Tag Archives: community water fluoridation

Debunking anti-fluoridationist’s remaining 12 reasons for opposing fluoridation

New Zealand anti-fluoride campaigners have whittled their list of objections to community water fluoridation (CWF) down to 12 reasons. Maybe that’s progress – they used to tout a list of 50 reasons!

Let’s go through that list one by one and see if any stand up. I am responding here to each reason given in the Fluoride Free New Zealand’s (FFNZ) document Top 12 Reasons why Fluoridation Should End.

You can download a printable version of my responses.

1: Fluoride works by a surface reaction with existing teeth but research shows that it has a beneficial systemic effect with developing teeth.

The document asserts that “Fluoride promoters now claim that if there is any benefit from fluoride it is from contact with the surface of the tooth” and cite as their authority a High Court judge (incidentally, from a ruling that went against anti-fluoride campaigners). A High Court Judge is hardly an authority on scientific matters

Yes, the surface or “topical” action at the tooth surface is understood to be the predominant mechanism for existing teeth. The US Center for Disease Control illustrates this in its figure from the document Recommendations for Using Fluoride to Prevent and Control Dental Caries in the United States).

But, I pointed out in my article Cherry-picking and misinformation in Stan Litras’s anti-fluoride article, research also suggests fluoride is incorporated into the developing teeth of children and this helps provide protection.

Newbrun (2004), for example, stressed in a review of the systemic role of fluoride and fluoridation on oral health:

“The role of systemic fluoride in caries prevention is neither “minimal” nor “of borderline significance.” On the contrary, it is a major factor in preventing pit and fissure caries, the most common site of tooth decay. Maximal caries-preventive effects of water fluoridation are achieved by exposure to optimal fluoride levels both pre- and posteruptively.”

Cho et al (2014) presented data showing that children exposed to CWF during teeth development retained an advantage over those never exposed to it. Systemic fluoride may not play a role with existing teeth but it does during tooth development – even if it is difficult to determine the relative contributions of systemic fluoride and “topical” or surface fluoride to lasting oral health.

2: Too much fluoride causes dental fluorosis but this is not relevant to CWF.

Some children from both fluoridated and non-fluoridated areas do exhibit dental fluorosis. This is thought to be due to excessive consumption of fluoridated toothpaste and one important factor used in determining the optimum concentration of fluoride used in CWF is to prevent the development of dental fluorosis.

Anti-fluoride propagandists usually cite horrific figures for dental fluorosis because they incorporate all forms of dental fluorosis, from the mildest to the most severe, into their figures. For example, they will cite Ministry of Health Oral Health Survey data to claim that New Zealanders have a prevalence of 45% dental fluorosis caused by fluoridation. In fact, the dental fluorosis of concern (the severe and moderate forms) is very rare and the NZ Oral Health survey (from which this data is taken) showed no difference between fluoridated and unfluoridated areas.

3: Fluoride is not a neurotoxin (or neurotoxicant) at concentrations used in CWF.

Sure, animals studies show effects at high concentrations and there are studies of possible negative cognitive effects from areas of endemic fluorosis where drinking water concentrations of fluoride are relatively high. However, studies from areas where CWF is used (Broadbent et al, 2014) or natural levels of fluoride in drinking water are similar (see More nails in the coffin of the anti-fluoridation myths around IQ and hypothyroidism) do not show any negative effect on cognitive ability. In fact, the research suggests that fluoride may actually improve cognitive ability and improve chances of employment and income in adults (see the last link).

The Lancet article cited by FFNZ did not classify fluoride as a “neurotoxin” and the only discussion of fluoride in that article related to the poor quality studies from areas of endemic fluorosis referred to above. Scientific journals publish research findings and reviews – they don’t pass regulations or get into classifications.

4: FFNZ’s reference to dose is simply an attempt to claim evidence from high concentrations studies is relevant to CWF. It isn’t.

All the research indicates that the optimum recommended concentrations used in CWF are high enough to help reduce tooth decay but low enough to have no negative health effects. Only very mild dental fluorosis. which is often judged positively by teenagers and parents, is a possible result of such low concentrations.

The US National Toxicology Review referred to will simply extend previous reviews of animal studies to include human studies. This research programme also plans to include some animal studies using low fluoride concentrations – precisely because most former studies have used high concentrations unrepresentative of CWF.

The fact that new research like this commonly occurs is a good thing as it helps guarantee that social health measures like CWF are safe and they provide confidence to the public that there is continuous monitoring that would pick up any formerly unseen problems.

5: Skeletal and dental fluorosis occurs in parts of the world with high drinking water fluoride concentration but this is not relevant to CWF

The World Health Organisation recommends that drinking water fluoride concentrations should be in the range  0.5 – 1.5 mg/l. High enough to support dental health but low enough to prevent skeletal fluorosis or dental fluorosis of any concern.

Anti-fluoride campaigners commonly refer to the negative health effects in areas of endemic fluorosis (eg., China, India, and Senegal) where drinking water fluoride concentrations are much higher than used for CWF. But those facts are completely irrelevant to the situation in countries like New Zealand. And they are irrelevant to CWF which uses much lower drinking water concentrations.

6: There is no credible evidence to suggest that fluoride is an endocrine disruptor at concentrations used for CWF

A number of animal and human studies have produced conflicting results for endocrine effects of fluoride. These studies suffer from the use of high or unspecified fluoride concentrations. Effects have sometimes been seen for human in areas of endemic fluorosis. Studies have often been confused because of confounding effects due to iodine deficiency (known to cause thyroid problems), calcium and water hardness.

This means that it is easy to cherry-pick individual studies to support claims of harm from fluoride but these are usually for areas of high fluoride concentration or the studies are flawed by the problem of confounding effects.

The authoritative 2014 New Zealand Fluoridation Review (Eason et al. Health effects of water fluoridation: A review of the scientific evidence) considered “alleged effects of CWF on health outcomes  . . . including effects on reproduction, endocrine function, cardiovascular and renal effects, and effects on the immune system. “ It concluded:

“The most reliable and valid evidence to date for all of these effects indicates that fluoride in levels used for CWF does not pose appreciable risks of harm to human health.”

