Category Archives: Science and Society

Fluoridation: What’s happening with the New Zealand legislation?

The second reading of the fluoridation bill is now on the order paper for the current parliament. Public submissions have been heard, the Health Committee has reported back to the House and the Ministry of Health (MoH) has provided its own responses to submissions.

Of course, we don’t know yet what the final Act will be like exactly. But the submissions, the committee report, and the MoH responses give us some idea of likely changes to the original bill.


I have described before how the anti-fluoride activist groups organise to deluge consultation processes with their submissions. This was certainly the case here and their submissions accounted for most of those opposed to the Bill.

However, because the legislation is about the decision-making process and not the scientific or ethical validity of social health policies simple opposition to fluoridation was irrelevant  – outside the scope of the bill. This was true of most submissions (85%) and these should be considered a waste of every bodies time.

I am surprised the anti-fluoride organisations organising this submission campaign chose to take such an irrelevant approach. Surely if they had put a bit of thought into their efforts they could have directed their submission at relevant aspects such as the consultation process, the decision-making body and the question of referenda.

That said, a small number of the anti-fluoride submissions did address aspects of the bill and these were considered by the Health Committee and the MoH.

Putting aside the anti-fluoride submissions which did not address the bill, 20% percent supported the Bill and 80% opposed to the Bill as currently drafted. Most supported extending fluoridation cover, but disagreed with specific parts of the Bill and suggested changes.

The legislation does not mandate fluoridation

This is a common misunderstanding promoted by anti-fluoride campaigners – obviously attempting to use scare-mongering to motivate their supporters. For example, Fluoride Free NZ formally names the legislation the Mandatory Fluoridation Bill which is dishonest – the correct name of the bill is Health (Fluoridation of Drinking Water) Amendment Bill.”

The bill transfers decision-making from local bodies to District Health Boards (DHBs) – but it does not require DHBs to make a decision about fluoridation. That is up to local DHBs and local conditions such as dental health, likely advantages and establishment costs.

Consideration of other health factors

A number of submitters expressed concern that while the bill requires DHBs to consider dental health effects, consideration of other possible health issues is not provided for. However,  the response from the MoH to this is:

“While DHBs are required to consider the evidence in relation to oral health, DHBs are not prevented from considering other factors, including the effect of fluoridation on overall health. However, officials do not consider it necessary for the Bill to require DHBs to consider these other factors.”

So, consideration of other health factors will depend on specific situations, the board members or public interest. Importantly, DHB’s are not prevented from considering wider health aspects.

Considering the science

I was interested to see that:

” The Ministry of Health is currently exploring options for the ongoing monitoring and assessment of research on fluoridation within the Ministry to align with the implementation of the Bill.”

The MoH sees this as carrying on the role formerly played by the now disbanded National Fluoridation Information Service. But this also goes some way to satisfying a suggestion in my own submission that the assessment of research on fluoridation is carried out by some sort of central expert body (see Fluoride, coffee and activist confusion). My concern was that the DHBs are not really suitable bodies for making expert reviews of the literature and evaluating the current state of the science. Handing this over to a central body could also prevent boards being deluged with misinformation and unsupported claims about the science – a feature of local body consultation which caused so much trouble to councils.

It was the pressure of submission campaigns including misrepresentation and false claims about the science which drove local bodies, who do not have the expertise to consider the science, to request a change to the legislation. DHBs will confront the same situation unless they can direct scientific consultation to a central expert body.

Community consultation

Many submitters (12%), both for and against fluoridation, suggested the bill should specifically require DHBs to consult the community about fluoridation decisions. While the bill did not make such specific requirements it also did not prevent such consultation.

In practice, public consultation will depend on the level of demand for it. It is up to DHBs to decide when consultation is appropriate and there is already a regulatory requirement for DHBs “to foster community participation in health improvement” which could cover that.

There is also provision for the Minister to describe a fluoridation decision as a “significant service change” which would require DHBs to undertake community consultation on regional service plans including fluoridation.

So, the anti-fluoride activist claims of denial of community consultation is wrong. While consultation is not specifically required it is not prevented by the bill and will depend on the level of public interest.

Engagement with local authorities

The health committee is recommending the bill be amended to explicitly require DHBs to consider the views of the drinking water supplier. This accommodates suggestions made by some local bodies who feared the imposition of decisions without considering their local situations.

However, the committee also suggested an amendment to make clear that engagement with local authorities does not require them to consult communities. The DHB which makes the ultimate decision would have that responsibility where necessary.

