Category Archives: Health and Medicine

Fluoride: More scaremongering using drug warnings


Some anti-fluoride campaigners are using drug warnings related to sodium fluoride tablets to claim such warnings should also be placed on the fluoridated water coming out of your tap.

This is silly on two counts:

  1. A tablet sold in a pharmacy is different to water in a tap and such warnings must be appropriate to the tablet and its possible use.
  2. Drug warnings like this are generally all-encompassing and do no imply, by themselves, that there is any danger.

So let’s compare the drug warnings for sodium fluoride tablets (using the web site that the campaigners rely on) with the warnings for other safe substances.

This is the warning for sodium fluoride from the site:

But compare this with the warning for sodium chloride from the site.


Using the anti-fluoride campaigners’ logic, they should also be campaigning against sodium chloride – the ordinary salt in so much of our food. Or the chloride in our tap water derived from natural sources and the chlorination treatments.

Their warnings that pregnant women, or people with allergies, shouldn’t be drinking tap water is just naive scaremongering.

Similar articles


Cochrane responds to misrepresentation of their fluoridation review


Image Credit: Cochrane Oral Health Blog

The latest Cochrane Review on community water fluoridation (CWF) was published in June. Here are a citation and link for those interested:

Iheozor-Ejiofor, Z., Worthington, HV., Walsh, T., O’Malley, L., Clarkson, JE., Macey, R., Alam, R., Tugwell, P., Welch, V., Glenny, A. (2015). Water fluoridation for the prevention of dental caries (Review). The Cochrane Library, (6).

Immediately after publication, anti-fluoride propagandists launched a campaign of misrepresentation and outright distortion of the review’s findings. I dealt with some of this, and commented on the review itself, in the following posts:

The wave of misrepresentation and situations concerned health professionals – some of their on-line feedback and responses are in the Cochrane blog posts – Little contemporary evidence to evaluate effectiveness of fluoride in the water and Our response to the feedback on the Cochrane fluoridation review).

The Cochrane Oral Health Group yesterday published an updated Plain Language Summary (PLS) for the review. If you want to look in detail here is the original version of the review, and here is the abstract and updated Plain Language Summary from the latest version (now online). Their short explanation for this is:

“Following feedback, from a variety of sources, we felt it was necessary to make the language of the PLS simpler.”

This is logical. The PLS is the only part of the Review most policy makers will read. The old version contained too many words like “bias” and references to research “quality” which may have been reasonable to an academic audience but conveyed an entirely different meaning to policy makers who do not have an academic or scientific background. Anti-fluoride campaigners have worked hard to use this in their misrepresentations and distortions aimed at policy makers as well as the public.

Some of the changes

The new PLS does not include the word “bias” and now describes the selection criteria pointing out most studies made after 1975 were excluded (because they did not include initial surveys). Readers will now be more aware that the lack of information in some areas resulted from these strict selection criteria and not from lack of research.

For example, the text:

“No studies met the review’s inclusion criteria that investigated the effectiveness of water fluoridation for preventing tooth decay in adults, rather than children”

has been replaced by

“Within the ‘before and after’ studies we were looking for, we did not find any on the benefits of fluoridated water for adults.”

And the text:

“There was insufficient information available to find out whether the introduction of a water fluoridation programme changed existing differences”

has been replaced by:

“We found insufficient information to determine whether fluoridation reduces differences in tooth decay levels between children from
poorer and more affluent backgrounds.”

Will the misrepresentation continue?

Of course it will. Even the most carefully worded summary can be distorted to misrepresent reported findings. Hopefully, though, these changes will make it harder for campaigners to pull the wool over the eyes of policy makers. The careful reader will now have a better idea of the limitations of the review resulting from the strict selection criteria. Hopefully, they will also be aware that statements like “We found insufficient information . . .” do not mean there is no information. Nor does the inability, within the restricted selection criteria, to find an effect mean there is no effect.