7: Bottle-fed babies do not receive harmful amounts of fluoride.

The FFNZ claim they do is a common anti-fluoride misrepresentation of the health recommendations concerning CWF and bottle-fed babies. These recommendations advise that use of fluoridated water to reconstitute baby formula is not harmful. They simply suggest that parents who are concerned should occasionally use non-fluoridated water for that reconstitution – a peace of mind thing.

For example, the American Dental Association advises:

“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. ”

Where parents want to reduce the risk of dental fluorosis they:

“can use powdered or liquid concentrate formula mixed with water that either is fluoride-free or has low concentrations of fluoride.”

Arguments based on low concentrations in human breast milk simply rely on the naturalistic fallacy – the claim that something is good or right because it is natural (or bad or wrong because it is unnatural). There are common concerns about deficient levels of some beneficial elements in human breast milk and recommendations for using supplements. See, for example, Iron and fluoride in human milk.

8: Fluoridation chemicals are not contaminant-laden waste products.

For example, fluorosilicic acid, the most commonly used fluoridation chemical in New Zealand, is a by-product of the fertiliser industry. When used for water treatment it must pass rigorous restrictions on contaminant levels. Certificates of analysis are required.


With these regulations and checks for water treatment chemicals, the concentration of any contaminant introduced into tap water by their use is much lower than the concentration of those contaminants already naturally present in the source water used. See Chemophobic scaremongering: Much ado about absolutely nothing for data based on a typical certificate of analysis for fluorosilicic acid and the natural concentrations of contaminants for the source water used by Hamilton City. The concentration of contaminants introduced into drinking water is well under 1% of the levels already naturally present in the water source (see graph).

9: Fluoridation is not a medicine and it does not violate human basic rights.

That was determined in High Court rulings – cases brought by anti-fluoride campaigners financed by the “natural”/alternative health industry. All appeals so far against those rulings have been rejected.

10:   Community water fluoridation is not suitable or necessary for many countries

A claim that only 5% of the world uses community water fluoridation is not relevant. Consider that just over 10% of the world do not have access to safe clean water so their people have more pressing concerns that water fluoridation. Many countries like China, India, and parts of North Africa use drinking water with fluoride concentrations that are excessive – fluoride removal or searches for alternative sources are their priority.

Even many developed countries or regions do not have reticulation systems which enable cost-effective fluoridation. This may be the case in Christchurch where the use of a number of bores may mean fluoridation of much of the city is not cost-effective.

Many countries already have natural concentrations of fluoride in their drinking water that are near optimum – making any supplementation unnecessary.

A recent review (O’Mullane et al., 2016) summarised the numbers of people around the world with access to beneficial levels of fluoride in their drinking water:

“General estimates for the number of people around the world whose water supplies contain naturally fluoridated water at the optimum level for oral health are around 50 million. This means that, when the numbers of people with artificially (369.2 million) and naturally fluoridated water supplies (50 million) at the optimum level are added together, the total is around 437.2 million.”

11: The effectiveness of community water fluoridation in reducing tooth decay is well established.

This fact is very often misrepresented by anti-fluoride campaigners. For example, in the FFNZ document, a recent New Zealand study is cited to argue that “there is no difference in decay rates between non-Māori children in fluoridated and non-fluoridated areas.” In fact, the authors of that study warned that the data for “non-Māori” children were misleading because it included data for Pacific Island children who have generally poorer dental health than other ethnic groups and are concentrated in fluoridated regions, thus distorting the data for non-Maori. When the data for all ethnic groups are considered separately it clearly shows the beneficial effects of community water fluoridation. This figure shows the non-Māori data corrected by removing the data for Pacific Island children. iut confirms that there is a difference in decay rates between fluoridated and non-fluoridated area.

Comparison of data for “other” (non-Māori/non-Pacifica) children in fluoridated (F) and unfluoridated (UF) areas. 5-year-old New Zealand children. dmft = decayed, missing and filled teeth.

FFNZ claims about the Cochrane Review and data from the District Health Boards and Ministry of Health are also incorrect. While the Cochrane Review did specifically exclude most recent studies because of its selection criteria it still concluded:

“Data suggest that the introduction of water fluoridation resulted in a 35% reduction in decayed, missing or filled baby teeth and a 26% reduction in decayed, missing or filled permanent teeth. It also increased the percentage of children with no decay by 15%. These results indicate that water fluoridation is effective at reducing levels of tooth decay in both children’s baby and permanent teeth.”

12: Community water fluoridation is only one part of successful dental health policies

These included regular fluoride varnishes, regular dental examinations, registering children into dental programmes, education measures such as guided toothbrushing, presenting children with toothpaste and toothbrushes, the involvement of parents in dental health and plaque checking and in dental health programmes generally. Health professionals see all these elements, including water fluoridation, as complementary. There is absolutely no suggestion that community water fluoridation means no other social dental health programme is used. However, in areas where community water fluoridation is not available health professionals will often introduce extra measures, such as wider use of fluoride dental varnishes, to help protect child dental health.

FFNZ misleads when it claims other aspects of a dental health programme can simply be substituted for water fluoridation. All parts of these programmes are complementary, one cannot normally be substituted for another.


So, none of the 12 reasons given by FFNZ for their opposition to CWF stand up to critical scrutiny.

Having whittled their original list down from 50 to only 12 reasons perhaps they should bite the bullet, face the facts, and continue whittling it down to zero.

That would then conform to the scientific information available.

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Premature births a factor in cognitive deficits observed in areas of endemic fluorosis?


Could the increased incidence of premature births explain cognitive deficits observed in areas of endemic fluorosis? Image credit: New Kids-Center.