The Committee also suggested “the Government consider whether
it intends to contribute funding towards the costs of establishing fluoridated water supplies” because there is a “moral hazard arising from the DHBs making a decision that will impose costs on local authorities and ratepayers.”  It looks like the Government has accepted this point as they have already made $12 million dollars available to local bodies setting up new fluoridation systems (see Government commits $12m to help councils cover costs of fluoridation in water supplies.).

Provision of non-fluoridated alternatives

Some local bodies have already introduced “fluoride-free” taps at the request of local anti-fluoride campaigners., The MoH is suggesting an amendment to the bill to make clear that “DHBs can direct local government water supplies in their region on a supply by supply basis if they wish.”

This could make it possible for specific local supplies, like Petone in the Hutt region or some supplies in Christchurch to remain unfluoridated if their communities demand it even if a decision is made to fluoridate a region.

The DHB or the director general of health?

Many of the submitters opposed to the bill in its present form suggest that the decision-maker should not be the DHBs but the Director-General of Health or central government. This is because of the likely low expertise of DHB members, low voter turnout for DHB elections and concerns of legal challenges to DHB decisions. There was also the expressed belief that the anarchic and dishonest coordinated submission campaigns previously experienced by local bodies would simply be transferred to the DHBs.

Some submitter proposed that fluoridation be mandatory thereby removing the need for an elected body to be responsible for the decision making.

The committee report and response from the MoH show that parliament will probably stick with the DHBs as the decision maker. There are some advantages in this (the DHB have responsibilities in health areas) and the proof of the pudding will be in the eating. Will the DHB approach to consultations be able to successfully give more credence to credible and peer-reviewed science than the misinformation and distortions of science promoted by anti-fluoride campaigners?

Possibly. I hope so.


Despite the anti-fluoride campaigns and the resulting deluge of misinformed or misleading submissions, the submission process has been successful. Problems in the current wording of the bill were identified and reasonable solutions to these problems have been advanced.

We should now see how MPs react to the bill and the recommended changes in the second reading. Anti-fluoride activists have carried on an intensive campaign of emails, letters and representations aimed at MPs. On the whole, this will have been counterproductive as MP are surely aware this bill is not about the science or ethics of fluoridation but simply the decision-making process.

I am picking that these campaigns have produced more heat than light and will have little influence on the progress of the bill. However, I do expect a lot of teeth-grinding, hairpulling, garment rending, lamentations that democracy doesn’t work or that various MPs should be shot or otherwise disposed of from anti-fluoride campaigners. This is already happening and will no doubt intensify when the final bill is passed into law.

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Anti-fluoridationists commonly misrepresent Ministry of Health data

Anti-fluoride activists tell porkies about the Ministry of Health’s data on child dental health. They cherry-pick the data to make it appear that community water fluoridation is ineffective. And when challenged to discuss the issue they run away.

I am currently dealing with family issues so am reposting this article, “A challenge to anti-fluoridationers to justify their misrepresentation of New Zealand research”  from April 2016.  It shows how local anti-fluoride activists are misrepresenting the Ministry of Health’s data on child oral health

One of the frustrations I have with the fluoridation issue is the refusal of anti-fluoride activists to engage on the science. They will pontificate, but they won’t engage in discussion.

On the surface, one would think there is a difference of opinion or interpretation of scientific issues and that could be resolved by discussion. Yet local anti-fluoride campaigners refuse to enter into discussion. Again and again, I have offered space here to local anti-fluoride campaigners so that they could respond to my articles and they have inevitably rejected the offer. They have also blocked me, and other people discussing the science, from commenting on any of their social media pages or web sites. Even when they, themselves, call for a debate they reject specific responses I have made accepting that call.

So I am left with the only alternative of responding to their claim with an article here – or on a friendly web or blog site. At least that gives me space to present my argument – I just wish I could get some intelligent responses enabling engagement on the issues.

Misrepresentations repeated

The latest misrepresentation of the science is a claim by the Auckland Fluoride Free NZ Coordinator, Kane Titchener, that recent research proves fluoridation [is] not needed.

It repeats the same misrepresentation made by Wellington Anti-fluoride campaigner, Stan Litras, which I discussed in my article Anti-fluoridation cherry-pickers at it again. Kane has either ignored my article, chosen to ignore it or possibly not even understood it.

So here we go again.

Kane claims:

“A New Zealand study published in Bio Medical Central Oral Health last month shows dental health improved the greatest extent for children in non-fluoridated areas. There is now no difference in dental decay rates between non-Maori children who live in fluoridated areas and non-Maori children who live in non-fluoridated areas, proving that fluoridation is not needed for children to obtain good dental health.”

