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.

Similar articles

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.”

Similar articles

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.

Similar articles

Here we go agian

Just when we seem to be making progress over Syria this has to happen. The US was starting to accept that the current elected president in Syria no long “has to go.” Peace talks are underway in Geneva.

And then President Bashar al-Assad had to torpedo all this progress by launching a chemical attack on little children in Idlib. What a fool.Well, if you believe that I guess you might believe anything.

Well, if you believe that I guess you might believe anything.

In the video above, the former British Ambassador to Syria, Peter Ford, presents a far more sensible analysis. He is imminently reasonable in his analysis – but unfortunately the same cannot be said for our mainstream media, leading European politicians and the representatives of NATO countries in the UN Security Council.

Lessons from Aleppo reporting

I think it disgusting for our media and these politicians to unquestioningly take at face value reports from Al Qaeda – the umbrella organisation for the “rebel”/”terrorist’ groups in Idlib, and their propaganda arms – the White Helmets and the Idlib Media Center. Hell, we saw all this before. The propaganda from the Jihadists in east Aleppo, propagated by the White Helmets and the Aleppo Media Center. Reports of chemical attacks, massacres, bombing the “last” schools and hospitals.

In the end, the Aleppo Media Center and the White Helmets left with the jihadist fighters under the surrender agreement and have now set up in Idlib.

Now independent reporters have access to the parts of Aleppo formerly held by the jihadis what do we find? Schools used as arms factories, remaining evidence of the chemicals they used to manufacture chemical weapons.

And the jihadis have used, and still use, chemical weapons in both Syria and Iraq. Yet, strangely, those events, while they sometimes are reported in our mainstream media, never get the NATO Ambassadors running to call UN Security Council Meetings.

Of course, I do not know what really happened in Khan Sheikhoun, Idlib. We really don’t yet have the facts – as UN officials have pointed out. It seems to me unreasonable to assume that the Syrian air force used chemical weapons in their attack on jihadis there. After all, the Syrian government gave up all their weapons, under US supervision, in 2013. And what could they possibly have to gain? They are doling so well, militarily, at the moment. They don’t need this sort of bad publicity.

Dogs returning to their own vomit

No, the Syrian government is not gaining from this event – but the “rebels”/”terrorists” are. And so are those who wish to torpedo the peace conference – or worse, organise a NATO military attack on Syrian armed forces and aerodromes.

But haven’t we seen all this before. isn’t this what was attempted in 2013 with the blaming oaf a similar chemical attack on the Syrian government. Isn’t this, as Peter Ford says, just like “dogs returning to their own vomit.”

Hopefully, other politicians have a memory – and a conscience. They will not be fooled by yet another attempt to justify intervention. To justify “regime change.”

Hopefully, they will, at least, have more sense than the current gung-ho politicians from NATO. Hopefully, they will refuse to pass judgement until they have some facts. Hopefully, they will not be so silly that they trust the word of Al Qaeda and its propaganda arms.

Similar articles

The Putin Derangement Syndrome

Rolling Stone has come out with a name for a madness which seems to be sweeping the US  – and even more widely – at the moment. The Putin Derangement Syndrome.

The latest clinical evidence for this illness must surely be this report from the BBC on the deaths of 14 or more Russians in a Metro bombing in St Petersburg.  A report suggesting that somehow President Putin was responsible!

Such “reporting” is simply obscene. But in this world where the people with a Putin derangement syndrome seem to prevail such stupid allegation becomes evidence and then fact.

Will the St Petersburg bombing of 2017 be added to that already long list of Putin’s crimes? You know – the Moscow apartment bombings, the Moscow Metro bombings, the murders a Denis Voronenkov (murdered in  Kiev by a member of the neo-Fascist Azov brigade but blamed on Putin), Boris Nemtsov, Alexander Litvinenko, Boris Berezovsky, Paul Klebnikov, Anna Politkovskaya, etc., etc. All attributed to Putin, no evidence – but the simple allegations have become facts in the minds of this suffering from the Putin Derangement Syndrome.

Hell, it has apparently become necessary candidates for cabinet office in the US to give the politically correct answer to the questions – Do your believe Putin is a murderer? or Do you believe Putin is a war criminal?

Bugger the evidence – we just want to you come on board and show that you also suffer from the Putin Derangement Syndrome before we let you do this job.

And what about those who have died? Do we not wish to honour them? How does the Washington Times honour those people and their families by publishing (at least for a time) a photo of a protest in their report? As if the gathering was somehow celebrating the atrocity.