Anti-fluoridation activists are soon likely to be promoting a new paper reporting a study which found a relationship between maternal (in utero) exposure to fluoride and cognitive development delay in infants. Of course, they will be unlikely to mention the study occurred in an area of endemic fluorosis where drinking water fluoride concentrations are much higher than used in community water fluoridation (CWF). They are also unlikely to mention the possible role of premature births in cognitive development delay observed in the study.

The paper is:

Valdez Jiménez, L., López Guzmán, O. D., Cervantes Flores, M., Costilla-Salazar, R., Calderón Hernández, J., Alcaraz Contreras, Y., & Rocha-Amador, D. O. (2017). In utero exposure to fluoride and cognitive development delay in infants . Neurotoxicology

Valdez Jiménez et al., (2017) studied 65 mother-baby pairs in an area of endemic fluorosis in Mexico. The mothers had high levels of fluoride in their urine and this was negatively associated with cognitive functions (Mental Development Index – MDI) in the infants.

The concentration of fluoride in the tap water consumed by the mothers ranged from 0.5 to 12.5 mg/l, with about 90% of water samples containing fluoride above the World Health recommended maximum of 1.5 mg/l.

Fluoride in the mothers’ urine was also high – with the mean concentration for all the mothers of 1.9 mg/l  for the 1st trimester, 2.0 mg/l for the 2nd and 2.7 mg/l for the 3rd trimester. Urinary fluoride concentrations as high as 8.2 mg/l were found. This compares with a mean value of F in urine of 0.65 mg/L) for pregnant women residents in areas with low levels of F in drinking water (0.4 to 0.8 mg/l – similar to that recommended in community water fluoridation).

The MDI test used evaluates psychological processes such as attention, memory, sensory processing, exploration and manipulation, and concept formation. This was negatively associated with maternal urine fluoride concentrations – the association explaining about 24% of the variance.

Room of other influences

This data suggests that other confounding factors which weren’t measured could also contribute to the variation of the MDI results, and if such confounders were included in the statistical analysis the contribution from urinary fluoride may be much less than 24%.

However, I am interested in the data for premature births that were, unfortunately, not included in the statistical analysis. The paper reports “33.8% of children were born premature i.e. between weeks 28-36 and had a birth weight lower than 2.5 kg.” This is high for Mexico – as they say:

“The World Health Organization (WHO) in Mexico reported a rate of 7.3 cases per 100 births; compared with 33.8% of cases per 100 births that we observed in our study. We have 26.5% more cases than expected.”

According to their discussion, other researchers have also reported higher premature births in areas of endemic fluorosis, compared with non-endemic areas.

Is premature birth a mechanism explaining cognitive deficits?

This study differs from many others in that fluoride exposure to the pregnant mother, rather than the grown child, was investigated. While the authors tended to concentrate on possible chemical toxicity effects on the cognitive development of the child in utero it is also possible that indirect effects could operate. For example, premature birth and low birth weights could themselves be a factor in child cognitive development.

In fact, a quick glance a the literature indicates this may be the case. For example, Basten at al., (2015) reported that preterm birth was associated with “decreased intelligence, reading, and, in particular, mathematics attainment in middle childhood, as well as decreased educational qualifications in young adulthood.” It was also associated with decreased wealth at 42 years of age.

The influence of endemic fluorosis on premature births and birth weights may not involve fluoride directly. Health problems abound in endemic areas – as well as the obvious dental and skeletal fluorosis complaints also involve muscles, blood vessels, red blood cells, the gastrointestinal mucosa and other soft tissues. It is easy to see such health problems influencing the prevalence of premature births and birth weights.

Not relevant to CWF

Of course, none of this is relevant to community water fluoridation. Such fluoridated areas do not have the health problems of areas with endemic fluorosis where drinking water concentrations are much higher. But, of course, this does not stop opponents of CWF claiming that similar problems occur at the lower concentrations.

In case anyone attempts to use this suggestion as an argument against CWF I should mention the only study I could find that makes the link between CWF and fluoridation. Often cited by anti-fluoride campaigners it is a poster paper:

Hart et al., (2009). Relationship between municipal water fluoridation and preterm birth in Upstate New York.

Presented at an Annual Meeting of the American Public Health Association the study appears not to have been published in a peer-reviewed journal. While the authors claim to have found a small, but statistically significant, increase in premature births in fluoridated areas this could be due to a number of possible confounding factors.With only a brief abstract to go on it is impossible to critically assess the study  – in fact, I suspect the non-publication is probably an indication of poor quality.

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More nails in the coffin of the anti-fluoridation myths around IQ and hypothyroidism


Large Canadian study finds no effect of fluoridation on thyroid health

A new Canadian study shows no relationship of cognitive deficits or diagnosis of hypothyroidism with fluoride in drinking water. This work is important because it counters the claims made by anti-fluoride campaigners. While the campaigners cite scientific studies to support their claims, those studies are usually very weak, or irrelevant because they involve areas of endemic fluorosis where drinking water fluoride concentrations are much higher than in situations where community water fluoridation (CWF) is used.

The study is reported in:

Barberio, A. M. (2016). A Canadian Population-based Study of the Relationship between Fluoride Exposure and Indicators of Cognitive and Thyroid Functioning; Implications for Community Water Fluoridation. MSc Thesis, University of Calgary

This new study is important as it has the advantages of using a large representative sample of the Canadian population, with extensive data validation and quality control measures. It also uses individual-level estimates of fluoride exposure on the one hand, and thyroid health and cognitive problems on the other.

Fluoride exposure was measured both by concentration in tap water for selected households and concentration in urine samples from individuals.

Thyroid health

The Canadian study found:

“Fluoride exposure (from urine and tap water) was not associated with impaired thyroid functioning, as measured by self-reported diagnosis of a thyroid condition or abnormal TSH level.”

This contradicts the conclusions from the population-level study of Peckham et al., (2015) which reported that fluoridation was correlated with the prevalence of hypothyroidism. That study is quoted extensively by anti-fluoridation activists but has been roundly criticised because it did not include the influence of confounders – particularly iodine which is known to influence thyroid health.