Although he doesn’t cite the study (wonder why), his use of two figures from the study show he is writing about the paper:

Schluter, P. J., & Lee, M. (2016). Water fluoridation and ethnic inequities in dental caries profiles of New Zealand children aged 5 and 12–13 years: analysis of national cross-sectional registry databases for the decade 2004–2013. BMC Oral Health, 16(1), 21.

His claim relies on the comparison of data for “non-Māori” children in fluoridated and fluoridated areas. No – he doesn’t misrepresent the data – he just ignores the discussion by these authors of problems with simple interpretation of the data for non-Māori because of the fact it is not ethnically uniform. In particular, he ignores the qualifications they place on the data because of the inclusion in non-Māori of data for Pacifica who have poorer dental health than the rest of this group and live predominantly in fluoridated areas. This, in effect, distorts the data by overestimating the poor oral health for “non-Māori” in the fluoridated areas.

The apparent convergence

The data used in this study were taken from the Ministry of Health’s website. This divides the total population of children surveyed into the ethnic groups Māori, Pacific and “Other.” While the “other’ group will not be completely uniform (for example including Pakeha, Asian, other groups) it becomes far less uniform when combined with the Pacific group to form the non-Māori group.

So, Kane salivates over this figure from the paper especially the plots for  non-Māori ethnicities in fluoridated (F) and non-fluoridated (NF) areas.


Fig. 1 No obvious decay experience (caries-free) percentages and mean dmft for 5-year old children over years 2004 to 2013, partitioned by Māori and non-Māori ethnicities and fluoridated (F) and non-fluoridated (NF) areas

Yes, that convergence is clear and I can see why Kane is clinging to it – who can blame him. But he completely ignores the warning from the paper:

“It is likely that a substantial driver of this convergence was due to significant changes within the dynamic and heterogeneous non-Māori groups both within and between DHB regions. In effect, the ecological fallacy – a logical flaw whereby analyses of group data are used to draw conclusions about an individual – may be operating within the non-Māori group.”

When the Pacific data is removed (as is the case for the “other” group effectively made up from non-Māori and non-Pacifica) we get the plots below.


Comparison of data for “other” (non-Māori/non-Pacifica) children in fluoridated (F) and unfluoridated (UF) areas.

Nowhere near as useful for Kane’s confirmation bias and the message he wants to promote. OK – there is still some evidence of convergence from about 2007 on between fluoridated and unfluoridated children. But the graphs do show that community water fluoridation is still having  a beneficial effect. And this apparent convergence could be explained by things like the introduction of “hub and spoke” dental clinics after 2004. One problem with this raw data is that children are allocated according to the fluoridation status of the school – rather than their residence. This will lead to incorrect allocation in some cases.

Some data for Pacifica

Just to underline the problems introduced by inclusion of Pacific in the non-Māori group of the study consider the data for Pacifica shown below.


Data for 5-year-old children. dmft = decayed, missing and filled teeth. The “other” group is non-Māori and non-Pacifica

The oral health of Pacifica is clearly poorer than that of the “other” group.

Also, Pacifica make up about 20% of the non-Māori fluoridated group. So they will influence the data for the non-Māori fluoridated group by reducing the % caries free and increasing the mean dmft.

So Kane, like Stan, is blatantly cherry-picking. He is misrepresenting the study – and its author – by ignoring (or covering up) the qualifications regarding the influence of inclusion of pacific in the non-Māori fluoridated group.

The challenge

Now, I repeat the offer I have made in the past to give a right of reply to both Kane Titchener and Stan Litras. They are welcome to comment here and if they want more space I am happy to give space for separate articles for them in the way I did for the debate with Paul Connett. Now I can’t be fairer than that, can I?

So what about it Stan and Kane? What are your responses to my criticisms of the way you have cherry-picked and misrepresented this New Zealand paper?

NOTE: I have sent emails to both Kane and Stan asking them to respond and offering them right of reply.

UPDATE 1: Great minds and all that – Stan Litras sent out a press release today calling for a nation-wide debate on this issue (see FIND calls for a national debate on fluoridation). However, the seriousness of his request is rather compromised by his reply to my offer of a right of reply to the above article. He did respond to my email very quickly. This is what he wrote:

“Thanks for the offer, Ken, but I have not visited your blog site for a long time, as I object to the way you attempt to defame and discredit me.

You play the man and not the ball, which is not the mark of a reasonable person.

I hope to address that in due course as time permits, but for now I must leave you to indulge yourself without my company.”

