USA: NTP Ties Fluoride To Childhood IQ Loss, Bolstering Plaintiffs’ TSCA Suit

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USA: NTP Ties Fluoride To Childhood IQ Loss, Bolstering Plaintiffs’ TSCA Suit

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NTP Ties Fluoride To Childhood IQ Loss, Bolstering Plaintiffs’ TSCA Suit

InsideEPA.com - March 15, 2023

By David LaRoss

The National Toxicology Program (NTP) has quietly unsealed its 2022 draft report on fluoride toxicity, publishing for the first time its finding “with moderate confidence” that common drinking water fluoridation levels are associated with drops in childhood IQ -- a conclusion environmentalists plan to use in their suit seeking TSCA limits on fluoridation.

“This review finds, with moderate confidence, that higher fluoride exposure (e.g., represented by populations whose total fluoride exposure approximates or exceeds the World Health Organization Guidelines for Drinking-water Quality of 1.5 [milligram per liter (mg/L)] of fluoride) is consistently associated with lower IQ in children,” NTP says in the abstract of its nearly 1,600-page draft report, posted to its website on March 15.

But the federal health agency added that “More studies are needed to fully understand the potential for lower fluoride exposure to affect children’s IQ.”

NTP has long resisted publishing any drafts of the report, which has gone through several cycles of revision and peer review over several years -- including a downgrade from a unified “monograph” to a “state of the science” report avoiding conclusions on hazard and separate meta-analysis, following a critical National Academies of Science, Engineering and Medicine (NASEM) peer review.

But the agency agreed to release the most recent version as part of anti-fluoridation groups’ long-running Toxic Substances Control Act (TSCA) suit, Food & Water Watch, Inc. (FWW), et al. v. EPA, after the plaintiffs and Judge Edward Chen of the U.S. District Court for the Northern District of California identified it as key evidence for an upcoming trial.

FWW and its allies petitioned EPA to regulate fluoride in drinking water under TSCA in 2016, seeking to bar a practice that has long been used to address the public health goal of limiting tooth decay.

The plaintiffs later sued the agency after it denied their request, seeking what would be a landmark, first-time court decision on whether published research supports officials’ refusal to craft a particular TSCA rule.

In particular, due to the law’s mandate that challenges to petition denials go forward as “de novo proceedings,” Chen is in the novel position of weighing the science himself rather than merely deciding whether EPA’s decisions were reasonable.

However, he has been reluctant to make that decision. The case has so far led to a second petition -- which EPA also denied -- and a bench trial in 2020 where Chen declined to hand down a ruling. He chose instead to stay the case indefinitely to await further research on fluoride toxicity -- most prominently the NTP project.

Chen lifted the stay late last year, agreeing with the plaintiffs that waiting for a final version of NTP’s report could be futile because its timeline has been pushed back repeatedly amid multiple rounds of interagency critique and peer review. The environmentalists claim those decisions were driven by “agencies with strong partisan interests” in continuing drinking water fluoridation, rather than any concerns over the quality of the research.

Although EPA has consistently argued that relying on a draft document would be improper, NTP agreed in February that it would release the 2022 version and associated materials, including its meta-analysis, peer review report and other comments.

The March 15 publication thus clears the way for both sides in FWW to use the draft and supporting documents as evidence in an expected second trial, which Chen has yet to schedule.

Draft Report

According to the 2022 draft, NTP scientists found 72 published studies “directly addressing the relationship between fluoride exposure and children’s IQ,” and identified 19 of those as “high-quality” based on metrics for risk of bias in their conduct, data reporting and study design.

“The results from 18 of the 19 high-quality (low risk-of-bias) studies (3 prospective cohort studies from 2 different study populations and 15 cross-sectional studies from 13 different study populations) that evaluated IQ in children provide consistent evidence that higher fluoride exposure is associated with lower IQ scores,” the draft says.

It notes that specific figures varied between studies, including some impacts that would not be statistically significant on their own but contribute to the broader finding of an association between fluoride exposure and neurological harm.

For instance, describing the cohort studies -- those that tracked a set of subjects over time -- the draft says, “In summary, although not every analysis found a statistically significant association, together the three studies provided consistent evidence that increasing maternal fluoride levels were associated with lower IQ scores in the children.”

Similarly, it says, 15 of the 16 “high-quality” cross-sectional studies -- those that collect data from each subject only once -- “reported a consistent association between fluoride exposure and lower IQ scores in children,” and 14 of those “reported significant associations.”

The draft continues, “Overall, the cross-sectional studies consistently provide evidence that higher fluoride exposure is associated with lower IQ scores in children. Several cross-sectional studies conducted multiple analyses (e.g., reported results for multiple exposure metrics, endpoints, subpopulations). Although some of these variations are heterogeneous and are not comparable across studies, the consistency of the results across multiple metrics contributes to the confidence in the data.”

The document also includes extensive comments from peer reviewers and others, including margin notes addressing individual word choices or lines as well as materials dated from 2021 that relate to NASEM’s letter peer review of a previous draft, most prominently NTP’s responses to the reviewers’ recommendations.

SOURCE:
https://insideepa.com/daily-news/ntp-ti ... -tsca-suit
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