Tag Archives: fluoride

Fluoridation and ADHD: A new round of statistical straw clutching

“To clutch at straws – the act of reaching for a solution no matter how irrational or inconsequential.” Source: Advanced Vocabulary for English Language Learners

Anti-fluoridation activists are promoting a number of new scientific papers they argue support their campaigns. But one has only to critically read these papers to see they are clutching at straws. Their promotion relies on an unsophisticated understanding of statistics and confirmation bias.

I will look at one paper here – that of Bashash et al., (2018) which reports an association between maternal prenatal urinary fluoride and prevalence of child ADHD.

The paper is:

Bashash, M., Marchand, M., Hu, H., Till, C., Martinez-Mier, E. A., Sanchez, B. N., … Téllez-Rojo, M. M. (2018). Prenatal fluoride exposure and attention deficit hyperactivity disorder (ADHD) symptoms in children at 6–12 years of age in Mexico City. Environment International, 121(August), 658–666.

I discussed an earlier paper  by these authors – Bashash et al., (2016) which reported an association between maternal neonatal IQ fluoride and child IQ – (also heavily promoted by anti-fluoride activists) in a number of articles:

Promotion of the new paper by anti-fluoride activists suffers from the same problems I pointed out for their promotion of the earlier paper. In particular it ignores the fact that the reported relationships (between maternal neonatal urinary fluoride and cognitive measure for children in Bashash et al., 2016, and prevalence of child  attention deficit hyperactivity disorder – ADHD – in Bashash et al., 2018) were very weak and explain only a very small amount of the variation. This raises the possibility that the reported weak relationships would disappear if significant risk-modifying factors were included in the statistical analyses.

Bashash, et al., (2018)

Whereas the earlier paper considered measures of cognitive deficits in the children the current paper considers various measurements related to ADHD prevalence among the children. These include parent rating scales (CRS-R). Three were ADHD-related scales from the Diagnostic and Statistical Manual of Mental Disorders (DSM) (Inattention Index, Hyperactivity-Impulsive Index and Total Index [inattentive and hyperactivity-impulse behaviours combined]). They also include several other indexes related to ADHD.

A number of computer-assisted indexes (CPT-II) were also determined.

Most indices were not significantly associated with maternal prenatal urinary fluoride. However, the authors reported statistically significant (p<0.05) relationships for indices of Cognitive Problems + Inattention, ADHD Index, DSM Inattention and DSM ADHD Total.

The data and the relationships were provided in graphical form – see figure below – taken from their Figure 2:

There is obviously a wide scatter of data points indicating that the observed relationships, although statistically significant, explain only a small part of the variation in the indices.

So, just how good are the relationships reported by Bashash et al., (2018) in explaining the variation in these ADHD-related indices? I checked this out by digitally extracting the data from the figures and using linear regression analysis.

Index

% Variance explained

Cognitive problems + Inattention 2.9%
ADHD Index 3.1%
DSM Inattention 3.6%
DSM ADHD Total 3.2%

In fact, these relationships are extremely weak – explaining only a few per cent of the observed variation in the ADHD related indices. This repeats the situation for the cognition-related indices reported on the Bashash et al., (2016) paper (see Maternal urinary fluoride/IQ study – an update).

The fact these relationships were so weak has two consequences:

  1. Drawing any conclusions that maternal neonatal fluoride intake influences child ADHD prevalence is not justified. There are obviously much more important factors involved that have not been considered in the statistical analysis.
  2. Inclusion of relevant risk-modifying factors in the statistical analysis will possibly remove any statistical significance of the relationship with maternal urinary fluoride.

Credible risk-modifying factors not considered

Bashash et al., (2108) do list a number of possible confounding factors they considered. These did not markedly influence their results. however, other important factors were not included.

Nutrition is an important factor. Malin et al., (2108) reported a signficant effect of nutrition on cognitive indices for a subsample of the mother-child pairs in this study (see A more convincing take on prenatal maternal dietary effects on child IQ).

