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Debating science

The Science March in Palmerston North. Credit: Erin Wilson, Twitter.

This last week has certainly raised the profile of the “science debate” in New Zealand. Most importantly we saw big turnouts for the Science March in several major cities – a demonstration that lots of scientists and supporters of science feel that science could be threatened – or at least that it is unappreciated by the politicians and other decision-makers. Maybe even by a section of the public.

And at the other end of importance, we saw a childish spat by local anti-fluoride activists who had attempted to use a member of Parliament’s experience of miscarriages to make the scaremongering claim that these were caused by community water fluoridation. Then they attempted to divert attention from the embarrassing (for them) widespread condemnation by promoting, through their own press releases,  the fake news they had organised a “TV debate” on fluoridation with a local scientist.

The Science March

The Science March was many things to many people. I saw it as a general demonstration of support for science and opposition to attempts to discredit science – examples being the science around climate change, vaccinations, evolution – and yes even fluoridation. Some of the media presented it as a demonstration against US president Trump and his policies – and there may have been many in the US Science Marches who had these motivations. But every country and every region have examples where politicians have downplayed scientific evidence or even attempted to discredit that evidence and the scientists who produced it. These sort of struggles went on long before Trump and they will go on after Trump.

For example, in New Zealand, we have some specific issues over water quality and climate change which are quite unconnected to the US and its politicians. We have to fight out those issues here. Scientists, anyway, strongly resist linking their issues to politics and political movements. We have had a few bad experiences from that. This resistance and the silly intervention of identity politics into the organisation of the US Science Marches did make many scientists wary of participation.

But, in the end, the Science Marches around the world had good turnouts and my impression is that participants felt they had been both worthwhile for science and good experiences personally.

Of course, the Science March will not make the problems go away. There is still a need for the day to day struggle on issues like climate change, water and environmental quality and even fluoridation. This is one of the points I attempted to make in my article Trump didn’t invent the problems – and his opponents didn’t invent protest.

Debating science

And this is where a continuing debate around science issues is important. To be clear – I am not using the word “debate” in the formal sense (more on that later) but in its most general sense. And not necessarily debate involving specific contact between adversaries.

Issues about water quality and the environment come up continually in New Zealand. In the media, in local body and parliamentary considerations, and in government statements. A lot of the commentary may downplay the science on the issue or overplay economic and financial aspects. Some of the commentaries may be outright anti-science – or present misinformation, even distortions, about the science. Activist claims about the “dangers” of the use of 1080 to control predator pests are an example.

The misinformation and downplay of scientific information cannot be allowed free passage – it must be challenged. Hence there is a debate – again not a formal debate, but a debate, nevertheless. The public is exposed to various claims and counterclaims via the media and the internet. Regional bodies and parliamentary committees are deluged with submissions and scientists and supporters of science have a role to play there too.

Scientists and supporters of science should not stand aside and let the opposition win by default – simply because they abhor the political process or ego-driven participation in media reports. But they need to choose their battles – and they need to consider the effectiveness or otherwise of different forms of participation in public debate.

Problems with formal debates

So what about formal debates of the sort the Fluoride Free New Zealand (FFNZ – the local anti-fluoride organisation) claimed via their press releases to have organised? A TV debate between New Zealand Scientist Professor Michelle Dickinson from Auckland University, and Dr. Paul Connett – chief guru at the US Fluoride Action Network. This proved to be a kickback from FFNZ, a diversion from the bad publicity that came their way when Dickinson publicly criticised their use of scaremongering tactics in an email sent to a Green member of parliament. Public commenters were disgusted at the FFNZ claim the miscarriages she had suffered were caused by community water fluoridation.

Professor Dickinson pointed out she had not agreed to a TV debate (which FFNZ then childishly used in another press release to claim she had reneged). And Dr. Paul Connett did not even publicly respond – indicating that while the debate challenge had been made in his name he knew nothing about it.

Kane Titchener, the Auckland FFNZ organiser who made the challenge to Michelle Dickinson, is a bit of a Walter Mitty character and often makes debate challenges in Paul Connett’s name, but without his authorisation. These challenges are his way of avoiding the discussion of the science when he is outgunned. He made a similar challenge to me four years ago – I called his bluff and nothing happened. The debate I did eventually have with Paul Connett was arranged through Vinny Eastwood (a local conspiracy theorist who promote anti-fluoride propaganda), not Kane Titchener – who was probably not even in contact with Connett.

But, in general, scientists are unwilling to take part in the sort of formal debates Kane Titchener was proposing. There are often similar challenges made to evolutionary scientists by creationists and religious apologists, and to climate scientists by climate change deniers. Scientists generally feel their opposition make these challenges in an attempt to gain recognition or status they do not deserve. (I think in this particular case Kane Titchener may have naively thought he could use Michelle Dickinson’s connections with TV personalities to get Connett on TV – something he has found impossible on his recent visits to NZ).

Another, more important, reason is that such formal debates are usually more entertainment than information. In fact, debating is a recognised form of entertainment often driven by egos and aimed at ‘scoring points’ which appeal to a biased and motivated audience. They are rarely a way of providing information and using reasoning to come to conclusions – which is the normal and accepted process of scientific discussion.

Good faith discussion

Don’t get me wrong – I am not opposed to all forms of one-on-one “debate” or discussion. These can be useful – especially when the audience is not stacked by biased activists. An exchange of scientific views or information in front of an interested but unbiased audience can be a useful and good experience.

Similarly on-line, written debates or discussion of the sort I had with Paul Connett in 2013/2014 can also be useful (see Connett & Perrott, 2014. The Fluoride Debate). In this format, ego and debating or entertainment skills are less effective. Participants need to produce information – and back it up with evidence, citations or logic. And one’s discussion partner always has the opportunity to critically comment on that information.

I feel that debate was successful – it enabled both sides to prevent information in a calm way without put downs or ego problems. I often use that debate when I want to check out citations and claims. Interestingly, though, Paul Connett behaves as if the debate never happened – claiming that no-one in New Zealand has been prepared to debate him. The FFNZ activists do the same thing. Ever since that debate, I have been blocked from commenting on any anti-fluoride website or Facebook page in New Zealand and internationally. It’s almost as if some sort of Stalinist order went out to treat me like a “non-person.”

A challenge to anti-fluoridation activists

If these activists are so keen on debating the issue then why don’t they allow it to happen? Why do they block pro-science people from commenting on their Facebook pages? Why do they ignore open letters and offers of rights of reply of the sort I sent to Stan Litras and other anti-fluoride activists (see A challenge to anti-fluoridationers to justify their misrepresentation of New Zealand research). Why did Lisa Hansen – the solicitor for the NZ Health Trust who has been making incorrect scientific claims in her High Court cases opposing fluoridation ignore my offer of a right of reply (see Open letter to Lisa Hansen on NZ Fluoridation Review)? Even the “great helmsman” himself, the man who Kane Titchener seems to think will answer all the questions, refuses to respond to offers of right of reply (see Misrepresenting fluoride science – an open letter to Paul Connett).

Why do these people ignore such opportunities?

One thing I noticed about the submission made by opponents of community water fluoridation to the recent parliamentary Health Committee consideration of the Fluoridation Bill was the overwhelming reliance on scientific claims in almost all their submissions. Claims that fluoridation causes IQ loss, fluorosis and a whole host of sicknesses. Many of the submitters actually used citations to scientific journals or attached copies of scientific papers.

These people claim they have science on their side – yet they seem to be extremely shy about discussing that science in any open way. Why is that?

No, it’s not a matter of Walter Mitty types making debate challenges in the name of Paul Connett. Why don’t Kane Titchener, Mary Byrne, Stan Litras, Lynn Jordan (alias Penelope Paisley on Facebook) and similar activists who love to make “authoritative” scientific claims in submissions or behind the protection of a ring-fenced Facebook page or website participate in an honest open debate?

For a start – what about stopping these silly”challenges” in Paul Connett’s name. Then they could remove restrictions on the discussion on the websites and Facebook pages they control.

And, yes, I would be happy for them to participate in good faith scientific discussion in articles on this blog. That is what my offers of the right of reply to my articles were all about.

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Anti-fluoridation activist Paul Connett has a senior moment about our debate

Paul Connett, from  the US anti-fluoride group, the Fluoride Action network, was interviewed today on the Radio new Zealand’s Jesse Mulligan programme. You can listen to the interview at Complaints against anti-fluoride ads not upheld.

jesse

Jesse Mulligan interviewed Paul Connett about his anti-fluoride views

Unsurprisingly, Paul presented the same  tired old arguments against community water fluoridation. And I can understand why he should once again promote his own anti-fluoride book. After all, it has 80 pages of references (most of them broken links to Fluoride Action Network web pages)! And it is surely natural for an author to be proud of their book.

But he seems to suffer from senior moments, or at least memory blocks, when he claims that the arguments in his book have never been confronted. That people refuse to debate with him about these arguments.

Has he really managed to eradicate all memory of our rather long on-line debate about those very arguments? He specifically required that our debate have the format of him advancing arguments from his book and that I would respond to them.

The full debate is available here (see Fluoride Debate) or it can be downloaded as a pdf document (see The fluoride debate). It’s a useful document – about 212 pages long – fully referenced and Paul’s arguments are presented completely unedited – just as he presented them.

I know Paul was unhappy at how the debate went. Since then he has asked me never to contact him again and I was immediately banned from commenting on all the local anti-fluoride websites and Facebook pages. I have also been blocked from commenting on the US Fluoride Action Network’s Facebook page.

OK, I can understand Paul may have felt disappointed with his response to my debunking of his claims – but to pretend the debate never happened?

Interestingly, this is not an isolated behaviour by anti-fluoride activists. Local anti-fluoride people have also made similar claims that no one will debate with them. However, they seem to run quickly in the opposite direction when they do get a response to their offer to debate. Stan Litras is one example where time and time again I have critiqued his anti-fluoride claims and offered him a right of reply. He always refuses but still publicly claims that no one will debate with him.

Paul lost it a bit in his interview today when Jesse mentioned the NZ fluoridation review carried out by the Royal Society of NZ and the office of the Prime mInister’s Chief Science Advisor. He made a few ill-advised disparaging comments which came across as shrill when compared with the explanations from Sir Peter Gluckman, the Prime Ministers Chief Science Advisor, who was given the opportunity to respond to Paul’s criticisms.

The Interview and Sir Peter’s response is worth listening to. You can download it or listen to it at Jesse Mulligan, 1–4pm.

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Misrepresenting fluoride science – an open letter to Paul Connett

Connett Blenheim

A poster for Connett’s Blenheim meeting – scaremongering because there is no proposal for mandatory fluoridation in New Zealand.

A new year and a new speaking tour of New Zealand by US anti-fluoride campaigner Paul Connett. Looking over the presentation he is giving at his New Zealand meetings I find he has absolutely nothing new to say. It’s all been said before – and all his claims have been debunked before.

His visit this year is slightly unusual – the first time I am aware he has visited in winter. Perhaps the local anti-fluoride movement has decided they need to get him early because of the impending introduction of new legislation on community water fluoridation (CWF).

In this open letter to Paul, I respond briefly to the points he makes in his current presentation and will link to a fuller discussion of each point in earlier posts. Many of these links will be to my debate with Paul Connett 3 years ago. You can download the full debate (Connett & Perrott, The Fluoride debate – 2014) or find the individual posts at Fluoride Debate.

Finally, I have offered Paul the right of reply here. I believe that participation in a good-faith discussion is the most scientifically ethical response to my open letter.


Dear Paul,

I wish to challenge claims you made in your 2016 New Zealand speaking tour. Most of these claims were refuted in our 2013/2014 debate but it is worth itemising some of them here because you are continuing to rely on them.

I, of course, offer you the right of reply and access to an open good faith discussion here if you feel I have misrepresented you in any way.

Fraudulent charges of scientific fraud

Fraud claim

From Connett’s 2016 New Zealand presentation

Scientific fraud is an extremely serious offence and accusations should not be made lightly. Yet you have accused New Zealand scientists involved in the Hastings trial of scientific fraud without even citing the study’s reports or publications. You have relied simply on an out-of-context sentence in a letter from a departmental official and unsubstantiated claims about changes in methodology. I pointed this out to you in our 2013/2014 debate  yet you are persisting in this defamation of researchers who are no longer here to defend themselves. You have even gone as far as producing an internationally distributed newsletter entitled “New Zealand Fluoridation Fraud” which was promoted by Fluoride Free NZ activists in this country.

You base your charge of “fraud'” on:

  1. An out of context quote from an internal letter by a director,
  2. Abandonment of Napier as the planned control city at the beginning of the study, and
  3. Alleged changes in the diagnostic procedures used during the course of the trial.

1: A letter from a divisional director expressing his frustration at developing a description “with meaning to a layman” is not evidence of “fraud,” or an attempt to distort the evidence. Scientists are always being urged by officials to make their findings more accessible and understandable to the public.   Your presentation of it as such is equivalent to the 2009/2010 “climategate” misinformation campaign launched by climate change deniers using out-of-context quotes from scientists emails. In that case, we know the real fraud was carried out by those attempting to deny the science and discredit the scientists.

2: Yes, the original plan was to use Napier as a control non-fluoridated city alongside the fluoridated city of Hastings. This was abandoned when data showed a lower incidence of tooth decay in Napier and it was judged unsuitable as a control because of differing soil chemistry which would have introduced an extra confounding factor. While this reduced the Hastings experiment to a longitudinal study, comparisons were made with other non-fluoridated New Zealand cities.

Surely this was a sensible solution to a problem? – and these are always occurring in long-term studies as any researcher familiar with such studies will confirm. Yet, in our debate, you irresponsibly described these reasons as “bogus.” As I said in our debate:

“That is the problem with conspiracy theories – they paint the world black and white which is very unrealistic. I expected far more professionalism from Paul than this.”

This is not the sort of rational assessment expected from a scientific review but sounds more like the declaration of a biased political campaigner.

3:  The diagnostic procedure used in the Hastings experiment were described in the first paper of the series reporting results (Ludwig 1958). Subsequent papers (Ludwig and Ludwig, et al., 1959, 1962, 1963, 1965, 1971) refer to this description and confirm it continued to be used. So where is the evidence for a change in diagnostic procedure?

Yes, there were changes in tooth filling procedures used by New Zealand dental nurses around the time this trial started. But even the anti-fluoride  Colquhoun & Wilson (1999) confirm attempts were made to use a consistent filling procedure in the trial – quoting from a file they received from their Official Information Act request:

“At the commencement of the Hastings fluoridation project steps were taken to ensure that the practice of preparing prophylactic type fillings by dental nurses was discontinued.

Of course, longer term trial like this always have a possibility of technician (or dental nurse) differences and good trial managers attempt to reduced such differences.

Perhaps one way to confirm that such “teething problems” (pardon the pun) did not have an overriding effect is to see that the improvements in oral health measured as differences from the 1954 start were also observed if 1957 was taken as the start (and also for later dates). In our debate I showed this to be a fact using the graphs below.

Hastings data shows similar improvement in oral health even if the project had started in 1957. Plots are for different ages.

Paul, you description of honest research, no matter what its limitations, as fraudulent is irresponsible. Considering your motives for this description and the way you have distorted the situation I would even describe your behavior itself as fraudulent.

Misrepresenting WHO data.

You repeat the same misleading interpretation of the World Health Organisation (WHO) data that we discussed in our debate where you attempted to avoid my criticisms and in the end did not have a sensible response. Despite the refutation, you continue to promote the following misleading graph every chance you get (see also Fluoridation: Connett’s naive use of WHO data debunked):

WHO data

Slide from Connett’s 2016 New Zealand presentation

These data do not support your claim of no difference between the rates of improvement of oral health in fluoridated and unfluoridated countries because there is no attempt to account for all the different factors influencing dental health. Robyn Whyman pointed this out in his report for the National Fluoridation Information Service – Does delayed tooth eruption negate the effect of water fluoridation?:

“Inter-country comparisons of health status, including oral health status, are notoriously difficult to interpret for cause and effect, because there are so many environmental, social and contextual differences that need to be considered.”

It is far more rational to compare regions within countries and you have purposely omitted the WHO data where fluoridated and unfluoridated areas within individual countries were compared.

Here is that WHO data for Ireland which shows a clear benefit in fluoridated areas.

