Tag Archives: Calgary

Fluoridation science and political advocacy – who is fooling who?

misinformation

It is a false balance to equate the advocacy of scientific and medical experts concerned with truth and child health to the advocacy of ideologically-motivated anti-fluoride and anti-vaccination activists known for their misrepresentation of science. Credit: World Congress for freedom of scientific research

I thank Dr Ghali for taking up my offer of a right of reply to my article Scientific integrity requires critical investigation – not blind acceptanceThis sort of discussion is important and I am pleased he took the time to read my article.

Unfortunately, he did not respond to my point about the need to critically examine research findings and claims. Or my point that he seemed to be attempting to “sweep aside” critical reviews which are inherently part of the scientific process. His characterisation of the letter sent by 30 academic and health experts to the US National Institute of Environmental Health Science (NIEHS) about the  Green et al (2019) study (see Experts complain to funding body about quality of fluoride-IQ research) was unjust and simply avoided the necessary discussion.

However, in his reply, he raises a new issue that is worth discussion. That of how scientists should respond to “advocacy positions.”

Equating political and scientific/health advocacy

He says:

“. . we tried in our presentations to shed some light on the controversy, and to show how advocacy positions have focused on attacking both the evidence on benefits of fluoride (e.g., the multi-pronged attacks on Lindsay McLaren’s study on CWF), and the more recent evidence on potential negative cognitive effects in developing brains.”

This characterisation falls into the trap of equating the advocacy of anti-fluoride activists, organisations like the Fluoride Action Network (FAN) and Fluoride Free NZ (FFNZ), who are well known for distorting and misrepresenting the science, with scientific and medical experts who are attempting to present a good faith expert scientific interpretation and critique of current research.

I believe this is a dangerous position because it comes across to policymakers as saying the scientists disagree with each other, that there is not a majority consensus,  and equates the standard of science presented by both sides. This impression is, of course, very much favoured by political activists because it is an easy way of discrediting scientific information, of avoiding the need to properly and objectively consider the information.

I saw this myself when the fluoridation issue was being considered by the local Hamilton City Council in 2013. Councillors were clearly not up to the job of considering the science (and why should they be) so reacted to any attempt to present scientific details by arguing that “scientists disagree with each other,” that there are “two sides to the science.” In the end, they even based their decision on things like the number of submissions as the deciding factor instead of on the science.

Incidentally, the voters in Hamilton did not let the council get away with such a sloppy disregard for the science and of their own previously expressed majority support for fluoridation. A new referendum was demanded and the result confirmed that of the previous referendum showing 70% support for community water fluoridation.

I cannot understand why Dr Ghali promotes this understanding – even to the extent of appearing to favour those who misrepresent the science above those who are attempting a good scientific critique. For example, he describes the anti-fluoride activist attacks on the science merely as “strong” and “rooted in positional anti-fluoride advocacy,” while he refers to “the unusually vigorous attacks on the fluoride cognition studies” and argues these are “seemingly rooted in the challenging findings of those studies. “

Interpreting normal scientific critique as an “attack”

Dr Ghali specifically mentions the fluoridation cessations study of McLaren et al (2016) as being strongly attacked. Part of that “strong attack” was a published critique of FAN members – Neurath et al (2017) – the sort of critique fully acceptable and expected in the scientific community. McLaren et al., (2017) in turn responded to that critique. Again a normal and necessary process in science. In fact, the opening sentence in this response was:

“Thank you for the opportunity to respond. We are pleased to see thoughtful debate in the peer‐reviewed literature and agree that careful consideration of study limitations can stimulate improvement.”

That is how such critiques should be dealt with – welcomed and responded to. That should have been the way to respond to the critique of the 30 scientific and medical experts who responded to the Green at al (2019) study in their letter (see Experts complain to funding body about quality of fluoride-IQ research).

Yet  Dr Ghali’s response to that letter was:

  • He described it as “The notion that you can just talk away 10 years of research.”
  • He leapt to an emotional defence of the authors of the Green study, saying: “I respect the doers of the research and the deliverers of the evidence and don’t think they should be shot for tough messages.”
  • He uses phrases like  “once published it can’t be unpublished” and refers to this critique as “sweeping aside because one disagrees.”
  • And in his response here (see Scientific integrity & fluoridation – Dr Ghali responds) he reverts to this emotional rejection of the normal scientific critique saying  he could not “pretend that the new studies do not even exist or that they are fatally flawed with irrelevant results.”

Ignoring the real political attacks on the science

But where is his emotional response to the way anti-fluoride activists have resorted to disgusting personal attacks on Lindsay McLaren for her work? That is surely unacceptable in any scientific discussion

An example of the personal attacks on Lindsay McLaren for her fluoridation cessation work. Source: Why the anti-fluoride haters are attacking a Calgary academic, calling her a ‘fraud’

Or to the way that these activists have misrepresented and distorted the findings of the Green et al (2019) study?

Image used in advertising campaigns of FAN and FFNZ which completely misrepresents the scientific findings.

This sort of scaremongering advertising has appeared quite widely in newspapers and public billboards in New Zealand and caused a lot of concern among health professionals and their patients.

Who is advocating for what?