Their statistical analyses show that nutrition could explain over 11% of the variation in child cognitive indices indicating that nutrition should have been included as a possible risk-modifying factor in the statistical analyses of Bashash et al., (2016) and Bashash et al., (2018). I can appreciate that nutrition data was not available for all the mother-child pairs considered in the Bashash et al., papers. However, I look forward to a new statistical analysis of the subset used by Malin et al., (2108) which includes prenatal maternal urinary fluoride as a risk-modifying factor and tests for relationships with child ADHD prevalence.

Could the reported weak relationship disappear?

Possibly. After all, it is very weak.

The problem is that urinary fluoride data could simply be a proxy for a more important risk-modifying factor. That is, urinary fluoride could be related to other risk modifying factors (eg. nutrition) so that the relationship with urinary fluoride could disappear when these other factors are included.

I illustrated this for a earlier reported relationship of child ADHD prevalence with extent of fluoridation in US states (see Perrott 2017 – Fluoridation and attention deficit hyperactivity disorder – a critique of Malin and Till (2015)). In  that case the relationship was much better than those reported by Bashash et al., (2016) and Bashash et al., (2018) – explaining 24%, 22% and 31% of the variance in ADHD prevalence for the years 2003, 2007 and 2011 respectively. The relationships are illustrated in their figure:

Relationships between water fluoridation (%) and child ADHD prevalence for 20013 (red triangles), 2007 (blue diamonds) and 2011 (purple circles). Malin & Till (2105)

Yet, when other risk-modifying factors (particularly mean state elevation) not considered by Malin & Till (2015) were included in the regression analyses there was no statistically significant influence from fluoridation prevalence. In this case fluoridation prevalence was related to altitude and was simply acting as a proxy for altitude in the Malin & Till (2015) regression.

Conclusion

As the authors admit, this study:

“was not initially designed to study fluoride exposure and so we are missing some aspects of fluoride exposure assessments (e.g., detailed assessments of diet, water, etc.).”

However, they do say these “are now underway” so I look forward with interest to the publication of a more complete statistical analysis in the future.

There are other problems with the data (for example the paucity and nature of the urinary fluoride measurements) and these are the sort of issues inevitably confronting researchers wishing to explore existing data rather than design experimental protocols at the beginning.

Readers should therefore always be hesitant in their interpretations of the results and the credibility or faith that they put on the conclusions of such studies. The attitude should be: “that is interesting – now let’s design an experiment to test these hypothetical conclusions.”

The problem is confirmation bias – the willingness to give more credibility to the findings than is warranted. Scientists are only human and easily succumb to such biases in interpreting their own work. But this is even more true of political activists.

The reported relationships are weak. Important risk-modifying factors were probably not included in the statistical analyses. The observed relationships may simply mean that urinary fluoride is acting as a proxy for a more important risk-modifying factor (like nutrition) and the weak relationship may disappear when these are considered.

So scientific assessment of this study will be extremely hesitant – interpreting it, at best, as indicating need for more work and better designed research protocols.

But, of course, political activists will lap it up. It confirms their biases. Political activist organisations like the Fluoride Action Network are heavily promoting this paper – as they did with the earlier Bashash et al., (2016) paper.

But they are simply clutching at straws – as they often are when using science (or more correctly  misrepresenting and distorting the science) to support their political demands.

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A more convincing take on prenatal maternal dietary effects on child IQ

Image credit: Nutrition and Pregnancy: Choline For Baby’s Development

Prenatal maternal nutrition is more likely to influence child cognitive abilities than fluoride. A new paper shows this by considering the effects of good or bad prenatal nutrition for the women in the Basash et al., (2016)  study that anti-fluoride campaigners promote. The new data shows that nutrition is more important than fluoride.