Barberio (2016) also suggests that the different recommended fluoride concentrations used for CWF in Canada and the UK, and the fact that the Peckham et al (2015) study did not involve individual measures, could also be factors in the different findings.

Cognitive functioning

The Canadian study reported:

“Fluoride exposure (from urine and tap water) was not associated with self-reported diagnosis of a learning disability.”

Barberio (2016) did also investigate a more detailed diagnosis for cognitive problems and found:

“Higher urinary fluoride was associated with having ‘some’ compared to ‘no’ cognitive problems . . . . however, this association:

  • Was weak;

  • Was not dose-response in nature; and

  • Disappeared when the sample was constrained to those for whom we could discern fluoride exposure from drinking water.”

I guess anti-fluoride activists might latch on to this last point regarding urinary fluoride but, at least as far as tap water fluoride is concerned, there was no relationship with learning difficulties.


So – yet another large-scale study contradicts anti-fluoridationist claims. It shows that CWF has no influence on cognitive problems or thyroid health.

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Water fluoridation – what to expect in the near future


Community water fluoridation (CWF) will persist in science news for the foreseeable future – not for any valid scientific reason but because of reaction to political pressures against it. This is particularly so in New Zealand where our parliament will be discussing legislative changes to fluoridation decision-making this year.

This is not to say that all the relevant news will be political. There is still ongoing research into the efficacy, cost-effectiveness and possible health effects of fluoridation. Although much of this is a response to pressure from opponents of this social health policy.

So what scientific and political news about CWF should we expect to see in the coming years?

The legislation

In the immediate future, this will be dominated by the new parliamentary legislation [Health (Fluoridation of Drinking Water) Amendment Bill– at least in New Zealand. However, US anti-fluoride campaigners are following this legislation very closely, and will probably become involved in submission on it, so I expect this will also get coverage internationally. At least in the alternative health media which has stong links to the US anti-fluoride activist organisation, Fluoride Action Network (FAN), and which routinely carry their press releases.

The NZ Parliamentary Health Committee is currently taking written submissions on the fluoridation bill. The deadline for these is February 2. Readers interested in making their own submission can find some information on the submission process in my article Fluoridation: members of parliament call for submissions from scientific and health experts.

The bill itself simply transfers the decision-making process for fluoridation from local councils to District Health Boards. But most submissions will inevitably be about the science and not the proposed changes to decision-making – and, considering the promise of the local anti-fluoride group to shower the committee with “thousands and thousands of submissions,” will misrepresent that science. I will be interested to see what allowance the committee chairman makes for such irrelevant submissions when it comes to the public hearings, which could begin as early as February.

The bill has support from all the parliamentary parties, except the small NZ First which apparently wants councils to keep responsibility for fluoridation decisions, but wants to make binding referendums obligatory. So, I predict the bill will be passed this year. However, there will probably be attempts at the committee stages to amend it to transfer decision-making to central government, probably the Ministry of Health. Such an amendment appears to be supported by the Labour Party, but not by the National Party.

The “IQ problem” – a current campaign

There will be some news about research on the question of possible cognitive effects of fluoride in drinking water in the next few years. Not because there is any concern about this among health professionals. But because the claim that fluoride causes a drop in IQ is pushed very strongly by anti-fluoride activists. While they have a long list of claimed negative health effects of fluoridation the IQ claim is currently central to their political campaigns.

The campaigners claim scientific support for this claim. But that support comes mainly from a number of poor quality papers outlining research results from areas of endemic fluorosis (where drinking water concentrations of fluoride are much higher than the optimum levels used for CWF), mainly in China. FAN has a lot invested in this claim because it financed the translation of many of these otherwise obscure papers into English.There is general agreement among health specialists that these studies are not relevant to CWF. Investigation of areas where CWF is used, and where natural fluoride levels are similar to those used in CWF have not shown any neurological effects due to fluoride.

There is general agreement among health specialists that these studies are not relevant to CWF. Investigation of areas where CWF is used, and where natural fluoride levels are similar to those used in CWF have not shown any neurological effects due to fluoride.

However, FAN is strongly pushing the idea that cognitive effects of fluoride (rather than very mild dental fluorosis) should be the main criteria used in determining the recommended maximum levels of fluoride in drinking water. They currently have a petition in front of the US Environmental Protection Agency (EPA) promoting this claim. This may make the news in the near future as the EPA must respond this month and the likely rejection of the petition will no doubt cause a flurry of press releases.

Paul Connett, who with other members of his family runs FAN, has also attempted to use the scientific publication path to promote this claim. His arguments and calculations defining an extremely low maximum concentration, are very naive and his draft paper has already been rejected by journals several times. However, he no doubt lives in hope for its eventual acceptance somewhere. If he is successful this will be trumpeted to the high heavens by his supporters because while they describe Paul Connett as the international authority of water fluoridation he actually has no proper scientific publications in that area.

Research on neurological effects

We expect some research publications in the next year or so from the current US National Toxicity Program research on claims that fluoride at the concentrations used in drinking water fluoridation could have neurological effects. This research is basically a systematic review – according to the proposal:

an “evaluation of the published literature to determine whether exposure to fluoride is associated with effects on neurodevelopment, specifically learning, memory, and cognition.”

The motivation for this work, apart from the political pressure arising from activist claims, is to attempt to evaluate possible effects at concentration relevant to CWF. (Most published animal and human studies have involved higher concentrations). As the proposal says:

“Previous evaluations have found support for an association between fluoride exposure and impaired cognition; however, many of the studies included exposure to high levels of fluoride. Most of the human evidence was from fluoride-endemic regions having high background levels of fluoride, and the animal studies typically included exposure during development to relatively high concentrations of fluoride (>10 mg/L) in drinking water. Thus, the existing literature is limited in its ability to evaluate potential neurocognitive effects of fluoride in people associated with the current U.S. Public Health Service drinking water guidance (0.7 mg/L).”

I discuss the background to the US National Toxicity Program fluoride research in my article Fluoride and IQ – another study coming up.