The political position of the anti-fluoride activists is clear – they advocate to end fluoridation or prevent it where it is being considered. This advocacy comes from ideological positions as can be seen with their alliance with anti-vaccination activists in Health Liberty and their funding by the “natural”/alternative health industry (eg., Mercola.com and the NZ Health Trust and see Big business funding of anti-science propaganda on health).

But it is simply wrong to put the advocacy of scientific and medical experts as operating at the same level. This is made clear in the letter from the 30 experts (that Dr Ghali dislikes) which says in its summary:

“The aim of science is to gain a better understanding of our natural world and to build a shared knowledge base for the benefit of all. Every scientist is interested in the truth. If fluoride at common levels of maternal exposure does lead to lower IQ scores, we would certainly want to know. This is why transparency related to the Green article is crucial.”

To be clear – the scientific and medical experts are advocating for good science and the health of the public, especially children. That is what drives their legitimate demand for transparency in the science.

So, I think Dr Ghali is disingenuous to present a false balance between the arguments of scientific and medical experts and the ideologically-driven anti-fluoride activists. He is wrong to treat scientific and medical experts as just another “advocacy group” like FAN. And he is especially wrong to use this false balance to ignore or discredit normal scientific critique which is so essential to good science.

Dr Ghali falsely equates the advocacy of anti-fluoride activists as illustrated by this scaremongering billboard with the advocacy of medical and scientific experts who are concerned about child health and want to know the truth.

Dr Ghali’s characterisation of the new fluoride cognitive studies

I also find the way Dr Ghali’s presentation of both the recent cognitive studies and the expert discussion of them disturbing. he says:

“The new cognition studies (led, interestingly, by two Canadian public health research teams) and the ensuing NTP draft report from the US are now such that it would have been absurd for us to pretend that the new studies do not even exist or that they are fatally flawed with irrelevant results.”

Who the hell is pretending that these studies do not exist? How is a rational, good-faith scientific critique of these studies pretending they “do not even exist?”

As for the question of the possibility these studies “are fatally flawed with irrelevant results,” how can anyone ever decide that question if the scientific critique of the studies is not permitted – or thoughtlessly, even emotively, disregarded?

Even Dr Ghali admits these studies have limitations (although I am unaware of any discussion by him of those limitations). Surely an honest scientific discussion of the is work requires a discussion of these limitations – and that is exactly what the letter from the 30 experts did. It listed ten important limitations – yet Dr Ghali wishes to dismiss the letter. He has certainly shown no interest in considering the specific limitations of the study.

These limitations may well mean the results are irrelevant to the question of community water fluoridation. I have argued that in several articles. I think the conflicting and contradictory results from the different papers and different databases (ELEMENT in Mexico City, MIREC in Canada, INMA in Spain, and NHANES in the USA) do suggest the quality of the results mean they should not directly influence health policy. I have also raised the issue of naive presentation of statistical analysis, reliance only on p-values with no discussion of the small size of the effects as indicated by the inability of the relationships to explain more than a few per cent of the variance in cognitive factors. There is also the problem of using a large number of factors with the inevitable p-hacking – a problem which, I believe, is actually quite widespread in science and needs to be countered.

Dr Ghali appears to argue that these new studies are not fatally flawed despite acknowledging they have “limitations” and that the results of the studies are relevant to CWF. But how can he come to that conclusion without making an objective analysis of the study’s methodology, considering the weak nature of the relationships reported? He is certainly not performing a proper scientific review by simply taking the authors’ claims as fact.

Dr Ghali appears to argue that these new cognition studies be given a free pass – that they not be subjected to the normal scientific process of proper peer-review and critical analysis. He appears to be turning a blind eye to the way these studies have been misrepresented and their finding distorted in scaremongering advertising by anti-fluoride organisations. Does he not realise his attitude plays directly into the hands of the ideologically motivated anti-fluoride and anti-vaccination activists? Can he not draw an appropriate conclusion from the fact that his arguments are being promoted by ideologically motivated activists known for their misrepresentation and distortion of science?

Conclusions

If readers think I have been too harsh in my discussion here they should consider that Dr Ghali’s response did not in any way deal with the points I raised about the need for ongoing scientific discussion. In fact, he went further suggesting that I, or others,  may be pretending “that the new studies do not even exist or that they are fatally flawed with irrelevant results.”

That is patently not true as I have critiqued and discussed these studies in a number of articles here – there is no pretence in my position or the position of others who have participated in a principled discussion of the limitations and faults in this work.

I also did not appreciate Dr Ghali’s suggestion that we could “have a chat some time.” In my experience invitations to private chats as a substitute for participation in a good-faith open scientific discussion are simply a bureaucratic attempt to close down that discussion – or to silence a participant.

Another important factor is that while Dr Ghali attempts to discredit those who honestly critique these new cognitive studies from a scientific perspective he is apparently unwilling to criticise anti-fluoride activists who misrepresent the work and use that misrepresentation in scaremongering claims and advertising campaigns. I specifically asked Dr Ghali if he could point me to any video content where he was critical of the anti-fluoride campaigners – so that I could use it in this post as a balance to the video in my article Scientific integrity requires critical investigation – not blind acceptance where he strongly criticises those participating in a scientific critique. He did not respond which make me think he is unable to find anything where he has subjected anti-fluoride activists to the same emotive attack as he leveled at those critiquing the Green et al (2019) paper.

