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Richard, any increase in dental fluorosis associated with community water is of only the questionable or very mild form. The more serious moderate and severe forms are associated with excessive F consumption - eating toothpaste etc.
of course, it may not be obvious whether cognitive deficits are caused by toxicants or physiological deficiencies. But it is wrong to restrict one's hypotheses in the way the Granbdjean, Till, Choi group have.
For example, the Swedish research showing a relationship of improved quality of life and income with fluoride concentration in drinking water is an interesting result. It seems to me that a physiological mechanism linking better oral health with success in life (something that I think is obvious) is a more credible mechanism than a claim that increased fluoride somehow magically causes one to earn more in later life.
![accurate-photos-of-fluorosi[1].jpg](https://community.aarp.org/t5/image/serverpage/image-id/53009i93D56F777E179C0B/image-size/large?v=v2&px=999 "accurate-photos-of-fluorosi[1].jpg")
KenP - If you didn't co-author the study on sexual abuse, contact PubMed about the misfile.
https://www.ncbi.nlm.nih.gov/pubmed/?term=Perrott%20KW%5BAuthor%5D&cauthor=true&cauthor_uid=25576911
"In this prospective birth cohort study from 6 cities in Canada, higher levels of fluoride exposure during pregnancy were associated with lower IQ scores in children measured at age 3 to 4 years. These findings were observed at fluoride levels typically found in white North American women. This indicates the possible need to reduce fluoride intake during pregnancy." - Conclusion in Green et al, 2019
"The problem is that it's an uncontrolled dose – everyone is exposed to different levels. It may be prudent for pregnant women to reduce ingesting fluoride during pregnancy.” - Christine Till, PhD (2018)
What advocates of fluoridation fail to take into consideration is that good scientists should take care to report data and facts, and although they can draw conclusions within the confines of the data, scientists should neither dictate medical treatment nor stray beyond what the data reveals. This is what Dr. Till is doing.
The other item that fluoridationists seem to have a problem with is that using municipal water to mass medicate the population is a violation of individual medical consent and as such constitutes medical assault on those who object or who are ignorant of the harm caused them, i.e. the unborn.
FLUORIDATION ADVOCACY ORGANIZATIONS - (on AARP)
Johnny Johnson is the president of the American Fluoridation Society, a 501(c)(3), created in 2015 to promote fluoridation policy. Apparently the AFS has assetts in excess of $100k. The same membership created the American Fluoridation Institute, a 501(c)(4), in 2019, apparently for further financial benefits and lobbying opportunities.
Ken Perrott directed me to his other published fluoride related document (an opinion piece claiming that kids with dental fluorosis likely do badly in school because they disengage due to embarrassment over their unatractive teeth instead of because of neurological damage). His conflict of interest statement on that paper states that KenP's affiliation is Making Sense of Fluoride which he writes is an incorporated society in New Zealand that focuses on community water fluoridation.
The 3rd article that comes up in PubMed under KenP's name is not about fluoridation. This 1998 article is about coping mechanisms of those who experienced childhood sexual abuse. The author (KenP says it's a different KenP) proposes that reframing the abuse is generally a positive strategy. That is interesting because the language and approach our KenP uses in fluoridation reframes the discussion and fluoridationist lobbyists emphasize changing the topic to 'win' the debate, i.e. 'reframing.'
CarryAnne, you say:
"What advocates of fluoridation fail to take into consideration is that good scientists should take care to report data and facts, and although they can draw conclusions within the confines of the data, scientists should neither dictate medical treatment nor stray beyond what the data reveals. This is what Dr. Till is doing."
I suspect you did not mean what you wrote at the end of this, although I agree that in her promotion of this work Christine Till is not behaving as an objective scientist.
I have no illusions about the politics of science and have written about it specifically regarding Till's work - see Politics of science – making a silk purse out of a sow’s ear.
Specifically, I am concerned that while she is definitely aware of the work of Huber et al (2015) and Perrott (2018) showing the relationship of ADHD prevalence to altitude and the lack of a relationship with fluoridation when this is considered she and her coauthors studiously ignore that research in their discussion.
I am also concerned that she appears to have responded to this be studiously refusing to include the full statistical analyses in the more recent papers. While this covers the fact that the reported relationships are extremely weak and therefore meaningless I do concede that she and her co-authors have published the data allowing others to do their own analyses. I suspect, though, that she will continue to ignore these critiques.
It is concerning that she and her coauthors also studiously refused td to comment on the fact their own figures show no effect of community water fluoridation on child IQ in the Green et al study. See the data extracted from their Table 1 [please ignore the (SD)].
This is even more concerning because anti-fluoride campaigners have made claims completely in conflict with that data and, so far, Till has not repudiated those claims. See this recent billboard:
Finally, I am concerned at the poolcy of the journal where Green et al published. It now appears that it will not publish critiques or responses to the paper (They have a 4-week deadline) and this is sad because it interferes with peer review - I strongly believe that scientific peer review should continue after publication - see We need more post-publication peer review and that policy makes this far more difficult.