I am disappointed that their changes did not make the situation of dental fluorosis clearer. They do now stress that most of the dental fluorosis studies reviewed “were conducted in places with naturally occurring – not added – fluoride in their water.” But this is not adequate:

“results of the studies reviewed suggest that, where the fluoride level in water is 0.7 ppm, there is a chance of around 12% of people having dental fluorosis that may cause concern about how their teeth look.”

is just not adequate

The choice of 0.7 ppm will be seen as relevant to the concentration used in CWF – but this does not mention that any difference between the  prevalence in fluoridated and unfluoridated areas is very small and not statistically significant. In other words, their comments on dental fluorosis are still not relevant to CWF.

Similar articles

ChildSmile dental health – its pros and cons


There is some local interest in the Scottish ChildSmile dental health programme. Partly because anti-fluoride campaigners are promoting it to local bodies as an alternative to community water fluoridation (CWF). Their interest is possibly due to the opt-in nature of the programme which they see as satisfying there demands for “freedom of choice” (in this case the choice means excluding their own children from the programme which, after all, does include fluoride treatments).

However, health professionals in the UK are more balanced in their opinions. While welcoming ChildSmile they do not see it as an argument against CWF – rather as “the next best thing – a rather expensive substitute for the fluoridation schemes that have never been introduced.”

I have written about the ChildSmile programme before (see Fluoride debate: Ken Perrott’s closing response to Paul Connett?). But here is some more detail I have picked up from discussion online with health professionals.

What is the ChildSmile programme?

On the surface, the ChildSmile programme supplies children with toothbrushes and toothpaste:

“The core programme involves supervised daily toothbrushing for all Scottish three and four year olds attending nursery schools (but not those who don’t attend nurseries). This has been extended to five and six year olds in primary schools in those areas (not necessarily across entire local authorities) counted as being among the 20% most deprived in Scotland.”

Data suggest that about 82% of three and four-year-olds are participating. The children who do not take part do not benefit.

ChildSmile also includes twice-yearly application of fluoride varnish to children’s teeth.  The programme 2013/2014 targets included this:

“At least 60% of 3 and 4 year old children in each SIMD quintile to receive at least two applications of fluoride varnish per year by March 2014.”

In addition to toothbrushing and varnishing, Childsmile involves 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.

Is it a substitute for CWF?

Not really, but health professionals see it as the “next best thing.” Appropriate for situations where there is no CWF. But it only covers children – and then only those children whose parents give consent (many don’t). In contrast, CWF benefits adolescents and adults, as well as children. Families can, of course, “opt out” od CWF (by using water filters or different sources), but numbers will be lower than those excluded by “opt-in” procedures.

It is wrong to see such programmes as alternatives to, or separate from, CWF. Elements of the ChildSmile programme were already present before ChildSmile was introduced. Similar elements will also be common in countries like New Zealand.

Is it effective?

Childsmile was introduced in 2008 so it is a little early to judge its effectiveness. Scottish children’s dental health has improved and the programme most likely has assisted that.

For example, 58% of five-year-olds were free of decay in 2008, compared with 68% in 2014. The average decayed, missing and filled teeth (dmft) score for this age group has fallen over that period from 1.86 to 1.27.


However, there does not seem to have been a reduction in dental health inequalities between children from different social groups in Scotland. In 2008, 42% of children from the most socially deprived quintile of Scottish five-year-olds were free of decay compared with 73% of those from the least deprived quintile. In 2014, 53% of five-year-olds in the most deprived quintile were free of decay compared with 83% of those from the least deprived quintile.


According to the Scottish National Dental Inspection programme the absolute inequality between the most and least deprived children remains at 30% (comparing percentages of children without tooth decay), according to surveys conducted in 2008, 2010, 2012 and 2014.

Another concern is that children in the most deprived quintile of five-year-olds have not reached the national target set in 2010 that 60% of them should be free of decay.

Of course, the ChildSmile programme has no effect on the oral health of  current adolescents and adults.

What about the cost?