And in Germany, the government decided they wouldn’t taint the Brandenburg Gate with the Russian colours because the atrocity was not “exceptional.” Yet after similar attacks in Paris, Brussels, London, Istanbul , Nice and Jerusalem, the Berlin landmark was shown in solidarity with the victims in the national colors of the respective countries. After the massacre of an Islamic assassin in a gay club in Orlando in Florida with about 50 deaths last summer, the Brandenburg Gate was immersed in the rainbow colors of the gay movement.

In attacks in other countries, Berlin showed less selectivity. – Quelle: ©2017

OK, give the malady a clinical name. Call it the Putin Derangement Syndrome. Or perhaps, just be a bit more honest and call it old-fashioned racism (see Western racism and the stereotyping of Russians).

Whatever – I just find the attitude obscene.

Similar articles

March ’17 – NZ blogs sitemeter ranking

Image credit: Blogging for Beginners (Perth) | April 2017

There are about 300 blogs on the list, although I am weeding out those which are no longer active or have removed public access to sitemeters. (Let me know if I weed out yours by mistake or get your stats wrong).

Every month I get queries from people wanting their own blog included. I encourage and am happy to respond to queries but have prepared a list of frequently asked questions (FAQs) people can check out. Have a look at NZ Blog Rankings FAQ. This is particularly helpful to those wondering how to set up sitemeters. Please note, the system is automatic and relies on blogs having sitemeters which allow public access to the stats.

Here are the rankings of New Zealand blogs with publicly available statistics for March 2017. Ranking is by visit numbers. I have listed the blogs in the table below, together with monthly visits and page view numbers. Meanwhile, I am still keen to hear of any other blogs with publicly available sitemeter or visitor stats that I have missed. Contact me if you know of any or wish help adding publicly available stats to your bog.

You can see data for previous months at Blog Ranks

Subscribe to NZ Blog Rankings Subscribe to NZ blog rankings by Email Find out how to get Subscription & email updates Continue reading

Another anti-fluoridation whopper

We are all used to political activists fiddling statistics – but this has gone too far. Local anti-fluoride activists are so narcissistic they are now presenting their own clamouring as representing public opinion – even putting figures to it.

I find this really offensive. As a Hamiltonian, I objected to the undemocratic put our council took in stopping fluoridation in 2013. The attitude of voters was clear from a previous referendum which showed overwhelming support fo this safe and effective social health measure.Protests led to another referendum in October 21013 and again overwhelming support for community water fluoridation (CWF). A clear result and several months later the council reversed its stance –  we now have community water fluoridation again.

Yet anti-fluoride activists argued to reject the referendum result – so what is all the talk now about Patea and Waverly? Are they now objecting to a council which rejected the views of its electors?

Not at all. No referenda were held in Patea or Waverly. As far as I can tell there were no household surveys either. Simply the normal consultation process involving submissions. So where does Fluoride Free NZ (FFNZ) get its figures for the views of residents for the above poster? Are 85% of Patea and 75% of Waverly really opposed to CWF?

Again, no. Those figures represent the proportion of submissions presented to the council arguing against CWF. In fact, half of those submissions came from out of town – somewhere else in New Zealand or overseas. (Paul Connett, from the USA, and other members of his political activist group, the Fluoride Action Network, are regular submitters to New Zealand councils). This is typical of the way that these activists submerge councils with “submissions” when CWF is considered. Many submissions are simply copies or form letters.

By the same logic, FFNZ could argue that 75% of Hamiltonians were against fluoridation (because the overwhelming proportion of submissions to the council were). Despite the clear referenda results showing the opposite. In fact, FFNZ does list the submission number in the case of Hamilton as one of their referenda results!

Now we expect FFN to argue that over 90% of New Zealanders oppose fluoridation because that was the proprtion of anti-fluoride “submissions” to the recent selct committee hearings on the current fluoridation bill!

As they say – pull the other leg.

Wait – there is more!

But FFNZ goes even further over the top in their facebook presentation of this poster. They claim:


“In 2012 the South Taranaki District Council asked residents of Patea and Waverley if they would like fluoridation chemicals added to their water supply. The resounding answer was “NO”. However, Council went ahead and voted for it anyway. Because of the blatant disregard for the community’s wishes, New Health New Zealand took STDC to court. STDC have now spent $320,000 fighting this when they could have just backed off from fluoridation. This issue is going to go to Supreme Court some time in the future.
You have to wonder who these people are working for don’t you.”

