Anti-fluoridation cherry-pickers at it again

Anti-fluoride campaigners seem to be a sixes and sevens on whether community water fluoridation (CWF) is effective or not. Some will accept CWF is effective in improving oral health but moan about the ethics or reports of harm. Others will simply claim CWF is not effective.Stans-lie-annot

Stan Litras is a Wellington dentist and anti-fluoride campaigner in the later camp. He continually denies that CWF is effective and claims he has science to back up his claim. However, what he actually means is that of he cherry-picks the science, holds his mouth the right way and prevents you from looking at the context and data – he can find a quote to support his position.

I have debunked his claims before in my articles – such as, Cherry-picking and misinformation in Stan Litras’s anti-fluoride article and Cherry-picking and misinformation in Stan Litras’s anti-fluoride article. But he is at it again. This time he is misrepresenting a recent New Zealand research paper in a recent letter to the Christchurch Press.

There are several misrepresentations in his letter but here I will just take issue with the highlighted text. Stan claims:

“The DHB’s Dr Martin Lee published a research paper recently which showed little or no benefit from water fluoridation, a finding consistent with the modern weight of evidence.”

It is always best to check out such claims and I have hunted down the paper Stan probably refers to. It is:

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.

This is linked to the full-text version so readers can check out the paper itself.

Far from showing “little or no benefit” from water fluoridation the abstract actually says:

“Significant and sustained differences were observed between Māori and non-Māori children, and between CWF and non-CWF exposed groups.”

Stan ignored that sentence but latches on to (or cherry-picks) the next sentence:

“However, a convergence of dental profiles between non-Māori children in CWF and non-CWF regions was observed.”

But he ignores completely the authors’ discussion of this apparent convergence. Obviously, the discussion doesn’t support Stan’s anti-fluoride bias! But that discussion is interesting and worth considering.

Is there a convergence?

I have noted this convergence before in my articles Cherry picking fluoridation data and Fluoride debate: Response to Paul’s 5th article where I used similar data to that used in Schluter & Lee (2016). That data is available on the Ministry of Health’s website.

The graphs below show the raw data for all (“total”) children and for Māori:



So, yes, there is a convergence in the sense that the differences in the oral health of children in fluoridated and unfluoridated areas appears to be reducing with time. I have speculated that the apparent convergence could have something to do with 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 thew school – rather than their residence. This will lead to incorrect allocation in some cases.

However, this paper suggests another reason for the convergence which I hadn’t considered.

Changes in and composition of the non-Māori group

The authors say:

“Another notable feature was the apparent convergence of prevalence estimates amongst non-Māori children in CWF and non-CWF areas. 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.”

This is interesting and is supported by the data.

First, let’s note that while I compared data for Māori children with the total data in my figures above these authors have actually compared data for Māori and non-Māori. This shows a clearer convergence for non-Māori children than for all children – see this figure for 5-year-old children from the paper (dmft = decayed, missing and filled teeth per child):


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

The picture is similar for year 8 children.

So you can see why anti-fluoride campaigners would love to cherry pick the non-Māori data. I predict that Stan and other anti-fluoridation campaigners will be reproducing parts of this figure in their propaganda for future use.  That graph is just too good for them not to cherry-pick.

But we need to remember that the non-Māori group is not ethnically uniform. In particular, Pacifica make a large contribution to this group. That contribution is unevenly distributed between the fluoridated and fluoridated groups. And it has changed over time.

  • In 2013 about 86% of Pacific live in fluoridated areas – over the period covered by these MoH records this proportion has varied between 80 and 90%.
  • In 2013 Pacifica make up about 12% of the non-Māori group (between 2007 and 2o13 this has varied between 9.0 and 12.7%)
  • In 2013 Pacific make up about 19.3% of the non-Māori fluoridated group (between 2007 and 2013 this has varied between 14.9 and 20.7% of the non-Māori fluoridated group).

MoH data confirms problem of Pacific inclusion

So the oral health of Pacifica can have a relatively large influence on the data for the non-Māori group – particularly for the fluoridated non-Māori group where they are included. This becomes important when we realise that the oral health of Pacifica is markedly poorer than for the rest of the non-Māori group. I have illustrated this using the average of data for fluoridated 5-year-olds in the period 2007 – 2013.


