (NTP) report that linked fluoride exposure and lower IQ in children set the hazard level at 1.5 mg/L, but one of the key studies at the center of the trial set the level at 0.2 mg/L.The lawsuit is being brought under the Toxic Substances Control Act (TSCA), which regulates the legal levels of human exposure to toxic substances such as lead.David Savitz, an epidemiology professor at Brown University, was part of the expert panel that advised Health Canada on how to interpret this study and other data. The EPA called Savitz as a witness because he was also part of the National Academies of Sciences, Engineering and Medicine (NASEM) expert panel that reviewed the NTP report linking fluoride exposure to lower IQs in children.NASEM and the NTP authors did not agree on all changes to the report suggested in NASEM’s review. The NTP’s Board of Scientific Counselors adjudicated final changes, but their report remains unpublished.Savitz served on the Health Canada panel at the same time that he was a paid consultant to the EPA in the lawsuit, and was called to testify in support of the EPA’s position that water fluoridation should continue in the US.Steven Levy, a member of the American Dental Association’s National Fluoridation Advisory Committee, was also on the five-person Health Canada panel. In October 2021, he helped convince the City of Tama, IA to reinstate water fluoridation."I emphasized the caries-preventive benefits and the safety of community water fluoridation," Levy told American Dental Association News. "Those in low-socioeconomic status households and otherwise undeserved will be hurt the most. Community water fluoridation helps all ages and it is the most cost-effective approach to caries prevention."

Health Canada study found 'strong evidence' fluoridated water could lower children's IQ

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