ChildSmile is far less cost-effective than CWF. Let’s compare the cost of CWF in England with the costs for the ChildSmile programme in Scotland

CWF serves 6 million people in England, costs around £2.1 million a year and is benefiting everyone with natural teeth, regardless of age, education or socioeconomic status. It benefits all children. So the cost per person of is around 35 pence per annum, although if we exclude people with no natural teeth it is likely to be a little higher than that – an average cost of about 40 pence per person benefiting.

If we take a narrow view and assume only children and adolescents aged 0 to 17 (21% of the population in England ) benefitted from CWF the cost would apply to around 1.26 million out of the 6 million supplied with fluoridated water. On that basis, the cost of CWF would be £1.67 per year for each child benefitting.

In contrast:

The total national ChildSmile budget for 2013/14 was £14,956,000, according to a statement by the Minister responsible to the Scottish Parliament in July 2013. This covers  everything attributable to Childsmile – the toothbrushing programme, plus targeted varnish applications and associated oral health education initiatives.  Assuming that around 120,000 Scottish children aged between three and six are benefiting, it works out at a cost of around £125 per child per annum.

Compare the Childsmile costs of around £125 per child per annum with the CWF costs of about 40 pence per person per annum or even £1.67 per year for each child benefitting. CWF is obviously many times less expensive that ChildSmile.

What is the attitude of Scottish dentists?

The British Dental Association supports CWF and in Scotland has come out publicly to call for communities to move towards introducing water fluoridation. That position undermines the arguments of New Zealand anti-fluoridation groups claiming that Childsmile is an adequate substitute for water fluoridation. The professional body representing dentists in Scotland does not see it that way.

The BDA in Scotland points out that CWF would be beneficial to children and elderly people. It argues that water fluoridation “would complement the Childsmile programme” by helping cut the overall burden of tooth decay and reducing dental health inequalities in the elderly. We could look at it another way and see that a Childsmile programme could complement water fluoridation. After all, we must remember that initiatives such as Childsmile rely on personal compliance and that they benefit only those taking part. They give no benefit for the rest of the population, unlike CWF.

CWF and ChildSmile are are not mutually exclusive. Children in fluoridated areas should be encouraged to brush their teeth regularly with a fluoride toothpaste and to receive dental check-ups. Bear in mind, also, that components of a ChildSmile programme, such as supervised toothbrushing, were in use in parts of Scotland before the introduction of the full programme. Elements of the ChildSmile programme will also be in current use in New Zealand.


Despite claims of anti-fluoride propagandists, the ChildSmile programme is not a simple alternative to CWF. And it is wrong to see it as such in New Zealand.

It is far less cost-effective – the Scottish programme costs around £125 per child per annum compared with 40 pence per person per annum (or £1.67 per year for each child benefitting when benefits to adults are excluded) and therefore far less likely to be put in place as an alternative to CWF.

ChildSmile is an “opt-in” programme so its coverage is far lower than CWF which is an “opt-out.” This is important when social differences in oral health are important.

However, the contact between children and their families on the one hand and public health nurses, health visitors and dentists on the other, is very valuable and may have wider benefits than oral health alone. (I am thinking of problems caused by child neglect and abuse).

I think these sort of programmes are socially very helpful and strongly support them. The cost is, of course, a limiting factor. However, elements of such social programmes may be possible within budget constraints that health authorities face.

Health programmes like ChildSmile, or elements of that programme, can be very effective even in areas where CWF exists. They can give that extra boost to the oral health of children and can, therefore, complement CWF.

There are many areas where CWF is not feasible because of low population density, lack of suitable water reticulation systems or local political opposition to CWF. I believe that programmes like ChildSmile, or parts of that programme, can be very helpful in those situations. Northland and particularly NZ’s Far North are obvious examples.

Finally, let’s not be diverted by the programme name. I am sure that elements of the Scottish ChildSmile programme are already in place in New Zealand, or parts of New Zealand. Given the costs of such programmes, and budget limitations, these programmes do have the advantage that they can be targeted to regions or social groups where the need is the greatest.