The Bashash et al. (2016) reported a weak relationship between prenatal maternal urinary fluoride and child cognitive outcomes or IQ (see Fluoridation: “debating” the science?). Anti-fluoride campaigners latched on to the paper because it seems to offer critical “evidence” for their claims that community water fluoridation lowers IQ. They argue that IQ, rather than the risk of dental fluorosis, should be the main consideration when considering community water fluoridation.

But a new study shows that prenatal maternal nutrition is a better predictor of neurodevelopmental outcomes for children than is urinary fluoride. This study used data from the same set of Mexican women/child pairs as Bashash et al., (2016).

Here is the citation for the new study:

Malin, A. J., Busgang, S. A., Cantoral, A. J., Svensson, K., Orjuela, M. A., Pantic, I., … Gennings, C. (2018). Quality of Prenatal and Childhood Diet Predicts Neurodevelopmental Outcomes among Children in Mexico City. Nutrients, 10(8), 1093.

Misrepresentation  of the Bashash et al., (2016) study

I have dealt with this in a number of articles. Basically my argument was not with the study itself (although it obviously lacks consideration of important risk-factors in it statistical analysis) but with the way anti-fluoride activists use it to draw unwarranted conclusions.

A key problem they ignore is that the relationships reported by Bashash et al., 2016 can explain only about 3% of the variation in the cognitive measurements. This strongly suggests that the relationship with prenatal urinary fluoride would probably disappear if more important risk-modifying factors were included in the statistical analysis. My article “Predictive accuracy of a model for child IQ based on maternal prenatal urinary fluoride concentration.”  explains this and is available online.

The new Malin et al., (2108) study now provides some risk-modifying factors, specifically diet, which explains the data better than does urinary fluoride.

Readers wishing to refer back to my earlier posts on misrepresentation of the Bashash et al., (2106) study can read:

Diet as a predictor of neurodevelopmental outcomes

The statistical analyses in this new paper are quite complex because the authors considered nutrient mixture and not simply each nutrient in isolation. Their argument for this is that we consume nutrients as mixtures and that interactions between nutrients is always possible.

The study, therefore, looked at the relationship of different neurodevelopmental outcomes in the children with prenatal maternal diet. Initially the authors considered the predictive ability of nutrition by considering “good” or “bad” diets based on U.S. dietary guidelines.

A bad diet during pregnancy may harm your future child’s neurodevelopment. Credit: © ivanmateev / Fotolia

Good maternal prenatal nutrition had a significantly positive effect on all the neurodevelopmental outcomes measured. In contrast, poor nutrition had a significantly negative effect on all the outcomes (see table below). Weighted Quartile Sums (WQS) were used to create indices for the individual diets.

I compared the predictive ability of prenatal maternal nutrition used here with the prenatal maternal urinary F approach used by Bashash et al., (2016) using data digitally extracted from their supplemental figures (S1 and S2 – see below). This was for the verbal development score of the children. Unfortunately, this was the only individual data presented.

Clearly, there is a lot of scatter in the data – to be expected where a number of risk-modifying factors are involved. However, the data showing a positive effect of good maternal prenatal nutrition on the verbal score of the children explains 7.1% of the variation. The data for poor prenatal nutrition explains 11.2% of the variation.

Compare this with the predictive ability of the data present by Bashash et al., (2016) where maternal prenatal urinary fluoride could only explain 3% of the variation of the child cognitive scores (see Maternal urinary fluoride/IQ study – an update).

Malin et al., (2018) were able to show which nutrients contributed most to the positive or negative neurodevelopmental outcomes of the children. They concluded:

“mothers who consumed more nutritious diets during pregnancy tended to have children with more favorable neurodevelopmental outcomes, while mothers who consumed less nutritious diets and/or higher levels of sodium, saturated fat, and/or sugar during pregnancy tended to have children with poorer neurodevelopmental outcomes. This suggests that the consumption of more comprehensively nutritious prenatal diets favorably affects child  neurodevelopment, while the consumption of less comprehensively nutritious prenatal diets may hinder it.”

