Tag Archives: Denmark

Fluoridation: Open letter to Democrats for Social Credit

The only New Zealand political party opposing community water fluoridation relies on false information

The only political party in New Zealand campaigning against community water fluoridation is the Democrats for Social Credit. It is a minor party, nor represented in Parliament and of little influence. However, it does have connections with Fluoride Free NZ, the main anti-fluoride activist group, and its members have imposed anti-fluoridation policies on some groups they belong to. Two examples are Grey Power and the Hamilton Residents & Ratepayers Association – both of which presented anti-fluoride submissions to the recent parliamentary health committee hearings.

I wish to promote an open discussion with the Democrats for Social Credit about their anti-fluoridation policy so have sent them this Open Letter. If they are open to a good-faith discussion I am happy to provide space on this blog for an exchange of views on their policy.

David Trantor, Health Spokesperson for Democrats for Social Credit

Dear David Tranter,
Health Spokesman,
Democrats for Social Credit

You wrote an open letter to the Minister of Health critiquing the government’s policy on community water fluoridation (CWF) and posing some questions about dental health programmes, documented evidence relating to CWF and human rights aspects you consider relevant.

Here I take issue with some of your claims – particularly about dental health in Denmark and the scientific evidence supporting CWF. I believe the evidence does not support the anti-fluoridation policy of your party and your party should reconsider that policy.

If you believe my arguments here are mistaken or otherwise wish to defend the current anti-fluoride policy of your party I am open to a good-faith exchange of opinions and offer you the right of reply and the opportunity for a further discussion on this blog.

Natural fluoridation in Denmark

You point to the good dental health in Denmark and assert “they have never fluoridated their water.” This is true – but you ignore the fact that much of the Danish population benefits from natural levels of fluoride in their drinking water.

Unlike New Zealand parts of Denmark have drinking water fluoride concentrations similar to the optimum concentrations recommended for CWF. Map 1 from Kirkeskov et al., (2010) shows the distribution of different drinking water fluoride concentration ranges.  Map 2 shows the population distribution. We can see a significant fraction of the Danish population does have access to drinking water containing fluoride.

Map 1: Distribution of natural drinking water fluoride concentrations in Denmark. The town of Nexo is on the Baltic island of Bornholm – shown in the top left-hand rectangle.

Map 2: Population distribution in Denmark.

These natural levels of drinking water fluoride are beneficial to oral health in Denmark. Here is some data from Kirkeskov et al., (2010) illustrating this. The following graph compares the dental decay (numbers with more than 2 decayed, missing or filled teeth surfaces – dmfs) at various drinking water fluoride concentrations for 5 year-olds born in 1989 and 1999.

As we can see, the extent of decay declines with fluoride concentration.

There is a similar pattern for 15-year-olds born in 1979 and 1989. This figure shows the relative numbers with more than 2 decayed missing or filled teeth surfaces, DMFS, for 15-year-olds.

And the same pattern for 15-year-olds with more than 6 decayed, missing or filled tooth surfaces.

Danish dental health programmes

You refer to a “Nexux” programme and argue that this could be an alternative to CWF in New Zealand.

I think you are referring to the programme run in Nexo – a town on the east coast of the Baltic island of Bornholm, Denmark. It is a successful local dental health programme, but only one of several in Denmark. Nexo was in an area of very low socio-economic status and introduced a dental programme at the end of 1987 aimed at improving the dental health fo children.  Ekstrand & Christiansen, (2005) give this description of the programme:

“Since 1992, the program has been offered to children from the age of 8 months. It is based on three closely interrelated principles applied according to the individual child’s needs: (1) education of parents, children and adolescents in understanding dental caries as a localized disease, (2) intensive training in home-based plaque control and (3) early professional, non-operative intervention, including professional plaque removal, local application of 2% NaF and application of sealants. In the period when the children have erupting permanent first or second molars, the parents and children are instructed in using a tooth brushing technique specially designed for erupting molar teeth.”

As you can see it is a rather intensive programme and is not a Denmark-wide programme. It has been successful in Nexo, where 15-year-olds had DMFS (decayed, missing and filled tooth surfaces) values in 1986 (before introduction of the programme)  slightly higher than the Danish average. The equivalent values of DMFS for Nexo were the third lowest for all municipalities in 1993 and the lowest in 1999 (Ekstrand & Christiansen, 2005).

Elements of the Nexo programme will be used in other parts of Denmark, and in other countries. Especially where school-based programmes exist.

Incidentally, Map 1 indicates the concentration of natural fluoride in the drinking water on the island where Nexo is situated is similar to that recommended for community water fluoridation. Ekstrand et al., (2005) reports that the fluoride concentration in the Nexo drinking water is 0.8 mg/L.