So much for his wish for a “national debate” when he will not front up to a critique of his claims about the science.

UPDATE 2: Kane Titchener today also posted a press release today which was the text of the article I discuss in this post (see NZ research proves fluoridation not needed). He also responded quickly to my e-mail. The full text of his response was:

Who is this?”

Rather strange – considering he often pesters me with emails.

So I guess both of them have turned down my offer.

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ChildSmile – a complement, not an alternative, to fluoridation


New Zealand Health Boards already run elements of the Scottish ChildSmile dental health programme and do not see it as an alternative to community water fluoridation

I am currently dealing with family issues so am reposting this article,ChildSmile dental health – its pros and consfrom September 2015.  Local antifluoride activists are busy presenting ChildSmile and similar programmes as alternatives to fluoridation. They aren’t – and New Zealand District health Boards alreeayd operate elements of these programmes where they consider them effective.

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 their 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.

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Fluoridation helps protect adult teeth as well as children’s

Photo credit: Seniors Benefit From Drinking Water Together

Recent research reveals that community water fluoridation benefits adults as well as children.

While research into the effects of fluoridation in adults started earlier than for children, early studies suffered from a lack of information on effects of socioeconomic status and other confounding factors.  Recent studies with adults have been more robust but there is still some confusion – especially since the often cited recent Cochrane systematic survey of the scientific literature on fluoridation was unable to draw conclusions on this because of the strict inclusion criteria used was not suitable.

This new study checked the effects of lifetime access to fluoridation on the dental health of adults from a city in southern Brazil.  It concluded that lifetime access to community water fluoridation is associated with lower tooth decay in adults.

The study is:

Peres, M. A., Peres, K. G., Barbato, P. R., & Hofelmann, D. A. (2016). Access to Fluoridated Water and Adult Dental Caries: A Natural Experiment. Journal of Dental Research, 95(8): 1-7.

The full text of the paper is available here.

The researchers adjusted their data for well-known confounders such as socioeconomic status, the pattern of dental visiting, smoking, educational attainment, income, and age. Use of fluoridated toothpaste was common for all subjects so could not explain the results.

The final data, adjusted fo confounders, showed a greater protection with a longer exposure to fluoridated water. The figure below shows this data for  DMFT (decayed, missing and filled teeth) and DFT (decayed and filled teeth). The use of both measures helps to accommodate the fact that some teeth are missing for reasons other than decay.

The data is present as ratios of DMFT and DFT for the shorter exposure periods ( <50% and 50%-75%) to the values of DMFT and DFT for exposures of >75%.

So, once again a study showing the benefits of community water fluoridation. this time for adults with long time exposure to fluoridation.

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Fluoridation: the truth about heavy metal contamination

Anti-fluoride activists going on about contaminants in drinking water due to fluoridation have it all wrong. If they avoided their knee jerk, chemophobic reactions to certificates of analysis and did some calculations they would realised they are making a fuss about absolutely nothing.

I am currently absorbed in dealing with family issues at the moment so am reposting this article, .” Unfortunately is is still very much relevant.

Sometimes anti-fluoride propagandists end up shooting themselves in the foot. This always seems to happen when they produce “evidence’ that fluoridating chemicals are loaded with toxic heavy metals.

It feels like shooting fish in a barrel to debunk their use of analytical figures because the data they produce always shows them to be completely wrong. I wrote about this before in Fluoridation: emotionally misrepresenting contamination. So, I am effectively repeating myself by discussing the meme image below that Fluoride Free NZ is currently circulating in social media.

Hill lab

Still, this time, I will show how insignificant these analytical figures by comparing the calculated final concentrations in tap water – due to addition of the chemical – with measured concentrations for these contaminants in Hamilton tap water.

Added contaminants as percentage of MAVs

But first – what contribution would this sample of fluorosilicic acid make to the contaminant levels in Hamilton’s tap water – and how do these levels compare with the maximum acceptable values (MAVs) defined in New Zealand’s Drinking Water Standards? The values for the MAVs are published in:

Ministry of Health. (2008). Drinking-water Standards for New Zealand 2005 ( Revised 2008 ) (Vol. 2005). Wellington.

In this table, the “Tap water (mg/L)” data are the calculated final concentrations after addition of the fluoridating agent in the meme. The “%age of MAV” data are these values expressed as a percentage of the maximum acceptable values (MAVs) for the contaminants.