It is sad that the journal editor could only see discussion of this research in the non-scientific media instead of his journal.
CarryAnne, I will just remind you of an important quote you presented here:
“When studying any matter, ask yourself two things: what are the facts and what is the truth that the facts bear out. Never let yourself be diverted by what you wish to believe, or what you think would have beneficent social effects if it were believed. Look only and solely at what are the facts.” - Bertrand Arthur William Russell, logician and Nobel laureate on evidence and data analysis (1959)
As I said at the time this is so true. And in fact, that is the attitude all credible scientists take - to look at the evidence, data, discussion, logic. Not rely on "authority" statements, promotions, unsupported claims, etc.
This is the attitude I take so, please, be aware that your continued resorting to "authority" statements mean nothing to me. Show me the data.
And in this respect, this data from Green et al is what should be discussed - especially the huge scatter of the data and the fact the best fit line is meaningless in terms of prediction.
I am glad you accept the fact shown in Perrott (2018) that inclusion of elevation in the regression of Marlin & Till (2015) shows that fluoridation has absolutely no effect. Of course, this does not prove a cause for elevation - but it does show that the relationship reported by Malin & Till was false.
Of course, if you prefer opinions instead of intelligently considering the evidence that is your prerogative and, while it is unscientific, it is the usual approach anti-fluoridationists take. But one can select opinions to suit any bias.
In the end, the only thing of value is the data.
[Incidentally, I have several other peer-reviewed publications on fluoride - look them up - one of them relevant to IQ - Perrott, K. W. (2015). Severe dental fluorosis and cognitive deficits. Neurotoxicology and Teratology, 48, 78–79.]
CarryAnne, Love the quote from Betrand Russell. Sums up my whole approach. Facts, data, evidence are what should ground us.
As you will notice this has been my whole approach in this and other discussions. I have approached my analysis of the Green et al. paper by looking at, and dealing with, the data. I am not influenced by authority statements - either from the author, coauthors, editor or those who had early access to the paper and set out to promote it.
An Editorial note is unprecedented, as this editor specifically said. it is not something I have come across before in my extensive research and publication experience.
I have written in detail about the handling of the data - I obviously do not agree with your unsupported claim this was "impeccable." But then again I deal with the facts, evidence, data - not personal "authority" assurances. And the fact that the editorial review was contentious (and the editor specifically mentioned contentious statistical review) surely supports my point.
Yes, the mean IQ values provided in Table 1 are not "adjusted" - how could they be. They are plain means, not the result of a regression model.
Yes, in the regression model adjustment for other confounders did influence the association or coefficient - it reduced it (from -2.6 to -1.95 for all children, from -5.01 to -4.49 for boys and about the same 2.23 to 2.40 for girls).
This is quite normal. When a model includes a range of risk-modifying factors that influence the outcome the correlation coefficients for a particular factor is reduced compared for unadjusted regressions. Sometimes, as in the case of the Malin & Till (2015) ADHD paper, adjustment actually removes an association completely. (In this case, their reported association of ADHD with fluoridation disappeared completely when the altitude was included in the adjustment - see Perrott, K. W. (2018). Fluoridation and attention deficit hyperactivity disorder a critique of Malin and Till (2015). British Dental Journal, 223(11), 819–822).
Apart from the fact that reference to adjustment is irrelevant to simple mean values it is surely straw grasping to talk about adjustment in the vain hope of converting a non-significant difference into a large difference. But I notice a few anti-fluoride campaigners are now starting to attempt this with a vague reference to "adjustment."
More worrying to me is the fact that the authors did not even refer to that specific data in their discussion. If there was an argument based on "adjustments" that would have been the place for it to be made.
But another, more political, point. There is nothing in the Green et al study to justify the claims of anti-fluoride campaigners in New Zealand that the study shows that "Fluoridated water lowers kid's IQ." Quite the opposite. That claim is completely wrong and will probably lead to action from our advertising authority. It is false scaremongering - probably why several local authorities have ordered the offending billboards be taken down.
Your claim that I have only concentrated on the mean values form the papers Table 1 is completely wrong. I have spent some time showing that the regression analysis used by Green et al produces a best-fit line explaining only 1.3% of the variance in IQ. This is a fundamental and important point. This, together with the suspect nature of the regression (the data was not normally distributed so probably violated an inherent assumption) means that the much-touted value of the regression coefficient is meaningless. A simple look at the figures published in the paper confirms that assessment (see below). How could the much-touted coefficient of 4.49 predict the real values?
CarryAnne, I do not see you engage properly with any data. You instead rely almost exclusively on "authority" statements. While that is normal for anti-fluoride campaigners it is extremely poor behavior for any scientists. In fact, it is not at all scientific.
I leave you with this graph from the Green et al. (2109) paper which surely shows that the claims based on the best-fit line have absolutely no predictive power. They are meaningless. It is surely significant that the anti-fluoride campaigners promoting and misinterpreting this paper never show this data.
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