Canadian Professor Christine Till will soon start a study looking at cognitive and behavioral factors using a data set for pregnant women exposed to contaminants. She intends to investigate the possibility of relationships with markers for fluoride consumption (see ). Anti-fluoride campaigners hold out great hope for results from this study because Till’s previous research is widely used by them to claim that fluoridation causes increased prevalence of attention-deficit hyperactivity disorder (ADHD). However, that research was flawed because potential confounders were not considered properly. In fact, her reported statistically significant correlations disappears when the confounders are included (see  ADHD linked to elevation not fluoridation).

Problems in areas of endemic fluorosis

Health effects including cognitive deficits: The World Health Organisation recommends that drinking water fluoride concentrations should not be higher than 1.5 mg/L because of negative health effects of high concentrations. Many areas of the world do have high drinking water fluoride concentrations and those areas suffer from endemic fluorosis – dental and skeletal fluorosis. This is, of course, a serious problem and there is a continuous stream of research papers devoted to these areas.

This research is not relevant to CWF (where the optimum concentration of 0.7 mg/L or similar levels is used). But, of course, anti-fluoride campaigners will continue to cite these papers as “evidence” against CWF. We may even see an expert on endemic fluorosis being toured in New Zealand to provide scientific credibility to the anti-fluoride campaign. Dr. Ak.K. Susheela, who works on endemic fluorosis in India and has links with FAN, has been speaking at meetings organised by the anti-fluoride movement in North America and has been suggested as a speaker the local anti-fluoride campaigners should bring to New Zealand.

I expect there will be more papers reporting IQ deficits in areas of endemic fluorosis and these will most probably continue to use a chemical toxicity model to explain their results. I personally am interested in the possibility of researchers considering other models, such as the psychological effects of dental and physical deformities like dental and skeletal fluorosis (see Perrott et al. 2015. Severe dental fluorosis and cognitive deficits). Unlikely, considering how research can get locked into pet paradigms, but one can but hope.

Defluoridation: Another big issue in areas of endemic fluorosis is the need to lower drinking water fluoride concentrations. This if often done by finding alternative sources but there is continuing research on treatment methods to do this.

Again, not relevant to CWF – but I do follow this research and find some of it interesting chemically. Perhaps it reminds me of my own research many years ago.


The controversy around CWF is not going to go away. The opposition is strongly grounded in the “natural”/alternative health industry. It has plenty of financial and ideological resources and its message appeals to a significant minority of the population.

Most of the public interest this year will relate to the new legislation – expect plenty of press releases from the anti-fluoride groups as they organise to make and advertise their submissions, and express their anger at the probably inevitable decision that will go against them.

However, there will be a continuing dribble of research reports of relevance to CWF and to the claims advanced by anti-fluoride campaigners. While it is normal for a social health policy to be continually monitored and its literature reviewed, some of this research is a direct result of concerns raised by campaigners and activists.

Many in the scientific community find this sort of political activity annoying. But it does have its up side. CWF has been one of the most hotly contested social health programmes. Consequently is has received more than its fair share of literature reviews and new research.

And that is a good thing. Anti-fluoride activists often claim there is little research on the health effects of CWF. But that is just not true. Ironically it is the very political activity of such campaigners which has led to CWF being one of the most thoroughly researched social health policy.

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Fluoridation: New scientific review of fluoride and oral health

fluoride-oral-healthWant to get up to date on  research about community water fluoridation (CWF) and the effects of fluoride in dental health in general?

Have a read of this new review. It’s published in a special issue of  Community Dental Health devoted to the WHO approach to the prevention of dental caries through the use of fluoride. And is also deals with possible health effects of fluoridation and fluoride in general.

The Paper is:

O’Mullane et al (2016). Fluoride and Oral Health. Community Dental Health 33, 69–99.

Summary and recommendations

The paper summarises the general conclusions and recommendations about CWF as follows:

1. Community water fluoridation is safe and cost-effective and should be introduced and maintained wherever socially acceptable and feasible.
2. The optimum fluoride concentration will normally be within the range 0.5-1.0 mg/L.
3. The technical operation of water-fluoridation systems should be monitored and recorded regularly.
4. Surveys of dental caries and enamel fluorosis should be conducted periodically. For effective surveillance the World Health Organization suggests that clinical oral health surveys should be conducted regularly every five to six years in the same community or setting.

Requirements for a CWF programme

But it is interesting to read its conclusions about the requirements for implementation of water fluoridation. This gives us an idea of why some areas do not fluoridate and what the technical and social requirements are for a successful CWF programme. These are the sort of things that district health boards will need to consider under the current legislations being considered by the New Zealand parliament.

Here is their list:

1. A prevalence of dental caries in the community that is high or moderate, or firm indications that the caries level is increasing.
2. Attainment by the country (or area of a country) of a moderate level of economic and technological development.
3. Availability of a municipal water supply reaching a large proportion of homes.
4. Evidence that people drink water from the municipal supply rather than water from individual wells, rainwater tanks or other sources.
5. Availability of the equipment needed in a treatment plant or pumping station.
6. Availability of a reliable supply of a fluoride-containing chemical of acceptable quality.
7. Availability of trained workers in the water treatment plant who are able to maintain the system and keep adequate records.
8. Availability of sufficient funding for initial installation and running costs.

How many people have access to CWF internationally?

The review has an appendix providing data on worldwide totals for populations with artificially and naturally fluoridated water. This is very useful and anti-fluoride campaigners are well-known for misrepresenting this information in their attempts to claim that most countries reject CWF.

Here is the table for artificial CWF programs:


It says in summary:

“The estimated worldwide total of people supplied with artificially fluoridated water as at April 2011 is 369,226,000 in 25 countries, including the United Kingdom, the United States, Canada, Brazil, Chile, Argentina, Peru, Panama, Guyana, Guatemala, Republic of Ireland, Spain, Serbia, Australia, New Zealand, Fiji, Malaysia, Singapore, Vietnam, Brunei, China (Special Administrative Region of Hong Kong), Papua New Guinea, Republic of Korea (South Korea), Israel and Libya.”