Similar articles

The Alternative Medicine Racket

We are so used to the bad press that pharmaceutical companies and the health service get that it is worth standing back and having a critical look at what the “natural”/alternative health industry gets up to.

And that is not jut the pseudoscience and magical claim. It also the political manipulation and manoeuvring.

This video is quite timely.

Source: The Alternative Medicine Racket « Science-Based Medicine

Similar articles

Fluoridation: Freedom of choice – and responsibility

PN Tap

Alia Grant, 7, collecting “fluoride-free” water from the Papaoeia Park tap in Palmerston North. Credit: Warwick Smith/ Fairfax NZ

Apparently a source of “fluoride-free” water provided by the Palmerston North City Council since last May has seen little use. Despite the council providing the “fluoride-free” public tap at the request of campaigners, the data on its use shows an average of only about 4 people a day drawing water from it (see comments by Palmerston North City Councillor Aleisha Rutherford and email to her from council officials).

This data will interest other councils, like the Hamilton City Council, who are considering installation of similar “fluoride-free” taps. They might question whether such low use warrants the costs involve (more that $90,000  for Palmerston North and a budgeted $60,000 for Hamilton). But I am more interested in what this low usage implies for they way anti-fluoride campaigners have exerted their own freedom of choice.

Freedom of choice involves responsibility

I have always argued for freedom of choice on issues like community water fluoridation (CWF) where opinions are divided. I believe that freedom of choice is actually guaranteed by democratic processes.

Yes, I know, the minority sometimes complain that such democratic decisions remove their freedom of choice – and certainly anti-fluoride propagandists make much of this. Often claiming that the minority’s freedom of choice, in this case, is more important than the health of the community as a whole.

But that argument is disingenuous. Such choices are about the availability of a service or social health measure – not about having such services or health measures imposed on people. There is always a choice – and that is the great thing about democratic decisions. The community supports socially provided health care and secular education. But that in no way prevents the minority, who oppose such measures, the freedom to organise their own healthcare or education. Free secular education and healthcare is not imposed on anyone.

So, it seems obvious to me that someone who genuinely believes fluoridation is not OK should be responsible enough to take their own steps to either filter the water supply or arrange for a different source if they find themselves in the minority. I am not for a minute suggesting they give up their belief, or even their attempts to convince others. Just that they be responsible, accept the majority have spoken and that the majority decision should prevail – at least until there is a democratic change of mind.

Given the ready availability of alternative water sources or filtration devices, it would be silly not to take advantage of them. That is exactly what I would do if in that situation. But very few of my anti-fluoride discussion partners on this issue, when asked, acknowledge they take such steps. Instead, they will often complain about costs, even claiming these costs are prohibitive, and moan about having fluoridation “forced” on them.

Water filters a common

So the low usage of this “fluoride-free” tap indicates to me that people who seriously object to fluoridation of their water supply are already taking their own steps to remove it – most probably using a relatively cheap filter. And, I believe their use of such filters probably predates any public action they have taken on the issue. Similar filters are, after all, quite common and many people use them for aesthetic reasons to remove the taste of chlorine or organic matter.

So why do anti-fluoride activists make such a fuss – attempting to deny a democratically accepted social health measure to people who support it? After all, any personal claims of their own sensitivity to fluoride are surely invalid if they have exercised their freedom of choice and taken steps to filter their water or find another source.

The water consumption data for the “fluoride-free” tap in Palmerston North suggests that all but a very few (perhaps 4 people?) are responsibility taking their own steps to filter the water. This fuss, then, surely has nothing to do with their own situation. I can’t help thinking it derives from their own ideological and political beliefs about what society as a whole should do.

Perhaps these ideological and political beliefs, rather than any scientific fact, are the real source of their claim about the danger of community water fluoridation?

See also


My talk to the Reason & Science Society – an invite

RSSAuckland readers are welcome to come along to a talk I am giving at Auckland University next Thursday.