So somehow the South Taranaki District High Council is to blame for the expenses involved in defending itself against court action – action taken by a lobby group of the New Zealand “natural”/alternative health industry. A big business worth billions that is pumping something like $100,000 a year into court actions agaisnt fluoridation. See Who is funding anti-fluoridation High Court action?Big business funding of anti-science propaganda on health and Anti-fluoridationists go to Supreme Court – who is paying for this?

How ridiculous – even for these political activists.

Similar articles

2018 Global Atheist Convention

Looks like we are going to have another regional global atheist convention.Such

Such conventions were held in Melbourne in 20110 and 2012 and were very successful. However, a lot has happened between prominent atheists since then. People have fallen out and personal campaigns have been promoted for and against personalities. I hope these conflicts do not jeopardise this planned convention.

I guess it will depend on the invited speakers. Salman Rushdie and Ayann Hirsi Ali will be interesting and attract lots of people. I look forward to announcements of other speakers in the planned line up.

So, I have my questions at the moment – but will certainly consider attending if the other speakers are as interesting.

Must renew my passport.

Meanwhile – if you are interested here is the message from the organisers:

The Atheist Foundation of Australia is pleased to announce the third Global Atheist Convention in Melbourne in February 2018.

Bringing together like-minded thinkers, and those who want to challenge their current thinking, the three-day exhilarating event will feature world-renowned speakers and entertainers.

Sign up today for speaker and ticketing announcements.

Similar articles

Fluoridation: Making sense of the Ministry of Health data

Image credit: Built in Colorado

Every year local anti-fluoride activists eagerly await release of the latest Ministry of Health (MoH) data on the oral health of New Zealand School children. These data are a mine of examples which can be cherry-picked to argue that community water fluoridation is ineffective – or even that the oral health of children in non-fluoridated areas is better than fluoridated areas.

Well, the latest data (for 2015) has just been released and the anti-fluoridationist reaction is typical. They are presenting selected data to argue that “the gap [between the numbers of caries-free children in fluoridated and non-fluoridated areas] has become practically non-existent.”

And the make a big thing of comparing this “practically non-existent” gap with the 40% difference claim they attribute to the MoH. Needless to say, they are wrong.

Let’s have a look at what the 2105 data shows, how this compares with data from previous years and what the limitations of the data, and consequently any conclusions drawn from the data, are.

The data

The figures below show the data – I have included it in graphs showing the data for earlier years. Notice that the data is for Māori and “Other.” This is because the “Total” figures in the data tables throw all ethnic groups together and are therefore misleading. As I have pointed out several times in the past (Anti-fluoridation cherry-pickers at it again A challenge to anti-fluoridationers to justify their misrepresentation of New Zealand researchDebunking anti-fluoridationist’s remaining 12 reasons for opposing fluoridation and Schluter & Lee 2016 noted in their paper 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), Pacific island children, whose oral health is poorer than other groups, are concentrated in fluoridated areas of Auckland. This distorts the “Total” figures (in particular underestimating the oral health for fluoridated areas). Local anti-fluoride propagandists have taken advantage of this in the past to make untruthful claims.

The “Other” group will be mainly Pakeha, but also will contain some Asian. I have not included the data for Pacific island children – the relatively small number in non-fluoridated areas mean the comparison is rather erratic.

Data are presented for “% caries-free” – the proportion of children with no tooth decay, and mean dmft – the average number of decayed missing or filled tooth for each child.

5-year-old children

In summary, the reduction of dental decay (using % caries-free figures) for 5-year-old Māori varied between 8% and 60% in the years 2005 – 2015 and was 25% in 2015.

In summary, the reduction of dental decay (using % caries-free figures) for 5-year-old “Other” varied between 3% and 22% in the years 2005 – 2015 and was 3% in 2015.

Year 8 children

In summary, the reduction of dental decay (using % caries-free figures) for year 8 Māori varied between 12% and 48% in the years 2005 – 2015 and was 12% in 2015.

In summary, the reduction of dental decay (using % caries-free figures) for year 8 “Other” varied between 5% and 27% in the years 2005 – 2015 and was 5% in 2015.

Average effects

It’s worth looking at average effects out over several years to limit the effect of variability in the data. The is the result of the effect of fluoridation in reducing tooth decay (using % caries-free figures) – average effect in the period 2005 – 2015.