Natural fluoridation

The review also summarises data for people receiving fluoride through the natural levels of fluoride in their drinking water:

Natural fluoridation in the 25 countries operating artificial fluoridation schemes

“In the 25 countries with artificially fluoridated water there are an estimated 18,061,000 million people drinking naturally fluoridated water at or around the optimal level. That brings the total in these 25 countries consuming optimally fluoridated water to around 387,287,000 million.”

Other countries with natural fluoridation

“In addition, there are a further 27 countries with naturally fluoridated water supplied to an estimated 239,903,000 million people. However, it should be stressed that, in many instances, the naturally occurring fluoride level is in excess of the optimum – for example, in China, India, Argentina, Tanzania, Zambia and Zimbabwe. Total worldwide population drinking optimally fluoridated water.”

In summary – 437 million have access to fluoridated water

Combining data for artificial and natural fluoridation the review concludes:

“General estimates for the number of people around the world whose water supplies contain naturally fluoridated water at the optimum level for oral health are around 50 million. This means that, when the numbers of people with artificially (369.2 million) and naturally fluoridated water supplies (50 million) at the optimum level are added together, the total is around 437.2 million.”


This review is useful for anyone wanting an up-to-date picture of CWF, possible health effects and other issues.

I recommend that anyone active in the dental health area or who needs to respond to questions about fluoridation from the public have their own copy. they will refer to it again and again.

This link goes straight to the download of the pdf.

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Fluoridation cessation studies reviewed – overall increase in tooth decay noted

Anti-fluoride activists love to trot out studies where no increase in tooth decay was found after community water fluoridation  (CWF) ceased. They are cherry-picking, of course, because they ignore the studies which do show a decline in dental health. I have written about this before in What happens when fluoridation is stopped? and Anti-fluoridationist’s flawed attacks on Calgary study.

So I am pleased to see a new, just published, review of fluoridation cessation studies. Also pleased that it confirms my impression of the literature.

In short, this review concluded that:

“Overall, the published research points more to an increase in dental caries post-CWF cessation than otherwise.”

The study is published in this paper – it’s open access so you can download a pdf or see the full text:

Mclaren, L., & Singhal, S. (2016). Does cessation of community water fluoridation lead to an increase in tooth decay ? A systematic review of published studies. J Epidemiol Community Health 2, 1–7.

Unsurprisingly, these sort of studies have problems – humans cannot be treated as laboratory rats. Researchers must rely on ordinary data for dental health collected before and after cessation.

Nevertheless, these researchers managed to find 15 instances of cessation occurring in 13 countries and reported in 29 publications. Several of these were excluded because they did not consider specific cessation effects  but reported on the enduring benefits of CWF even after cessation when children were exposed to CWF in the first 4 years of life. Evidence supporting a beneficial systemic effect of CWF in developing teeth. Another instance was excluded because of the complexity of its reports results didn’t enable any conclusion about effects.

Of the remaining situations, eight showed an increase in tooth decay after CWF was stopped. These occurred in Europe, Asia and North America. This paper was obviously submitted before the publication of the Calgary cessation study (Measuring the short-term impact of fluoridation cessation on dental caries in Grade 2 children using tooth surface indices) which also showed an increase in tooth decay (see Anti-fluoridationist’s flawed attacks on Calgary study for a discussion of this paper). So there are really nine instances showing an increase in tooth decay.

The other three instances did not show an increase in tooth decay. These occurred in East Germany, Finland and Cuba. These last three are, of course, the only studies anti-fluoridationists ever mention.

It’s worth quoting an observation from the paper which could help explain these different results:

“Importantly, in all three interventions, there were other factors which could have contributed to findings observed. In Finland, the CWF-cessation community started to provide fluoride tablets to children postcessation. In East Germany, postcessation fissure sealants were paid for by statutory health funds. In Cuba, postcessation, all children received fluoride mouth rinses fortnightly, and children aged 2–5 years received 1–2 fluoride varnish applications annually. Those initiatives could have offset an impact of cessation on dental caries.”

This is a really useful review as the cessation literature has not been properly reviewed before. For example, the recent Cochrane Review only considered one cessation study and concluded: “there is insufficient information to determine the effect of stopping [CWF] on caries levels.” The authors stress the need for researchers to take advantage of research opportunities presented by CWF cessation.

The authors stress the need for researchers to take advantage of research opportunities presented by CWF cessation ( there is a lot of it about in some countries). The also say there is a need for information on how cessation impacts different socio-economic groups and how decisions about cessation are made.

CWF cessation studies are just one area where anti-fluoride campaigners cherry-pick the literature. This example underlines why readers must always treat claims made by these campaigners critically. Always look at the original studies, the data, other treatments, etc.  And check other research these campaigners are hiding.

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Anti-fluoridationists misrepresent new dental data for New Zealand children


Another whopper from the anti-fluoridation movement in New Zealand.

They claimed yesterday that “data released by the Ministry of Health today confirm that water fluoridation is having no noticeable effect in reducing tooth decay” (see DHB Data Show No Benefit From Water Fluoridation).

Yet a simple scan of the data (which can be downloaded from the MoH website) shows this to be patently untrue.

Here is a graphical summary of the New Zealand-wide data for 5-year-olds and year 8 children. It is for 2014 and I have separated the data ethnically as well as presenting the summary for all children (“total”).

DMFT and dmft = decayed, missing and filled teeth.


214---8-yrNow – don’t these figures show the press release headline and the first sentence  are completely dishonest?

The data for all children (“total”) Maori and “other” show children in fluoridated areas have a higher percentage of caries-free teeth and a lower mean value of decayed, missing and filled teeth. The data for Pacifica are less definite – because the vast majority of Pacific children live in fluoridated areas. I discussed this further in my last post A challenge to anti-fluoridationers to justify their misrepresentation of New Zealand research.


So the headline and main message of the anti-fluoridationists press release were outright lies. However, they will fall back on the claim that the press release does contain some facts.  But these are just cherry-picked snippets taken out of context to confirm the bias of the anti-fluoride mind.