As I said in my post Fluoridation: Connett’s naive use of WHO data debunked:

“I showed this graph to Connett at the beginning of our debate on fluoridation. throughout the next few months he continued to confuse the issue and I kept coming back to it. Finally, he said in his closing statement, “My apologies. I should have checked back.”

An acknowledgment, of sorts, that his use of the WHO data is wrong in his graphs – but he continues to misrepresent it in this way!”

Isn’t it about time you stopped promoting this invalid and misleading use of the WHO data?

Nexo and ChildSmile are complimentary to CWF – not alternatives

Nex and CS

From Paul Connett’s 2016 New Zealand presentation.

You are being disingenuous in promoting oral health programmes like the Danish Nexo and Scottish ChildSmile programmes, as “alternatives” to community water fluoridation (CWF). Health authorities do not see them as alternatives – more as possible complimentary social programmes. The British Dental Association supports both the Scottish ChildSmile programme and CWF. In Scotland it has come out publicly called for communities to move towards introducing water fluoridation. In the absence of CWF, UK health professionals see ChildSmile as “the next best thing – a rather expensive substitute for the fluoridation schemes that have never been introduced.”

I discussed the ChildSmile programme in my article ChildSmile dental health – its pros and cons and in our debate (see Fluoride debate: Ken Perrott’s closing response to Paul Connett?). It, and the Nexo programme, use approaches of child and parent education, toothbrushing supervision and programmes, and  health education initiatives based principally on public health nurses and health visitors attaching themselves to particular schools in order to give oral health advice to children and parents. Subject to parental consent, they also arrange for children who are not registered with a dentist to undergo check-ups and, if necessary, treatment.

Both programmes also provide regular fluoride varnishes for children’s teeth (so much for being an alternative to fluoride).

The point is that elements of these programmes are probably already incorporated into the social health policies of many countries. They certainly are in New Zealand. The introduction of a social health policy like CWF does not mean that programmes like the Nexo and Childsmile, or elements of them, are abandoned by health authorities. The research still shows that CWF reduces tooth decay even when other programmes like this, the use of fluoridated toothpaste and restriction of sugar consumption are practiced (see for example Blinkhiorn et al., 2015).

Interestingly, though, because sometimes programmes like tooth varnishes are targeted at the more vulnerable children in non-fluoridated areas these may lead to difficulties in drawing conclusions from simple comparison of fluoridated and unfluoridated areas. I discussed this in my article on mistakes in one of John Colquhoun’s  papers – Fluoridation: what about reports it is ineffective? – where children from non-fluoridated areas received preferential fluoride varnishing.

There is no single “silver bullet,” for solving the problem of tooth decay so why not use programmes like CWF and Childsmile/Nexo, or elements of the these, together?

In fact, that is exactly what is happening in New Zealand.

Asserting CWF out of step with the science

You claim:

“A better guide as to what nature thinks about the safety of fluoride is the level found in mother’s milk.”

This is simply weird, a naive example of the naturalistic fallacy.

Nature doesn’t think – such an arguments could be used against everything humanity has done to ensure that we have a better quality and length of life than “offered by nature.” As I pointed out in our debate, we are used to other elements being deficient in mothers milk and therefore requiring supplementation (see also Iron and fluoride in human milk for discussion of an evolutionary perspective vs a naive appeal to nature).

Your assertion:

“in mammals not one single biochemical process has been shown to need fluoride to function properly”

is simply deceptive – knowingly so. Fluoride may not play a biochemical role but it does play a chemical one. It is a normal and natural component of bioapatites – bones and teeth. And when present in optimum amounts confers strength and low solubility. Surely as a chemist you are familiar with the fact that minerals like apatite usually do not occur in the ideal form, as end members of a chemical series. In practice, no bioapatites are “fluoride-free.”

I demonstrated the difference between real world apatites and the ideal end members in our 2013/2014 debate using this figure. As a chemist this should be obvious to you.

apatite-2

In the real world bioapatites like bones and teeth always contain fluoride as a normal and natural constituent. The end members hydroxylapatite and fluoroapatite are not real models for natural bioapatites.

You claim that:

“With fluoridation: the chemicals used are not pharmaceutical grade but contaminated waste products from the phosphate fertilizer industry.”

But none of the chemicals used in water treatment, or the water itself, are of  “pharmaceutical grade.” Water plants and water treatment have their own grading system for the chemicals used.

In fact, comparing the certificated concentrations of contaminant elements in fluoridating chemicals used with the same contaminants already in the source water, we find that fluoridating chemicals are not a real source of contamination. We should be more concerned about the source water itself. I presented data to show this in my article Chemophobic scaremongering: Much ado about absolutely nothing. In most cases contamination from the fluoridating chemical is less than 1% of the contaminant concentration already in the source water.

Your reference to “contaminated waste products” is simply naive (or dishonest since you have chemical training) chemophobic scaremongering

Misrepresenting facts on dental fluorosis

dental fluorosis

Paul Connett cites an irrelevant figure in his 2016 New Zealand presentation.

Your claims regarding dental fluorosis are presented as an argument against CWF and in that context are very misleading:

1: The deceit of not identifying contribution from CWF.

Your slide refers to all forms of dental fluorosis and to all areas – fluoridated and fluoridated. It is very misleading to infer that CWF is responsible for a dental fluorosis prevalence of 41%  of dental fluorosis. In fact, CWF makes only a small contribution – often not detectable as was the case with the New Zealand Oral Health survey illustrated below (see Dental fluorosis: badly misrepresented by FANNZ).

Unfortunately, even the recent Cochrane Fluoridation Review (Iheozor-Ejiofor et al., 2015) mistakenly presented the dental fluorosis data without differentiation between fluoridated and non-fluoridated areas. My calculations from their data indicated tyhe prevalence of dental fluorosis due to CWF is more like 7% – much less than your 41% (see  Cochrane fluoridation review. III: Misleading section on dental fluorosis).

2:  Scaremongering by not differentiating between mild and severe forms.

Your 41% sounds scary – especially with the implication it is caused by CWF. But at least your acknowledge that the prevalence of more severe forms is much less. That is obvious from my figure above and from your later slide acknowledging a 3.6% prevalence of moderate and severe dental fluorosis in American teens.

This figure from the National Research Council review shows that CWF (which usually uses a concentration of 0.7 ppm) does not contribute at all to severe dental fluorosis.

Severe-dental-fluorosis

Usually only the moderate and severe forms of dental fluorosis are considered of aesthetic concern – and the milder forms are often judged favourably by parents and teenagers.

What you did not say is that CWF does not contribute at all to moderate and severe forms. These forms are completely irrelevant to the discussion of CWF and it is dishonest to use it as an argument against CWF. Again, my calculation from the Cochrane data indicates the contribution of CWF to dental fluorosis of aesthetic concern was within the measurement error.

If you are really concerned about dental fluorosis, and especially the more severe forms of aesthetic concern, you should be paying attention to high natural sources of fluoride in some regions, industrial pollution and the possibility of obsessive consumption of toothpaste by children.

Brain damage?

Brain

Wild claim by Connett in 2016 New Zealand presentation. There is absolutely no evidence that CWF is harmful to the brain.

Paul, you have been uncritically dredging the scientific literature for articles you can use to imply fluoride is toxic or a neurotoxicant. Of course you will find studies supporting your bias that you can cherry-pick. A similar uncritical dredging will produce far more articles showing water is toxic! Such confirmation bias is scientifically unethical. We should always read the scientific literature intelligently and critically.

Applying a bit of objectivity we see that almost all the studies you rely on use exposure levels far greater than the recommended levels for CWF. Many of the animal studies considered exposure 50 to 100 times those levels or more. The quality of many of the research reports you rely on is not good – a point I think you have acknowledged in the past.  The human studies you rely on have, almost without exception, involved regions of endemic fluorosis quite unrepresentative of regions where CWF is used (I discuss the two exceptions below). None of them properly considered relevant confounding factors.

The exceptions

You promote Malin and Till (2015) as evidence that CWF causes attention deficit hyperactivity disorder (ADHD). You have made no critical assessment of that study. If you had you would have found that when relevant confounders like altitude, poverty and home ownership are included there is not statistically significiant relation of ADHD prevalence with CWF. I demonstrated this in my article ADHD linked to elevation not fluoridation. Coincidentally, the importance of altitude was confirmed in another study which you completely ignore. That study is:

Huber, R. S., Kim, T.-S., Kim, N., Kuykendall, M. D., Sherwood, S. N., Renshaw, P. F., & Kondo, D. G. (2015). Association Between Altitude and Regional Variation of ADHD in Youth. Journal of Attention Disorders.

Unfortunately, the scientific literature is full os such inadequate studies where confounding factors are ignored. Great for confirming biases but, by themselves, absolutely useless if we want to get to the truth.

Peckham et al., (2015) is another example you use. They claimed a relationship of hypothyroidism with CWF but refused to include iodine deficiency (a well established cause of hypothyroidism) in their statistical analysis.

Studies from areas of endemic fluorosis

You extract a lot of mileage out of the studies by Xiang and his coauthors (eg Xiang et al., 2003) – and they are probably the better studies in your collection. But even here your confirmation bias leads you to draw unwarranted conclusions. I showed this in my articles Connett fiddles the data on fluorideConnett & Hirzy do a shonky risk assesment for fluoride and Connett misrepresents the fluoride and IQ data yet again.

For example you claim (correctly) that Xiang found a statistically significant correlation of IQ with urinary fluoride. But a dispassionate consideration of the data shows this relationship explains only 3% of the variance in IQ. I suggest to you that inclusion of some relevant confounders in the statistical analysis would probably cause the correlation with urinary fluoride to be non-significant. This parallels the situation reported by Malin and Till (2015) for ADHD (and here they were able to explain over 20% of the variance in prevalence of ADHD by fluoride – before inclusion of confounders like elevation when the explanatory power of fluoride disappeared).

You have from time to time acknowledged the poor quality of the reports you rely on regarding fluoride and IQ but have said that “there must be something in it” because there are so many reports. There may well “be something in it” but you will not make progress by jumping to your ideologically motivated conclusions favouring chemical toxicity. Just think about it. Those studies occurred in areas of endemic fluorosis – where skeletal fluorosis and severe dental fluorosis are common. It is reasonable to expect such disfiguring and disabling diseases may impact the quality of life, learning ability and IQ of inhabitants. I suggested this mechanism for explaining the data in my article Severe dental fluorosis and cognitive deficits.

CWF is never used in areas of endemic fluorosis so such an effect on cognitive abilities would not occur. And that is consistent with the existing studies which do not show and IQ deficits resulting from CWF (see, for example, Broadbent et al., 2014 and my article IQ not influenced by water fluoridation).

Paul, you are disingenuous to pose the question in your presentations:

“What primary studies (not self-serving government reviews) can you cite that allow you to confidently ignore or dismiss all the evidence of fluoride’s potential to damage the brain?”

We must remember that this is posed in the context of your campaign against CWF and there is no primary study, or review, indicating “potential damage to the brain” from CWF. When you assert “Over 300 studies have found that fluoride is a neurotoxin” you are relying on animal studies where high concentrations of fluoride were used and poor quality studies from areas of endemic fluorosis. None of the studies you rely on are relevant to CWF. It is simply unprofessional scaremongering to promote these sort of political messages:

neurotoxin

Scaremongering slide from Connett’s 2016 New Zealand presentation

I demonstrated in my article Approaching scientific literature sensibly how such uncritical dredging of the literature is meaningless. A Google Scholar search for  produced 2,190,000 results for water toxicity but only 234,000 for fluoride toxicity. So let’s paraphrase your question:

“What primary studies (not self-serving government reviews) can you cite that allow you to confidently ignore or dismiss all the evidence of  water’s potential to damage the body?”

Misrepresentation of evidence supporting CWF

Randomised control trials

Again you raise the red herring of the lack of randomised controlled trials (RTCs) showing CWF effective. As I pointed out to you in our 2013/21014 debate  there is also a lack of RTCs showing CWF not effective – and that must surely tell you something. Simply there are no RTCFs on the subject (although there are on other forms of fluoride delivery like fluoridated milk – see Stephen et al., 1984).

The fact is that such trials are practically impossible with social health measures like CWF. The American Academy of Pediatrics comments in their article on the Cochrane Fluoridation Review:

“it would be a logistical nightmare to try creating a public water system that pumps fluoridated water to the first house on the block, delivers non-fluoridated water to the following two houses and then provides fluoridated water to the 4th and final house on that block.”

This was acknowledged by the Cochrane Reviewers in their discussion. Your mate, and fellow member of the Fluoride Action Network leading body, Bill Osmunson, argues that such an RTC is possible. But his description of how it would be setup shows he is not really serious. He suggests that housing developments be built with several different water reticulation systems and houses be attached to these different systems by flipping coins!

There are some areas of investigation, such as drug efficacy, where RTCs are possible and ethical – but social health measures like CWF is not one of them. That does not prevent an objective analysis of all others sorts of investigation and data which enables health authorities and decision makers to make reliable decisions on such issues.

The Cochrane Fluoridation Review

Paul, I am shocked that with your scientific training you resort to a complete misrepresentation of the recent Cochrane Fluoridation Review (Iheozor-Ejiofor et al., 2015):

Cochrane 1

Connett misrepresented the findings of the Cochrane Fluoridation Review in his 2016 New Zealand presentations

Surely you are not that naive? The reviewers had selection criteria for inclusion of studies in their calculations. This excluded most modern cross-sectional  studies – on the basis of unavailability of data before CWF was started – not quality as you imply. Those restrictions meant they were unable to draw conclusions on the factors  in your slide – but they were discussed, and the studies cited, in the discussion section of the review. These non-selected studies do show that CWF is beneficial to adults (Griffin et al., 2007Slade et al., 2013), provides benefits even when fluoridated toothpaste is considered (see Water fluoridation effective – new study and Blinkhorn et al., 2015) and reduces social inequalities (Riley et al., 1999). The research also shows tooth decay increases when CWF is stopped (see Fluoridation cessation studies reviewed – overall increase in tooth decay noted and Mclaren & Singhal 2016).

How is it that you ignore the language in the review referring to limitations imposed by its selection criteria and then present their qualified conclusions as if they were facts. Can you not understand sentences like?:

“Around 70% of these studies were conducted before 1975. Other, more recent studies comparing fluoridated and non-fluoridated communities have been conducted.We excluded them from our review because they did not carry out initial surveys of tooth decay levels around the time fluoridation started so were unable to evaluate changes in those levels since then.”

Why did you persistently ignore the qualifications in their conclusions imposed by their selection criteria expressed in the common phrase?

“We found insufficient information . . . “

And, why did you purposely ignore the specific conclusion:

“Our review found that water fluoridation is effective at reducing levels of tooth decay among children. The introduction of water fluoridation resulted in children having 35% fewer decayed, missing and filled baby teeth and 26% fewer decayed, missing and filled permanent teeth.We also found that fluoridation led to a 15%increase in children with no decay in their baby teeth and a 14%increase in children with no decay in their permanent teeth.”

Yes, that was followed by the disclaimer “These results are based predominantly on old studies and may not be applicable today.” But that only means the reviewers could not draw specific conclusions about today because they had excluded modern studies.

You have purposely ignored the issues around study selection and presented their inability to draw conclusions as evidence that there is no effect. That is not a scientific assessment of the review – it is a blatantly propagandist exercise in cherry picking motivated by an ideological position. An exercise in public relations, not proper scientific assessment.

Topical vs systemic

I think one change that did come out of our debate is that you now tend to qualify you claims about the systemic and topical roles of fluoride in preventing tooth decay. You use words like “primary” and “predominantly.” But you still confuse the issue by arguing that topical action is quite separate from ingestion when you ask”

“If fluoride works primarily on the outside of the tooth why swallow it?”

The fact is that fluoride, calcium and phosphorus in dental plaque and saliva (to which the CDC attributes the topical action of decay prevention) occur through ingestion of these nutrients in food and water. It is naive to separate the reaction at the tooth surface from ingestion of food and beverage.

You also ignore completely the evidence that ingested fluoride plays a beneficial systemic role with developing and so far unerupted teeth (see Ingested fluoride is beneficial to dental health and Cho et al., 2014).

And let’s not forget about our bones which benefits from appropriate amounts of fluoride in our diet (see Is fluoride an essential dietary mineral? and  Yiming Li et al., 2001)

Use of PR techniques – You are the guilty party

I have shown here how you have distorted and misrepresented the science around CWF. In doing so you are behaving as an ideologically driven lobbyist – not an objective scientist. You are not intelligently and critically assessing the scientific literature – you are cherry-picking and selectively quoting to promote your own agenda.