The Reason and Science Society (RSS) hosting the talk. It’s called “The Case for Community Water Fluoridation with Dr Ken Perrott”. Details are:

Day: Thursday 17th September
Time: 6:00 PM – 8:00 PM.
Location: Room 206-315, Arts 1 building, University of Auckland
Map of the talk location:

About this talk:
Community water fluoridation continues to be a controversial in New Zealand. Thames is the latest community to face this issue in an October referendum. Local bodies are frustrated by the lobbying the bombarded with on this issue and are asking central government to take responsibility for it.

Many of the claims made about fluoridation are misleading and scientific research is often distorted to support these claims. Dr Ken Perrott will describe what the science is really saying about community water fluoridation.

About the speaker:
Dr Ken Perrott is a retired research scientist. He is a scientific advisor for Making sense of Fluoride.

Event page (you need to join the RSS group to view it):

Similar articles

In the end, it came down to the science in Denver


Denver Board of Water Commissioners listen to information at the July 2015 fluoride information session.

In my update to the post Subverting democratic consultation on the fluoride issue I reported that Denver Water has voted unanimously to continue community water fluoridation.  They have now produced a web article explaining their decision – see  The “why” behind our fluoride policy.

I think this comment sums it up:

“In the end, it came down to the science. And there’s a lot of it.On Aug. 26, the Denver Board of Water Commissioners voted to continue its practice of community water fluoridation.”

That decision came after a thorough review where both supporters and opponents of community water fluoridation presented their cases to the board.

“After reviewing the presentations, the extensive research on this issue, and the advice of public health and medical professionals in Colorado, the board announced there would be no change in its water fluoridation policy.

The resolution the board adopted at its meeting stated: “Nothing we heard through the presentations or learned in research would justify ignoring the advice of the public health agencies and medical organizations or deviating from the thoroughly researched and documented recommendation of the U.S. Public Health Service.””

And that is how it should be. Public officials should listen to the experts – scientific and health. Of course, they must also listen to criticism of expert recommendations, but such critical opinions must be carefully and critically weighed up. Denver Water board members appear to have done this.

The board said:

“Notably, every public health agency operating in our service area urged us to continue our practice of managing fluoride concentrations in our drinking water.”

This is supported by the list of presentations they considered as described in Denver Fluoride Fight Pits Activists Against Long-Standing Health Policy:

Number of comments in favor of fluoridation: 101

Organizations in favor of fluoridation:

  • Denver Public Health Department
  • Denver Health
  • Denver Environmental Health
  • Tri-County Health Department (Adams, Arapahoe, Douglas)
  • Jefferson County Public Health
  • Colorado Department of Public Health and Environment
  • Colorado Dental Association
  • American Dental Association
  • Colorado Academy of Pediatric Dentistry
  • Colorado Medical Society
  • Colorado Academy of Family Physicians
  • Deans of the University of Colorado Dental, Medical and Public Health Schools
  • Various community organizations

Number of comments opposed to fluoridation: 1,078
Organizations opposed to fluoridation:

  • Fluoride Action Network
  • New York State Coalition Opposed to Fluoridation
  • Concerned Residents of Peel to End Fluoridation
  • We Are Change Colorado”

Similar articles

Subverting democratic consultation on the fluoride issue


Credit: Making Sense of Fluoirde

Denver Water, which as Colorado’s largest water provider, has been reviewing its water fluoridation policy. It will announce its decision in the next few days but I found its description of the consultation process interesting.

[Update: Denver Water has now voted unanimously to continue community water fluoridation (see Good News – Denver Water Votes to Continue Community Water Fluoridation!). A complete failure for the anti-fluoride campaigners who worked hard to defeat fluoridation in Denver.]

A spokeswoman for the board, Stacey Chesman said Denver Water had received nearly 1,200 comments, from as far away as New Zealand, with 1,078 opposed to fluoridation, and 663 of those submitting their comments on postcards created by We Are Change Colorado. Every public health agency in Denver Water’s service area urged it to continue fluoridating water (See Water systems sink teeth into debate over drinking it).