Average reduction of tooth decay: 2005 – 2015

  5-year-olds Year 8 children
Māori 33% 27%
“Other” 11% 15%

Problems with the data

Of course, this data is not meant to provide definitive measurements – it is simply the records for oral health (% caries-free and dmft) for different regions. There has been no determined effort to make sure that the resident regions of the child are the same as the school region. While there is some separation into ethnic groups there has been no effort to take into account factors like sex differences, socio-economic influences, dietary differences, and other dental treatment differences. For example, in some regions the health authorities have a programme of treating children in non-fluoridated areas with fluoride varnishes or taking extra steps to provide access to dentists.

It’s interesting that the anti-fluoride people prefer such data to more definitive data corrected for problems. Well, they do at the moment as they are cherry picking to support their claims (see MoH says Fluoridation reduces dental decay by 40% – No it doesn’t!). They are very critical of data from the MoH’s New Zealand Oral health Survey. The MoH acknowledged limitations inherent in this survey for determining an effect of fluoridation – and the anti-fluoride people love to quote that acknowledgment. But at least the Survey did give data:

“for people living in non-fluoridated areas, which are adjusted for age, sex, ethnic group and neighbourhood deprivation to allow appropriate comparisons with people living in fluoridated areas.”

Instead, the anti-fluoride people rely on cherry-picked comparisons from data where no such adjustments have been made. And they never acknowledge the limitations of that data.

Fluoride Free NZ cherry-picks data without correcting for ethnic differences, etc., to make their claim.

The “Halo Effect”

The graphs above do show a tendency for the fluoridated and non-fluoridated lines to approach each other. One could speculate on the reasons and more definitive studies are required to check out such speculation. But here are some of my ideas:

The results could be influenced by changes in residential vs school or dental clinic location. For example, the introduction of “hub and spoke” dental clinics during the 2000s may mean that more children now live in a region with different access to fluoridated water than that for the clinic or school. The recent provision of extra dental care, such as fluoride varnishes or more dentist visits in non-fluoridated areas, is also a likely possibility.

But another possibility is that the efficacy of community water fluoridation is declining – maybe because of better health care, diet, and parental responsibility. In fact, the evidence indicates that community water fluoridation may now have less importance in some cases than dietary intake from other food sources. This graph from a US Environmental Protection Agency report (Fluoride: Exposure and Relative Source Contribution Analysis) shows fluoridated water may now contribute less than 50% of the dietary intake for many children and certainly no more than 70%.

Percentage Media Contribution to Total Daily Fluoride Intake. Figure 7-1 in EPA report Fluoride: Exposure and Relative Source Contribution Analysis.

This has resulted in a “Halo effect.” Because processed foods and beverages now contain more fluoride than in the past (when non-fluoridated water may have been used in processing) the difference in total dietary fluoride intake between children living in fluoridated and non-fluoridated areas has been reduced. The common use of fluoridated toothpaste also contributes to this “Halo Effect.”

This does raise the question – if community water fluoridation is less important as a dietary source perhaps it could be stopped? Although the warning is that if community water fluoridation was stopped perhaps other dietary sources like processed foods and beverages would have a lower fluoride content and dietary intake would then fall below optimum levels.

It’s a complex issue.


Once again the local anti-fluoride activists have been caught out misrepresenting the MoH data by cherry-picking and purposely ignoring important factors like ethnicity.

Similar articles


Fluoride, coffee and activist confusion

Havana Coffee Works in Tory Street, Wellington. Great coffee and chance to see roasting in action. On the site of what was the old Wellington Milk Department in the 1950s.

I have been in Wellington for the Parliamentary select committee hearings on fluoridation. Well, that was the excuse – I was really there to catch up with my family (always a joy and am amazed at how tall my grandson has become) and to enjoy the great food in Wellington cafes.This time I

This time I also set out to acquire some freshly-roasted coffee beans from one if the many roasters in Wellington.

The Havana roaster turned out to be a surprise. Not only are their coffee beans excellent ( I am looking forward to getting home and drinking coffee made with them) – they are based in Tory Street as the site of what used to be the old Milk Department. Some of you may still remember the days when milk was delivered to your house in the middle of the night by a milkman. My Dad was one of those milkmen, and my siblings and I all spent time helping him deliver milk in the dead of night. So that building brought back memories. Even got to walk along Channing street on the way back to my hotel. You wouldn’t know it now but that street was very disreputable in the 50s because of the opium dens in the old houses.

Select Committee Hearings

These were interesting. Submissions were called for on  Health (Fluoridation of Drinking Water) Amendment Bill currently before parliament. This legislation is not about fluoridation itself. It is about how decisions should be made – about the process, not the science. In effect, it proposes transferring decisions from local councils to District Health Boards.