Personally, I think this sort of behaviour is unethical for a scientist. Sure, we all have our biases and beliefs and this can influence our interpretation of the literature. But you are consistently misrepresenting the science – and continue to do so even after you have been shown wrong.

Perhaps this is unsurprising considering you are essentially a political lobbyist campaigning against a social health policy. You lead a lobby organisation – the Fluoride Action Network. This organisation receives finance from the “natural”/alternative health industry – most publicly from Mercola. According to tax returns you and other members of your family, personally receive monthly payments from these funds.

It hypocritical for you, then, to disparage honest scientists and their publications in the way you have done regarding the Hastings project. Your bias (and refusal to deal with the science) comes out in your description of scientific reviews and papers as “dummy reviews,” “bogus,” “self-serving government reviews,” etc.

In one of your final slides you claim the alleged PR tactics by scientists:

“Would not be necessary if science was on the promoters’ side – but it is not.”

In fact, it is you that are on the wrong side of the science and that is why you resort to misrepresentation, distortion, fear mongering and slander.

You also claim:

“After 6 years there has been no detailed or documented response to our book The Case Against Fluoride.”

And

“Proponents will very seldom agree to publicly debate either myself or other leading opponents of fluoridation.”

Yet, isn’t that exactly what I did in our Fluoride Debate of 2013/2014? And didn’t I give a platform on my blog for you to make all your points and to present the arguments from your book?

And isn’t it a fact that in most forums where your lobby against CWF you, in fact, lose because the scientific arguments against you prevail? You make a big thing of every single victory you achieve against CWF but are silent about the larger number of losses.

As we are discussing the refusal to debate let’s be honest. Your organisations, internationally and locally, attempt to prevent supporters of science from involvement in their discussion forums. I personally have been banned from all local anti-fluoride forums and from the Fluoride Action Networks Facebook forum.

This suggests to me that neither you nor your supporters are willing to take part in a good-faith discussion of the science around CWF. You are simply behaving like a political and commercial lobbyist – not a scientist for whom such discussion should be welcome.

Nevertheless, once again I offer you a right of reply to my comments in this article. In fact, I would happily welcome such a reply as this would be in the best traditions and interests of the science.

References

I have included only citations where links were not available.

Ludwig, T. G. (1958). The Hastings Fluoridation project I. Dental effects between 1954 and 1957. New Zealand Dental Journal, 54, 165–172.

Ludwig, T. G. (1959). The Hastings fluoridation project: II. Dental effects between 1954 and 1959. New Zealand Dental Journal, 55, 176–179.

Ludwig, T. G. (1962). The Hastings fluoridation project III-Dental effects between 1954 and 1961. New Zealand Dental Journal, 58, 22–24.

Ludwig, T. . (1963). Recent marine soils and resistance to dental caries . Australian Dental Journal, 109–113.

Ludwig, T. G. (1965). The Hastings fluoridation project V- Dental effects between 1954 and 1964. New Zealand Dental Journal, 61, 175–179.

Ludwig, T. G. (1971). Hastings fluoridation project VI-Dental effects between 1954 and 1970. New Zealand Dental Journal, 67, 155–160.

Ludwig, T. G.; Healy, W. B.; Losee, F. L. (1960). An association between dental caries and certain soil conditions in New Zealand. Nature, 4726, 695–696.

Ludwig, T.G.; Healy, W. B. (1962). The production and composition of vegetables in home gardens at Napier and Hastings. New Zealand Dental Journal, 58, 229–233.

Ludwig, T.G.; Pearce, E. I. F. (1963). The Hastings fluoridation project IV – Dental effects between 1954 and 1963. New Zealand Dental Journal, 59, 298–301.

Xiang, Q; Liang, Y; Chen, L; Wang, C; Chen, B; Chen, X; Zhouc, M. (2003). Effect of fluoride in drinking water on children’s intelligence. Fluoride, 36(2), 84–94.

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Debating fluoridation and tyranny – Tom O’Connor responds

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Individual consent – what does it mean and how is it obtained?

This article below is a guest contribution from Tom O’Connor responding to my article Attempting a tyranny of the minority on fluoridation. I invited Tom to discuss the issue here, and offered him a right of reply because I think there is value in discussing the points he raised in his Timaru Courier opinion piece and  that I critiqued in my article.

Unfortunately, in this issue, the scientific arguments are very often a proxy for underlying values issues, at least on the part of opponents of fluoridation. It is in the nature of values issues that there is no “correct” answer (in contrast to arguments about facts). Nevertheless, the values issues are important so I hope they can be developed in discussion here around Tom’s original opinion piece and his response here. In the end, such issues are decided by democratic and political means so open discussion of the issues is important.


Firstly I am not opposed to the use of fluoride to combat tooth decay per se. Nor do I have any “anti-fluoride mates” as you put it. If the government wants to make fluoride freely available there are many ways of doing that without imposing it on everyone.

There are three main elements to the fluoride debate. The first is the efficacy or otherwise of fluoride as a preventative for tooth decay.

The second is the use of reticulated potable water as a means of delivering anything other than clean water to the community.

The third is the issue of mass medication, or mass treatment or mass therapy of people without individual consent and practical convenient and affordable alternatives. Legislating to declare a medical treatment is not a medical treatment simply on the ground that the dose rate is measured in parts per million is one of the most stupid and dishonest things I have ever seen any government do. Many medications are measured in such minute quantities.

The Grey Power Federation objection to the proposed addition of fluoride to potable reticulated water is based on the third element only. We do not have a policy in the first element simply because we do not have the expertise or scientific qualifications to develop such a policy. We have not considered the second element.

That policy has been, in my view, adequately explained in the Timaru Courier opinion piece you refer to. The following comments are therefore mine alone and do not necessarily reflect the opinion of Grey Power members or anyone else.

Efficacy

As you rightly point out there is probably nothing to be gained in participating in the endless argument between proponents and opponents of fluoride as an oral health treatment. Both sides have accused the other of engaging in pseudo-science and scare mongering. Both are, to some extent, probably accurate and in agreement on that point alone. However, where doubts exist, it is probably better to err on the side of caution.

Reticulated water

Territorial local authorities have the responsibility to provide potable water to their communities where no other sources are available or suitable. The principle responsibility of local authorities, as outlined in the Drinking Water Standards for New Zealand, administered by the Ministry of Health, is to ensure drinking water is as free from all other substances and organisms as possible. Using reticulated potable water to convey anything else, be it medical or not, is contrary to that principle.

The use of chlorine to remove micro-organisms and other pathogens is designed to remove unwanted and potentially unsafe matter from drinking. At the end of that process there is not supposed to be any detectable chlorine. That there often is demonstrates the difficulty of getting the addition of trace elements correct. That is a very different matter to the deliberate introduction of an additional substance which many people don’t want.

Mass treatment and individual consent

This is not the first time mass medication or treatment has been introduced in New Zealand. Iodine deficiency, as a cause for goitre, was discovered in the early 1900s and to address the problem table salt was iodised at up to 80mg of iodine per kilogram of salt in 1938. This was accompanied by an extensive public education programme and there was always un-iodised salt as a practical, convenient and affordable option on grocer shop shelves for those who did not want it.

Suggesting that those who object to fluoride in the water they pay their local authority to deliver can obtain alternative supplies from a community tap or buy it from the supermarket is unacceptable. These options are not possible, practical, convenient or affordable for many people.You may also recall a recent proposal to add folic acid to all bread products as a means of addressing a reproductive issue for women. The public outcry which saw that proposal dropped was not solely based on doubts about the efficacy of folic acid but the fact they many people simply did not want their bread medicated with anything for any reason.

You may also recall a recent proposal to add folic acid to all bread products as a means of addressing a reproductive issue for women. The public outcry which saw that proposal dropped was not solely based on doubts about the efficacy of folic acid but the fact they many people simply did not want their bread medicated with anything for any reason.

There are practical and cost effective methods of providing fluoride for those who want it. Forcing it on those who don’t want it is simply unacceptable in a free society.

Tom O’Connor


I will post a response to Tom’s arguments in a few days. Meanwhile, readers are welcome to make their own arguments in the comments section.

Ken Perrott

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NZ Fluoridation review – Response to Micklen

I welcome open and transparent discussion here so am thankful to Dr Micklen for his response (see NZ Fluoridation review – HS Micklen responds to critique). Unfortunately he is the only author or “peer-reviewer” of Fluoride Free NZ’s report criticising the NZ Fluoridation review to accept my offer of a right of reply to my critiques. A pity, as if any of them think I have got things wrong, and they can support this with evidence, I certainly want to know about it. There are three aspects to Dr Micklen’s reply – dental fluorsis chronic kidney disease and his critique of my letter in the journal Neurotoxicology and Teratology –   Perrott (2015). I will deal with these separately.

Dental fluorosis

I appreciate Dr Micklen is unhappy about my criticisms of his article, and my suggestion his comments of dental fluorosis were muddled. I may have been a bit harsh but he has still not responded to my specific criticism that he:

“unfairly attributes the more severe forms [of dental fluorosis] to community water fluoridation (CWF). Consequently he calculates a cost of dental treatment which is wrong.”

The key problem is that Micklen is assuming that all the  medium and severe dental fluorosis can be attributed to CWF, whereas none of it can. Briefly reviewing the argument – the figure below is from the NZ Ministry of Health’s Our Oral Health – the same source Micklen used. My comment on the relevance of the different grades of dental fluorosis was:

“Moderate and severe grades of dental fluorosis are common in areas where fluorosis is endemic, but relatively rare where CWF is used. Occurrences in the latter case, despite the low concentrations of fluoride in treated drinking water, will have other causes – high natural levels in well water, industrial pollution, excessive consumption of toothpaste, etc.”

The important factor is that severe and moderate forms of dental fluorosis are not caused by CWF. CWF can contribute to mild and very mild forms of dental fluorosis but because these are usually judged positively they certainly don’t need expensive veneers – my dentist colleagues advise simple microabrasion usually works. So Micklen was wrong to suggest the cost of cost of veneers (up to $1750 per tooth) should be attributed to CWF because such costs would be encountered in non-fluoridated areas as well. (In fact, if Micklen had calculated costs for such treatment in non-fluoridated areas using the “Oral Health” data in the literal way he did for the fluoridated areas,  he would have found costs to be higher than in non-fluoridated areas! Certainly doesnt’ support his claim but a meaningless result because of the small numbers and large variability).

Chronic kidney disease

Micklen accuses me of  using “a piece of grammatical legerdemain to pretend that I [Micklen] called for CKD sufferers to be warned to avoid tap water, which I did not.” Granted he left himself a way out by actually writing:

“I suspect that most opponents of fluoridation would call for CKD sufferers to be warned to avoid tap water. Possibly the NZ health authorities have done so.”

OK, so its not a direct personal recommendation (perhaps he doesn’t belong to the group of “most opponents of fluoridation”) but a reader could be excused for getting that message and in this context it comes across as “dog whistling.” However I will accept his assurance now that:

” In fact, I am inclined to agree with him [me] that that might be extreme in the present state of knowledge.”

As for questions like: “Does further research on the topic receive any funding priority, for example?” – well this is a round about way of giving the message that it doesn’t. Perhaps he should actually check that out and give some evidence instead of making an unwarranted implication. This tactic of posing unfounded questions to convey an unwarranted message is typical of the approach Micklen and Connett take in their book The Case against Fluoride. I criticised this tactic in my exchange with Paul Connett (see Fluoride Debate). I reject Micklen’s suggestion that:

“Perhaps it would be embarrassing, too, for a government to insist on putting fluoride in the water and then advise a substantial number of people not to drink it – or so one might think.”

That is silly – it is like a conspiracy theory. Why would genuine health authorities refuse to give warnings to a small group of people who might be put at risk from a social health policy that is beneficial to the vast majority? Surely they are used to such situations. I also think he is waxing lyrical with the word “substantial!” The numbers involved would be very small, if any, and such a group would already be advised about a number of risks to them because of their condition and treatments. Micklen also lets his ideological position take over  by drawing the implication from my article that I am saying CWF is “effective and safe – for some.” Far from it. Surely I am saying it is effective and safe for the vast majority (which is what we can expect from a social health policy) and simply recommending (as in all such policies) that the small group of people, if any, who might be at risk should use alternatives. I am actually saying that CWF is effective and safe for at least  the vast majority and that claims to the contrary should be backed up with evidence which should be considered critically

Severe dental fluorosis and cognitive deficits

I thank Dr Micklen for his comments on my letter in the journal Neurotoxicology and Teratology – (Perrott 2015). I am pleased he accepts the hypothesis that severe dental fluorosis could explain observations of cognitive deficits is worth considering and  he agreed with the other reviewers the letter was worth publishing. Influence of age I take his point that the poor appearance of teeth may not influence young children (ages 6-8 as in the small the group Choi et al, (2015) studied). However, this is pure speculation on his part and is surely a detail. A detail that should be considered in any planned research incorporating this hypothesis, but not in itself a reason for rejecting the hypothesis out of hand – surely? Unless, of course, he can give evidence to support his suggestion. I notice that he does not support the idea with any citations so suspect the idea is more one of straw-clutching  than a serious suggestion. Actually most, but not all, of the citation I used did indeed refer to work with older children. Some were review papers and did not limit their review to any age group. Aguilar-Díaz, et al., (2011) considered children from 8 – 10 years old, Do and Spencer, (2007) studied 8-12 year olds and Abanto et al., (2012) 6-14 year old children. Chikte (2001) studied three groups: 6, 12, 15 year olds. However, I found a quick literature search showed reports of negative effects of oral defects like tooth decay on the child’s quality of life. Kramer et al., (2013) reported this for ages 2 – 5, Scarpelli et al., (2013) for 5 year olds and Cunnion et al., (2010) for 2 – 8 year olds. So, I suggest on the available evidence the negative influence of severe dental fluorosis on quality of life (and possibly cognitive deficits) is likely to occur even in younger children who have not “reached an age to be self-conscious about their appearance.” I don’t think young children are as immune to social attitudes and personal appearance as Dr Micklen suggests. Does effect depend on how common dental fluorosis is?  Dr Micklen suggests that:

“Since fluorosis was common in the community [the children studied by Choi el., 2015], having the condition would not appear abnormal.”

Again I think he is indulging in straw-clutching, or special pleading. special-pleading-fallacy Clearly medium and severe dental fluorosis is far more common in this Chinese group than in countries like New Zealand which use CWF. In the graph below I compare their data with that for New Zealand and USA. Incidentally, this figure shows why the data from Choi et al., (2012, 2015) should not be used as an argument against CWF – yet that is what Micklen did in his original article. DF---good-and-bad But this does not mean that those children with more severe forms will not stand out against the children with less severe forms. There is always a range of appearances of such defects in a group of children. Some will obviously suffer more than others because of their appearance. If Choi et al., do continue to include detailed analysis of dental fluorosis in their future work on this issue then it will be possible to compare cognitive deficit measurements with dental fluorosis indices in a larger group. Such data will be interesting. However, discussion of details like this is premature. My letter simply raised to idea as an alternative worth considering and encouraged the group to continue including detailed dental fluorosis measurements in future work. I was also concerned that they were not being sufficiently open-minded in their choice of a working hypothesis. I concluded my letter with:

Researchers need to be careful not to limit their possible hypotheses or research approaches. Unfortunately Choi et al. (2014) appear to be doing just this with their plans for a larger scale study targeted only at “fluoride’s developmental neurotoxicity.”