Impurity MAV (mg/L) Tap water calculated (mg/L) %age of MAV
Aluminium 0.1 8.69E-05 0.0869
Antimony 0.02 < 3.56E-07 <0.0018
Arsenic 0.01 1.26E-05 0.1264
Barium 0.7 4.27E-06 0.0006
Cadmium 0.004 2.37E-07 0.0059
Chromium 0.05 4.74E-06 0.0095
Copper 1 1.19E-06 0.0001
Iron 0.2 1.62E-04 0.0810
Lead 0.01 2.37E-07 0.0024
Manganese 0.04 3.56E-06 0.0089
Mercury 0.007 < 1.98E-07 <0.0028
Molybdenum 0.07 < 3.56E-07 <0.0005
Nickel 0.08 3.95E-06 0.0049
Selenium 0.01 < 1.98E-07 <0.0020
Uranium 0.02 2.05E-06 0.0103

Sorry, I have had to use scientific formating for some numbers because the final calculated concentrations in tap water are so low. On average, the calculated concentration  of these contaminants due to the fluoridating agent is about 0.02% of the MAV.  The largest relative contribution is for arsenic – just over 0.1%.

Regulations require that the contribution of contaminants from fluoridating agents should always be less than 10% of the MAV . The actual level of contaminants in this particular sample is well below those regulated maxima.

The Fluoride Free NZ meme is just promoting naive chemophobic scaremongering about absolutely nothing. These activists just haven’t bothered calculating what the analytical data means for the final concentrations in tap water. Or even bothered comparing the data with the regulated maximum amounts allowed for fluoridating chemicals. These values are available in Standard for the Supply of Fluoride for Use in Water Treatment.

Added contaminants as a percentage of concentrations in inlet water and treated water.

Let’s now compare the estimated contribution from contaminants in this sample of fluorosilicic acid to the levels of the very same contaminants in the Hamilton water. I have taken data from this document issued by the Hamilton City Council:

Waikato River and Treated Drinking Water Comprehensive Analysis Report 2013/14

The next table is for samples taken on 18th July 2013 at the intake to the treatment plant (that is the source water before treatment). The “Added FSA%” is the calculated level of impurity resulting from fluoridation expressed as a percentage of the impurity naturally present in the source water.

Impurity Intake (mg/L) Added FSA%
Aluminium 1.68E-01 0.05
Antimony 8.50E-04 <0.04
Arsenic 1.96E-02 0.06
Barium 1.88E-02 0.02
Berylium <1.10E-04 0.18
Cadmium <5.30E-05 0.45
Chromium <5.30E-04 0.89
Copper <5.30E-04 0.22
Iron 2.94E-01 0.06
Lead 1.18E-04 0.20
Manganese 2.15E-02 0.02
Mercury <8.00E-05 <0.25
Molybdenum 3.80E-04 <0.09
Nickel <5.30E-04 0.75
Selenium <1.10E-03 <0.02
Tin <5.30E-04 0.22
Uranium <2.10E-05 9.78
Zinc 8.13E-01 0.00

Now, a similar calculation and comparison – this time “Added FSA%” is the calculated level of impurity resulting from fluoridation expressed as a percentage of the impurity already present in the “treated water” – which is the final tap water. (At this time the Hamilton water supply was not fluoridated).

Impurity Treated (mg/L) Added FSA%
Aluminium 2.04E-02 0.43
Antimony 8.00E-04 <0.04
Arsenic <1.10E-03 1.15
Barium 1.26E-02 0.03
Berylium <1.10E-04 <0.18
Cadmium <5.30E-05 0.45
Chromium <5.30E-04 0.89
Copper 8.00E-04 0.15
Iron <2.10E-02 0.77
Lead 4.82E-04 0.05
Manganese 1.75E-03 0.20
Mercury <8.00E-05 <0.25
Molybdenum 3.70E-04 <0.10
Nickel 3.52E-03 0.11
Selenium <1.10E-03 <0.02
Tin <5.30E-04 0.22
Uranium <2.10E-05 9.78
Zinc 4.82E-03 0.14

The extremely low levels of contaminants – both calculated and already in the intake water and final treated water – mean some of the calculations are rather meaningless. Especially as some of the analysed values are given as less than the detection limit.

However, the very low calculated contribution of contaminants from this fluorosilicic acid sample – usually < 1% of that naturally present – shows how ridiculous the Fluoride Free NZ claims about contamination introduced by fluoridating agents is.

Never trust anti-fluoride campaigners

Fluoride Free NZ is simply scaremongering – relying on naive chemophobia where just the chemical name and analytical data (even where the “<” symbol indicates below the level of detection) seem to scare people.