Pressure for the law change came from local councils who were sick to death of the hounding from activists and being forced into making decisions – not about whether to fluoridate or not – but about the science. Activist submitters continued to deluge them with passionately-worded submissions full of scientific claims – councillors with no scientific skills were being forced into making decisions about the science – were the activists correct in their claims that fluoridation causes all the ills known to mankind or should they accept the science presented by the experts. After all, activist submissions could look very sciencey – they were often full of citations to the scientific literature!

True to form the anti-fluoride activists deluged the select committee with submissions which were irrelevant to the bill – very few of them actually suggested changes or showed any evidence they had read the bill. No, they did their usual trick of preaching about the “science” – their claims of harmful effects from fluoridation and that it does nothing for oral health anyway.

It is amazing to hear people make outrageous claims about the scientific literature – claims which make clear they have never bothered to read the source they are citing. I guess they think they can get away with such porkies and misrepresentations because they are talking to politicians. However, my impression was this failed at these hearings – unless submitters raised suggestions about the process they were simply politely thanked and sent away.

So I found it frustrating to hear such lies being peddled about the science (and discussion by the public was not allowed) but confident in the fact the select committee was just humouring these people. Responses from committee members were always about process – not the scientific claims.

My submission

There were only a few submissions which dealt properly with the wording of the bill – the vast majority were just empty anti-fluoride rhetoric. I made a submission as an individual scientist but also as part of the Making Sense of Fluoride (MSoF) team. It was great to catch up with MSoF people who I tend to talk with on-line every day but have not till now met in person.

This was my oral submission:

As Monty Python used to say: “And now for something completely different.”

I support this bill as far as it goes but don’t think it will solve the basic problems without changing the way the science is considered. I want to suggest a change.

The current submissions show the problem. This committee has been inundated with large numbers of written and oral submissions. Many of these are duplicates or form letters. Most are opposed to community water fluoridation and usually make scientific claims – such as fluoride is a neurotoxin, that it causes a high prevalence of dental fluorosis or uses contaminated chemicals.

Submissions often cite scientific articles – some have even attached copies of these articles. This sort of thing can impress the layperson – perhaps some of the members of this committee are impressed? After all, it is easy to fool the ordinary person with scientific claims, citations, documents and publications. Advertisers do it all the time.

But this committee is simply not considering the science. Political committees – parliamentary, local body or District Health Board should not make scientific decisions. They do not have the skills for this. Yet that is what most of these submissions are asking of this committee. It’s what was being asked of local councils and it will be what is asked of DHBs.

Consideration of the science behind community water fluoridation requires people with scientific and health skills. Such people need to check evidence provided, check citations when they are presented, check what the scientific literature actually says (which could be very different to what submitters claim). Proper scientific consideration requires that the claims and cited scientific literature need to be considered intelligently and critically. The wider literature needs to be consulted. Cited claims need following up.

I have attached a couple of documents that do this – these are responses to documents used by several submitter arguing against community water fluoridation.

The current wording this bill requires DHBs to consider the scientific evidence. That just invites opponents of community water fluoridation to inundate DHBs with the sort of submission this committee has received – and local councils have been inundated with. DHBs are no better equipped to deal with this than this committee or local councils.

I suggest a change requiring DHBs to take advice on the scientific evidence from central bodies – the Ministry of Health and the Public Health Advisory Committee. This would transfer responsibility for scientific considerations to central bodies better equipped to do that evaluation.

The Public Health Advisory Committee has a legislated role to consider questions like this and advise the Minister. It is also able to consult interested organisations, experts like the Royal Society and the Prime Minister’s Chief Scientific Advisor who performed the most recent fluoridation review. It can also consult appropriate individuals.

This would not remove the right of lay persons to make submissions about the science – it simply redirects those submissions to a more appropriate body.

I think a change like this should be welcomed by everybody. It removes from DHBs the impossible job of making decisions about the science they are not equipped to make. It provides a proper venue for the science to be considered intelligently and critically. It is a credible and authoritative body for scientific organisations, health organisations, activist groups and the ordinary person who has concerns on this issue – whether for or against community water fluoridation.

After all – if someone has a genuine concern or has evidence they think will stand up to scientific scrutiny why should they want to waste time submitting it to a committee of politicians? Wouldn’t they be far happier knowing they are appealing to people who have the skills to evaluate their concerns properly?

Similar articles