Unfortunately none of this group have yet responded to my letter. So, again, I thank Dr Micklen for his feedback on that letter – and his acceptance of the right-of-reply to my article critiquing the FFNZ report. See also:

References

Abanto, J., Carvalho, T. S., Bönecker, M., Ortega, A. O., Ciamponi, A. L., & Raggio, D. P. (2012). Parental reports of the oral health-related quality of life of children with cerebral palsy. BMC Oral Health, 12, 15. doi:10.1186/1472-6831-12-15 Aguilar-Díaz, F. C., Irigoyen-Camacho, M. E., & Borges-Yáñez, S. A. (2011). Oral-health-related quality of life in schoolchildren in an endemic fluorosis area of Mexico. Quality of Life Research : An International Journal of Quality of Life Aspects of Treatment, Care and Rehabilitation, 20(10), 1699–706. Chikte, U. M., Louw, A. J., & Stander, I. (2001). Perceptions of fluorosis in northern Cape communities. SADJ : Journal of the South African Dental Association = Tydskrif van Die Suid-Afrikaanse Tandheelkundige Vereniging, 56(11), 528–32. Choi, A. L., Sun, G., Zhang, Y., & Grandjean, P. (2012). Developmental fluoride neurotoxicity: A systematic review and meta-analysis. Environmental Health Perspectives, 120(10), 1362–1368. Choi, A. L., Zhang, Y., Sun, G., Bellinger, D., Wang, K., Yang, X. J., … Grandjean, P. (2015). Association of lifetime exposure to fluoride and cognitive functions in Chinese children: A pilot study. Neurotoxicology and Teratology, 47, 96–101. Cunnion, D. T., Spiro, A., Jones, J. a, Rich, S. E., Papageorgiou, C. P., Tate, A., … Garcia, R. I. (2010). Pediatric oral health-related quality of life improvement after treatment of early childhood caries: a prospective multisite study. Journal of Dentistry for Children, 77, 4–11. Do, L. G., & Spencer, A. (2007). Oral Health-Related Quality of Life of Children by Dental Caries and Fluorosis Experience. Journal of Public Health Dentistry, 67(3), 132–139. Kramer, P. F., Feldens, C. A., Ferreira, S. H., Bervian, J., Rodrigues, P. H., & Peres, M. A. (2013). Exploring the impact of oral diseases and disorders on quality of life of preschool children. Community Dentistry and Oral Epidemiology, 41(4), 327–35. NZ Ministry of Health. (2010). Our Oral Health Key findings of the 2009 New Zealand Oral Health Survey. Perrott, K. W. (2015). Severe dental fluorosis and cognitive deficits. Neurotoxicology and Teratology. Scarpelli, A. C., Paiva, S. M., Viegas, C. M., Carvalho, A. C., Ferreira, F. M., & Pordeus, I. A. (2013). Oral health-related quality of life among Brazilian preschool children. Community Dentistry and Oral Epidemiology, 41(4), 336–44.

NZ Fluoridation review – HS Micklen responds to critique

I have posted several articles in a series critiquing contributions to the Fluoride Free NZ report Scientific and Critical Analysis of the 2014 New Zealand Fluoridation Report which is aimed at discrediting the recent review Health Effects of Water Fluoridation: a Review of the Scientific Evidence produced by the Royal Society of NZ together with the Office of the Prime Minister’s Chief Science Advisor. The articles in this series are collected into a pdf document which can be downloads from Download report analysing anti-fluoride attacks on NZ Fluoridation Review.

In an attempt to encourage a discussion on the fluoridation review and the FFNZ report I offered all the authors and “peer-reviewers” of the FFNZ report the right of reply to my critiques. So far Dr H. S. Micklen (whose article I critiqued in Fluoride Free NZ report disingenuous – conclusion), is the only one to take up this offer.

Here is his reply. 


I thank Dr Perrott for reproducing my notes on the NZ Fluoridation Review and appreciate his comments. My appreciation would be warmer had he spent less time using his imagination and paid more attention to what I actually wrote.  He has me bustling around, agenda in hand, clutching at straws here, raising bogeys there, scaremongering, relying on this, calling for that, and getting confused about different grades of fluorosis (as if..,). All nonsense.  If I “distort the science” as Perrott’s headline proclaims, he does a great job of distorting the distortion.

Most of my short piece merely commented on a few places where, in my opinion, the NZ report failed – through error, omission or incompetence – to reach proper standards of objectivity and impartiality and exhibited ill-founded complacency. Since the NZ report was highly biased in favour of fluoridation, any criticisms of it are likely to have an anti-F flavour. Too bad; I was dealing with the report’s view of the science, not pushing my own. I avoided speculating on the outcome of issues that I consider unresolved, dental fluorosis (where Perrott makes nonsense of what I wrote) being the only exception.

Most of these issues have been argued over ad nauseam and I shall not try to unscramble Perrott’s lucubrations. The question of chronic kidney disease and its possible cardiovascular consequences is perhaps an exception. I gave credit to the Review for discussing the paper by Martin-Pardillos. Agreeing with the Review’s opinion that the results needed to be confirmed, I remarked “The interesting question is, what should happen meanwhile?” That is not a rhetorical question. What does, or should, happen when an alarm bell sounds over a long-established procedure? Does further research on the topic receive any funding priority, for example?  Perrott uses a piece of grammatical legerdemain to pretend that I called for CKD sufferers to be warned to avoid tap water, which I did not. In fact, I am inclined to agree with him that that might be extreme in the present state of knowledge. Perhaps it would be embarrassing, too, for a government to insist on putting fluoride in the water and then advise a substantial number of people not to drink it – or so one might think. But Perrott concludes “Any patients who are particularly worried can then take steps like using filtered water for their own peace of mind. This seems more appropriate than denying the rest of the population access to a simple, effective and safe (for them at least) social health policy like CWF.”  So that’s all right then, thanks to the patients, whom Perrott doubtless consulted, being willing to promote the alleged greater good. He has pricked a hole in the old mantra, though: “effective and safe – for some”.

Perrott asked for my feedback on his idea about the possible effect of dental fluorosis on IQ.  Since then his paper has appeared online as a short article in Neurotoxicology and Teratology. Perhaps the best thing I can do at this stage is pretend that it had arrived on my desk for peer review. I would have commented as follows.

“This communication refers to a recent paper by Choi et al (2014) that reports certain cognitive defects in young children affected by moderate-severe dental fluorosis. Choi et al suggest that this is due to an adverse effect of fluoride on the developing brain. The present author proposes an alternative explanation, namely that fluorosis itself, and the stress of living with it, can affect learning and general quality of life and result in poor performance in certain types of cognitive test. This appears to be a novel idea and, as such, is suitable in principle for publication as a short communication. There is, however, a fundamental question that the author should be invited to address and clarify with a view to possible resubmission.

“The paper is somewhat discursive and lacking in focus and in the course of it the author seems to lose track of what age group he is talking about. Surprisingly, he does not mention the age of Choi’s (2014) subjects, which averaged 7 years  (range 6-8). When he finally presents evidence that moderate-severe fluorosis is aesthetically displeasing and likely to impair quality of life, all of it relates to older children, mainly teenagers, who have reached an age to be self-conscious about their appearance and have been living with fluorosis for several years. In contrast, 16% of Choi’s (2014) subjects had no erupted permanent teeth at all and in the remainder eruption of the first permanent teeth would have been very recent. Since fluorosis was common in the community, having the condition would not appear abnormal. The crucial question is whether the author is proposing that the quality of life of these young children is so compromised by fluorosis as to impair their performance in cognitive tests. Apparently the answer is a tentative affirmative: It is just possible that the negative quality of life associated with oral defects like severe dental fluorosis contribute to cognitive deficits reported by Choi et al. (2012, 2014)’

“The author needs to discuss this issue in a transparent fashion so that readers can judge for themselves whether the proposal is plausible. Conversely, if he is not making such a proposal, that too should be made clear.

“The author might wish to refresh his memory of the paper by Hilsheimer and Kurko (1979), which really is of virtually no relevance to his argument.”

I hope this helps.

H S M 12 February 2015

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Fluoride debate: A response to Rita Barnett-Rose – Daniel Ryan

Dan Ryan 2

Daniel Ryan from the Making Sense of Fluoride group

Daniel Ryan President of the Making Sense of Fluoride group responded to the scientific claims made in Rita Barnett-Rose’s unpublished paper Compulsory water fluoridation: Justifiable public health benefit or human experimental research without informed consent“.

That section of Rita’s paper was posted as the first article in this exchange yesterday at Fluoride debate: The scientific evidence against fluoridation – Rita F. Barnett.

Daniel’s critique is available to download as a pdf.


Compulsory water fluoridation: A response to Rita Barnett-Rose – Daniel Ryan

Introduction

I have contacted Associate Professor Rita Barnett-Rose about her unpublished paper Compulsory water fluoridation: justifiable public health benefit or human experimental research without informed consent.”  It concluded that “The evidence continues to suggest that compulsory water fluoridation is no longer justifiable as a public health benefit” and “human rights burden and economic costs are not reasonable or justifiable”.

There were claims about the science which (presumably) are important for the legal/ethical conclusions. We at Making Sense of Fluoride (MSoF) felt there was misinformation on the science and a public exchange would be a good way to engage in a discussion of the claims – even withdrawing those claims if found wrong. We thank Rita for listening to us and hope that we find common ground even if it’s just in the science.

Discussion

For the most part of this discussion I will stick to pages 13-19 with the header “Scientific Evidence against Compulsory Water Fluoridation” and breaking down into the sub-headers.

First off, looking at the sources used, there are many that are comments and articles from political activists rather than primary research sources. For example Fluoride Action Network is not a credible scientific organisation. This is not a good way of reviewing the scientific literature; in fact it is very poor practice. This is a fundamental problem with this paper.

The paper starts off saying there is mounting scientific evidence against fluoridation. The evidence used was an opinion piece from John Colquhoun. Dental Watch has a paper “Why We Have Not Changed Our Minds about the Safety and Efficacy of Water Fluoridation: A Response to John Colquhoun” that critiques his paper:

“His paper rehashed earlier criticisms of water fluoridation, using selective and highly biased citations of the scientific and non-scientific literature”.

Why I Am Now Officially Opposed to Adding Fluoride to Drinking Water” from Dr. Hardy Limeback and “Dr. William Hirzy Portland letter” are also opinion pieces. It is important to note that Dr. Hardy Limeback is a member of the Advisory Board of Paul Connett’s Fluoride Alert Network. Dr. William Hirzy works for Fluoride Action Network as a paid political lobbyist. “Mounting scientific evidence”– nothing could be further from the truth. There is not one reputable health organisation that is against fluoridation.

1: Dental Fluorosis

There is no argument that having too much fluoride when the teeth are forming will cause dental fluorosis but this isn’t the case for fluoridation. There is little difference in frequency and severity of fluorosis between non-fluoridated and fluoridated areas, something which Barnett-Rose (2014) seems to ignore. The CDC source given was looking at fluorosis as a whole and not at fluoridated vs non-fluoridated, but it states that “community water fluoridation programs were developed to add fluoride to drinking water to reach an optimal level for preventing tooth decay, while limiting the chance of developing dental fluorosis”. If there were any large differences in fluorosis then I would be all for another look into balancing the levels of fluoride in those areas. In fact health authorities in many countries continually monitor research findings for this very reason and that was the reason for the National Research Council (2006) review which did recommend reducing the primary MCL of 4 ppm.

Any increase in fluorosis due to CWF would be in the very mild to mild fluorosis range. The dental fluorosis about which they speak in Warren’s et al. (2009) “Iowa study” is overwhelmingly of the barely detectable nature. The 2009 New Zealand Oral health Survey found very little difference between fluoridated and non-fluoridated areas, in terms of the levels of mild to very mild fluorosis (which has no effect on appearance, form or function of teeth), as shown on the graph below. In fact, Lida & Kumar (2009) have demonstrated mildly fluorosed teeth to be more decay resistant.

fluorosis-NZ

The statement that fluorosis is “the first sign of fluoride toxicity” is debatable. What sign of which particular toxicity? Just because there might be other effects which have not yet been shown is not proof that there are other effects. It presumably has been a common feature of teeth through the centuries and is harmless.

The American Dental Association website says:

“Yes, it is safe to use fluoridated water to mix infant formula. If your baby is primarily fed infant formula, using fluoridated water might increase the chance for mild enamel fluorosis, but enamel fluorosis does not affect the health of your child or the health of your child’s teeth”.

The recommendation by health authorities that parents use unfluoridated water to make up formula is a peace-of-mind suggestion, not a firm recommendation. For example the CDC says:

“However, if your child is exclusively consuming infant formula reconstituted with fluoridated water, there may be an increased chance for mild dental fluorosis. To lessen this chance, parents can use low-fluoride bottled water some of the time to mix infant formula”.

For infants and children in their tooth-developing years of 0-8, the upper limit (UL) for fluoride is lower, but only due to a risk of development of mild dental fluorosis. That’s why the UL for daily fluoride jumps to 10mg/day after age 8, once the teeth are formed.

The rest of the “Dental Fluorosis” section in Barnett-Rose (2014) talks about moderate to severe dental fluorosis, which is not caused by community water fluoridation and so is pointless to discuss.

2: Skeletal Fluorosis and Bone Fractures

Again, there is no disagreement that chronic exposure to high levels of fluoride can cause skeletal fluorosis and increase the risk of bone fractures. But you don’t see these problems at levels of 0.7-1.2 ppm in community drinking water. The Institute of Medicine has established that the daily upper limit for fluoride intake from all sources, for adults, before adverse effects will occur, short or long-term, is 10 mg. There is no quality research to show skeletal fluorosis can develop at the levels of 0.7-1.2ppm. Even the source used in Barnett-Rose (2014) says “Crippling skeletal fluorosis may be produced by levels of 10-20 mg/day over 10-20 years”.

National Fluoridation Information Service has released a report this month on fluorosis and concluded:

“There are no known health risks associated with CWF in New Zealand, and no severe dental fluorosis, or skeletal fluorosis, has been found. While fluoride is incorporated into teeth and bones, there is no robust evidence of toxic accumulation of fluoride in other tissues in the body”. It also noted in its conclusion “As with many vitamins and minerals, such as iron, and vitamins A and D, fluoride intakes at high levels can be toxic. However, it is impossible to experience acute fluoride toxicity from drinking water optimally fluoridated at levels between 0.7 mg/L to 1.0 mg/L (MoH, 2009), and there is no evidence of skeletal fluorosis resulting from CWF in New Zealand. It makes sound clinical sense to ingest a substance at a level that achieves maximum benefit with minimal adverse effects (Bowen, 2002)”.

One needs to be careful of cherry picking scientific studies. When you look at all the data you will find bone fracture is not an issue. Vestergaard et al. (2007), in a meta-analysis that used 25 studies, came to the conclusion that “there was no effect on hip or spine fracture risk”. He also noted that “in subgroup analyses a low fluoride dose (< or =20 mg/day of fluoride equivalents) was associated with a significant reduction in fracture risk”. This showed that fluoridation can help bones when at the optimum fluoride levels.

Ingestion of some fluoride is necessary as the bioapatites in our body contain both fluoride and carbonate as normal, natural components. The incorporation of ions like fluoride into bioapatites can change their solubility product by several orders of magnitude according to Driessens (1973). Posner et al. (1963) attribute the improved stability of bone to “the isomorphous substitution of fluoride in the apatite structure”.

3. Pineal Gland and Endocrine Disruption Studies

Fluoride can accumulate in the pineal gland. Calcification of the pineal gland is caused by calcium, phosphate and old age. Because the bioapatites in calcified tissues are actively undergoing mineralisation and remineralisation they easily incorporate fluoride into their structure and this leads to higher concentration of fluoride in calcified tissues than in bones generally. No evidence of harm has been found.

There is no known link to hypothyroidism at the levels we get in water fluoridation. I’m not sure where the evidence for “The fluoride dose capable of reducing thyroid function is low – just 2 to 5 mg per day over several months” from Barnett-Rosie (2014). Her source, the Fluoride Action Network website, points to a study Galletti & Joyet (1958), which says:

“Our aim was to elucidate the inhibitory effect of chronic administration of fluoride upon thyroid function in cases of hyperthyroidism. It was demonstrated that such an action appears only occasionally among persons subjected to massive doses of this substance”.

The study was working with prolonged administration of a daily dose of 2-20 mg (on top of their diet). This was also a very small study of 15 people who suffered from hyperthyroidism. Galletti also noted that

“Despite the relatively large amounts administered (up to 20 mg. of F~ for one injection), neither immediate nor delayed toxic manifestations were observed”.

This demonstrates my point that primary sources should be used, and definitely not activist websites.

The ADA concludes on its fluoridation facts document:

“There is no scientific basis that shows fluoridated water has an adverse effect on the thyroid gland or its function”.

It also states:

“The researchers concluded that prolonged ingestion of fluoride at levels above optimal to prevent dental decay had no effect on thyroid gland size or function. This conclusion was consistent with earlier animal studies”

4. Cancer Studies

Bassin (2006) data presentation did not show how many cases and controls were included in each of the models; and fluoride exposures were estimated rather than measured directly. The authors commented that “Further research is required to confirm or refute this observation”. The NHMRC (2007) observed that:

“Shortcomings in their study mean the results should be interpreted with caution pending publication of the larger study results. Co-investigators of Bassin point out that they have not been able to replicate these findings in the broader Harvard study that included prospective cases from the same 11 hospitals”.