For example, comparing data for Christchurch and Nelson-Marlborough with those for  Auckland and Counties-Manukau is just disingenuous if the ethnic differences (which we know clearly play a role in oral health) are not considered. Similarly, reference to the 2o14 “overturning” of the Hamilton Council decision to stop fluoridation is just silly considering that there are no separate data for the city and the Hamilton Council fiasco over water fluoridation overlapped the period the data covers.

Of course, this press release has been processed through the international anti-fluoridation – “natural”/alternative health media channels so expect to be bombarded with international reports based on these lies.

The lesson from this little story – don’t take claims made by anti-fluoridation campaigners, or similar activists with an anti-science agenda, at face value. Always check them out.

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Fluoridation decisions to be made by District Health Boards


Image credit: Constant Contact

This has been on the cards for a while. In recent years ideologically and commercially motivated activists have played havoc with the consultations organised by local body councils. Councils have shown by their own actions they are not capable of considering the scientific and health evidence related to community water fluoridation. The political intrigues of local bodies and the lack of scientific skills have prevented sensible decisions in many cases – and resulted in reversals of decisions – sometimes within a few weeks. yet New Zealanders have in most places voted to support community water fluoridation.

Councils have asked the central government to remove decisions on fluoridation from their responsibility. And now the government has decided to do just that.

This is the text of today’s  press release from the Hon Dr Jonathan Coleman, Minister of Health, and the Hon Peter Dunne, Associate Minister of Health (see Fluoridation decision to move to DHBs):

DHBs rather than local authorities will decide on which community water supplies are fluoridated under proposed changes announced today by Health Minister Jonathan Coleman and Associate Health Minister Peter Dunne.

“New Zealand has high rates of preventable tooth decay and increasing access to fluoridated water will improve oral health, and mean fewer costly trips to the dentist for more New Zealanders,” says Dr Coleman.

“This change could benefit over 1.4 million New Zealanders who live in places where networked community water supplies are not currently fluoridated.

“Water fluoridation has been endorsed by the World Health Organization and other international health authorities as the most effective public health measure for the prevention of dental decay.”

DHBs currently provide expert advice on fluoridation to local authorities.

“Moving the decision-making process from local councils to DHBs is recognition that water fluoridation is a health-related issue,” says Mr Dunne.

“Deciding which water supplies should be fluoridated aligns closely to DHBs’ current responsibilities and expertise. It makes sense for DHBs to make fluoridation decisions for their communities based on local health priorities and by assessing health-related evidence.”

A Bill is expected to be introduced to Parliament later this year. Members of the public and organisations will have an opportunity to make submissions to the Health Select Committee as it considers the Bill.

See also: DHBs could make call on fluoridating water

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Fluoridation: Whakatane District Council makes the Hamilton mistake


Here we go again.

The Whakatane District Council has ignored the results of their own referendum and decided to stop community water fluoridation (CWF). (see Council votes to stop fluoridationand Whakatane mayor stands by fluoride decision).  This mirrors almost exactly the behaviour of the Hamilton City Council three years ago.

But are the Whakatane councillors (or, at least, the 6 who voted to stop CWF) so short of memory that they did not learn from the Hamilton experience? There the decision resulted in protests and petitions, eventually forcing the council to hold yet another referendum at the end of 2013. That showed, once again, clear support (about 70%) for CWF and the council later reversed their decision.

A thoroughly bad experience for that council and a humiliating one for the city. We had the picture of council politicians pretending to know better than the health and scientific experts and attempting to impose their own ideologically motivated position on the voters. It got so silly the council even issued their own leaflet providing oral health advice – advice which was out of step with that issued by health authorities!

Councils ignore voters wishes at their own peril. The Whakatane District Council anti-fluoridationist Mayor, Tony Bonne, justified his move by referring to the low voter turnout in the referendum. Are we to take it that if he loses the next election he will ignore that result and refuse to step down because of the low voter turnout?

Referendum results

The 2013 referendum in the Whakatane District showed that 60.5 per cent of those who voted were in favour of fluoridation, with 39.5 per cent against. However, in the only areas currently fluoridated – Whakatane City and Ohope – support for CWF was even greater – 65.8 per cent and 70.5 per cent respectively. The council is surely silly to ignore that vote without a good reason.

“We listened to the experts.”

Mayor Bonne declared “we listened to the experts” before making the decision. But who the hell were these experts?:

Supporting CWF –  Dr Neil de Wet of Toi Te Ora Public Health and local dental practitioner John Twaddle. OK, these people seem to have some qualifications to be described as “expert.”

Opposing CWF – Mary Byrne and Jon Burness of Fluoride-Free New Zealand. What expertise do these people have? – why should their word be accepted?

Well, they are both activists, belonging to the local activist group which is a chapter of the US Fluoride Action Network. That body is financed by the “natural”/alternative health industry – particularly by the Mercola on-line business.  (Local anti-fluoride actions, such as those in the High Court, have similarly been financed by the NZ health Trust – the lobby group for the local “natural”/alternative health industry. See Who is funding anti-fluoridation High Court action? and Corporate backers of anti-fluoride movement lose in NZ High Court).

Mary has no expertise I know of except her activism. Jon is an alternative health practitioner and business person. He specialises in kinesiology and is a member of the  Society of Natural Therapists and Researchers, NZ. As part of his business he runs the Whakatane Natural Health Centre.

Whakatane Natural Health Centre …… bringing together a comprehensive range of therapies for mind, body and soul. Kinesiology, Massage Therapy, Bowen Tech, Hypnotherapy, Lymphatic Drainage, Herb and Allergies, Acupuncture. – See more at:

OK, everyone has to make a living and I do not want to question the sincerity of either Mary or Jon.