This example illustrates, once again, that the claims made by anti-fluoride and similar activists should never be accepted at face value. They should always be checked against reliable sources.

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Bottle fed infants: fluoridated water not a problem

Parents need no longer be concerned about using fluoridated water for baby formula. Photo credit: Life insurance for your heirs

New recommended fluoride dietary intakes by infants and young children in Australia and New Zealand were recently published. The updated values are available online at Nutrient Reference Values for Australia and New Zealand.

This is a regular update – the Australian National Health and Medical research council advises these recommendations be reviewed every 5 years. But the new recommendations are interesting because the upper limit for fluoride intake for infants and young children is substantially higher than the previously recommended upper limit.

Public health policy in Australia and New Zealand aims to adjust fluoride intake at the population level to be high enough to prevent dental caries but low enough not to cause moderate or severe dental fluorosis or other adverse effects. But health professionals have noted an anomaly in recent years.  Dietary intake of fluoride by children may exceed the previously recommended upper levels – even when community water fluoridation levels are within the recommended targets. Despite this the occurrence of moderate or severe dental fluorosis in Australia and New Zealand was rare.

This led to health authorities acknowledging that, for example, bottle-fed infants may sometimes exceed the upper limits for dietary fluoride intake – but still recommending this was harmless. Anti-fluoride activists misrepresented this advice by claiming health authorities were recommending that fluoridated water not be used for preparing formula for bottle feeding. Their claims are incorrect and alarmist. The “warning” simply provided advice that there was no risk of harm but the if parents were concerned they should occasionally use non-fluoridated water to make up baby formula.

In part, this current report is a response to that conundrum.

Why the change?

Anti-fluoride propagandists will no doubt attack this change. They have made capital out of the situation in the past by claiming that infants and young children are getting dangerous levels of fluoride in their diet. They, of course, ignore or hide the fact that despite this, levels of moderate and severe dental fluorosis have not been a problem. They, also misrepresent the situation regarding dental fluorosis and its causes – see Dental fluorosis: badly misrepresented by FANNZ and Water fluoridation and dental fluorosis – debunking some myths.

However, the expert working group who reviewed the literature and came up with the new recommendations did have their reasons. And these were more than just the absence of moderate and severe dental fluorosis.

They also concluded the previous recommendation was not consistent. This is because it was based on the US Environmental Protection Agency’s use of mean dietary intake and not the higher percentile fluoride intake which should have been used for the upper limit.

Consequently, their recommendation for the upper limit of fluoride intake for children up to 8 years of age is 0.20 mg F/kg bw/day (kg bw = kg body weight). The previous limit was 0.1 F/kg/ bw/day. This produces the following upper limits for children of different ages.

In Australia and New Zealand, the estimated upper range of total daily fluoride intake for different age groups ranges from 0.09to 0.16 mg F/kg bw/day – considerably lower than the new recommended upper limit of 0.2 mg F/kg bw/day.


Will anti-fluoride campaigners top claiming that bottle-fed infants consume dangerous levels of fluoride if their formula is made with fluoridated water?

And the rest of us should not longer make the concession that intake levels are above the recommended upper limits – because they aren’t.

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Citing scientific studies and the arrogance of ignorance

Image credit: Why Citing a Scientific Study Does Not Finish An Argument

One thing that gets me going (as readers here probably know) is the way scientific citations are cherry-picked and dragged in to support biased positions. It’s a common form of confirmation bias in the fluoridation debate. And I get even angrier when the perpetrators of this thoughtless and cherry-picking citations will then claim they “have science on their side.”

Parroting citations and (often unconnected) claims are not what science is about!

So I was very pleased to see this article Why Citing a Scientific Study Does Not Finish An Argument by Jonny Anomaly and Brian Boutwell at Quillette. They point out that throwing down a gauntlet like “actually, studies show . . . “ often kills the discussion:

“It’s hard to know what to say when people cite scientific studies to prove their point. Sometimes we know the study and its relative merits. But most of the time we just don’t know enough to confirm or refute the statement that the study is supposed to support. We are floating in a sea of information, and all we can do is flounder around for the nearest buoy to support a view that’s vaguely related to the conversation.”

I think this is why anti-fluoride propagandists rarely get challenged when they come out with their misinformed claims that fluoridation causes IQ loss, ADHD, hypothyroidism, etc. Their discussion partners are often not familiar enough with the scientific literature to challenge the claims. Of course 99 times out of 100 the propagandist is also completely unfamiliar with the literature and is simply parroting a claim they saw in one of their “nature news” newsletters, or similar. And surely throwing out citations one has never read is a clear example of the arrogance of ignorance.