There is no demonstrable link between fluoride and cancer. The American Cancer Society says:

“The general consensus among the reviews done to date is that there is no strong evidence of a link between water fluoridation and cancer”.

The National Cancer Institute says:

“Fluoride in water helps to prevent and can even reverse tooth decay. More than 60 percent of the U.S. population has access to fluoridated water through public water supply systems. Many studies, in both humans and animals, have shown no association between fluoridated water and cancer risk”.

This is backed up by systematic reviews e.g. the York Review (2000) reported “No clear association between water fluoridation and osteosarcoma”. The National Research Council (2006) commented:

“Assessing fluoride as a risk factor for osteosarcoma is complicated by the rarity of the disease and that population is all generally exposed to some level of fluoride”.

SCHER (2010) reported:

“a possible link between fluoride in drinking water and osteosarcoma, but studies are equivocal. No evidence from animal studies to support the link, and thus fluoride cannot be classified as to its carcinogenicity”.

5. Lower IQ’s in Children

It is debatable that Mullenix et al. (1995) interpretation on the study was flawed, it doesn’t matter if it was in a “well-respected peer reviewed journal” or not. Plenty of well-respected journals have released poor papers. One such example was Wakefield’s (1998) claim of a link between vaccines and autism, published in The Lancet.

The study by Mullenix et al. (1995) was refuted by Ross & Daston (1995):

“In summary, much of the ambiguity in the interpretation of these results could have been avoided with information from two concurrent or historical control groups: 1) a group to define the behavioral signature resulting from long term adulteration of the drinking water, and 2) a group to define the behavioral signature of animals with hippocampal damage in this testing system. Such controls are an essential feature of test validation and experimental design. Novel behavioral chemicals of unknown toxicity are dosed, and all possible results interpreted as neurotoxicity. Instead, both positive and negative control materials should be evaluated, and the results linked with well-characterized functional and morphological indices of neurotoxicity.

We appreciate the opportunity to provide our interpretations of this study. We do not believe that the study by Mullenix et al. can be interpreted in any way as indicating the potential for NaF to be a neurotoxicant.”

On top of that, it is also debatable if plasma levels in rodents due to high levels of fluoride are equivalent to those in humans. The National Research Council (2006) discussed the contradictory data used for attempting to show a ratio between humans and rats for blood plasma levels and concluded:

“Dunipace et al. (1995) concluded that rats require about five times greater water concentrations than humans to reach the same plasma concentration. That factor appears uncertain, in part because the ratio can change with age or length of exposure. In addition, this approach compares water concentrations, not dose. Plasma levels can also vary considerably both between people and in the same person over time (Ekstrand 1978)”.

Choi (2012) described 27 studies found majority in obscure Chinese scientific journals. China is not artificially fluoridated and the studies used high levels of naturally occurring fluoride in the well water of various Chinese, Mongolian, and Iranian villages. The concentration of fluoride in these studies was as high as 11.5 ppm. By the admission of the Harvard researchers, these studies had key information missing, used questionable methodologies, and had inadequate controls for confounding factors. These studies were so seriously flawed that the lead researchers, Anna Choi, and Philippe Grandjean, were led to issue a statement in September of 2012. Anna Choi said:

“These results do not allow us to make any judgment regarding possible levels of risk at levels of exposure typical for water fluoridation in the U.S. On the other hand, neither can it be concluded that no risk is present“.

Broadbent et al. (2014) used data from the Dunedin Multidisciplinary Study, which is world-renowned for the quality of its data and rigour of its analysis, and found no significant differences in IQ by fluoride exposure, even before controlling for the other factors that might influence scores. It controlled for childhood factors associated with IQ variation, such as socio-economic status of parents, birth weight and breastfeeding, and secondary and tertiary educational achievement.

6: Benefits from Systemic Fluoride Intake?

For this section I’ll limit the discussion to the benefits of systemic and topical intake of fluoride.

Even if the primary role of fluoride was topical, water fluoridation has a beneficial effect and makes a good delivery system. Consumption of fluoridated food and water enables transfer of fluoride to saliva and biofilms on the teeth. This fluoride, together with calcium and phosphate on the saliva, reduces acid attack on the teeth and so helps prevent tooth decay. Because fluoride concentrations in saliva decrease within an hour or so after brushing, fluoridated water complements use of fluoridated toothpaste. Our teeth are in more regular contact with food and water than they are with toothpaste.

Buzalaf et al. (2011) reports:

“More than 60 years of intensive research attest to the safety and effectiveness of this measure to control caries. In this case, however, it should be emphasized that despite being classified as a ‘systemic’ method of fluoride delivery (as it involves ingestion of fluoride), the mechanism of action of fluoridated water to control caries is mainly through its topical contact with the teeth while in the oral cavity or when redistributed to the oral environment by means of saliva. Since fluoridated water is consumed many times a day, the high frequency of contact of fluoride present in the water with the tooth structure or intraoral fluoride reservoirs helps to explain why water fluoridation is so effective in controlling caries, despite having fluoride concentrations much lower than fluoride toothpastes, for example. This general concept can be applied to all methods of fluoride use traditionally classified as ‘systemic’. In the light of the current knowledge regarding the mechanisms by which fluoride control caries, this system of classification is in fact misleading”.

Featherstone (2000) also demonstrated that:

“The cariostatic effects of fluoride are, in part, related to the sustained presence of low concentrations of ionic fluoride in the oral environment, derived from foods and beverages, drinking water and fluoride-containing dental products such as toothpaste. Prolonged and slightly elevated low concentrations of fluoride in the saliva and plaque fluid decrease the rate of enamel demineralization and enhance the rate of remineralization”.

The main benefit is from topical application but systemic ingestion still plays a role. Buzalaf et al. (2011) also states that:

“Evidence also supports fluoride’s systemic mechanism of caries inhibition in pit and fissure surfaces of permanent first molars when it is incorporated into these teeth pre-eruptively”.

Quality studies continue to show fluoridation to be effective today. Newbrun (1989), Brunelle & Carlos (1990) and Griffin et al. (2007) have proven water fluoridation continues to be effective in reducing dental decay by 20-40%.

National Research Council Report:

I will touch on the National Research Council (2006) report as Rita has asked me to give my assessment and it is used throughout her paper. The 2006 NRC Committee was charged with evaluating the adequacy of the US EPA primary (4 ppm) and secondary (2 ppm) MCLs for fluoride to protect the public against adverse effects, it did not look at the benefits. The EPA’s guidelines are not recommendations about adding fluoride to drinking water to protect the public from dental caries. Guidelines for that purpose (0.7 – 1.2ppm) were established by the U.S. Public Health Service. It reported:

“this report does not evaluate nor make judgments about the benefits, safety, or efficacy of artificial water fluoridation. That practice is reviewed only in terms of being a source of exposure to fluoride”.

After the Committee looked at all relevant fluoride literature, it recommended that the EPA primary MCL for fluoride be lowered from 4.0 ppm. The stated reasons for this recommendation were the risk of severe dental fluorosis and bone fracture with chronic ingestion of water with a fluoride content of 4.0 ppm or greater. No other reasons. Had this Committee had any other concerns with fluoride at this level, it would have stated so and recommended accordingly. Additionally, this Committee made no recommendation to lower the EPA secondary MCL for fluoride, 2.0 ppm which water fluoridation at 0.7ppm is 1/3 of this value.

In March of 2013, Dr. John Doull, the internationally respected toxicologist who chaired the NRC committee, made the following statement:

“I do not believe there is any valid, scientific reason for fearing adverse health conditions from the consumption of water fluoridated at the optimal level.”

Final recommendation of this Committee showed nothing that doubt on the safety of fluoride at the recommended optimal level. It also has no bearing on water fluoridation so using the NRC report to as a reason to stop fluoridation would be misguided.

Conclusion

I have outlined major flaws of the science of this paper, with the major criticism being not using primary sources. There was no assessment of the quality of the evidence. One should start with secondary reviews published in peer-reviewed, high-impact journals, including meta-reviews, review articles, and Cochrane Collaboration reviews; otherwise, high quality clinical trial reports with fairly large number of subjects.

Any further discussions on the ethics or legal matters with fundamental flaws in the science would make any exchange confusing and pointless.


Rita Barnett-Rose’s response to Daniel Ryan’s critique will be posted tomorrow. See Fluoride debate: Response to Daniel Ryan’s critique – Rita Bartlett-Rose

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Fluoride debate: The scientific evidence against fluoridation – Rita F. Barnett

Recently an unpublished paper by Rita F. Barnett, an associated professor of Legal Research and Writing at Chapman University, was heavily promoted by Paul Connett’s Fluoride Action Network and associated social media groups. Although basically a legal paper it did have a comprehensive section on the scientific  aspects of fluoridation.

Rita F. Barnett

She argued that the science indicated that community water fluoridation was neither effective or safe and was criticised for that. One of her critics, Daniel Ryan from the Making Sense of Fluoride group, participated in an exchange with her about the science.

As this has only been available in downloadable pdf format I am posting this exchange over the next few days as part of the ongoing fluoridation debate.

This post today is the section from Rita Barnett’s paper in which she argues that the science does not support community water fluoridation.


Scientific evidence against compulsory water fluoridation

(extract from Compulsory water fluoridation: Justifiable public health benefit or human experimental research without informed consent by Rita F. Barnett.)

Fluoridation proponents have historically characterized those opposing or questioning fluoridation as “irrational, fanatical, unscientific, or fraudulent,” regardless of the legitimate scientific credentials of those opposing fluoridation.64 However, the mounting scientific evidence against fluoridation has begun to persuade an increasing number of scientific researchers and dental and medical professionals, and even some formerly avid fluoride proponents.65

While a comprehensive review of all existing and emerging toxicological, clinical and epidemiological studies weighing against fluoridation or urging further research is beyond the purview of this article, a brief discussion of some current areas of concern follows.

1: Dental Fluorosis

Dental fluorosis occurs when children absorb too much fluoride. This excess fluoride “causes the biochemical signal to go awry, thereby creating gaps in the crystalline enamel structure.”66 When the tooth finally erupts, is it unevenly colored, and may even be pitted and brown.67

Although early fluoride proponents claimed that mild dental fluorosis was the only potential, and relatively rare, negative side effect to systemic fluoride exposure, today about 30-40% of American teenagers show visible signs of dental fluorosis, with the rate as high as 70-80% in some fluoridated areas.68

Exposure to multiple sources of fluoride beyond fluoridated water supplies may partly explain the higher than expected rates of dental fluorosis, the first sign of fluoride toxicity. Indeed, it is nearly impossible today to avoid consuming fluoride even in non-fluoridated areas, since fluoride is now found in fluoridated toothpaste, the pesticide residue on fresh produce, processed food and beverages made with fluoridated water, and many pharmaceuticals.69 Yet, research from the Iowa Fluoride Study, the largest long-running investigation on the effects of fluoride, has indicated that the most important risk factor for dental fluorosis is exposure to fluoridated water.70 Perhaps for this reason, the American Dental Association now recommends that parents use non-fluoridated water for infant baby formula, while the Institute of Medicine recommends that babies only consume a miniscule 10 micrograms of fluoride daily, a near impossible feat when babies are fed infant formula reconstituted with fluoridated water – even where levels are within the “optimal” range of 0.7- 1 ppm.71

Despite the fact that dental fluorosis not only produces unattractive teeth but may also increase the risk of tooth loss, the EPA and other U.S. public health officials downgraded even moderate to severe dental fluorosis from an adverse health effect to a purely cosmetic one.72 This downgrade has been largely perceived as a bow to political pressure rather than a legitimate health risk assessment.73 In any event, “it is widely acknowledged that dental fluorosis is a manifestation of systemic toxicity,” leading to far more serious health risks than unattractive teeth alone.74

2: Skeletal Fluorosis and Bone Fractures

Fluoride, of course, is not equipped with a smart GPS, able to provide benefits to teeth while bypassing bone and other organs of the human body.75 Instead, approximately 93% of ingested fluoride is absorbed into the bloodstream, and while some of it is excreted, roughly 50% is deposited into bone, potentially leading to skeletal fluorosis.76 Skeletal fluorosis is characterized by painful and limited joint movement, spinal deformities, muscle wasting, and calcification of the ligaments.77 Numerous studies have already linked skeletal fluorosis to excess fluoride intake, and although health officials had formerly insisted that skeletal fluorosis would not develop unless a person ingested 20 milligrams of fluoride per day for over 10 years, current research now suggests that doses as low as 6 mg/day can cause early stages of the disease, and that skeletal fluorosis can develop even with fluoride levels as low at 0.7 to 1.5 ppm, the range used in many fluoridation schemes throughout the United States.78 Unfortunately, skeletal fluorosis may go undetected or misdiagnosed because some of the symptoms mimic symptoms of arthritis or other bone diseases, and because many doctors do not know how to diagnose it.79

In addition to skeletal fluorosis, epidemiological studies have now also linked high fluoride exposure to an increase in bone fractures, especially in vulnerable populations such as the elderly and diabetics.80 Related studies have shown that people once given fluoride to “cure” osteoporosis wound up having increased fracture rates.81

3: Pineal Gland and Endocrine Disruption Studies

Researchers have now discovered that an even greater amount of fluoride accumulates in the pineal gland than in teeth and bone.82 The pineal gland is responsible for the synthesis and secretion of the hormone melatonin, which regulates the body’s circadian rhythm cycle and puberty in females, and helps to protect the body from cell damage from free radicals.83 While it is not yet known if fluoride accumulation affects pineal gland function in humans, experiments have already found that fluoride reduced melatonin levels, interfered with sleep-wake cycles, and shortened the time to puberty in animals.84

In addition, studies have now shown that fluoride can contribute to hypothyroidism (an underactive thyroid), which is unsurprising, since fluoride was once used as a prescription drug to reduce thyroid gland function in patients with hyperthyroidism (an overactive thyroid).85 The fluoride dose capable of reducing thyroid function is low – just 2 to 5 mg per day over several months. This is well within the range of what individuals living in fluoridated communities are receiving on a regular basis.86

4: Cancer Studies

Numerous studies have now suggested a link between cancer and fluoride.87 However, perhaps even more disturbing than the evidence supporting the fluoride-cancer link is the evidence suggesting that political and other agendas have played a large part in the outright suppression of this evidence.88

First, in the early 1950’s, Dr. Alfred Taylor, a biochemist at the University of Texas, conducted a series of experiments in which cancer prone mice consuming water treated with sodium fluoride were found to have shorter lifespans than cancer-prone mice drinking non-fluoridated water.89 After discovering that his first round of tests had been contaminated because both groups of mice had eaten food containing fluoride, Dr. Taylor repeated the experiment, and found the same results – a shorter life span for the mice drinking the fluoridated water. However, because these damaging results appeared around the launch time of the early fluoridation schemes, and because public health officials had already come out in staunch support of fluoridation, Dr. Taylor’s work was misrepresented. Specifically, fluoridation proponents falsely claimed that Dr. Taylor had never conducted the second study revealing that the fluoride-cancer link was still present when the necessary controls were put in place.90

Then, in 1990, a study conducted by the U.S. government’s National Toxicology Program (“NTP”) found a positive relation for osteosarcoma (bone cancer) in male rats exposed to different amounts of fluoride in drinking water.91 When NTP downplayed the results in order to avoid a public outcry over compulsory fluoridation, a storm of controversy erupted, with a number of scientists outraged at the failure to report the cancer linked results accurately.92

Finally, in 2006, Elise Bassin and her colleagues at the Harvard School of Dental Medicine published a study in the peer-reviewed journal Cancer Causes and Control, which also showed a link between fluoridation and osteosarcoma in young men.93 Incredibly, Bassin’s own dissertation advisor at Harvard, Chester Douglass, wrote a commentary in the same journal warning readers to be “especially cautious” about Bassin’s results. This lead to yet another controversy, with Bassin’s defenders calling for an ethical investigation of Douglass, since, as it turned out, Douglass had some conflicts of interest and was the editor in chief of a newsletter for dentists funded by Colgate. 94

5: Lower IQ’s in Children

Researchers have also begun to focus on the damaging effects fluorides appear to have on the human brain. In the 1990’s, researcher Phyllis Mullenix studied the brain and behavioral effects of sodium fluoride on rats.95 Her study revealed that pre-natal exposure to fluoride correlated with life-long hyperactivity in young rats, while post-natal exposures often had the opposite, “couch potato” effect.96 Although Mullenix’s research was published in a well-respected peer reviewed journal, the fluoride proponents attacked her methodology and declared her results flawed.97 Since then, however, forty-six other studies have emerged showing a connection between excess exposure to fluoride and lowered IQ’s in children, with 39 of the 46 finding that elevated fluoride exposure is associated with decreased IQ, and 29 of the 31 animal studies showing that fluoride exposure impairs the learning and/or memory capacity of animals.98

In 2012, after conducting a meta-analysis of 27 of the fluoride-human IQ studies, conducted mostly in China, a team of scientists from Harvard’s School of Public Health and China’s Medical University in Shenyang concluded that the studies suggested an average IQ decrease of about seven points in children exposed to raised fluoride concentrations.99 In 2014, one of the chief authors of the initial 2012 meta-analysis, Harvard professor Philippe Grandjean, concluded in a follow-up article that “our very great concern is that children worldwide are being exposed to unrecognized toxic chemicals that are silently eroding intelligence,” and that fluoride’s effect on the young brain should now be a “high research priority.”100 Notably, a majority of the 27 studies analyzed were of water fluoride levels of less than 4 mg/L, which falls under the allowable concentrations of fluoride under current EPA regulations.101

6: Benefits from Systemic Fluoride Intake?

