Tag Archives: neurotoxic

Another embarrassment for anti-fluoride campaigners as neurotoxic claim found not to be justified

Anti-fluoride campaigners have made the classic mistake of promoting claims based on a draft report. Now peer reviewers have found the claim unjustified and the report will be rewritten. But will the anti-fluoride brigade stop making the claim?

Anti-fluoride campaigners have just lost another of their propaganda claims with the release of a US National Academies of Science (NAS) peer review of the recent National Toxicity Program’s (NTP) draft monograph discussing fluoride exposure and neurotoxicity.

Ever since the release of this draft last October anti-fluoride campaigners have been making hay out of this statement on page 2 of the draft (and repeated several times in its text):

“Conclusions: NTP concludes that fluoride is presumed to be a cognitive neurodevelopmental hazard to humans.”

In general, these campaigners have presented this conclusion as a finding of the NTP, even though the draft includes this statement on every page:

“This DRAFT Monograph is distributed solely for the purpose of pre-dissemination peer review under the applicable information quality guidelines. It has not been formally disseminated by NTP. It does not represent and should not be construed to represent any NTP determination or policy.”

In a clear case of counting eggs before they hatch, the anti-fluoride campaigners now face the embarrassment of losing this claim because the NAS peer reviewers have found the conclusion is not supported by the evidence presented in the draft report. The NAS press release announcing the results of their peer review clearly says:

It “does not find that NTP has adequately supported its conclusion that “fluoride is presumed to be a cognitive neurodevelopmental hazard to humans.”

For readers wanting more detail these are the relevant documents:

Anti-fluoride activists response to the NAS peer review

The peer review has been out for only a few days and the anti-fluoride propagandists on social media have already denounced it (without reading it in most case) as only one committee’s opinion. Or they have indulged in the straw-clutching of quoting the NAS peer review’s sentence after the one that found the conclusion fo the NTP report was not supported. This says.

“The committee emphasized its finding does not mean that the NTP’s conclusion is incorrect; rather, further analysis or reanalysis is needed to support conclusions in the monograph.”

Perfectly normal for a scientific assessment and, in this case, a bit of a face-saver for the NTP (in many of its details the NAS peer review is quite scathing). And if the NTP has done a reasonable job of accessing the literature we all know that no “further analysis or reanalysis” will magically support the draft claim.

But, as an indication of the embarrassment of these people the “authoritative” comment on the peer review from Paul Connett, leader of the anti-fluoride US activist group Fluoride Action Network (FAN) almost reads like an endorsement of the peer review. Despite FAN having originally stressed the faulty NTP draft conclusion that “fluoride is presumed to be a cognitive neurodevelopmental hazard to humans” Connett does not even mention the NAS finding in his press release (see Federal report finding fluoride lowers IQ of children reviewed by National Academy of Sciences.“) Strangely he quotes: “The NAS emphasized its finding ‘… does not mean that the NTP’s conclusion is incorrect.'” without even saying what that conclusion was.

The rest of Connett’s comments amount to spin – putting a brave face on his disappointment at this major loss. His claim that “The NAS suggestions should strengthen the draft report’s conclusion that fluoride is a presumed neurotoxin in children” is fanciful given that the material reviewed by the NTP simply does not support this claim.

He is also attempting diversion with his claim “The NAS review has been misinterpreted by fluoridation defenders. The NAS did not independently review the scientific evidence but instead limited itself to comments on whether the NTP clearly and thoroughly explained their methods” The fact is very few comments have been made by “fluoridation defenders” yet – the peer review has been public for only a few days – barely enough time for busy scientists to get around to reading it. And I have not seen a single person claim that the NAS peer reviewers “independently reviewed the evidence.”

What was required of the peer review?

The peer review report makes their action and purpose very clear. They were not tasked with making an independent review of the literature but their job went a lot further than limiting themselves to “comments on whether the NTP clearly and thoroughly explained their methods”

The NTP Project Information document Peer Review of the NTP Monograph on Systematic Review of Fluoride Exposure and Neurodevelopmental and Cognitive Health Effects) provided a list of requirements for the peer reviewers who were asked to address the following questions:

  • Has the systematic review protocol been followed and modifications appropriately documented and justified?
  • Does the monograph accurately reflect the scientific literature?
  • Are the findings documented in a consistent, transparent, and credible way?
  • Are the report’s key messages and graphics clear and appropriate?  Specifically, do they reflect supporting evidence and communicate effectively?
  • Are the data and analyses handled in a competent manner?  Are statistical methods applied appropriately?
  • What other significant improvements, if any, might be made in the document?
  • Does the scientific evidence in the NTP Monograph support NTP’s hazard category conclusions for fluoride in children and adults?”

The NAS peer reviewers clearly answered the last question with an emphatic No! This is not changed by the desperate straw clutching of propagandists who quote the (inevitable and polite) qualification that a further “further analysis or reanalysis” might provide support. Nor is it changed by Connett simply refusing to acknowledge or comment on that very important finding of the peer review committee.

Other findings of the NAS peer reviewers

The NAS peer review report is quite extensive (it’s 48 pages long) and covers several other important issues besides its rejection of the main conclusion. Issues related to how good the original protocol was and how closely it was followed, bias resulting from incomplete consideration of all the findings (negative as well as positive) and selection in the literature considered, issues related to statistical analysis and presentation, and problems with accounting for the range of different fluoride exposure measures and outcome parameters.

I might return to some of these issues later as I think they are relevant to other reviews in this area – especially the recent review of Grandjean (2019) – Developmental fluoride neurotoxicity: an updated review. This has similar faults – and some extra faults of its own.

But it is clear that in it’s current form the draft NTP report is not credible. Its conclusion is flawed and there are a number of other problems. It will have to be extensively rewritten to take the peer reviewers comments into account. I look forward to the new, and hopefully much better, version.

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