The fact is: “All of us lack the time to understand more than a small fraction of scientific research.” But when the discussion partner is familiar with the cited studies the propagandist quickly lurches into a Gish Gallop – or deletes the online discussion and bans the person. Those of us who have entered into this debate with the motivation of clarifying the science will know what I am talking about.

We should be wary of arguments relying on citations even in cases where the proponent has read the literature. Citing an individual study is really meaningless:

“Of course, that’s not always how science works, or how knowledge is spread. A single study is rarely anything more than suggestive, and often it takes many replications under a variety of circumstances to provide strong justification for a conclusion. And yet, poorly supported studies often make their way into newspapers and conversations as if they are iron clad truths.”

That’s another thing that angers me – even fairly reputable magazines will report individual studies as if we should take the results as “gospel truth,” without even considering the quality of the research – let alone any supporting research.

The problem of correlations

Often such poorly supported studies rely on correlations – and the way commenters and the media cite such correlations as “evidence” is another bugbear of mine. The authors rip into this problem:

“Correlations are everywhere, and given enough data from enough studies, we will find correlations that are surprising and interesting. But . . .  causation is difficult to infer, and some correlations are flukes that don’t admit of a common cause, or that can’t be consistently replicated.

“We are pattern-seeking creatures, and correlations are patterns that cry out for explanation. But sometimes our political views infect our prior beliefs, and these beliefs lead us to look for patterns until we find them. Given enough tests and time, we will find them.”

I am amazed at how studies relying on the poor use of correlations often make it into scientific journals. I have written about one example in ADHD linked to elevation not fluoridation.” There is a similar situation for the recent paper of Hirzy et al. (2016) which I discuss in Anti-fluoride authors indulge in data manipulation and statistical porkies. Although I understand that particular paper was rejected by several scientific journals before it ended up in Fluoride which accepts anything that is anti-fluoridation.

Frankly, I think more papers like this should be challenged and that journals have an ethical responsibility to publish critiques of such papers. Unfortunately, I think I am being a bit idealistic here as many editors have their own biases.

When it comes down to it I think even with the scientific literature it is a case of reader beware. One should never take citations at face value – especially when used to confirm a biased argument. Rather than accepting such arguments we should follow them up, read the cited paper – and other papers in the research area of we have time. We should approach all such claims using citations critically and sensibly.

This is in line with the conclusion the authors make to their article:

“We’re not advising you to commit social suicide by interrupting every conversation with a demand for more evidence. But we do think the phrase “studies show…” should be met with cautious skepticism, especially when the study supports the politically-motivated preconceptions of the person who’s talking.”

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Debating science

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

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

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

The Science March

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

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

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

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

Debating science

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

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

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

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

Problems with formal debates

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

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

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

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

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

Good faith discussion

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

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

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

A challenge to anti-fluoridation activists

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

Why do these people ignore such opportunities?

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

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

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

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

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

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No, fluoridation is not associated with leading causes of death

We are all going to die but fluoridation isn’t killing us.

Oh, dear – the local anti-fluoridation people are at it again. More cases of fiddling statistics  – and yet again the guilty party is the US anti-fluoridation activist Karen Favazza Spencer. She should really take some advice about statistics.

Although I suspect she doesn’t care – she is just once again cherry picking in an attempt to paint a bad picture of community water fluoridation.

In this case, she claims the death rates for the leading causes of death in the USA are up to 30% higher in the more fluoridated states than in the less fluoridated ones. And here is her cherry-picked table to “prove it.

Her conclusions are wrong, of course. Look at what we find if we use the data for all the states instead of a few selected ones,  and look at it for signs of any correlation between fluoridation extent and death rates? The data is readily available.

I have done this and found a statistically significant correlation in only one case – cancer. Here is that data and the regression line accounts for about 10% of the variance in cancer rate. Obviously, other factors are involved.

But, wait – there is more. As I explained in my last post Anti-fluoridationists exploit infant deaths by fiddling statistics such statistically significant associations often disappear when other important factors are included in the regression analysis.

So let’s look at what happens when we include mean state elevation in the statistical analysis. As I explained last time there is an association between fluoridation extent and mean state elevation which means that fluoridation is often acting as a proxy for elevation in statistical analyses. Multiple regressions including both fluoridation extent and mean state elevation picks this up.

This table shows the results of such multiple regressions.