With so many current studies linking fluoride to serious health risks beyond dental fluorosis, the question remains whether fluoride’s public health benefits outweigh any and all of these risks. The Centers for Disease Control has deemed water fluoridation one of the “top ten health achievements of the 20th Century.”102 Proponents therefore insist that even if there are a number of recognized risks of fluoridation, there has been enough evidence to show that these risks are remote and are far outweighed by the benefits.103 Yet much of the available scientific data today suggests that any benefit from fluoride in terms of preventing tooth decay has been from topical application, rather than systemic ingestion.104 Moreover, even the benefits of topical fluoride treatments have been recently questioned, since most dental caries today are in the “pits and fissures” of the molars rather than on the flat surface of teeth, and various studies have now indicated that fluoride has no impact on the pits and fissures.105

Research conducted over the last twenty years has also shown that the estimated reduction in tooth decay due to compulsory water fluoridation has been grossly exaggerated. While at one time proponents boasted a 50-65% reduction in tooth decay, a great deal of current evidence suggests the real percentage is significantly lower, with some studies showing no measurable reduction at all. 106 Confounding claims of benefit even further, numerous studies have shown a substantially similar decline in the dental caries rate in countries that do not fluoridate, and in areas within the United States that remain unfluoridated.107

Nor have the asserted economic benefits of compulsory water fluoridation come to fruition. In fact, a number of economic evaluation studies have indicated that the costs of dental care may actually be higher in fluoridated communities than in non-fluoridated communities.108

Unfortunately, rather than considering the new data objectively, public health officials and dental lobbies spearheading fluoridation schemes often ignore, reject, or suppress the evidence that does not toe the pro-fluoride party line.109 Nevertheless, as evidence against fluoridation continues to 20 Compulsory Water Fluoridation [23 Sept 14 accumulate in a variety of health risk areas, two conclusions seem readily apparent. First, there remain significant unanswered questions about the risks and benefits of systemic fluoride, and further research before imposing or continuing fluoridation schemes seems not only scientifically prudent, but ethically necessary. Second, it is no longer acceptable for public health officials to simply dismiss the accruing negative data and to continue to insist that the levels of fluoride children and adults are receiving on a daily basis are without any serious health consequences. Fortunately, tentative moves by the EPA and other federal agencies suggest that at least some public health authorities are inching towards similar conclusions.

References

64 See e.g. Hileman, supra note 18, at 4. See also Graham, supra note 17, at 195 (noting a pro-fluoridation report characterizing fluoride opponents as follows: “The opposition stems from several sources, chiefly food faddists, cultists, chiropractors, misguided and misinformed persons who are ignorant of the scientific facts on the ingestion of water fluorides, and, strange as it may seem, even among a few uniformed physicians and dentists.”). See also Leila Barraza, Daniel G. Orenstein, Doug Campos- Outcalt, Denialism and Its Adverse Effect on Public Health, 53 JURIMETRICS J. 307, 307 (calling those who oppose fluoridation “denialists” who “misuse science to advocate positions that contradict the overwhelming weight of existing evidence”).

65 See e.g., John Colquhoun, Why I Changed My Mind About Water Fluoridation, 41 PERSPECTIVES IN BIOLOGY AND MEDICINE 1 (1997); Dr. Hardy Limeback, Why I Am Now Officially Opposed to Adding Fluoride to Drinking Water, FLUORIDE ACTION NETWORK (April 2000), http://fluoridealert.org/articles/limeback/; J. William Hirzy, Dr. William Hirzy, Former Head of EPA’s Headquarters Union Recommends Portland Flush Fluoridation Proposal (March 2013), FLUORIDE ACTION NETWORK, http://fluoridealert.org/content/hirzy_portland/.

66 Fagin, supra note 26, at 78.

67 Fagin, supra note 26, at 78; Hileman, supra note 18, at 9.

68 See Beltran-Aguilar, et. al., Prevalence and Severity of Dental Fluorosis in the United States, 1999-2004, NCHS DATA BRIEF NO. 53 (2010), http://www.cdc.gov/nchs/data/databriefs/db53.pdf. See also Czajka, supra note 13, at 125.

69 Beltran-Aguilar, supra note 68; Peckham, supra note 13, at 165.

70 Fagin, supra note 26, at 79 (children exposed to fluoridated water were 50% more likely to have dental fluorosis than children living in non-fluoridated areas).

71 Peckham, supra note 13, at 165-66.

2 See Hileman, supra note 18 at 10.

73 Id.

74 Peckham, supra note 13, at 166.

75 Limeback, supra note 65 (“it is illogical to assume that tooth enamel is the only tissue affected by low daily doses of fluoride ingestion.”); Colquhoun, supra note 65 (“Common sense should tell us that if a poison circulating in a child’s body can damage the tooth-forming cells, then other harm also is likely.”).

76 Czajka, supra note 13 at 125.

77 Null, supra note 17, at 74.

78 Czajka, supra note 13, at 125.

79 Null, supra note 17, at 74; Hileman, supra note 18, at 13.

80 Fagin, supra note 26, at 79.

81 See Null, supra note 17, at 74-75.

82 Jennifer Luke, Fluoride Deposition in the Aged Human Pineal Gland, 35 CARIES RESEARCH 125-128 (2001). See also Czajka, supra note 13, at 126.

83 Fluoride Action Network, Pineal Gland, FLUORIDEALERT.ORG, http://fluoridealert.org/issues/health/pineal-gland/ (last visited June 25, 2014) (discussing/listing pineal gland studies).

84 Id.

85Fluoride Action Network, Thyroid, FLUORIDEALERT.ORG, http://fluoridealert.org/issues/health/thyroid/ (last visited June 25, 2014) (discussing/listing numerous thyroid studies).

86 Null, supra note 17, at 71. See also Fluoride Action Network, Endocrine, FLUORIDEALERT.ORG, http://fluoridealert.org/issues/health/endocrine/(last visited June 25, 2014) (discussing/listing numerous endocrine system studies).

87 Fluoride Action Network, Cancer, FLUORIDEALERT.ORG, http://fluoridealert.org/issues/health/cancer/ (last visited June 25, 2014) (discussing/listing numerous cancer studies).

88 See e.g., Null, supra note 17, at 77; Graham, supra note 17, at 229-240.

89 Null, supra note 17, at 77.

90 Id.

91 NTP Toxicology and Carcinogenesis Studies of Sodium Fluoride in F344/N Rats and B6C3F1 Mice (Drinking Water Studies), 393 NATL. TOXICOL. PROGRAM TECH REP SERV. 1-448 (1990).

92 Null, supra note 17, at 78-79.

93 E. B. Bassin et. al., Age Specific Fluoride Exposure in Drinking Water and Osteosarcoma, 17 CANCER CAUSES & CONTROL 421-28 (2006) (finding an association between fluoride exposure in drinking water during childhood and the incidence of osteosarcoma among males but not consistently among females). See also S Kharb et. al., Fluoride Levels and Osteosarcoma, 1 SOUTH ASIAN J. CANCER 76-77 (2012) (finding positive correlation between fluoride and osteosarcoma).

94 Fagin, supra note 26, at 80. 95 Phyllis J. Mullenix, Neurotoxicity of Sodium Fluoride in Rats, 17 NEUROTOXICOLOGY AND TERATOLOGY 169-177 (1995).

96Fagin, supra note 26, at 80. See also Null, supra note 17, at 74 (describing an ad campaign promoting a fluoridated spring water “for kids who can’t sit still.”).

97 Fagin, supra note 26, at 80.

98 Fluoride Action Network, Brain, FLUORIDEALERT.ORG, http://fluoridealert.org/issues/health/brain/ (last visited June 25, 2014) (discussing/listing numerous brain studies).

99 See Anna L. Choi et. al, Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis, 120 ENVIRON. HEALTH PERSPECT. 1362-1368 (2012).

100 Philippe Grandjean & Philip Landrigan, Neurobehavioural Effects of Developmental Toxicity, 13 THE LANCET NEUROLOGY, 330-338 (2014) (“untested chemicals should not be presumed to be safe to brain development, and chemicals in existing use and all new chemicals must therefore be tested for developmental neurotoxicity.”). See also Diana Rocha-Amador, Decreased Intelligence in Children and Exposure to Fluoride and Arsenic in Drinking Water, Cad. Saude Publica, Rio de Janeiro, 23 Sup. S579-587 (2007).

101 See discussion infra Sec. III.

102 CDC FLUORIDATION, supra note 18.

103 Hileman, supra note 18, at 2.

104 See Czajka, supra note 13, at 127.

105 See e.g., Letter from Dr. Paul Connett to Scientific Committee on Health and Environmental Risks, the European Committee, at #7 (March 30, 2009), available at http://www.fluoridealert.org/wp-content/uploads/scher.march_.2009.pdf (“Since 1950, it has been found that fluorides do little to prevent pit and fissure tooth decay…This is significant because pit and fissure tooth decay represents up to 85% of the tooth decay experienced by children today.”).

106 Hileman, supra note 18, at 5.

107 Hileman, supra note 18, at 6-7. See also Michael Connett, Tooth Decay Trends in Fluoridated vs. Unfluoridated Countries (March 2012), FLUORIDEALERT.ORG, http://fluoridealert.org/studies/caries01/ (noting that decay rates in non-fluoridated countries have declined at the same rate as those in fluoridated countries).

108 Hileman, supra note 18, at 7. 109 See e.g., Voices of Opposition Have Been Suppressed Since Early Days of  Fluoridation, CHEMICAL & ENGINEERING NEWS (August 1, 1988), available at
http://www.nofluoride.com/CEN_Voices_of_opposition.cfm.


Daniel Ryan’s first response to Rita’s unpublished paper will be posted tomorrow – see Fluoride debate: A response to Rita Barnett-Rose – Daniel Ryan

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Download The Fluoride Debate

Fluoride-debate-pdf

I have put together the posts from the exchange between Paul Connett and me in the form of a single document. This will be more convenient for anyone who wishes to browse the articles. Hunt down details or refer to material off-line. Click in the image or this link to download a pdf of The Fluoride debate document.

For those who have not followed this exchange here is a bit of history and explanation from the document.


This is a collection of articles written by Paul Connett and Ken Perrott in their exchange of opinions on the fluoridation of drinking water and related issues. While loosely titled The Fluoride Debate this was in no way meant to be a debate in the gladiatorial sense. It was not about “winners” and “losers.” Our intention was to discuss the science in a format encouraging good faith discussion and intelligent participation from commenters.

I leave it to readers to decide how successful, or otherwise, we have been in this.

Introducing the authors

The authors in this “debate’ have similar academic and professional backgrounds. Both have PhDs in chemistry, worked as research chemists and are now retired. Neither of us have done original research on fluoridation specifically, although both have become involved in the public discussion of it since there retirements.

Paul Connett is an executive director of the Fluoride Action Network and campaigns throughout the world against fluoridation. He is, together with James Beck & H. Spedding Micklem, author of the book “The Case Against Fluoride.” Paul has made several speaking tours in New Zealand as part of his campaign and will have another tour in February, 2014.

Ken Perrott is a retired research chemist. These days he writes a blog, Open Parachute, which deals issues related to science, human rights, philosophy and religion. Many of his articles have argued against pseudoscience and the misrepresentation of science. He has written a number of articles on scientific issues related to fluoridation.

Format of debate

The exchange occurred as posts on the blog Open Parachute. Paul originally proposed it as 5 pairs of articles with Paul starting and raising specific arguments against fluoridation followed by my reponse.– Paul Connett’s specific argument first with my response second. I thought this would be a convenient size for a series of blog articles.

Paul’s first article went live on October 30, 2013. Without the discipline of an external moderator the series ended up a longer than originally planned – we ended up with 8 pairs of articles, with my final closing article posted on January 23, 2014.

Responding to requests from commenters about my own personal, rather than scientific, motivations I also posted an extra article Why I support fluoridation on November 11. Inevitably its content was also debated.

Editing of articles

The articles here are basically the same as originally posted in the debate. I have corrected some typos and added reference lists to my own articles recognising that the hot links provided in a blog article may not be suitable for all readers of this document. I have avoided editing or altering Paul’s articles except for a few minor issues like adjusting image size.

Comment discussions

Many others, representing both sides of the “debate,” participated in this exchange through the comments section of each article. Some commenters were very well informed, often with professional experience related to fluoridation. There were almost 2000 comments in total with many of them containing useful information and citations. Unfortunately it is not feasible to include the comment discussion here but I urge interested readers to browse through them on-line.

Links to debate

You can easily find original blog articles, together with comments, at the link Fluoride Debate.

Advice to readers

Such lengthy articles, and so many of them, might be intimidating to some readers. My advice is to browse, read the articles that interest you or cover issues of interest. I imagine only the most dedicated reader would start at the beginning and read to the end.

Any reader wishing to make contact with me can do so via my About me blog page.

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Fluoride debate: Final article – Ken Perrott

This is the last, final, article in the Fluoride debate. There will be nothing more. It is  Ken Perrott’s response to Paul Connett’s last article Fluoride debate: Paul Connett’s Closing statement.

For Paul Connett’s original article see – Fluoride debate Part 1: Connett.


“Skeptical scrutiny is the means, in both science and religion, by which deep thoughts can be winnowed from deep nonsense.”― Carl Sagan

Paul has used his right of reply and it really is time to close off this exchange.

I am not going to sieve through Paul’s long article and comment point by point – we are well past this. Instead I will discuss a basic issue central to the exchange (Paul’s reference to “weight of evidence analysis”) and show with several examples how superficial, and unscientific, Paul’s understanding of the approach is.

“Weight of evidence” – different things to different people

Weight of evidence can mean anything from a vague metaphorical description to a methodological approach or a theoretical/conceptual framework. Paul doesn’t clarify any further, but when he talks about balancing one set of studies or papers against another I find his concept very mechanical. It reminds me of the way the Hamilton City Council treated the submissions to last year’s hearings on the fluoridation issue (see my article When politicians and bureaucrats decide the science). Council staff reported:

“Of the 1,557 submissions received 1,385 (89%) seek Council to stop the practise of adding fluoride to the Hamilton water supply. 170 (10.9%) seek Council to continue the practise of adding fluoride and 2 (0.1%) submitters did not indicate a stance.”

Council, and Council staff, were impressed by these numbers – after all, place the submission printouts on a kitchen scales and of course the anti-brigade wins! Silly, I know, but this was one of the arguments staff supplied to council for ignoring the result of the referendum (where almost 70% supported fluoridation), at their November 2013 meeting. This extract from the draft resolution submitted by staff:

“All evidence has been considered carefully by Council and, while finely balanced, Council preference is to continue not to fluoridate the city water supply because: . . .

vi. Not fluoridating the city water supply reflects the majority of views expressed through the Council tribunal process.”