It is sad to see such partisanship in one who has had the responsibility of reviewing the research in this area.

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Scientific integrity & fluoridation – Dr Ghali responds

Video produced by Calgarians for Kid’s Health which is campaigning for the return of Community water fluoridation to Calgary, Canada. Dr Ghali’s presentation to recent Calgary City Council hearings on fluoridation has been promoted by anti-fluoridation activists.

In my recent article Scientific integrity requires critical investigation – not blind acceptance I expressed some concerns with arguments presented by Dr Ghali in his presentation to the Calgary City Council. The video accompanying the article is one that the Fluoride Action Network and Fluoride Free NZ are using in their campaign against community water fluoridation. A campaign which currently concentrates on misrepresentation of recent fluoride-IQ studies – and resorts to blatant scaremonger.

I offered Dr Ghali a right of reply to my article and he has sent me the following. As it arrived in an email form I have edited it slightly but not changed any of the arguments.


I appreciate your indicating in your email below that you sensed that the recent video posted by the Fluoride Action Network might be presenting just a portion of my comments, without the context of my full presentation (and the presentation of key public health colleagues) at the recent City of Calgary committee meeting on community water fluoridation.  That is indeed the case, and I would greatly appreciate your taking a look at the entire presentation if you have time to do so.  Also, the presentation should be viewed in relation to the full O’Brien Institute report on CWF (that I attach for your convenience).

The link to the full special council meeting is below.  Our O’Brien Institute presentations begin at approximately 17 minutes into the 9 hour meeting, and our main presentations last for 55 minutes followed by some Q&A.  We then reappear as a panel (that includes AHS public health leaders) at about 6h40m into the video.

https://pub-calgary.escribemeetings.com/Players/ISIStandAlonePlayer.aspx?ClientId=calgary&FileName=2019-10-28.mp4

At a high level, we tried in our presentations to shed some light on the controversy, and to show how advocacy positions have focused on attacking both the evidence on benefits of fluoride (e.g., the multi-pronged attacks on Lindsay McLaren’s study on CWF), and the more recent evidence on potential negative cognitive effects in developing brains.

I must say that this journey into the fluoride issue has been quite eye opening, as it exposes the challenge of making sense out of a complicated controversy (– which is, interestingly, the name of your organization…[in my email I had included my position as a scientific advisor for Making Sense of Fluoride]).  You will see in the opening part of my presentation to the City of Calgary that there is an interesting and extensive body of literature on the challenge of integrating science and advocacy (and balancing science vs. advocacy).   The matter of CWF is a particularly challenging one in that regard, as the strong attacks on, for example, the CWF cessation studies (including Lindsay McLaren’s), are rooted in positional anti-fluoride advocacy, just as the unusually vigourous attacks on the fluoride cognition studies are seemingly rooted in the challenging findings of those studies (– both MIREC and ELEMENT are, after all, both NIH-funded prospective cohort studies unlike any of the prior cognition studies, that despite some limitations are clearly also more notable studies than the cognition studies that preceded them).

The O’Brien Institute was tasked with providing Calgary City Council with a non-positional description of the existing studies and evidence.  The new cognition studies (led, interestingly, by two Canadian public health research teams) and the ensuing NTP draft report from the US are now such that it would have been absurd for us to pretend that the new studies do not even exist or that they are fatally flawed with irrelevant results.

Do watch the entirety of the City of Calgary CWF committee meeting, and let me know if you would like to have a chat some time.   And thank you again for your email.


I am still concerned about the way Dr Ghali presents this issue but he also raises an important point about advocacy which needs discussion. So I will be responding to this post with a blog article ion a few days.

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Scientific integrity requires critical investigation – not blind acceptance


Some people seem to want to close down any critical discussion of the current research into the relationship between water fluoride and child IQ. They appear to argue that claims made by researchers should not be open to critical review and that the claims be accepted without proper consideration of the data and evidence.

Anti-fluoride campaigners, of course, argue this way any time the research they promote is questioned. After all, they have a bias to confirm and an ideology to support and rely on claims that often don’t stand up to proper consideration. I expect that, but I am concerned to hear these arguments from scientific reviewers of this research.

In the video above Dr William Ghali of the Canadian O’Brien Institute for Public Health counters critiques of some research with the comment: “the studies can’t be undone and they can’t be unpublished.”

Of course they can’t – but they can, and should, be critically considered – not blindly promoted as the best things since sliced bread. Critical consideration is, or should be, the normal scientific reaction to newly published studies.

Dr Ghali is one of the authors of a recent review of the science around community water fluoridation, COMMUNITY WATER FLUORIDATION: A REPORT FOR CALGARY CITY COUNCIL. He made the above comment during his presentation to a recent meeting of the Calgary City Council – the video above contains a section of his presentation (selected and promoted by the Fluoride Action Network (FAN) an anti-fluoride activist organisation).

I am amazed at that comment – and other comments of his. I could understand if he was responding to the research critiques by explaining where they were mistaken or misinterpreted the evidence – we should always consider the factual evidence in our scientific discussions. But he seems personally upset that anyone should pursue a normal scientific critical discussion. He admits to getting angry at:

“The notion that you can just talk away 10 years of research.”