Pretty impressive, eh? Twelve hundred submissions and about 90% oppose community water fluoridation (CWF). But look again – over 60% of the opposing submissions were on postcards provided by the anti-fluoride propagandist group “We are Change Colorado.”

Manipulating council consultations

That reminds me of the Hamilton City Council’s fluoride considerations two and a half years ago. That Council’s  summary of submissions 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.”

The Hamilton numbers are so similar to those in Denver that one might wonder if the same people or organisations organised many of the submissions. And, I suspect, the Denver number of 90% opposed is just as unrepresentative of the public’s view as the Hamilton 90% – as shown by the subsequent Hamilton referendum where 70% of voters supported CWF! (See When politicians and bureaucrats decide the science).

The postcard tactic used in Denver is also much the same as the New Zealand Fluoride Free organisation providing submission templates  (templates A, B, C, D, were used in Hamilton) and submission guides. And the comment that Denver water received submissions “from as far away as New Zealand” also rings a bell – many of the submissions received by the Hamilton City Council were from as far away as the USA. And, in fact, video links were used to enable oral submissions by anti-fluoride propagandists from the USA!

What we have seen in these two cases – and many others in New Zealand, the USA, Canada and Australia – is a highly efficient organised campaign from “out-of-towners” intent on subverting the consultation process and the democratic rights of local citizens. A process which one might think mature and sensible civil leaders could easily recognise and discount. However, some of these leaders are easily fooled. In Hamilton, the local council gave the high numbers of anti-fluoride submissions they got as one of the main reasons for deciding to stop CWF. This seemed to them more important than the real referenda results!

A fluoride referendum in Thames

In New Zealand, the small town of Thames will hold a referendum on fluoridation of their water supply in November (see Thames fluoride referendum set for 5 November). Campaigning will start soon and no doubt we will see the same circus of whirlwind visits from out-of-towners, propaganda from overseas anti-fluoride propagandists (who promote themselves as “world experts” on the subject), and billboard, newspaper and radio advertising – probably paid for by the “natural”/alternative health industry.

I hope the people of Thames will be rightly suspicious of these “out-of-towners,” and ideologically and commercially motived propagandists, and instead listen to the advice of their own social health and dental experts.

Similar articles

Alternative reality of anti-fluoride “science”

Paul Connett made many unsupported claims in his presentation against community water fluoridation (CWF) to Denver Water. Here I debunk a claim where he rejects most scientific studies on the cost-effectiveness of CWF.

Different grades of dental fluorosis

Connett asserted two things in his presentation:

  1. Previous research showing the cost effectiveness of community water fluoridation (CWF) has been made obsolete by a single new paper.
  2. Something about this new paper (Ko & Theissen, 2014) makes it more acceptable to him than previous research – and he implies you

Plenty of research shows CWF is cost-effective

Connett has cherry-picked just one paper, refused to say why and, by implication, denigrated any other research results. And there are quite a few studies around.

Here are a just a few readers could consult:

Of course, the actual figures vary from study to study, and various figures are used by health authorities. But generally CWF is found cost-effective over a large spectrum of water treatment plant sizes and social situation.

Connett relies on a flawed study

Connett relies, without justification,  on a single cherry-picked study:

Ko, L., & Thiessen, K. M. (2014). A critique of recent economic evaluations of community water fluoridation. International Journal of Occupational and Environmental Health, 37(1), 91–120.

This is a very long paper which might impress the uninitiated. To give it credit, it does make lengthy critiques of previous studies on cost effectiveness. But it has a huge flaw – its treatment of the cost of dental fluorosis.

It rejects warranted assumptions made by most studies that the adverse effects of CWF on dental fluorosis are negligible: They say:

“It is inexplicable that neither Griffin et al. nor other similar studies mention dental fluorosis, defective enamel in permanent teeth due to childhood overexposure to fluoride. Community water fluoridation, in the absence of other fluoride sources, was expected to result in a prevalence of mild-to-very mild (cosmetic) dental fluorosis in about 10% of the population and almost no cases of moderate or severe dental fluorosis. However, in the 1999–2004 NHANES survey, 41% of U.S. children ages 12–15 years were found to have dental fluorosis, including 3.6% with moderate or severe fluorosis.”