Nexo is a complement to, not a substitute for, CWF

Each country and region adopt health programmes appropriate to their circumstance. In New Zealand, we have programmes which include some aspect of the Nexo programme or similar programmes like the ChildSmile programme in Scotland (see ChildSmile dental health – its pros and cons and ChildSmile – a complement, not an alternative, to fluoridation). For example the use of fluoride varnish treatments, especially in non-fluoridated areas.

New Zealand can learn from the experience of other countries and in practice, we may introduce some aspects of other programmes. But blanket transfer of full programmes is rare.

The important aspect, though, is none of these programmes is considered an alternative to fluoridation. They are considered as complementary to CWF, and not substitutes for CWF.  The Danish Dental Association has supported fluoridation for areas of low natural fluoride concentrations. Similarly, the British Dental Association in Scotland supports both ChildSmile and CWF and has publicly called for communities to move towards introducing water fluoridation.

In fact, we can consider that the programme used in Nexo (where the drinking water contains fluoride at 0.8 mg/L) actually complements the effect of natural community water fluoridation.

“Documented evidence”

You ask the Minister:

“Why do you ignore all the documented evidence against fluoridation instead of applying positive dental health policies such as the Denmark example?”

The “Denmark example” is dealt with above and it is not what you suggest. Similarly, I suggest the “documented evidence” you refer to really doesn’t give the viable argument “against fluoridation” you imply.

Unfortunately, you do not present any of this “documented evidence” for discussion. Perhaps, if you respond positively to my suggestion of a right of reply and an ongoing discussion, you can give this evidence.

“Informed consent”

You refer to the “H&D Commissioner’s Code of Rights” asserting that:

“no-one can be medicated without giving their informed consent” and “people have the right to give – or refuse – their INFORMED consent when fluoridation is applied to public water supplies?”

Well, I am all for people being properly informed and providing consent to the treatments used for their water supply. I see this as a democratic issue and I support democracy.

But you destroy your argument by suggesting fluoridation is a “medication” when it clearly is not – either legally or rationally. The legal argument was surely settled by the High Court decision in 2014 (see Corporate backers of anti-fluoride movement lose in NZ High Court) where Justice Rodney Hansen concluded:

“[80] In my view, fluoridation cannot be relevantly distinguished from the addition of chlorine or any other substance for the purpose of disinfecting drinking water, a process which itself may lead to the addition of contaminants as the water standards themselves assume. Both processes involve adding a chemical compound to the water. Both are undertaken for the prevention of disease. It is not material that one works by adding something to the water while the other achieves its purpose by taking unwanted organisms out.

[81] The addition of iodine to salt, folic acid to bread and the pasteurisation of milk are, in my view, equivalent interventions made to achieve public health benefits by means which could not be achieved nearly as effectively by medicating the populace individually. . . . All are intended to improve the health of the populace. But they do not, in my view, constitute medical treatment for the purpose of s 11″ [the relevant section of the NZBORA].”

Is scientific knowledge  really “one-sided” propaganda

You also weaken your argument by claiming:

“the one-sided propaganda used to support fluoridation is not informing people”

Describing objective scientific research and findings as “one-sided” simply displays your own bias – and willingness to discredit or ignore the science. Again, you do not give specific examples of the science you consider “one-sided propaganda” – hopefully, you will do so if you take up my offer of a right of reply and a continued discussion.

Democratic rights

You assert:

“when fluoridation is forced upon people it is nothing less than mass medication concerning which people have no opportunity to give – or refuse – their consent.”

The common anti-fluoride claim that people are having fluoridated water forced upon them always raises the picture in my mind of a person being held down and water being forced down their throat as in force-feeding.

Of course, that is ridiculous – for a number of reasons.

  • In New Zealand, there has usually been a democratic public consultation of some sort before the introduction of CWF – or even after its introduction. Local bodies have surveyed residents or used referenda. They have also used a consultation procedure relying on submissions from the public.The opportunity “to give – or refuse – their consent” has in most cases been far greater than for most decisions made by our representatives in this democracy of ours. Some voters find it annoying when asked for such consent (preferring their representatives decide) but I firmly believe it important to include the public in controversial decisions – even where the controversy results from scaremongering rather than facts (as it does with CWF).
  • There are alternatives for the minority. This means that democratic decisions made by a community can actually be a win-win situation. The majority get the social policy they want and have voted for. the minority have access to alternatives. In fact, most anti-fluoride activists already use alternatives – they filter their tap water or source a different supply. Some cities already provide “fluoride-free” water sources to help this. Sometimes I think the real motivation of these ideologically driven activists is to deny this social health policy to others rather than any real concern they have for their own access to water.
  • Some activists will acknowledge there is no evidence of any harmful side effects from CWF but invoke a “precautionary principle” to argue against it. They should be mollified by the fact that CWF is one of the most extensively researched topics. In a sense, we must thank the ideologically and commercially motivated anti-fluoride campaigners for this. Their activity is rarely successful in preventing CWF or fooling most of the public. But it does mean that researcher keep an eye on the arguments and are continually checking them out.