And

“I respect the doers of the research and the deliverers of the evidence and don’t think they should be shot for tough messages.”

Yet he himself is denying respect to scientists who critically discuss research (by authors that he appears to be protective of) and is attempting to “shoot” down researchers who discuss the problems in that research. He accuses scientific critics of attempting to  “simply sweep aside scientific findings because one disagrees with the results.” Yet he attempts to “sweep aside” the normal scientific critique of research – rather than deal specifically and factually with the criticisms themselves.

Sometimes it is necessary to “talk away 10 years of research” if the critical scientific consideration of the research findings show them to be faulty. We are talking about science – not religion.

Nothing sacred about scientific findings

There is nothing sacred about scientific findings – they are and always must be open for critical consideration and critique. Publication in a reputable journal and inclusion of big names in the author list is no guarantee of good science. And all scientific findings must be considered as provisional – most of what is considered factual in science often turn out to be wrong, at least in part. This is how science progresses and critical analysis and scientific critique of published work is key to that development.

Critique of published research is vital and it should never be ignored, “swept aside” or discredited by saying things like “once published it can’t be unpublished” of referring to critiques as “sweeping aside because one disagrees.” Good scientific critique is not swayed by authority or author’s claims but looks at the data, findings and interpretations – critically. It is not an evidence-free “sweeping aside.” In a good-faith open scientific exchange, the response to criticism should be the same.

Having said this I can understand a little of what is driving the two people in their comments in the above video – comments that are critical of scientific commenters but ignore the way the anti-fluoride movement has misused and misrepresented this research. The O’Brien review they were authors of was roundly criticised for its weaknesses when it was made public. On the other hand, the anti-fluoride advocates lavished it with praise – for these very same weaknesses.

Scientists are human (actually very human) and, of course, sensitive to criticism. Even the best scientist will often react defensively and attempt to discredit critics rather than deal with the contents of the criticisms.

Misrepresentations

The only time Dr Ghali gets at all specific in this video section is in his criticisms of the letter sent by 30 academic and health experts to the US National Insitute of Environmental Health Science (NEHS) about the study (see Experts complain to funding body about quality of fluoride-IQ research). This letter expressed concern about the study recently published by Green et al (2019) listing a number of specific scientific limitation of the study (see If at first you don’t succeed . . . statistical manipulation might help and Experts complain to funding body about quality of fluoride-IQ research)  The letter also expressed concern about the poor statistical reporting of the data and lack of transparency regarding methodology.

After listing ten scientific concerns the experts made a specific request:

“We urge NIEHS to ask the Green authors to release their RIF data set and provide a thorough explanation of their analytical methods. Doing so could enable an independent review that would bring clarity and ensure the scientific record is accurate.

Should the Green researchers not voluntarily release their data, please advise us on what the process would be to have the data set released so an independent analysis of the Green data can be conducted.”

But this is how Dr Ghali specifically commented on this important expert’s letter:

“Twenty or so North American academics [actually 30 North Americans and experts from the UK and Australia] wrote to the NIEHS denouncing the recent Canadian study critiquing it on many levels  Making assertions the team at York University refused any access to their data and their refusal to permit reanalysis and they are not being transparent. The allegation is false. The authors are in fact  in an active process of discussing with health Canada a Teflon bias-free process of making the data available for a secondary analysis. And again, there is one thing that gets under my skin are assertions, attacks on messengers.” [My emphasis]

Come off it. On the refusal to make data available the expert’s letter mentions only:

“In recent weeks, at least two of the Green authors have declined to respond affirmatively to requests from other researchers for access to the data and analytical methods they used.”

It did not “denounce” the study (scientific critique is not “denouncing”), and it definitely did not assert the whole team was refusing any access. It simply pointed out that no one at that stage had reacted positively to the request for access to the data. That is not, as Dr Ghali claims an “attack on messengers.” Nor is it, as he claims, a “false allegation.”

A respectful and scientifically ethical response to the expert’s letter would be for  Dr Ghali to consider and respond to the list of ten limitations of the study described in the letter. But instead, he has misrepresented the letter and made a false allegation himself regarding the request for access to data.

Where is the scientific integrity in that?

As an aside, I am a bit cynical about the authors’ claim that they are “discussing with health Canada a Teflon bias-free process of making the data available for a secondary analysis.” Dr Ghali appears to be in more intimate contact with the authors than the rest of the scientific community because this is the first I have heard of the authors’ response. But I fear the “Teflon bias-free process” referred to may, in the end, be a bureaucratic solution which makes the data available to only a select “trusted” few for their presumed approval.

The problem of transparency

Dr Ghali also misrepresents the letter by claiming it accuses the authors of lack of transparency. Yes, it expresses concern about the lack of statistical and methodological information but refers to this as a general problem in scientific publications, particularly where statistical analyses are involved. It even cites a published paper on this (Prager et al. 2019: Improving transparency and scientific rigor in academic publishing. Brain Behav. 9(1): e01141).

Another example relates to reliance on p-values:

“The American Statistical Association has established six principles on the use and analysis of p-values, one of which states: “Proper inference requires full reporting and transparency.” By releasing the data and a detailed explanation of their analytical methods, the Green authors would enable the scientific community to better assess whether their choice of p-value was appropriate.”