The silliness of such an approach is obvious when one starts to consider the quality and not the quantity of submissions. Here are a few examples from those opposing fluoridation:

Submission No 58:

I do not believe there is enough evidence to support the mass medication of our water supply’s for the good of all people. It is our right to choose to medicate ourselves with fluoride not the government right to force this medication I believe the fluoride in our water is toxic and needs to be stopped.

Submission 60:

Water Fluoridation is medication ‐ even if the pro fluoridationist say it is not. Council does not have the right to medicate the water. Please STOP!

Submission No 61:

From what I have come to understand, Fluoride is a toxin that has been and will continue contribute to chronic long term health illnesses. Fluoride a toxic substance we don’t want in our water supply for our younger generation to be exposed to.
Regards Connie

Submission No 65:

I do not want N0 KEMICALS into my drinking water.Thank you very much,Dorel”

Submission No 975:

“There is no acceptable reasoning to mass dose the whole population. There is a significant amount of information describing the side effects of Fluridation of the water supply. If people want extra Fluoride then they can take tables. 90% + of the fluoride added to the town supply ends up in the environment. There are more than 100 pesticides manufactured from Fluoride.”

Submission No 237:

I love New Zealand, it’s such a beautiful country. Fluoride is not necessary in the water supply. Please let people make their own choice about whether or not they want to ingest fluoride. It should not be forced upon anyone by adding it to the water supply. This is just plain and simply wrong!”

The local anti-fluoride activist organisation, the Fluoride Action MNetwork of NZ (FANNZ), promoted such meaningless submissions by proving a template form for their supporters. They were going for quantity and not quality – they are political activists, not scientists.

This shows why I reject the mechanical “weight of evidence” approach Paul often seems to be advocating. He certainly fights hard to avoid consideration of the quality of evidence he uses.

I can only agree with a “weight of evidence” approach if it is qualitative, not simply and mechanically quantitative. In fact, I would avoid the term and instead say our approach should be a balanced one, looking (as far as practicable) at all the evidence and considering it critically and intelligently.

Hence the quote from Carl Sagan at the head of this article.

I don’t think Paul does this. I show this in my comments and responses below.

From logical possibility to conspiracy

Paul’s book, The Case Against Fluoride, provides clear examples of a formula he uses to cast doubt on existing science, build up a library of claimed negative effects of fluoride in the human body and to suggest the scientific community conspires to suppress research findings and prevent important research from going ahead. It’s the sort of stuff ideologically driven opponents of fluoridation lap up enthusiastically. These tactics are not new – we have seen it all before with the creationists and the climate change deniers.

This formula has 3 steps:

1: Advance a claim with no real evidence. This can be done in several ways.

A): Establish a logical possibility. Paul uses a lot of “possibles,” “mays,” etc., in his book. No research evidence at all is required for this – just speculation and suggestion. For example:

“. . . if fluoridation were to increase the rates of hip fracture in the elderly, it would be serious and certainly grounds in itself to eliminate water fluoridation.” (p174).

“. .  a possible mechanism exists whereby fluoride could bring about an excessive production of TSH from the pituitary. This may help explain why . . .” (p163).

“These speculations need to be investigated.”     “Although more difficult to prove, it is reasonable to assume that many of the effects seen in vitro can occur in the whole body.” (p125)

“The bone is the principal site for fluoride accumulation within the body, and the rate of accumulation is increased during periods of rapid bone development as occurs in growth spurts during childhood. Thus, the cells in the bone are exposed to some of the highest fluoride concentrations in the body.” (p182)

This last speculation is fallacious as fluoride exists as a structural component of the solid bioapatites in the bone – not in solution – so the term “concentration” is misleading.

B): Use poor research evidence. He often uses the old trick of implying a cause from a correlation, or using research papers who have relied on this fallacy.

The graph below illustrates the fallacy. Most of us find the suggestion eating organic food is the cause of autism silly and we are not at all convinced – despite the excellent correlation. Maybe there are a few people who are so hostile to organic food that they take this suggestion seriously – we can see how their bias might lead them to claim this as evidence and even promote their story with such figures.

But replace the organic food sales with a vaccination statistic – we have a demographic who serious believe vaccinations are harmful and would easily lap up such a fallacious figure. (We are getting a bit close to the bone here – Paul’s Fluoride Action Network (FAN) is organisationally aligned with anti-vaccination (National Vaccine Information Center), anti-GM (Institute for Responsible Technology), and similar outfits through the Health Liberty Coalition.)

Now do the same with a fluoridation statistic and we are getting into very familiar territory. Think Declan Waugh and his graphs showing correlations between fluoridation and practically every illness known to humanity. In fact, Declan Waugh is doing this for autism on his Facebook page. Here is his graph.

Another approach is to just rely on poor quality research – selected to fit his desired conclusions. Consider Paul’s obsession with poor quality Chinese research papers showing a negative correlation of IQ and fluoride concentration in drinking water. These studies have problems with IQ measurement and confounding factors. How can one seriously claim causation when the studies don’t consider, for example, detailed analysis of education and family social conditions. Or other more important contaminants in the environment,

Paul sort of admits speculation or reliance on poor quality research but quickly leaves his admission behind in his eagerness to claim harmful effects:

“there are about twenty studies (albeit with questioned methodologies in some cases) suggesting potential damage to the brains of young children” (p156).”

“Although the validity of the scoring methods used for fractures is acknowledged by the authors to be questionable, this is a potentially important finding,” (p170)”

“At present there is no direct and unassailable proof that fluoridation per se harms anyone’s thyroid. This may be due to the paucity of studies conducted;” (p164)

“We emphasize that proof that fluoride acts on the thyroid in these ways in vivo is still lacking. Further research is needed, but, meanwhile, the mechanisms are plausible and based on existing science.” (p163).

“Although there is no direct evidence that fluoride can inactivate deiodinases, it is well known as an inhibitor of many enzymes, and the hormonal derangements reported in fluoride-exposed people have been interpreted in terms of effects on deiodinases.” (p162)

Paul builds his arguments on very flimsy foundations. He often admits as much but attempts to confound his readers with a fair bit of hand waving and Gish galloping.

2: Collect together any sources which can be interpreted to support the speculation. This may often need a bit of dredging – obscure journals or newsletters, comments recorded at meetings, foreign language sources, etc. Here a naive mechanical “weight of evidence” approach is useful as a pile of Byelorussian, Chinese, Indian, etc. papers from obscure or poor quality sources, often newsletters or reported statements and not scientific papers, weigh a hell of a lot more than one or two papers from reputable journals, by reputable research teams, who report contrary findings.

And of course the well-known problem of lack of reporting negative effects weighs in at zero.

Paul is very proud of the 80 pages of citations in his book. But many of them are repeated several time, are from sources not normally considered for scientific citation, or from sources difficult to track down. Very many of the citations are to his own activist FAN web site. A particularly disturbing aspect of the last sources (often used when referring to translation of foreign language material) is that very often the links lead nowhere. They have either been lost during web site reorganisation or may never have even existed. Who is to know?

3: Use the lack of reputable sources for his claims as evidence of a conspiracy. Paul can “double dip” with the “missing” research and publications from credible reasearch teams and journals. He records paucity of evidence from credible sources to support his own claims relying on poor quality sources, then implies the lack of material indicates at least an unwillingness to research problems or at worst a conspiracy not to do the research and/or hide the results. Of course such descriptors of unwillingness or conspiracy can also be turned on researchers or publications with contrary evidence. He can discount them by suggesting links with industry or personal bias – hence introducing a sort of negative quality to good research while refusing to allow judgement on the quality of the bad research.

For example:

“Most of the concerns about the immune system are largely speculative; once again the scarcity of literature on this reflects a lack of interest by governments that promote fluoridation. The same can be said about reproductive effects; despite an extensive literature indicating that, at high levels of exposure, effects of fluoride on the reproductive system have been observed in a wide range of animals and reptiles, very few human studies on the subject have been published or even undertaken.” (p197)

“The failure to explore the plausible connection between fluoridation and arthritis in any fluoridating country is difficult to understand. It is particularly surprising since the causes of most forms of arthritis (e.g., osteoarthritis) are unknown but are usually associated with the aging process. For those living in fluoridated communities the aging process will coincide with lifelong accumulation of fluoride in their bones and joints.” p170/171)

“We do not claim that these IQ studies add up to conclusive evidence that water fluoridation impairs cognitive development. . . . . it is wise to sit up and pay attention. The health authorities and governments of fluoridating countries show little sign of doing that.” (p156)

“A small minority of people, perhaps 1 percent, appear to be acutely sensitive to exposure to fluoride at the concentrations present in fluoridated water. The wide range of signs and symptoms resemble those seen in poisoning with larger amounts of fluoride. These findings date from the 1950s. However, far from leading to more extensive studies, they were ridiculed when introduced and have since been largely ignored.” (p136)

Fluoridation and IQ

Paul’s mechanical and selective understanding of “weight of evidence” sticks out like a sore thumb when he claims fluoride influences development of the child’s brain. Even though he notes the mainly Chinese studies he relies on had “questioned methodologies in some cases” (p156 of his book) this is perhaps his most favourite claim for rejecting fluoridation. In his last article he even spent some time developing a margin of error from the studies – rather previous, I think, as he had not established that the data he used was reliable or indicated causation

The European Scientific Committee on Health and Environmental Risks (2010) took a more intelligent and critical approach to the Chinese studies. This from their document Critical review of any new evidence on the hazard profile, health effects, and human exposure to fluoride and the fluoridating agents of drinking water:

“A series of studies on developmental effects of fluoride were carried out mostly in China. They consistently show an inverse relationship between fluoride concentration in drinking water and IQ in children. Most papers compared mean IQs of schoolchildren from communities exposed to different levels of fluoride, either from drinking water or from coal burning used as a domestic fuel. All these papers are of a rather simplistic methodological design, with no – or at best little – control for confounders, e.g., iodine or lead intake, nutritional status, housing condition, parent’s education level or income.”

This document concluded:

“Available human studies do not allow concluding firmly that fluoride intake hampers children’s neurodevelopment. A systematic evaluation of the human studies does not suggest a potential thyroid effect at realistic exposures to fluoride. The absence of thyroid effects in rodents after long-term fluoride administration and the much higher sensitivity of rodents to changes in thyroid related endocrinology as compared with humans do not support a role for fluoride induced thyroid perturbations in humans. Limited animal data cannot support the link between fluoride exposure and neurotoxicity,
noted in the epidemiological studies, at relevant non-toxic doses. SCHER agrees that there is not enough evidence to conclude that fluoride in drinking water may impair IQ.”

The NZ National Fluoridation Information Service (2013) also critically reviewed literature on this issue (see NFIS Advisory A review of recent literature on potential effects of CWF programmes on neurological development and IQ attainment).They concluded:

“The available evidence raises the possibility that high levels of fluoride in drinking water may have subtle effects on children’s IQ. However all of these studies have limitations in design and analysis, a clear dose-response relationship between DWFCs and assessed IQ are often not evident. The study authors are frequently very cautious in their comments, and several noted that any indicated negative effect applied only to high DWFCs. An hypothesis of fluoride neurotoxicity would also be supported by some experimental animal studies, however the great majority of these have only considered high fluoride intakes.

However collectively the data described are not robust enough to draw a firm conclusion that high fluoride levels in drinking water supplies contribute to retarded development of children’s brains. Also there is no clear evidence to suggest an adverse effect on IQ at lower fluoride intakes such as that likely to occur in New Zealand, where fluoridated water supplies contain fluoride in the 0.7 to 1.0 mg/L range.

Thus the balance of current scientific evidence does not suggest any risk for the development of full IQ potential for New Zealand Children from current community water fluoridation initiatives, where maximum DWFCs are 1 mg/L.”

Paul will respond that the studies were good enough to warrant further investigation but then he alleges that western researchers are either willfully ignoring these studies or even conspiring to suppress them and refuse to investigate further.

He never considers that, perhaps, the lack of better quality studies really is evidence of lack of effect – given the reluctance to publish studies with nil results.

Think about it, if there really was this effect from salt, milk or water fluoridation wouldn’t we be aware of it by now? After all, many countries do collect the sort of data about their populations, especially children, which would show any effect.

Maybe publication of the Choi et al (2012) meta-review will encourage more specialists to extract this data in their own countries and publish analyses. I personally know of one such study in New Zealand which shows no IQ effect of fluoridation. This study is of higher quality than the ones Paul relies on because  the data was sufficiently extensive to allow consideration of confounding effects (eg. breastfeeding, education, income level, etc.). A paper has recently been submitted for publication so unfortunately I cannot offer a citation until it is “in press.”

Osteosarcoma

Again, the importance Paul gives to a single study on fluoride and osteosarcoma illustrates his mechanical and selective approach to “weight of evidence.” He has not bothered including either the study by Comber et al (2011) of this issue in Ireland or the study by Levy & Leclerc (2012) for the US. Possibly because both of these concluded that water fluoridation has no influence on osteosarcoma incidence rates.

The NZ National Fluoridation Information Service (2013) briefly considered this literature and cancer incidence rates for New Zealand (see Community Water Fluoridation and Osteosarcoma – Evidence from Cancer Registries). Their conclusion:

“The analysis confirms that osteosarcoma is extremely rare in New Zealand with only 127 new cases registered during this period averaging 14.1 per year. The peak age is 10 to 19 years for both sexes. These rates indicate that there is no difference in the rates of osteosarcoma cases between areas with CWF and areas without CWF for both sexes, findings which are consistent with the two international studies.”

But, I guess, not consistent with the one study Paul relies on! A study Paul described as “unrefuted.”  See what confirmation bias does to “weight of evidence?” Although his “unrefuted” strangely conflicts with his qualification about this research in his book:

“The evidence that fluoride causes osteosarcoma is not clear-cut. The studies of the relationships in both animals and humans are mixed.” (p 181)

Update: Here’s another paper published this moth which I guess Paul will studiously avoid. Blakey et al (2014). Is fluoride a risk factor for bone cancer? Small area analysis of osteosarcoma and Ewing sarcoma diagnosed among 0-49-year-olds in Great Britain, 1980-2005.

Breast feeding and the naturalistic fallacy

I understand Paul’s points about dose and dosage – they are not difficult concepts. Obviously they are important when we consider ingestion of fluoride and other environmental elements by infants. My reading indicates that those involved in health advice and regulation do consider dosage when discussing fluoride. I am at a loss to know why Paul thinks this issue is being avoided.

Paul keeps returning to the low level of fluoride in breast milk so I can’t help think he is still trapped by the naturalistic fallacy. He even links this to IQ claiming “whether by accident or by evolutionary “design” mother’s milk is protective against lowered IQ.”

Paul may make some mileage out of the naturalistic fallacy if he stays with fluoride, but bring in the other trace elements which present problems because of deficient levels in human breast milk and the fallacy has far less credibility.

A brief scan of the literature shows breast fed children are prone to some microelement deficiencies. For example, Kodama (2004) and Domellöf, et al (2004) report deficient levels of zinc, selenium and iron in breast milk. Supplementation of breast-fed infants with micronutrients, including fluoride, is sometimes recommended.

Hastings project

Paul’s treatment of this issue shows how simple his concept of “weight of evidence” is. He relies only on one-sided discussions by Colquhoun (1987), Colquhoun & Mann (1986), and Colquhoun & Wilson (1999). He seems not to have done anything to check the original papers from the project and relies on a single out-of-context letter from a bureaucrat which he interprets  to his own satisfaction.

  1. Paul adamantly and publicly declares the Hastings fluoridation project a “fraud.” That is an extremely serious charge in the scientific community – scientific   fraud is one of the worst accusations possible and usually leads to loss of career. It is unprofessional to make such a charge without being prepared to pursue it legally. I question the ethics of such an attack on people who are no longer here to speak in their own defense.
  2. Paul says:
    “What convinces me the final report was a fraud was the authors did not mention the change in diagnosis when claiming the drop in tooth decay was due to fluoridation.”
    Yet he does not reference the “final report” or show any indication he has checked this charge rather than take it on trust from his anti-fluoridation sources.
  3. He claimed in his second to last article that the decision to drop Napier as a control city was made for “bogus reasons” – yet gave absolutely no evidence to support such a serious claim. He now wants to  avoid that responsibility by saying the issue (his claim) is a “red herring.” Sorry Paul, one should not avoid responsibilities – if you wish to make a serious allegation be prepared to back it up or withdraw and apologise –  not run away from it.