Two problems with that statement:

  1. The prevalence of “cosmetic” dental fluorosis may be about 10% but this cannot be attributed to CWF as non-fluoridated areas have a similar prevalence. For example, in the recent Cochrane estimates show “cosmetic” dental fluorosis was about 12% in  fluoridated areas but 10% in non-fluoridated areas (see Cochrane fluoridation review. III: Misleading section on dental fluorosis).This is a common, probably intentional, mistake made by anti-fluoride campaigners – to attribute the whole prevalence to CWF and ignore the prevalence in non-fluoridated areas. This highly exaggerates the small effect of CWF on the prevalence of “cosmetic” dental fluorosis – which in  any case does not need treatment. “Cosmetic” dental fluorosis is often considered positively by children and parents.
  2. The small numbers of children with moderate and severe dental fluorosis (due to high natural fluoride levels, industrial contamination or excessive consumption of fluoridated toothpaste) is irrelevant as CWF does not cause these forms. Their prevalence is not influenced by CWF.

So Ko and Theissen (2014) produce a different cost anlaysis because :

“. . . the primary cost-benefit analysis used to support CWF in the U.S. assumes negligible adverse effects from CWF and omits the costs of treating dental fluorosis, of accidents and overfeeds, of occupational exposures to fluoride, of promoting CWF, and of avoiding fluoridated water.”

We could debate all the other factors, which they acknowledge have minimal effects, but they rely mainly on the dental expenses of treating dental fluorosis:

“Minimal correction of methodological problems in this primary analysis of CWF gives results showing substantially lower benefits than typically claimed. Accounting for the expense of treating dental fluorosis eliminates any remaining benefit.”

They managed to produce this big reduction in cost-effectiveness by estimating costs for treating children with moderate and severe dental fluorosis – finding:

“the lifetime cost of veneers for a child with moderate or severe fluorosis would be at least $4,434.”


“For our calculations, we have assumed that 5% of children in fluoridated areas have moderate or severe fluorosis.”

See the  trick?

They attribute all the moderate and severe forms of dental fluorosis to CWF. Despite the fact that research shows this is not caused by CWF and their prevalence would be the same in non-fluoridated areas!

The authors’ major effect – which they rely on to reduce the estimated benefits of CWF – is not caused by CWF.

Connett is promoting an alternative “scientific” reality

The Ko & Theissen (2014) paper is one of a list of papers anti-fluoridation propagandists have come to rely on in their claims that the science is opposed to CWF. In effect, this means they exclude, or downplay, the majority of research reports on the subject – treating them like the former Index Librorum Prohibitorum, or “Index of Forbidden Books,” an official list of books which Catholics were not permitted to read.

The Ko & Theissen (2014) paper is firmly on the list of the approved studies for the anti-fluoride faithful. A few others are Peckham & Awofeso (2014), Peckham et al., (2015)Sauerheber (2013) and, of course, Choi et al., (2012) and Grandjean & Landrigan (2014).  You will see these papers cited and linked to on many anti-fluoride social media posts – as if they were gospel – while all other studies are ignored.

These papers make claims that contradict the findings of many other studies. They are all oriented towards an anti-fluoridation bias. And most of them are written by well-known anti-fluoride activists or scientists.

In effect, by considering and using studies from their own approved list and ignoring or denigrating studies that don’t fit their biases, they are operating in an alternative reality. A reality which may be more comfortable for them – but a reality which exposes their scientific weaknesses.

Lessons for Connett

I know Paul Connett is now a lost cause – he will continue to cite these papers from his approved list and make these claims no matter how many times they are debunked. But, in the hope of perhaps helping others who are susceptible to his claims, here are some lessons from this exercise. If anti-fluoride activists wish to support their claims by citing scientific studies they should take them on board.