Individual nutrients affected specific neurodevelopmental factors but they reported that prenatal dietary thiamine, vitamin B6, monounsaturated fats, fibre and calcium had beneficial effects. In contrast, lower monounsaturated fat, lower thiamine, lower fibre and higher saturated fat were associated with lower neurodevelopmental scores for the children.

Conclusions

If anti-fluoride activists are really concerned about child IQ and other aspects of child neurodevelopment then they should be campaigning on the importance of nutrition during pregnancy and stop diverting us by scaremongering about community water fluoridation.

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Fluoridation: “debating” the science?

How the anti-fluoride activist envisages their debate challenge – their hero standing up against the might of the health authorities. Image credit: From the Coliseum to the Cage

New Zealand last week saw another “debate challenge” from anti-fluoride activists. But are their regular challenges serious? And do gladiatorial “debates” before partisan audiences have any value in science anyway?

These people often back away when their bluff is called. Their challenges have more to do with political tactics than any elaboration or clarification of the science. They appeal to the macho and combative attitudes of the intended audience.

One thing for sure, such “debates” do not advance scientific knowledge one iota – nor are they meant to.

The anti-fluoride hero is always victorious in the eyes of the partisan and faithful audience. Image credit: The Real Lives of the Gladiators of Rome – The Unfathomable Sport of Life and Death

Three Wise Men – the anti-fluoride activists Paul Connett, Declan Waugh and Vivyian Howard – visited New Zealand last week. Fluoride Free NZ (FFNZ) advertised these activists as “international experts . . .  “sharing the latest research.” Of course, the implications that these activists actually do any original research on fluoridation or what they were sharing was their own research were completely false.

 

This was just another one of those annual visits from Paul Connett (head of the US Fluoride Action Network) and his mates with the aim of misrepresenting and distorting the science so as to promote the political campaigns of the local anti-fluoridation brigade.

Anti-fluoride campaign puts all its eggs in the IQ basket

New Zealanders are rather tired of this sort of activism but the visit does represent an escalation. This year Three Wise Men, a few years back Two Wise men (Paul Connett and  Bill Hirzy) and before that just one wise man (Paul Connett). Is this a sign of increasing desperation as New Zealand moves ever so slowly to handing over decisions on community water fluoridation to District Health Boards? Or is it a sign of increased funding of the Fluoride Action Network and associated activist groups by the “natural”/alternative health industry? After all, it must cost a bit to send three spokespersons around the globe for just two meetings.

One thing I take from this activity is that the anti-fluoride movement has decided to put all its eggs in one basket – the IQ story. They won’t stop blaming fluoridation for all the ills of the world – from obesity to gender confusion. But they are deliberately making a determined effort to bring their IQ story onto centre stage.

The real experts and all the research indicate the main possible negative health effect which must be considered when planning introduction of fluoridation is mild forms of dental fluorosis. In contrast, anti-fluoride activists in the USA and NZ are attempting to present the main health effect that must be considered is a claimed decline in IQ.

The FFNZ advert shows this is the message the Three Wise Men were promoting in New Zealand. But the “latest research” they were “sharing” was not theirs but that of Basash et al., (2016). Or, rather, they were sharing a misrepresentaion and distortion of that research to fit their scarmongering claims.

I won’t repeat my analysis of the Bashash et al., (2016) paper and its misrepresentation here – readers can refer back to my articles:

A draft of my article critiquing the Bashash et al., (2016) paper, “Predictive accuracy of a model for child IQ based on maternal prenatal urinary fluoride concentration.” is also available online.

The predictable debate challenge

No visit by Paul Connett would be complete without a challenge to debate the science with him. He is frustrated with the fact that his audiences are almost completely faithful anti-fluoride activists. The academics, experts and health authorities did not turn up to his meeting at Otago University so he claims “they don’t feel any obligation whatsoever to debate the science” and ”to simply ignore us is unacceptable” (see Anti-fluoride campaigner invites university debate).