But experts!! Tony Bonne is disingenuous to use that word. He should be representing his voters, not the alternative woo merchants, whatever his own personal ideological beliefs. It is a sad day when we elect councillors (or at least the six who voted for Bonne’s resolution) who cannot differentiate between acceptable scientific and health experts  on the one hand and ideologically driven activists and alternative “practitioners” using very questionable techniques on a gullible public on the other.

Councils not appropriate for fluoridation decisions

Mayor Bonne did, however, make sense with his statement that it should not be left to local bodies to make public health decisions and he would welcome stronger direction from central government. In that he actually agrees with Daniel Ryan, President of the Making sense of Fluoride group who said:

“There is just no excuse any more for John Key’s government to keep making councils juggle the expensive and diversionary hot potato. They want councils to focus on core business and be fiscally responsible – and they say they care about children’s health. With one simple measure on fluoridation they could have a really meaningful impact on all of that.”

The ball is in the government’s court on this issue – and has been for several years since local bodies formally asked central government and the Ministry of Health to take responsibility for decisions on CWF. There is really no excuse to leave this with councils whose decisions are so easily clouded by ideology and personal ambitions that they, or at least some of the council members, will happily ignore the advice of the real science and health experts and the wishes of their voters.

See also: Government considers fluoridation law change

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New study finds community water fluoridation still cost effective

Cyber-The-Vote-Cost-Benefit-Analysis-1A new report on the cost effectiveness of community water fluoridation (CWF) confirms it is still effective. The report is:

Ran, T., & Chattopadhyay, S. K. (2016). Economic Evaluation of Community Water Fluoridation: A Community Guide Systematic Review. American Journal of Preventive Medicine.

This study is a systematic review of the literature.  A total of 564 papers were identified, but after excluding studies which didn’t fit the inclusion criteria, this was whittled down to ten studies (8 peer-reviewed journal articles and 2 reports) published in the period 2001 – 2013. The studies were located in Australia, USA, Canada and New Zealand.

Intervention costs

The review found:

“Per capita annual cost ranged from $0.11 to $4.92 in 2013 U.S. dollars for communities with  >1,000 population. The variation in per capita annual cost was mainly attributable to community population size. Specifically,
per capita annual cost decreased as population size increased, after adjusting for factors such as discount rate.”


“per capita annual cost was the highest when population size was around 1,000. As community population size increased, per capita annual cost decreased. In particular, per capita annual cost for communities with >20,000 population was <$1.”


Intervention benefits

The caries reduction reported in the reviewed studies ranged from 15 – 33%.per capita annual benefits ranged

Intervention benefits included averted healthcare costs and productivity losses. The per capita annual benefits reported in these studies ranged from $5.49 to $93.19

Benefit-cost ratios

As would be expected the reported benefit-cost ratios varied with population size – ranging from 1.12 to 57.21.

So, the authors’ conclusion was:

“In summary, benefit–cost ratios were larger than 1.0 for communities of at least 1,000 people, indicating that CWF was cost beneficial for communities with no fewer than 1,000 people.”

Possible issues

The authors list a number of issues for consideration in future studies of this issue. Interestingly these include two that anti-fluoride campaigners argue have been ignored:

Cost of fluorosis: The authors say this should be included “if there is clear evidence of severe dental fluorosis.”

The only study to have included such costs is that of Ko & Theissen (2014). They included costs of repair or severe dental fluorosis – despite there being no evidence that CWF causes either moderate or severe dental fluorosis. Ko and Theissen made no attmept to justify inclusion of this cost and the “mistake” is not doubt due to the well-known anti-fluoride sympathies of Theissen (see Alternative reality of anti-fluoride “science” for a discussion of this paper).

Political costs: The authors give as an example “expenses associated with promoting CWF.”

Of course, this would also include the legal and referendum costs we have seen imposed on New Zealand local bodies over the last few years. But it should also include the private costs of those who campaign for and against CWF and the larger corporate costs of bodies like the NZ Health Trust which has initiated unsuccessful High Court action. The NZ health trust is a lobby group for the “natural”/alternative health industry and their costs no doubt eventually get passed on to the consumers of their products and services.

It would be interesting to see the breakdown of such political costs for different countries and regions. I imagine it would be hard to predict what these costs could be in an individual situation. Although I can appreciate local bodies may feel obliged to budget for such costs.

And I wonder if one should include the cost of legal justice and democratic consultation in a cost-benefit analysis. This could lead to people questioning parliamentary elections or their rights to challenge corporations and criminals in the courts.

Should anti-fluoride campaigners do their own cost-benefit analysis?

It’s a simple fact that anti-fluoride campaigners lose more of their struggles than they win – even in the USA. It’s also a fact that they see the threat of imposition of legal and consultation costs as a way of pressuring local bodies to avoid the issue. But, I wonder if they have ever undertaken a cost-benefit analysis on their own activities.

For example, given the failures of the High Court action by the campaigners over recent years and the lack of success in referenda held in New Zealand in 2013 and 2015 perhaps they should do a few “back of the envelope” calculations.

If they want to personally enjoy drinking water that is “fluoride free” then what is the most reliable intervention they could apply to achieve that benefit.

Consider two scenarios:

1: A political approach. The costs of referendum and consultation campaigns, their personal loss of income and free time in making submissions, organising Paul Connett’s Southern hemisphere holiday tours of New Zealand and Australia. Consider also the costs to the “natural”/alternative health industry in their taking and sponsoring legal actions.  Balance this against the very low likelihood of success – and possibly also consider the negative result of social criticism and discrediting that may represent a financial loss to those who run businesses or are practitioners in the “natural”/alternative health industry.

2: A personal responsibility approach. The cost of  purchasing a relatively cheap and effective water filter to lower the F concentration in their tap water. The capital cost would be a few hundred dollars per household and the annual costs would not be large. In fact, the NZ Health trust may help lower these costs by reinvesting the money they would otherwise lose in paying for unsuccessful court actions. The benefits would be immediate and clear. They would get the “fluoride free” water they have demanded. They would have a lot more free time to devote to their families and businesses. And they would not get the current condemnation they get from local body politicians and voters who resent the increased costs their actions have caused in the past.

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