All this is simply part of a good-faith scientific critique which should be normal in science and should never be squashed or prevented. Remember Ghali himself said messengers should not be shot for delivering a message.

But if we are to discuss the problem of transparency I am really concerned at the unwillingness of the authors, and their scientific defenders, to participate in a free good-faith scientific exchange on their findings.

I guess they can not be blamed for promoting their own research while being silent about its limitations, or for the fact that the journal which published their paper has a policy of not publishing any critiques of published paper after 4 weeks. But why should they promote their findings on social media but refuse to enter into any discussion on it?

For example, Rivka Green, the first author of the paper, opened a Twitter account where she promoted the paper. But when some discussion of the limitations started she withdrew and closed the account down.

In another example, a biostats PhD student at Pittsburgh university was making some general comments about the data in the Green paper on Twitter soon after its publication. But two of the authors approached his university department and supervisors and he was forced to delete his tweets. (This is information from the student  himself who is wary about going public because of this unpleasant exposure to academic politics and he is unsure of the consequences of making further comments).

I have had personal experience of the lack of transparency by Dr Chrsitine Till’s group (involved in the study reported by Green et al. 2019) and its supporters. My own critique of one of the early papers from the group (Malin & Till 2015) was denied consideration for publication in the publishing journal by the Chief Editor, Prof Grandjean, who publicly identifies with the group and the anti-fluoride movement (see Fluoridation not associated with ADHD – a myth put to rest). My critique was eventually published in another journal: (see Perrott 2018: Fluoridation and attention deficit hyperactivity disorder a critique of Malin and Till (2015). British Dental Journal, 223(11), 819–822). Christine Till is aware of this critique but purposely ignores it whenever she or her coauthors cite Malin & Till (2015) in their publications (see, for example, ADHD and fluoride – wishful thinking supported by statistical manipulation?).

And what about the lack of transparency displayed by Dr Ghali himself. He misrepresented the expert’s letter – but was also very selective in referring to other reviews of this study. For example, in the video above, he mentioned the CADTH (Canadian Agency for Drugs and Technologies in Health) review  on possible neurological effects of fluoride which was very critical of the Green et al. (2019) paper and quotes from two sections of the review which said:

“The evidence is weak due to multiple limitations  . . ” (p 5)  and “further well conducted research is needed to reduce uncertainty. ” (p 14)

But he ignores completely a more damning statement in the CADTH review which says:

“The study by Green et al., 2019 concluded that “maternal exposure to higher levels of fluoride during pregnancy was associated with lower IQ scores in children aged 3 to 4 years.” (p. E1) This conclusion was not supported by the data” (page 12)

A disclaimer

I am very conscious that I have relied on only one section of Dr Ghali’s presentation to the Calgary City Council. And that this section was cherry-picked by FAN to present him as an ally in their anti-fluoride campaign. I have not had the time to look at the full video of his presentation yet – it is available on YouTube: Dr. Ghali (O’Brien Institute) – Full Calgary Presentation on Fluoride. However, I think the comments made on this specific section of his presentation stand by themselves and needed a response.

Dr Ghali may well have made criticisms of the misrepresentation of this research by FAN, by the anti-fluoride campaigners also presenting to the Calgary City Council and by anti-fluoride campaigners in general. After all, FAN, which made the selection for this video and is promoting it is hardly likely to include such criticism.

So to be fair to Dr Ghali and to support the proper good-faith scientific exchange I am talking about I will email him and offer him the right of reply to this article.

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Flaw and porkie in anti-fluoride report claiming a flaw in Canadian study

Anti-fluoride group, Fluoride Action Network, ironically stamps their own critique of the Calgary fluoridation cessation study as “debunked.”

Anti-fluoride campaigners have launched another attack on a Canadian fluoridation cessation study. They claim it is flawed – but there is a huge flaw in their own critique.

I discussed their original attack in February last year (see Anti-fluoridationist’s flawed attacks on Calgary study). But this new attack is based on a published critique of the original study. I think that is good progress – the anti-fluoride campaigners have made a detailed critique and published it in the journal which published the original paper. The original authors have then responded. This is how things should be done.

Timeline

For those of you with the interest and time who want to go into the details, the original study was published in:

McLaren L, Patterson S, Thawer S, Faris P, McNeil D, Potestio M, Shwart L. (2016) Measuring the short-term impact of fluoridation cessation on dental caries in Grade 2 children using tooth surface indices. Community Dent Oral Epidemiol 2016.

The anti-fluoride critique was recently published in:

Neurath, C., Beck, J. S., Limeback, H., Sprules, W. G., Connett, M., Osmunson, B., & Davis, D. R. (2017). Limitations of fluoridation effectiveness studies: Lessons from Alberta, Canada. Community Dentistry and Oral Epidemiology, (October 2016), 1–7.

The response from the original authors was then published in:

McLaren, L., Patterson, S., Thawer, S., Faris, P., McNeil, D., & Potestio, M. (2017). Fluoridation cessation: More science from Alberta. Community Dentistry and Oral Epidemiology, (October), 1–3.