Similarly, he blamed others and claimed his anti-fluoride message was being ignored when only three MPs turned up for his meeting at the NZ Parliament Building last February. That was disingenuous as he had been given plenty of time for a presentation to the Health Committee during the consultations on the Fluoridation Bill last year. And MPs are regularly bombarded with huge amounts of propaganda from anti-fluoride activists. Obviously, MPs feel so inundated with such propaganda that they see no need to attend yet another meeting to hear the same old message.

Connett’s challenges to “debate the science” in front of a partisan audience have more to do with political propaganda and enthusing activists than with science. He knows scientific knowledge does not progress by holding gladiatorial circuses. It progresses by long, careful and detailed research, publication and peer review.

Neither of these Three Wise Men has performed any original research on community water fluoridation but they can still make their input via the peer review process – which include post-publication peer review via critiques of published papers.

To be fair, Connett and other members of the Fluoride Action network have occasionally presented such critiques. Two examples come to mind – the studies of  McLaren et al., (2016) and of Broadbent et al., (2015). These were critiqued in responses published in these same journals by a number of opponents of fluoridation. The original authors responded in the same journals. Arguments and extra data were presented in the responses and the science is better off for those critiques.

But science does not gain one iota from Connett’s attacks on the New Zealander Broadbent and other researchers in the media or in his meetings with the faithful. Such attacks and macho comments, often bordering on ad hominem, only discredit the attacker. They are not the way to discuss science and yet Paul Connett and his supporters challenge genuine scientists to participate in such “debates’ which are nothing more than testostorone-laden slanging matches.

A farcical example of a debate challenge

This time around I got personally involved because I called the bluff of activists making yet another debate challenge. It came out of an online discussion where I was attempting to correct some mistaken claims made by anti-fluoride activists. Here is the challenge:

Screenshot of my invite – just as well a have this as this Facebook page subsequently deleted the invitation and all comments I had made. I am officially a nonperson there.

A game of chicken followed where I attempted to get Fluoride Free NZ (FFNZ) and Paul Connett to formally stand behind the challenge. Chicken because I recognised it was a game. I had a scientific exchange (“debate”) with Paul four years ago – I think it was useful and I believe this is how good faith scientific discussions should take place (see Connett & Perrott, 2014: The Fluoride Debate for the full exchange). But Paul had made clear to me some time ago that he wanted no further contact with me.

Sure enough, FFNZ very quickly retreated from the possibility they had offered of a one on one debate. I emailed FFNZ:

“I think a one on one exchange would be best and as Paul and I have similar expertise he would be the logical discussion partner.”

Their response:

“No we will only agree to two on two.”

Paul confirmed that he would not debate one on one with me. I accepted a two on two “debate” but pointed out it was their responsibility, not mine, to organise the speakers. If they were not prepared to do that I suggested a two on one “debate” (especially as being the only speaker on one side this would give me extra presentation time) but made clear that I would effectively ignore Vyvyan Howard because our expertise did not cross over. (Vivyan agree with me that as he is a pathologist “you are correct that a direct discussion between us would be unbalanced.”)

I also made clear I would not tolerate any attempt to use that format to argue that I was isolated and could not find anyone else in New Zealand to support my arguments (an implication Paul made in our email exchange, and, of course, a claim being parroted by his supporters on social media).

Paul then formally withdrew. A pity as I love Wellington and was looking forward to a visit at someone else’s cost.

So a farce, But wait. there is more. The Facebook page, Rethink Fluoride, deleted their invitation to this “debate.” They then followed by deleting all my comments on their posts. Rather ironic as I had a few days before congratulated them by allowing open comments, and in particular allowing scientific comments – something all other anti-fluoride Facebook pages refused to allow.

Conclusion

Debate challenges by anti-fluoride activists are never genuine. They do not wish to discuss the science – they are simply using the challenges to enthuse their true-believing supporters. It is a form of attack on genuine researchers and health experts.

There is a time and place for good faith scientific exchange – post-publication peer review, for example, can give a genuine avenue for any real critiques to appear and be considered. Testosterone-laden gladiatorial debates before partisan audiences do not.

