The National Toxicology Program (NTP) on Wednesday this week released a draft report linking prenatal and childhood fluoride exposure to reduced IQ in children, after public health officials tried for almost a year to block its publication.

The US Department of Health and Human Services (HHS) and the Centers for Disease Control and Prevention (CDC) initially blocked the NTP from releasing the report, according to emails obtained via a Freedom of Information Act (FOIA) request.

But a court order stemming from a lawsuit filed by Food and Water Watch against the US Environmental Protection Agency (EPA) forced the report’s release this week.

The NTP, an interagency program run by HHS that researches and reports on environmental toxins, conducted a six-year systematic review to assess scientific studies on fluoride exposure and potential neurodevelopmental and cognitive health effects in humans.

The report, containing a monograph and a meta-analysis, went through two rounds of peer review by the National Academies of Sciences, Engineering, and Medicine. Comments from reviewers and HHS and NTP’s responses also were included in the report released on Wednesday.

According to its website, the NTP “removed the hazardous classification of fluoride” in response to comments in the peer-review process. Yet, the report states: “Our meta-analysis confirms results of previous meta-analyses and extends them by including newer, more precise studies with individual-level exposure measures.

“The results were robust to stratifications by risk of bias, gender, age group, outcome assessment, study location, exposure timing and exposure type (including both drinking water and urinary fluoride).”

“These findings fly in the face of the empty, unscientific claims US health officials have propagated for years, namely that water fluoridation is safe and beneficial,” said Robert F. Kennedy Jr, Children’s Health Defence chairman and chief litigation counsel. “It’s past time to eliminate this neurotoxin from our water supply.”

The controversial report will play a key role in determining the outcome of a lawsuit brought in 2017 by several non-profits against the EPA to end fluoridation of drinking water, plaintiffs’ attorney Michael Connett told The Defender.

“We had to fight hard to have this report even made public,” Connett said. “They [CDC and HHS] buried this. If they had gotten their way, this report would have never even seen the light of day,” Connett said.

Since the trial began in 2020, US District Judge Edward Chen has been waiting for the NTP to complete a systematic review of fluoride’s neurotoxicity before ruling on the case. Groups like the American Dental Association publicly pressured the NTP to “exclude any neurotoxin claims” from the reports.

Connett said during the trial, the EPA repeatedly claimed that the plaintiffs’ allegations about toxicity could not be verified because there was no “systematic review.”

The documents released Wednesday fill that gap.

Connett said, “So now what do we have? We have a systematic review by one of the pioneering, leading, most authoritative research groups on toxicology in the world.

“They just completed a systematic review that took them six years to complete, so if that’s not enough to demonstrate a hazard under the toxic substances control act, then how would any citizen group ever be able to meet the standard?”

According to the NTP report, “The current bodies of experimental animal studies and human mechanistic evidence do not provide clarity on the association between fluoride exposure and cognitive or neurodevelopmental human health effects.”

Yet, the report’s summary contradicts this statement by summarizing the evidence informing this conclusion, stating that nearly all studies examined for this literature review found evidence of cognitive or developmental issues associated with fluoride.

According to the report, eight of nine “high-quality studies examining cognitive or neurodevelopmental outcomes reported associations with fluoride exposure.”

Of the 19 high-quality studies assessing the association between fluoride and IQ in children, 18 reported an association between higher fluoride exposure and lower IQ in children. Forty-six of the 53 low-quality studies also found evidence of that association.

The meta-analysis also states, “The body of evidence from studies on adults is also limited and provides low confidence that fluoride exposure is associated with adverse effects on adult cognition. There is, however, a large body of evidence on IQ effects in children.”

The monograph and meta-analysis found that fluoride exposure at levels equivalent to 1.5 mg/L is associated with lower IQ in children. The abstract concludes: “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 mg/L of fluoride) is consistently associated with lower IQ in children.”

Levels of fluoride found in drinking water in the US are typically 0.7 mg/L, which is lower than the 1.5 mg/L levels found to be neurotoxic by the reports.

On that basis, HHS’ review of the reports recommended the NTP revise its assessment such that, “all conclusory statements in this document should be explicit that any findings from the included studies only apply to water fluoride concentrations above 1.5 mg/L.”

The NTP responded, “We do not agree with this comment. Our assessment considers fluoride exposures from all sources, not just water.

As discussed in the pre-publication 2022 NTP Monograph, because fluoride is also found in certain foods, dental products, some pharmaceuticals, and other sources, individual behaviours are likely an important determinant of actual exposures.”

Rick North, former CEO of the American Cancer Society’s Oregon division and Fluoride Action Network board member told The Defender that “people consume large amounts of fluoride through tea and other drinks and processed foods made with fluoridated water, not to mention pesticide ingestion and fluoride from air pollution.”

He also said that people’s fluoride exposure can depend on how much water they drink.

“Think about it,” North said. “Your level of risk depends upon, incredibly, how thirsty you are. That’s how absurd the entire premise of water fluoridation is,” he said.

The NTP confirmed that people exposed to levels of fluoride lower than 1.5 mg/L in the water system could have high levels of fluoride in their systems. It stated:

“Even in the optimally fluoridated cities [fluoridated at 0.7 mg/L] in Canada studied by Green et al. (2019), individual exposure levels, as documented by repeated urinary measurements, suggest widely varying total exposures from water combined with fluoride from other sources.”

It added, “Our moderate confidence conclusion is primarily based on studies with total fluoride exposure that approximates or exceeds what is generally associated with consumption of optimally fluoridated water [0.7 mg/L] in the United States.”

“We have stressed in our monograph that our conclusions apply to total fluoride exposures rather than to exposures exclusively through drinking water.”

“What the NTP is pointing to here is that in some communities, where the dose of fluoride in the water is 0.7 mg/L, the NTP has found levels of fluoride found to be associated with lower IQ,” Connett told The Defender.

• The Defender / By Brenda Baletti, a reporter for The Defender