David, I believe you are mistaken, or misinformed, about the dental health programmes in Denmark. You ignore completely the availability of effective natural levels of fluoride in much of Denmark’s drinking water and seem unaware of the nature of the Nexo programme or its limited area of operation.

Expert opinion considers programmes like Nexo and the Scottish ChildSmile are effective complements to CWF – not substitutes for, or alternatives to, CWF. I support our health officials considering use of similar programmes in New Zealand but it is misleading for the Democrats for Social Credit to advocate for such programmes simply as a way of preventing or opposing CWF – which is  an effective, beneficial and safe social health measure.

I appreciate you may not accept my arguments or the facts I have presented here. If that is the case I urge you to accept my offer of a right of reply and ongoing good-faith discussion and am happy to help this by making space available on this blog.

I look forward to your response.


Ekstrand, K. R., & Christiansen, M. E. C. (2005). Outcomes of a non-operative caries treatment programme for children and adolescents. Caries Research, 39(6), 455–467.

Kirkeskov, L., Kristiansen, E., Bøggild, H., Von Platen-Hallermund, F., Sckerl, H., Carlsen, A., … Poulsen, S. (2010). The association between fluoride in drinking water and dental caries in Danish children. Linking data from health registers, environmental registers and administrative registers. Community Dentistry and Oral Epidemiology, 38(3), 206–212.

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Large Swedish study finds no effect of fluoride on IQ


Fluoride levels in Swedish drinking water (mg/L). Variation between municipalities. Source: Aggeborn & Öhman (2016)

A significant new Swedish study shows fluoride in drinking water, at the concentrations used for community water fluoridation, has no effect on IQ or other measures of cognitive ability. Similarly, it has no effect on diagnosis or prescription of medicines for ADHD, depression, psychiatric illnesses, neurological illnesses or muscular or musculoskeletal diseases.

On the other hand, the study showed positive effects of fluoride on income and employment status – most probably because better dental health is beneficial in the labour market.

This work is reported in:

Aggeborn, L., & Öhman, M. (2016). The Effects of Fluoride In The Drinking Water.

The study covers most of the health effects that anti-fluoride campaigners complain about. It really should put all these complaints to rest as the quality of this new study is much better than anything the campaigners rely on for the following reasons:

  • It involved a much large sample. Over 700,000 individuals were involved. The numbers included in specific measurements varied but they were much greater than those used in the studies cited by anti-fluoride campaigners. For example, almost 82,000 were involved in the cognitive ability comparisons – compared with a few hundred at the most in the comparable studies cited by anti-fluoride campaigners.
  • Estimates of effects were much more precise (as expected with large numbers of subjects) than for previous studies. The effect of fluoride on cognitive ability was always close to zero and for practical purposes was zero.
  • Statistical analyses were based on continuously varying fluoride levels – a much better approach than the simple comparison of data for low and high fluoride villages used in the studies cited by anti-fluoride campaigners.

Sweden is an ideal country for studying effects of fluoride at these low concentrations. It does not have artificial water fluoridation but its drinking water contains naturally occurring fluoride. The fluoride concentration in drinking water depends on the geology of the region so different Swedish communities consume water with different fluoride concentrations.

This graphic from the paper shows the number of people drinking water with various concentrations of fluoride. Note – the steps are 0.1 mg/L and although concentrations above 2.0 mg/L occur they are relatively rare. Sweden makes no attempt to remove excess fluoride until the concentrations exceed 1.5 mg/L – the maximum recommended by the World Health Organisation. For comparison, the recommended optimum concentration in  New Zealand is 0.7 mg/L.


Histogram of numbers people drinking water containing naturally occurring fluoride at different concentrations. Source: Aggeborn & Öhman (2016)

Effects of fluoride on dental health

The Swedish data showed positive effects of fluoride on oral health. For example, the share of dentists visits “decreased by approximately 6.6 percentage points if fluoride is increased by 1 mg/l. This should be considered as a large effect.” Tooth repairs are closely related to fluoride. “If fluoride would increase with 1 mg/l, the share of 20-year-olds that had a tooth repaired would be decreased approximately 3.4 percentage points considering the 2013 sample. Again, this effect is large, especially for this cohort.”