Table: Association of death cause with fluoridation extent and mean state elevation. Results from a multiple regression

Fluoridation 2014

p value

Mean altitude

p value

Amount of variance accounted for (%)
Heart disease 0.542 NS 0.007 ** 19.7
Cancer 0.363 NS <0.001*** 38.6
Stroke 0.955 NS 0.180 NS 4.4
Alzheimer’s 0.274 NS 0.834 NS 3.3
Diabetes 0.955 NS 0.445 NS 1.4
Kidney disease 0.441 NS 0.017* 16.3

What does that tell us? Well, the apparent association of cancer death rates with fluoridation is false – it disappears when altitude is included.

None of the death rates for any of the causes of death had a statistically significant association with fluoridation. But heart disease, cancer, and kidney disease were significantly associated with altitude. These associations accounted for from 16% to 39% of the variances in the death rates. The role of mean state altitude may have something to do with the size of cities or possibly improved health at higher elevations (the death rates declined with elevation for all causes considered).

I can only finish with the same words of warning I used last time:

“So, once again the lesson is – never take at face value the claims made by anti-fluoridation activists – no matter how “sciency” their information looks or what data they invoke to “prove” them.

Always check such claims for yourself.”

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Anti-fluoridationists exploit infant deaths by fiddling statistics

A useful reminder of how activists lie with statistics

The local anti-fluoride people have not stopped rabbiting away with their “science” – searching for anything bad they can argue is caused by community water fluoridation. The latest claim they make – fluoridation is responsible for infant deaths!

And they have some statistics to “prove” this. The table below presented by well-known US anti-fluoride activist, Karen Favazza Spencer, in her article America First – Chemical Warfare on Infants:

That table is simply lifted from a conspiracy style web page Why Pregnant Women Should Not Drink Fluoridated Water.

OK – these statistics might fool some people – especially if you have a bias to confirm. But the more critical person might pick up that these figures are most likely cherry-picked and want to see the full data set or some analysis of the data.

It’s not hard to find this data as there are tables of all sorts of things for US people organised by state. So, is there a relationship between infant deaths in each state and the extent of fluoridation in each state?

There actually does appears to be one at first sight – here is the graph of the data for infant deaths in 213 plotted against the extent of fluoridation in 2012.


But, just a minute – it is not actually statistically significant (p=0.106) and would account for only about 5% of the variance in infant deaths. Fluoridation is certainly not the main factor – and probably involved at all if other factors are considered.

Here I will just take into account the influence of state elevation – because I know from previous work that fluoridation extent is related to mean state elevation (see ADHD linked to elevation, not fluoridation).

Here is that relationship for the extent of fluoridation in 2012:


So, the extent of fluoridation in each state is related to mean state elevation and this relationship is statistically significant (p=0.005). Actually not surprising as the larger and older cities where fluoridation might be expected are generally situated at lower elevations for a number of reasons.

But what is the relationship between infant death and mean state elevation? Well, it is stronger than for the extent of fluoridation (p=0.002). Elevation accounts for about 18% of the variance in infant deaths in 2013.


Finally, let’s combine both elevation and extent of fluoridation into a multiple regression and see what the relationship when both factors are combined.

This multiple regression shows a statistically significant association (p=0.007) of the extent of infant deaths in each state in 2013 with the mean state elevation. However, there is no statistically significant association (p=0.592) with the extent of state fluoridation.

So while infant deaths could be explained by mean state elevation and most probably one or more other factors, they certainly are not explained by the extent of fluoridation. Not at all!

Preterm birth and conspiracy theory

In her article, Karen Favazza Spencer makes the bald claim “Fluoridation is positively correlated with preterm birth and increased death rates by state “ – again citing from the conspiracy style web page mentioned above.

Sure, that page makes that claim – “Domestic water fluoridation was independently associated with an increased risk of PTB [preterm birth].”  But that is hardly credible evidence because that page goes on the say:

“This study was never published nor was any follow-up research done, despite the fact that 2 years earlier, the US Institute of Medicine reported: ‘Those born preterm have an appreciable risk of long-term neurological impairment and developmental delay.'”

Strange! It is not hard to find data for preterm birth. In fact, here it is for 2014 compared with the extent of state fluoridated in 2012:

Clearly, there is no association between preterm births and extent of fluoridation. Yet that web page claimed there was and that the information had been suppressed!

I guess that is another way ideologically motivated activists “prove” these sort of things – invoke a conspiracy theory to claim a relationship exists but the data is suppressed.

So, once again the lesson is – never take at face value the claims made by anti-fluoridation activists – no matter how “sciency” their information looks or what data they invoke to “prove” them.

Always check such claims for yourself.

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