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

So the poorer oral health of Pacifica will drag down the % caries free and drag up the mean dmft data for the fluoridated non-Māori group. However, this will have little influence on the unfluoridated non-Māori group because of the very small Pacific contribution.

We can confirm this with the raw data from the Ministry of Health website. That data is given separately for Māori, Pacifica and “other” (non-Māori/non-Pacific). The figure below shows this data for the 5-year-old children.


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

OK – there is still some evidence of convergence from about 2007 on between fluoridated and unfluoridated children. But the graphs do indicate that CWF is still having  a beneficial effect.

But I think Stan and his mates will prefer to cherry-pick the data for the non-Māori group and keep very quiet about the distorting effect that inclusion of Pacific in this group has had on the apparent convergence.

Note: I have used the raw Ministry of health data in this discussion. Schluter & Lee (2016) used standardised estimates to account for the difference in the numbers of unexamined children according to ethnicity.

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24 responses to “Anti-fluoridation cherry-pickers at it again

  1. Of course those who push fluoridation wouldn’t dream of cherry picking would they?

    University of York
    Professor Trevor A. Sheldon
    Head of Department


    In my capacity of chair of the Advisory Group for the systematic review on the effects of water fluoridation recently conducted by the NHS Centre for Reviews and Dissemination the University of York and as its founding director, I am concerned that the results of the review have been widely misrepresented. The review was exceptional in this field in that it was conducted by an independent group to the highest international scientific standards and a summary has been published in the British Medical Journal. It is particularly worrying then that statements which mislead the public about the review’s findings have been made in press releases and briefings by the British Dental Association, the British Medical Association, the National Alliance for Equity in Dental Health and the British Fluoridation Society……..


  2. Bill, your response appears to accept my criticisms of Stan Litras’s cherry-picking behaviour. Thanks for that.

    As for other examples of cherry-picking (it is, unfortunately, a common human behaviour) I am happy to discuss any examples you can provide.

    Could you be specific?


  3. Ken, having read your previous summary of the York report I see it is a waste of time quoting Trevor’s letter of indignation.

    I doubt if you knew that people at the time who opposed fluoridation were against being part of the review as it was thought that the review would be completely in favour of fluoridation and their participation would be used to show how fair the report was. It created a long lasting division amongst the National Pure Water Association officers at the time.

    When the government first proposed the review everybody thought that the York report would give fluoridation the thumbs up and they were shocked when it didn’t. A verdict the authorities could not accept and they did the cherry picking same as you do and OK so do I.
    But I believe that there are so many experts against, that common sense would say it is not worth continuing the practice of fluoridation because of the long term risk to our health.

    I’m against it because we know many people get fluorosis even in non fluoridated areas. I know one youngster with terrible teeth from too much fluoride in non fluoridated Southampton. I know it is not a pure fluoride and in the States they even get supplies from China.

    I’m against it as I am against enforced medication. Twenty years ago I was told I needed blood pressure tablets otherwise I may have a stroke or heart attack. I said no thanks I have a good diet and I exercise and I’m still here That’s freedom of choice.


  4. Bill – could you please link me to my summary of the York review? I don’t remember writing one )(:-) ) – but then again perhaps I am just being forgetful.

    However, I am aware of Sheldon and his role in the advisory group which was purposely set up to include anti-fluoride people and did not accept the recommendations of the review. I did contact him recently about his criticism of the recent Canadian paper which he cherry-picked and misrepresented. He told me he did this for the Fluoride Action Network – so I hardly see him as an objective observer.

    Interesting you tell me that people living in non-fluoridated areas get fluorosis – that is true. The NZ data shows that people in both fluoridated and non-fluoridated areas have a prevalence of dental fluorosis of about 45% – there was actually no real difference between the two areas.

    Sort of gives a lie to the claim that community water fluoridation causes dental fluorosis, doesn’t it?


  5. Again you are cherry picking, ignoring my comments you pick on something that confirms your position. My reply to it is if it is true fluorosis is equally prevalent isn’t it obvious we are all getting too much fluoride especially children who swallow toothpaste. Why push for more fluoride in areas that haven’t got fluoridation? More effort ought to be made to educate people on reducing fluoride.