Other data which have been used in the critique and which I will use here can be found in:

McLaren, L., McNeil, D. A., Potestio, M., Patterson, S., Thawer, S., Faris, P., … Shwart, L. (2016). Equity in children’s dental caries before and after cessation of community water fluoridation: differential impact by dental insurance status and geographic material deprivation. International Journal for Equity in Health, 15(1), 24.

And:

McLaren, L., Patterson, S., Thawer, S., Faris, P., McNeil, D., Potestioa, M. L., & Shwart. L. (2017). Exploring the short-term impact of community water fluoridation cessation on children’s dental caries: a natural experiment in Alberta, Canada. Public Health, 146, 56–64.

Most of the authors of the critique are listed as members of the Fluoride Action Network (FAN) team and I can understand that FAN would feel proud that their critique was published. However, I feel their press release was rather underhand to imply the original study is:

“seriously flawed science  . . . Citizens should be concerned that their tax dollars have funded this biased work.”

And that the work was funded by state and public bodies:

“whose policy is to promote fluoridation.”

But let’s look at the critique itself – because it has some pretty big flaws itself.

What did the original study find?

My article, Anti-fluoridationist’s flawed attacks on Calgary study describes the details of this study. But briefly, it showed that child tooth decay increased in the Canadian city of Calgary after cessation of fluoridation. It used a comparison fluoridated city (the nearby and similar sized city of Edmonton) – and just as well because tooth decay also increased in that city during that time. However, there was still an increase in tooth decay in Calgary after cessation of fluoridation even after correction for the increase due to other factors apparent in Edmonton.

What did the critique claim?

A number of the criticisms are debatable and relatively minor.

How suitable was Edmonton as a comparison city? Neurath et al., (2017) claim it wasn’t suitable (but did not suggest a better alternative). McLaren et al., (2017) claim there is “no better comparison community for Calgary than Edmonton.”

Confounding – Neurath claims consideration of confounding factors was inadequate. McLaren et al., (2017) refer to extra data in two other papers and describes their consideration of several likely confounding factors like public health programmes and use of sealants. Whether the correct factors or sufficient factors were considered is always a bone of contention between authors and critics and, in the end, available data and funding decides.

Study design – Neurath et al., (2017) argue for randomised controlled trials. McLaren et al. (2017) point out that in studies of social programmes one must go with what exists. They say:

“While we agree with the value of stronger designs, one must be thoughtful about evaluation of public health measures, which by definition are complex and context-dependent. We used the best available
data and design for our circumstances”

Data ignored?

But Neurath et al (2017)’s major criticism is that some important data was ignored. And they claim that when that data is included the conclusions are not valid.

Of course, the FAN authors are stretching things quite a bit. The original study was based on data for tooth surfaces – the decay, extracted and filled tooth surfaces (defs). This was used as it is more sensitive than the tooth data itself – the decayed missing and filled teeth (deft).

Data for defs were only available for the 2004/05 and 2014/15 surveys. Unfortunately, there were no defs data for the pre-cessation period closer to the time of cessation (2011). That is the sort of problem researchers face when dealing with existing surveys and existing social programmes.

But the bright sparks at FAN latched on to the fact there was a survey with deft data in Calgary closer to the cessation time – 2009/2010. The fact that there was no equivalent survey for Edmonton didn’t hold them back – they proceeded to imply the 2009/2010 data had been purposely held back, despite McLaren making clear she could not use that data for Calgary in the absence of similar data for Edmonton. That would have negated the requirement for a comparison city and the existing data surely shows that requirement was very wise.

So Neurath et al., (2017) chose to ignore the obvious requirement for a comparison city and proceeded to argue their case on the Calgary data alone. They argued the study was “fatally flawed” and that “key data [was] omitted.” The argument implied the study was somehow fraudulent and that the authors had hidden the 2009/2010 survey data – despite the fact this data is used in another of their papers!

Neurath et al., (2017) pretend that a comparison city is not really necessary – relying only on the tooth data (deft) for Calgary they argue that as 50% of the increased in tooth decay had occurred between the 2004/05 and 2009/10 surveys then the increases seen after cessation of fluoridation was due to the same trend (see their Figure 1 below). They argued this proved that cessation of fluoridation had no effect. Ignoring completely the Edmonton data.

So, an obvious flaw in their critique – but wait, there is more! They actually go so far as to falsify data.

Falsifying a “correction factor”

Not satisfied with the plots in Figure 1B they found a way to make the data look even worse for McLaren et al. (2015). They came up with a “correction” factor to convert the deft data for 2009/2010 survey into defs data. Here is their Figure 2 using the “converted” deft data

Looks bad, doesn’t it?

However, the trick is in the way the conversion factor is calculated. They “used the ratio of defs to deft in the 2013/2014 survey to make the conversion.” The table below for subset (dmft>0) data they used shows this produces a conversion factor of 2.41 – big enough to dramatically push the 2009/10 data point right up so that it is sitting on the Edmonton “trend line” in their Figure 2 above.

But they could have equally used the ratio of defs/deft in the 2004/2005 survey to make the conversion. That produces a much lower conversion factor of 1.63 – which is not at all consistent with their claim “when we applied this conversion [2.41] to the 2004/2005 Calgary survey, where both deft and defs are known, the calculated defs was very close to the known defs.”