I know from experience the complexity of long term trials involving many people doing different jobs. It is easy to take a bureaucratic letter out of context, oversimply or misinterpret problems of personal approaches to methodology and ignore the fact that managers of such trials inevitably face difficulties from factors outside their control. As for reporting findings, the data amassed and details of methodology and their changes can be mind-boggling for an outsider who attempts an understanding.

I will not pretend to have got my head around that project but here are a few observations:

  1. The findings from the trial were presented as scientific papers in the New Zealand Dental Journal (Ludwig and Ludwig, et al. 1958, 1959, 1962, 1963, 1965, 1971). The issues with Napier, originally proposed as a control, are discussed by Ludwig et al (1960), Ludwig & Healy (1962) and Healy et al (1962). Paul does not seem to have consulted any of these papers yet he considers his “weight of evidence” enough to make serious charges of “bogus” and “fraud!”
    The authors did not trumpet their study “showed that fluoridation was a great success” – scientists are usually more circumspect. In this case conclusions were more along the lines “The results obtained in Hastings during a period of  75-78 month’s fluoridation are very similar to results obtained overseas after a comparable period of fluoridation.” (Ludwig 1962).
  2. The important data was reported in papers from 1958 – 1971. These are very brief but all include the statement that further information on methodology, data and statistical analysis is available to interested people. The details Paul’s seems to want may be in that unpublished “further information.”
  3. Colquhoun & Mann (1986) and Colquhoun & Wilson (1987) both quote from unpublished reports and communications where discussion of diagnostics and methodological changes occurred. Colquhoun and Mann even report that researchers believed evidence from the Napier data indicates these changes did not have an overriding effect. Even a simple glance at the published data shows that the decline in tooth decay was not restricted to the early period where diagnostic and methodological changes would have been expected to exert any effect. Compare the plots below.

Hastings

Hastings data shows similar improvement in oral health even if project had started in 1957. Plots are for different ages.

I think Paul is irresponsible to make such damning charges of “fraud” without considering all the material. He actually has no evidence at all the project was a “fraud” or that the reasons for dropping Napier as a control were “bogus.” His behaviour is unprofessional.

The problems with longitudinal studies

There are inevitable problems with longitudinal trials of the sort which the Hastings Project eventually became. They are influenced by undetected confounding factors and hence can be difficult to interpret. This may not have been sufficiently recognised at the time and that may have coloured interpretation of the results.

But let’s not forget that much of the harsh criticism of fluoridation made by Colquhoun (1997) and Diesendorf (1986) rely on their own biased interpretation of such longitudinal trails. And today’s anti-fluoridation propagandists make the same mistake even though we now know better. Paul himself used the WHO data showing improvement in oral health in many countries in his first few articles to argue that fluoridation had no effect. He did not consider the multifactorial causes of that improvement or mention that where measurements made in single countries (like Ireland) clear differences between fluoridated and unfluoridated areas were seen.

Should we now accuse Paul of “fraud” because he made no mention of the full Irish data in his claim that the WHO data showed fluoridation ineffective?

Paul continually avoids systemic role of fluoride

He does this by stressing the surface mechanism initiating caries is “topical” and not “surface” and works hard to imply “topical application” methods are required. He has conceded to including the word “predominantly” when referring to the surface mechanism but seems not to understand the meaning of the word.

My dictionary definition for “predominant” is “Most common or conspicuous; main or prevalent.” The word does not mean “only” as Paul seems to assume.

Neither is tooth decay simply about the initiation of caries. It also involves the strength and hardness of the teeth where systemic fluoride plays a beneficial role – especially during teeth development in the pre-eruptive stage. Paul continually avoids this as he also does the normal and natural role of fluoride in bioapatites.

Paul has not even acknowledged the citations I have given supporting this systemic function for fluoride. I guess all I can do is add another one – published this month – Cho, et al (2014). Systemic effect of water fluoridation on dental caries prevalence.

Paul’s concessions

I guess we should acknowledge there has been some progress during this exchange as Paul has made a few concessions. It is worth recording them here to show they have occurred – but of course I am interested to see if he still repeats his original claims elsewhere.

Fluoridated and unfluoridated data for the Irish Republic. Finally Paul seems to understand my point on this. At least he apologises and said he should have checked.

I really can’t understand why he was confused  for so long (I raised is in my first article) but we all have our moments, I guess. He should now understand that use of WHO and similar data showing improvement of oral health in both fluoridated and unfluoridated areas is not a proof that fluoridation is ineffective. This fallacy is repeated again and again by opponents of fluoridation and ignores completely the multiple issues involve in oral health. Scientifically literate people should not resort to such fallacies.

I will be interested to see if he avoids this fallacy in future. A sign of good faith would be for him to remove or amend the section on the FAN website which promotes this fallacy.

Xiang et al’s margin of safety calculation. I asked Paul several times to clarify this because he was using a figure of 1.9 ppm yet Xiang’s paper was completely silent on how the value was obtained and seems to ignore the large variability of the data –  another sign of poor reviewing by the journal Fluoride. Paul now seems to have walked away from reliance on Xiang et al (2003) and a threshold value of 1.9 ppm and wants to take a different approach.

But, he still wants to use the poor quality Chinese data and does nothing to justify using that data in the absence of demonstration of any causal, and not incidental, relationship between fluoride in drinking water and IQ. I think this makes his calculations meaningless.

In the meantime could he please remove the sections of his FAN website arguing for the 1.9 ppm margin of safety?

What happens when fluoridation is stopped. Paul has accepted my point that at least in the cases of the former DDR and La Salud, Cuba, the results are consistent with use of alternative fluoride sources such as fluoridated salt, mouth rinses and dental applications. While admitting I had a valid point he says:

“Ken responded that in two of these studies other measures were taken which might have explained why tooth decay did not increase. I in turn argued that that if this was the case it shows that there are alternatives to fluoridation that work.”

Two points.

No one claims there are no alternatives to fluoridated drinking water. I have pointed out again and again that there are. So why the red herring? Paul was citing these studies to “prove” fluoridation is ineffective and I showed his conclusions were not justified.

Paul appears desperate to cling to any case I have not looked at. Must I go through every example and look at the details? Can he not do this himself? If there are no mitigating circumstances this would surely support the argument he wants to make. We should not do science this way. We should always approach the literature and research critically and intelligently.

Having conceded on La Salud and the former DDR is he prepared to modify his claims about these situations in his FAN website?

National Fluoridation Information Service

Some discussion of this body is important as Paul’s confusion extends a lot further than its name. He is demonstrating how he cynically uses terms like “weight of evidence analysis.” Cynical because he rejects the very body (NFIS) that is taking this scientific approach in New Zealand and throws his advocacy behind the body which is biased, uncritical and unintelligent in considering the evidence. The body which cherry-picks literature and interprets it selectivity to support its confirmation bias. He supports the NZ Fluoridation information Service (NZFIS).

As I wrote in my last article the NZFIS is an astroturf organisations set up by the FANNZ. Paul well knows that FANNZ has a clear bias and political aims with a declared purpose of “bringing about the permanent end to public water fluoridation (“fluoridation”) in New Zealand,” (quote from FANNZ rules).

Simple consideration of the NZFIS web site shows that it does no active work on the fluoridation issue. It’s material is old, biased and there is no current activity. However, the organisation is used for distributing biased press releases and attempting to claim scientific credibility. (See, for example, my recent article False balance and straw clutching on fluoridation.)

I can understand why Paul throws his support behind FANNZ and the NZFIS. They are part of the international tentacles of his organisation FAN. This is not about science or “weight of evidence analysis” at all. It’s about political activism.

So of course Paul must bad-mouth the organisation which is doing the work and taking a scientific approach in NZ – the National Fluoridation Information Service (NFIS). He says:

“My concern here is the use of taxpayer money (about 1 million dollars) to support the promotion of fluoridation rather than presenting a balanced view of the evidence.”

Well he would say that wouldn’t he? He treats public funding of NZFIS as a smear! That is the typical naive conspiracy theory approach taken by climate change deniers and any other anti-science organisation who attempt to discredit scientific findings. It distorts the facts completely – governments don’t employ scientists to produce a predetermined conclusion – if they wanted that theologians would be more appropriate and a lot cheaper. Research funding is not used to confirm a bias but to employ the people and resources who can answer important questions.

He also seems to think dropping a figure like “about 1 million dollars” acts as a smear. Let’s put this into context – here is the NFIS budget for 2012/2013. From the 2012-2013 annual plan.

NFIS-2013

And, no, the NFIS does not spend its time issuing misleading press releases or providing institutional status to political activists. Here is how an early evaluation document described its role:

“NFIS is an information and advisory service which will support District Health Boards and Territorial Local Authorities by providing robust and independent scientific and technical information, advice and critical commentary around water fluoridation.”

Go to the NFIS website and have a look at its output – it is professional and balanced. It is a laugh to even compare the barely operating astroturf NZFIS with it. Of course Paul wants to discredit the NFIS – he would like our scientists and health professional to rely on his own biased political organisations instead.

My criticism of FAN

Paul says that in making criticisms of FAN I am playing a “pro-fluoridation activist rather than a scientist.” I disagree because scientists must be concerned about the quality of material they consider. The must be aware of ideologically driven cherry-picking, opportunist use of selected research and the promulgation of unwarranted conclusions being promoted for political or ideological reasons. This is all part of looking at all the evidence critically and intelligently.

Scientists are concerned about poor quality and misinterpretation. It is disingenuous of Paul to make an accusation of activism to ignore or deny, the legitimacy of these concerns.

Paul claims that even if “FAN is a terrible organisation .  . . That does not affect the scientific case for and against fluoridation.” I agree – the scientific case rests on objective reality and the science itself – not on reputation or rumour. But the determination and presentation of a case is very much influenced by the bias and the ideological and political positions of an organisation making the case.

In my last article I analysed the way that FAN worked to demonstrate why their information and claims are unreliable. I believe that was perfectly justified from a scientific perspective.

Similarly I think my arguments above analysing Paul’s mechanical interpretation of “weight of evidence,” and what he means by it in practice, are also justified from a scientific perspective.

Surely such analyses must be part of the critical  and intelligent consideration of the arguments of organisations and people? Isn’t this what Carl Sagan meant with:

“Skeptical scrutiny is the means, in both science and religion, by which deep thoughts can be winnowed from deep nonsense.”

Concluding message

Several times I have stressed my motivations in this debate are scientific and not supporting a specific policy. I am concerned at the way the scientific literature and findings are being misrepresented by ideologically driven activists. We have seen this before on issues like evolutionary science and climate change. Similar misrepresentation is currently rife among advocates of alternative and natural medicine and health. I believe it must be opposed.

Hopefully many readers have taken my point on this. While I currently believe fluoridation of drinking water is a worthwhile social policy in New Zealand I don’t see it as the end of the world if it is rejected by a community. Nor do I see it as the only way of overcoming deficient levels of fluoride in our diet. And, of course, there is always the possibility that future research may change the current scientific consensus that fluoride at the levels used in water or salt fluoridation is safe and beneficial. Science is like that. Because our knowledge is always provisional, but improving over time, we sometimes do modify our conclusions.

So, if readers take my point about the need to overcome misrepresentation of science in these sorts of issues I will consider participation in this exchange worthwhile – even if most readers do not change their political views on support or opposition to fluoridation of water.

References

Balls, M., Amcoff, P., Bremer, S., Casati, S., Coecke, S., Clothier, R., … Zuang, V. (2006). The principles of weight of evidence validation of test methods and testing strategies. The report and recommendations of ECVAM workshop 58. Alternatives to laboratory animals : ATLA, 34(6), 603–20.

Blakey, K. et al (2014). Is fluoride a risk factor for bone cancer? Small area analysis of osteosarcoma and Ewing sarcoma diagnosed among 0-49-year-olds in Great Britain, 1980-2005. International Journal of Epidemiology, 2014, January 14.

Cho, H.-J., Jin, B.-H., Park, D.-Y., Jung, S.-H., Lee, H.-S., Paik, D.-I., & Bae, K.-H. (2014). Systemic effect of water fluoridation on dental caries prevalence. Community dentistry and oral epidemiology.

Choi, A. L., Sun, G., Zhang, Y., & Grandjean, P. (2012). Developmental fluoride neurotoxicity: A systematic review and meta-analysis. Environmental Health Perspectives, 120(10), 1362–1368.

Colquhoun, J. (1987). Education and fluoridation in New Zealand: an historical study. Ph.D. thesis. University of Auckland, New Zealand.

Colquhoun, J. (1997). Why I changed my mind about fluoridation. Perspectives in Biology & Medicine, 41(1):29-44.

Colquhoun, J.; Mann, R. (1986). The Hastings fluoridation experiment: Science or swindle? Resurgence & Ecologist, 16(6), 243–248.

Colquhoun, J., & Wilson, B. (1999). The lost control and other mysteries: Further revelations on New Zealand’s fluoridation trial. Accountability in Research, 6(4), 373–394.

Comber, H., Deady, S., Montgomery, E., & Gavin, A. (2011). Drinking water fluoridation and osteosarcoma incidence on the island of Ireland. Cancer causes & control : CCC, 22(6), 919–24.

Diesendorf M. (1986) The mystery of declining tooth decay. Nature 322 125-129.

Domellöf, M., Lönnerdal, B., Dewey, K. G., Cohen, R. J., & Hernell, O. (2004). Iron, zinc, and copper concentrations in breast milk are independent of maternal mineral status. The American journal of clinical nutrition, 79(1), 111–5.

Healy, W.B.; Ludwig, T.G.; Losee, F. L. (1961). Soils and dental caries in Hawke’s Bay, New Zealand. Soil Science, 92(6), 359–366.

Kodama, H. (2004). Trace Element Deficiency in Infants and Children — Clinical practice. Journal of the Japan Medical Association, 47(8), 376–381.

Levy, M., & Leclerc, B.-S. (2012). Fluoride in drinking water and osteosarcoma incidence rates in the continental United States among children and adolescents. Cancer Epidemiology, 36(2), e83–e88.

Ludwig, T. G. (1958). The Hastings Fluoridation project I. Dental effects between 1954 and 1957. New Zealand Dental Journal, 54, 165–172.

Ludwig, T. G. (1959). The Hastings fluoridation project: II. Dental effects between 1954 and 1959. New Zealand Dental Journal, 55, 176–179.

Ludwig, T. G. (1962). The Hastings fluoridation project III-Dental effects between 1954 and 1961. New Zealand Dental Journal, 58, 22–24.

Ludwig, T. . (1963). Recent marine soils and resistance to dental caries . Australian Dental Journal, 109–113.

Ludwig, T. G. (1965). The Hastings fluoridation project V- Dental effects between 1954 and 1964. New Zealand Dental Journal, 61, 175–179.

Ludwig, T. G. (1971). Hastings fluoridation project VI-Dental effects between 1954 and 1970. New Zealand Dental Journal, 67, 155–160.

Ludwig, T. G.; Healy, W. B.; Losee, F. L. (1960). An association between dental caries and certain soil conditions in New Zealand. Nature, 4726, 695–696.

Ludwig, T.G.; Healy, W. B. (1962). The production and composition of vegetables in home gardens at Napier and Hastings. New Zealand Dental Journal, 58, 229–233.

Ludwig, T.G.; Pearce, E. I. F. (1963). The Hastings fluoridation project IV – Dental effects between 1954 and 1963. New Zealand Dental Journal, 59, 298–301.

NFIS (2013) Community Water Fluoridation and Osteosarcoma – Evidence from Cancer Registries. (2013), (May).

NFIS (2013) A review of recent literature on potential effects of CWF programmes on neurological development and IQ attainment.

Scientific Committee on Health and Environmental Risks SCHER (2010).  Critical review of any new evidence on the hazard profile , health effects , and human exposure to fluoride and the fluoridating agents of drinking water.

Xiang, Q; Liang, Y; Chen, L; Wang, C; Chen, B; Chen, X; Zhouc, M. (2003). Effect of fluoride in drinking water on children’s intelligence. Fluoride, 36(2), 84–94.


The links to all the articles in the exchange are listed by date on the Fluoride Debate page. I will shortly  put the articles together in a PDF document (and maybe an eBook format) so readers can download and consult at their leisure. Maybe we could even use Paul Connett’s speaking tour of New Zealand early in the year to encourage people to read the exchange.

Thanks to Paul Connett for agreeing to this exchange (it was actually his idea to try it as an on-line exercise) and to all the people who participated in the comments discussion.

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