    You quote Prof Newton in a link as I’ve spoke to him my impression is not favourable My impression of Prof Peckham is far better he is open to the truth and a far nicer chap. There are many sincere people who are opposed to fluoridation who are not doing it for money as you sometimes accuse us.

    You wrote this last year Ken



  6. Bill – thanks for linking me to my article. As you will notice – if you read my article – it is not as “summary of the York report” as you originally claimed. It is a discussion of the way the York Review gets misrepresented. And I specifically mentioned Sheldon in that article – pointing out he was not an author of the review which anti-fluoride propagandists keep implying.

    You yourself used a Sheldon quote as if it was an authoritative statement from one of the authors – it is not. It is simply Sheldon’s personal opinion. He is anti-fluoride and his statements of opinion are of no value in themselves.

    I cannot comment on whether Peckham is a “nice chap” But I can comment ion his scientific writing and, like many people, I have been clearly critical of these. It is incredible that someone could write an article on hypothyroidism and declare – without any evidence – that iodine deficiency is not a factor. That is extremely poor science, confirmation bias. Even “nice chaps” can do bad science.

    Now, where Sheldon deals with specific evidence his claims can be discussed – as I did with his comments in the Canadian research in my article Anti-fluoridationist’s flawed attacks on Calgary study

    Of course, there are sincere people who oppose CWF for non-monetary reasons. I count some of these among my personal friends. But neither my friendship with them or their sincerity makes them correct. In the end, it is an objective consideration of the evidence which ensures the best approach to questions like this. Not friendship or subjective beliefs, no matter how sincere.


  7. Bill, the reason health professionals and scientists recommend (not push) community water fluoridation is because the evidence shows it is effective in reducing tooth decay and that it is safe.

    That is above and beyond the existence of mild forms of dental fluorosis or a condition which may be caused by factors other than fluoride. (This is why in NZ a more general medical term is usually used).

    Recommendations on CWF are based on balancing the advantages of better oral health against the small risk of a very small increase in mild forms of dental fluorosis.

    Yes – there is a need to educate people living in India, for example, about reducing fluoride. But that is not the case in NZ and most parts of the UK and USA. (Although we should obviously educate people not to eat their toothpaste, salt or cleaning products).


  8. What about this chap’s view
    Dr Geoff Pain ABC radio interview

    Prof Trevor Sheldon spoke for all of those involved in the York Review it isn’t just one man’s opinion.


  9. What about Pain’s pont of view? He is hardly a credible person – but what is your point?


  10. Just wanted your opinion on Dr Pain which you have now given.

    You made no comment on my point that Trevor Sheldon spoke for all those involved it wasn’t just his opinion as you claim.


  11. Bill, Sheldon’s comment was made in bis name – it is clearly his own opinion.

    He was not one of the authors of the review and had no authority to speak for them.

    Anyway – enough of expressing opinions. You referred to cherry-picking by me yet could not give an example.


  12. There is a video on the Internet where someone rang the York Uni and he got the same message as stated by Trevor Sheldon. The BMA, the BFS, the BDA did all rush in to say the York review supported them. It didn’t.

    Have you seen it?


  13. Bill. Now we have hearsay – and no specifics.

    Perhaps you should instead deal with the subject of this post – or have you conceded that Stan has been dishonest in his cherry-picking?


  14. What I write is opinion, we aren’t robots or in court. I get persuaded by integrity, humanity, factors you would .dismiss. You are sounding like Steven Slott.

    I doubt if Stan is dishonest, I expect he does cherry picks as you and I do. Same as the BDA, BMA, BFS, ADA, AFS

    You said this about Stephen Peckham.
    “It is incredible that someone could write an article on hypothyroidism and declare – without any evidence – that iodine deficiency is not a factor”

    I too can’t believe that Stephen would say that unless it is taken out of context. Stephen has the qualities I admire he cares and he is honest.. He has the courage to defy the combined medical opinion with all its risks to his career.
    He examined all the evidence on fluoridation and came to a different conclusion than you. He decided it is not safe or effective. He is now a professor. I would rather believe him than you.