Lesson 1: Make an intelligent assessment of all the relevant papers – don’t uncritically rely on just one.

Lesson 2: Don’t just accept the findings of each paper – interpret the results critically and intelligently. How else can one make a sensible choice of relevant research and draw the best conclusions.

Lesson 3: Beware of occupying an alternative reality where credence is given only to your own mates and everyone else is disparaged. That amounts to wearing blinkers and is a sure way of coming to incorrect conclusions. It also means your conclusions have a flimsy basis and you are easily exposed.

Lessons for everyone susceptible to confirmation bias.

Similar articles

Anti-fluoride propagandists get creative with statistics


According to a recently published survey, only 15% of New Zealanders are opposed to community water fluoridation (CWF).

Only 15% – yet anti-fluoride propagandists are using the same survey (or their limited reading of it) to claim that 58% of New Zealanders are opposed to (or do not support) CWF! (See Fluoridation problem for New Zealand, Most NZers do not support fluoridation, study saysFLUORIDATION’S FALLING POPULARITY NO SURPRISE, and Fluoridation’s Falling Popularity No Surprise.) That’s a huge difference. Someone must be using statistics in a creative way – or just outright lying.

The survey results were published in this paper:

Whyman, R. A., Mahoney, E. K., & Børsting, T. (2015). Community water fluoridation: attitudes and opinions from the New Zealand Oral Health Survey. Australian and New Zealand Journal of Public Health.

So anyone can check it out – although I recommend, as always, to read the full text. Often abstracts do not give the full information you want.

This survey reports data for various questions, but Table 2: “Estimates of ‘how in favour of water fluoridation’ (unweighted n, weighted percentage with 95% CI) opinions among adults (>=18 years of age)” is the relevant one here. The graphics below summarise the overall message (vertical bar is the 95% CI):


Or simplifying further into “for,” “against,” “neutral” and “do not know:”


So you can see the cherry-picking Mary Byrne from Fluoride Free NZ indulged in for her press release Most NZers do not support fluoridation, study says where she claims:

“This is the finding of a new survey carried out by Hawke’s Bay District Health Board: 58% of people did not support fluoridation even “somewhat”. This shows that people are really clear – New Zealanders do not agree with adding an industrial by-product, classified as hazardous, to our drinking water.”

She, no doubt would be offended by a claim that 85% of people support (or do not oppose) fluoridation – strongly or somewhat. Yet, her cherry picking is just as bad.

The real message from this survey for the anti-fluoride campaigners is that only 15% are opposed to community water fluoridation (CWF) – and then only 10% are strongly opposed.

As for the “creative license” of Mary Byrne and her fellow anti-fluoride propagandists, this message I picked up from a statistician’s cartoon sums it up:

You’ve heard of ‘Lies, Damn Lies, and Statistics.’ Well, apparently, they WERE lying about the statistics.”

The real message from the survey

The authors of this report did concentrate on the figure for those supporting CWF, or more importantly, the large proportion of people who are neutral (20%) or feel they just do not know enough to decide (22%). Interestingly, if these are excluded (as probably happens in referenda where a yes or no answer is required so that the neutral and undecided may not vote) the survey’s data translate into about 74% of the population supporting CWF and 26% opposing it. Not too different to recent referenda results (ranging from 58.1% support in Whakatane to 76.4% support in South Waikato).

However, health authorities are right to be concerned about the relatively large number of neutral and undecided people. The 15% who are opposed to CWF may largely be a “lost cause” because of their ideological stubbornness. But the data does show a need for more information on CWF and oral health in general.  It is likely that a better-informed population on this issue would lead to lower numbers of neutral and “do not know” people – and, very likely, a larger number of those who support CWF.

I have simply mentioned here the overall figures for support of, and opposition to, CWF but the study goes into a lot more detail and identifies sectors of the population requiring better education on the subject. Hopefully, we will see suitable oral health education programmes in future and a reduction in the neutral and “don’t know” numbers.

That can only be a good thing.

Similar articles