In fact, it may have been more appropriate to take the average conversion factors from the two available surveys. In the figure below I have done this (green data point) and compared this with the use of the conversion factors from the 2004/05 survey (purple data point) and that from the 2004/15 survey used by Neurath et al (yellow data point).

I guess this shows the danger of making these sort of adjustments – especially when there is a bias to confirm. And also that readers should beware of vague assertions of the sort:

“when we applied this conversion [2.41] to the 2004/2005 Calgary survey, where both deft and defs are known, the calculated defs was very close to the known defs.”

Conclusion

The McLaren et al., (2017) study has its limitations, limitations admitted and described by the authors. But, it is the FAN critique of Neurath et al., (2017) rather than the original study, that is fatally flawed. Flawed because of confirmation bias and a porky.

1: They ignored the necessary use of a comparison city and assumed the increase in tooth decay in Calgary was linear over the time between the two surveys McLaren at al used.

2: The use of any correction factor would be questionable but Neurath et al., (20127) clearly used a biased value to suit their argument. Further, they purposely misrepresented their correction factor by implying a similar value would have been obtained from the 2004/2005 survey data. Completely wrong.

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Anti-fluoridationist’s flawed attacks on Calgary study

antiscience-logic-web

Image credit: Why I will no longer approve anti-fluoride dishonesty – New Anthropocene

The anti-fluoride propagandists are at it again – attacking a recently published scientific paper because the reported data does not fit with their own agenda.

The are attacking this paper:

McLaren L, Patterson S, Thawer S, Faris P, McNeil D, Potestio M, Shwart L. (2016) Measuring the short-term impact of fluoridation cessation on dental caries in Grade 2 children using tooth surface indices. Community Dent Oral Epidemiol 2016.

The Fluoride Action Network (FAN) claims the study is “fatally flawed” and that “key data [was] omitted.” The local FAN organisation – Fluoride Free New Zealand (FFNZ) has gone further claiming the study is “basically a fraud.”

Serious (even slanderous) accusations – let’s see if those charges hold up.

What did the study find?

The paper reports changes in dental caries levels of grade 2 children in Alberta, Canada between 2005/2005 and 2013/2014. Two cities were chosen – Calgary (which stopped fluoridation in May 2011 – after having been fluoridated since 1991) and Edmonton where fluoridation started in 1967 and is still in place. This enabled an assessment of the effect of fluoridation cessation on the dental health of children in Calgary.

Dental caries actually increased in both cities but the data shows a larger increase in dental caries where fluoridation had been stopped (Calgary) than where it continued (Edmonton).

mean-defs

defs = decayed, extracted (due to caries) filled primary tooth surfaces.

The change in Calgary (3.8) is greater than for Edmonton (2.1) and the difference is statistically significant.

The above graphic is for all tooth surfaces – similar results were obtained with smooth surfaces only – Calgary change = 2.9 and Edmonton change = 1.6.

Important features of study

There are several important features of the paper and the data reported:

1: Whereas previous cessation studies had used tooth-level data this study used tooth surface-level data. The authors had previously reported tooth level data which showed similar results.

The WHO prefers and recommends tooth surface-level data to evaluate an intervention such as starting or stopping fluoridation because of its greater sensitivity. The study authors used  tooth surface-level data and focused on smooth tooth surfaces which are most likely influenced by fluoride in this age group.

Most earlier fluoridation cessation studies had used less sensitive tooth-level data so this study was a definite improvement

2: A comparison (or “control”) city was used – Edmonton. Many previous cessation studies suffered from not using a comparison community. Interpretation is more difficult without some sort of “control” as changes due to other factors may be important. Factors like different assessment personnel, changes in diet (eg sugar consumption or bottled water), changes in dental health care, etc. It is difficult to take account of all factors but the inclusion of a similar comparison community helps reduce their effects on the results.

Again, this study was a definite improvement over previous cessation studies which had not used a comparison community.

3: Pre-cessation data were collected several years before cessation. The authors list this as a limitation, saying:

“it would have been preferable to have data collected closer to the year of cessation.”

However, this being the real world, the study used the only tooth surface-level data available for Calgary and Edmonton. There was absolutely no question of data being omitted (or “fraud”) that the anti-fluoride campaigners allege.

So how has FAN supported their charges?

Well, basically by retreating from (or ignoring) the advantages of this study – use of tooth surface-level data and use of a comparison community.

1: They use the limitation that the pre-cessation tooth surface-level data was collected several years before cessation to resort to more recent 2009/2010 data. But, importantly, that data is not tooth surface-level and it is for only one city – Calgary! 

So, they claim, the researchers “omitted key data” – the 2009/2010 data – pretending the researchers had  “hidden” it. But that data was not surface-level data. And, far from “hiding,” it the same research group specifically used this tooth-level data in an accompanying  paper:

McLaren L, McNeil D, Potestio M, Patterson S, Thawer S, Faris P, Congshi S,  Shwart L. (2016). Equity in children’ s dental caries before and after cessation of community water fluoridation: differential impact by dental insurance status and geographic material deprivation. International Journal for Equity in Health 15: 24

2: They ignore completely the importance of using a comparison community. Sure, they might claim that no survey was taken in Edmonton in 2009/2010. But they have thrown the baby out with the bath water in their attempt to discredit the research. They have fallen back on the limitation of so many fluoridation cessation studies which rely on cross-sectional measurements at different times without using a control. Worse still, they do this despite the tooth surface-level data for Edmonton showing an increase in dental caries even though there had been no cessation of fluoridation! They are willingly falling into the trap of ignoring all the other factors which could influence the results.