  15. Bill, have you not read Peckham’s paper? 


  16. I’ll email Stephen if he isn’t too busy I’m sure he will take the time to answer why he wrote that.


  17. So, Bill, I take from your reply that you have not read Peckham’s paper.

    You really should not be discussuing this issue, and criticising people who have considered the evidence, if you have not bothered to read the papers.


  18. That is very telling Ken I would have thought you would be pleased to have Stephen contact you but never mind if that is your opinion Goodbye.


  19. Bill – I would, indeed, be pleased for Peckham to contact me – and would enjoy a discussion with him. I would even offer to run this discussion as a series of articles on this blog – as I did with Paul Connett.

    But, you are attempting to divert attention away from my observation that you are entering into discussion of a paper you haven’t even bothered reading. Unfortunately this is typical of so many anti-fluoride propagandists.


  20. He is now a professor. I would rather believe him than you.

    Oh look, an appeal to authority.

    And exactly how stupid is it?

    (Bill sticks fingers in ears, ignores the unamimous consensus position of the global scientific, public health, medical and dental communities, but still, suckered by his own confirmation bias, points to singular or minority contrarian opinion.)


  21. Yes OK Richard if you say so.
    Ken as Stephen was kind enough to reply I’m copying it to you. He does not want to follow it up with further letters and states why. This too is my last email.
    Dear Bill,

    In writing the article we were obviously very conscious of potential confounding factors and the journal referees asked us to check our findings and provide details of whether iodine, in particular, may have been a confounding factor.

    We looked at the data from the National Diet and Nutrition Survey which clearly showed that those aged 40+ in the West Midlands area consumed more than the recommended levels of iodine. There was also little regional variation in iodine consumption levels for people aged 40+ (the population we specifically included in our study). There are differences for younger women (referenced in the article) but this did not affect our modelling. In addition, we looked at the National Geographical survey data that also showed no difference in iodine levels in the environment (soil, air, water etc) and diet in different areas in relation to fluoridated areas (something we were asked to check by the journal referees).

    Interestingly while iodine consumption showed little difference it is plausible that fluoride interferes with iodine absorption – a point noted in the 2006 NRC report from the USA. This may in fact be the reason why we identified differences in hypothyroid prevalence. However, as yet this can only be supposition rather than proven by evidence.

    I have no interest in engaging with Ron Parrott given his views and dismissal of “tame scientists”, routinely attacking anyone who does not support fluoridation. We have responded with a wealth of supporting evidence to published critical commentaries which I hope will be published by the journal. The journal asked us to re-examine our analyses in the light of criticism – particularly from Public Health England – and this independent analysis confirmed our results.


  22. Bill, I find the purposeful misspelling of my name by anti-fluoride propagandists very childish and, in Stephen’s case, also unprofessional.

    His unwillingness to engage in a scientific discussion is also unprofessional.

    His paper has been broadly criticised for not including iodine as a confounder and it is not adequate for him to claim ” iodine consumption showed little difference.” He did not produce any data or do any analysis to show this and has simply cherry-picked and isolated comments supporting his bias and completely ignored others which do indicate a likely variation in iodine deficiency in the UK.

    I myself noted that distance from the sea was not even considered and this could be important when considering dietary fluoride.

    In my analysis of the Malin and Till ADHD paper ( I showed how such cherry-picking and avoidance of confounders can easily lead to the wrong conclusion. This was confirmed by a subsequent published paper (

    Anti-fluoride campaigners are continually committing this statistical fallacy – particularly in their promotion of the IQ/fluoride. So Stephen’s refusal to include iodine deficiency in his statistical analysis is just another example.

    His characterisation of mu critiques of research papers like his as personal attacks is just silly. Honest scientists should never be afraid of such critical analyses and should welcome this sort of discussion.

    Might I suggest that Stephen’s unwillingness to participate is a scientific discussion is an indication that he really is aware that the claims made in his paper do not really stand up to proper scientific scrutiny.

    After all, I am not the first, or last, scientist to make these sort of observations.


  23. I apologise for the incorrect name as it was my misspelling he just copied it.


  24. Bill, can you name a single mainstream scientific, medical, public health or dental community that disputes that a properly run community water fluoridation programme is both safe and effective as a means of promoting dental health in the community?


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