Cognitive ability

Relevant data was used from national education tests and psychological tests during the years of the Swedish military conscription. The statistical analysis produced estimates which were all very small and often not statistically significant. The estimates were sometimes negative and sometimes positive. For example, an estimate including covariates showed that “cognitive ability is increased by 0.045 Stanine points [equivalent to about 0.3 IQ points] if fluoride is increased by 1 mg/l (a large increase in fluoride). This should be considered as a zero-effect on cognitive ability.”

Other possible health effects

The authors considered the effects of fluoride on the prescription of medicines for ADHD, depression, and psychoses. They also looked at psychiatric and neurological diagnoses from outpatient and inpatient registers, as well as diagnoses of muscular and skeletal diseases. Anti-fluoride campaigners often claim fluoride has a harmful effect on these health problems.

The was no effect of fluoride on the possibilities of being prescribed any of these medicines.  For example “the probability of receiving ADHD medicines is decreased by 0.2 percentage points if fluoride is increased by 1 mg/l. In economic terms, this effect is a zero-effect.”

It was the same for all the diagnoses considered –  “The estimated effects are small and often statistically insignificant.”

According to the authors:

“In conclusion, we do not find that fluoride has any effects on these health outcomes. This further strengthens our argument that fluoride does not have any negative effects for levels below 1.5 mg/l on human capital development or health outcomes related to human capital development. It is also interesting that we do not find any effects on diagnoses for muscular and skeleton diseases, which has been a question also discussed in connection to fluoride.”

Annual income and employment status

The lack of any effect of fluoride on IQ and other psychological and non-psychological estimates suggest that fluoride would have no effect on long-term outcomes like income and employment status. However, the authors suggested that it could have a positive influence on these outcomes because of better dental health.

And this was the case. Estimates of the effect of fluoride on income were always positive and usually statistically significant. The authors estimated that “income increases by 4.2 percent if fluoride increases by 1 mg/l. This is not a negligible effect and the estimate should be considered as economically significant.”

Similarly for employment status. “If fluoride is increased by 1 mg/l, then the probability that the person is employed is increased by 2 percentage points. This result thus point in the same direction as the results for log income where both these results are significant in economic terms.”

Further analysis indicated “that when dental repairs increases by 1 percentage point, income decreases by 2 percent on the same aggregate level. This effect is clearly economically significant. This indicates that fluoride improves labor market outcomes through better dental health.”


This is an important study. It involved large numbers of people, estimated outcomes were far more precise than in previous studies, it used continuously varying concentrations of fluoride instead of simply comparing high fluoride and low fluoride villages, and it considered possible long-term outcomes like income and employment chances.

The advantages of this study compared with the generally poor quality studies cited by anti-fluoride campaigners should put to rest arguments used by those campaigners. In particular, it should make the current campaigns relying on to IQ and cognitive effects irrelevant.

The authors comment that their data shows there is no need to consider negative health effects on consideration of the cost-effectiveness of community water fluoridation. I wonder if, in fact, these results will encourage policy makers to consider the cost benefits of improved income and employment chances in future calculations of the cost-effectiveness of fluoridation programmes.

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From Melbourne to Copenhagen

Echos of last weekend’s Global Atheist convention in Melbourne are still reverberating around the internet and in the print media. There have been some shocking newspaper reports in Australia (eg. Speakers true love of hatred) but also some good ones (eg. Australia’s atheists are a happy bunch).

Probably what we should expect at this stage. After all this convention was unique – the first of it’s kind.

There is good news for all those atheists who missed the Melbourne convention, or did attend this awesome event and are now suffering withdrawal symptoms. The Atheist Alliance International, which co-organised the Melbourne Convention, has planned a series of such international events. The Melbourne Convention was just the first. The next International Atheist Convention will take place in Copenhagen in a few months (June 18-20). Have a look at Atheist Alliance International 2010 Copenhagen Convention for details.

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Does religion threaten human rights?

It worries me that as we approach the 60th anniversary of the the proclamation of the Universal Declaration of Human Rights the world seems to be facing a new threat to freedom of expression. This freedom is basic in democratic societies. It’s also vital to exposing, and overcoming, violations of human rights throughout the world.

I have commented before about attempts by some international Islamic organisations to restrict freedom of expression when it comes to issues involving violation of human rights in Islamic countries. This has extended to preventing criticism of religion in UN organisations. Other religions have extended a degree of support for this position internationally, and within some European countries.

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