3: The FAN press release attempts to discredit the researchers saying:

“The lead author of the study, Lindsay McLaren, is not an independent scientist on the fluoridation controversy.”

This “damning by association” of researchers with their institutions, the fact that they receive a wage from their employers and that they write articles about their scientific results (which do not support the claims of the anti-fluoridation lobby) is really disingenuous. It’s a way of discrediting any scientist who produces results an anti-science group does not like. (Anti-science groups often use this argument – for example, anti-fluoride activists haver told me I am not “independent” because I once worked as a scientific researcher and,  therefore, cannot be trusted!).

Ironically, they are hanging themselves with their own rope on this one. Their press release makes mileage by quoting an assessment from an “independent” scientist Dr Trevor Sheldon. I checked with Sheldon and he confirmed that he:

“was invited to comment on this by Fluoride Action Network.  I did not have much time to do this but agreed to do so and received no incentive or reward.”

Now, doesn’t that admission  compromise Sheldon as an “independent” commentator? He immediately responds to a request from an activist political organisation, a group funded by the “natural”/alternative health industry – without any qualms! That confirms in my mind the links and political sympathies Sheldon has with FAN that I have long suspected.

It is perfectly normal (and healthy) for credible scientists to disagree with published papers and there are publication mechanisms to do this effectively. For example “letters to the editor” or comments in the specific journal – or even alternative journals. The fact Sheldon chose an almost immediate critique in the newsletter of a political activist group confirms to me that he is not “independent” on this subject and that he, in effect, belongs to the stable of “tame” anti-fluoride scientists FAN makes regular use of in their press releases. People like Bill Hirzy, Kathleen Theissen, Bill Osmunson, Hardy Limeback, etc.

Some other critical details

FAN relied on Sheldon’s evaluation for their main criticism but there are other details in that evaluation which I can comment on.

1: Sheldon would have preferred “a randomised controlled trial where areas are randomly allocated to start/cease water fluoridation.”

Yes, that would have been nice wouldn’t it.But the fact this has never been done – and Sheldon himself has never initiated such a trial – rather indicates how impossible such a trial is. The Cochrane review of community water fluoridation, which anti-fluoride campaigners love to misrepresent, commented on the silliness of such complaints:

But the fact this has never been done – and Sheldon himself (and similar anti-fluoride critics) has never initiated such a trial – rather indicates how impossible such a trial is. The Cochrane review of community water fluoridation, which anti-fluoride campaigners love to misrepresent, commented on the silliness of such complaints:

“particularly for research questions where evidence from randomised controlled trials is never going to be available due to the unfeasibility of conducting such trials. Community water fluoridation is one such area.”

2: He attempts to  extrapolate from tooth-level data to “fill in the gaps” in the tooth surface-level data. This highly speculative analysis allows him to conclude that most of the increase in dental caries shown by children in Calgary occurred before the cessation of fluoridation.

He accuses the researchers of making a “heroic assumption” but it seems to me the assumptions involved in his extrapolation are worse than “heroic.” Yet  the analysis enables him to make conclusions which seem to be derived more from confirmation bias than from intelligent analysis of the data. Especially as he ignored any data from Edmonton.

3:  He comments on problems resulting from population movements, confounding factors, assessment methods and staff differences, sample size differences, etc. But these are common problems when attempting to make sense of existing data. Importantly, these problems and worse, plague the cessation studies that anti-fluoride campaigners continually quote to support their claims that community water fluoridation is ineffective.

Summary

The Calgary/Edmonton study does not have the limitations of most fluoridation cessation studies – in particular, a comparison community was used and the more sensitive and appropriate tooth surface-level data was used rather than tooth-level data. The period between the first assessment and cessation is an admitted limitation but certainly does not indicate the omission of data or hiding data as anti-fluoridationists are claiming. There was just no intermediate data available.

The resort to speculative extrapolation of tooth-level data for only Calgary is disingenuous as it ignores the low sensitivity of that data and the influence of other factors compensated for by the use of Edmonton as a comparison community.

Anti-fluoridation campaigners often make ready use of older cessation studies which showed no effect – despite the obvious limitation. In particular, they often use studies where no comparison community was included and ignore completely the other factors involved such as changes in dental health provisions or social health policies such as replacing fluoridation with mouth rinse campaigns.

It is, therefore, ironic for them to come out fighting in an attempt to discredit a study which has fewer limitations than the ones they rely on. Worse, to accuse researchers of purposely omitting data – or even of scientific fraud.

The real reason for these attacks on honest researchers is that the data just does not fit the anti-fluoridation agenda and therefore, in their eyes, must be discredited.

Oh, and beware of such activists using the word “independent’ to describe a researcher. It inevitably indicates someone with allegiances to their campaign. Someone who can be relied on to give the appropriate quote to be used in their press releases.

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