Anti-fluoride activists are disingenuously using these “debate challenges” to imply that experts and researchers have no confidence in their science and are afraid. It’s simply a macho tactic which often descends into ad hominem attacks.

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Anti-fluoride campaigners exhaust their legal channels with another loss

NZ Supreme Court Building, Wellington

The NZ Supreme Court has delivered its judgments and local anti-fluoride campaigners (and their big business supporters) seem to have come to the end of the line with their legal actions to prevent community water fluoridation (see Supreme Court rules against Taranaki anti-fluoride campaigners and Supreme Court rules South Taranaki fluoridation allowed).

Specifically, the Supreme Court delivered two judgments rejecting three appeals by NZ Health Inc. These appeals arose from High Court rejection of challenges by New Health NZ to prevent South Taranaki District Council from fluoridating drinking water in Patea and Waverly. While dealing with local situations these legal actions, ongoing since the end of 2012, inhibited other councils throughout New Zealand from making fluoridation decisions for fear of the cost involved in possible legal defences.

In effect, the Supreme Court judgements free up other councils to go ahead with fluoridation decisions, although the impending legislation transferring decision-making to District Health Boards may also cause delays.

The Supreme Court judgements were welcomed by health authorities and many New Zealanders concerned about the time wasting tactics used by anti-fluoride campaigners and their big business supporters.

Nature of the judgments

Court judgements can be complex but the Supreme Court provided a press release to help readers understand this case (see Fluoridation: New Health NZ v South Taranaki DC). This also provides a brief history of the legal actions since 2012.

Several things stand out to me.

The courts cannot rule on the science

The scientific arguments commonly presented by anti-fluoride campaigners are not considered in this judgement – this is as it should be. Courts do not decide the science.

Through this whole procedure lawyers for New Health NZ presented a litany of misrepresentations of the science we have come to expect from anti-fluoride campaigners. Apparently these campaigners are so used to relying on arguments misrepresenting the science they just could not help themselves even though the courts do not arbitrate on scientific matters.

I have always considered this somewhat strange. The strongest arguments that anti-fluoride campaigners can present relate to freedom of choice and the rights of minorities in social decisions. Yet they always seem to lead with misrepresentation and distortion of the science and only fall back to their strongest arguments when these misrepresentations are challenged by actual consideration of the science.

The statutory power of councils

New Health NZ argued that councils do not have the statutory authorisation to add fluoride to drinking water. The Supreme Court majority dismissed this ground for appeal. The dismissal was based on:

“the Council’s general power of competence in s 12 of the Local Government Act and in light of its duty under the Health Act to protect, promote and improve public health in its region. The relevant provisions had to be interpreted against the background that fluoridation had been lawful in New Zealand for decades prior to enactment.”

Claim that fluoridation breaches the NZ Bill of Rights.

On this question the Supreme Court:

“considered that the conferral of a statutory power to fluoridate water to levels prescribed by the drinking water standards was a justified limit on the right protected by s 11 of the Bill of Rights Act”

Or that:

“the Bill of Rights Act meant that local authorities could fluoridate water only where doing so in the particular district would be demonstrably justified in terms of s 5, an assessment which may depend on the local conditions.”

So, although there were subtle differences in the arguments of separate members of the court this claim by New Health NZ was rejected.

Not a unanimous decision

No doubt anti-fluoride activists will make much of the fact that there were differences between members of the Supreme Court on some details. I don’t think such differences are at all surprising or will necessarily give these asctivists the comfort they will attempt to derive from them. One of the judgements (NZSC59.pdf) gives detials of the arguments presented by sperate court members

The issues considered by the Court relate to interpretations of the Health Act and the NZ Bill of Rights. This involves considerations of ethical issues and the practical implementation of democratic procedures. There is no pre-ordained right or wrong answers to such matters and they are normally decided by prevailing procedures, ethical approaches and political matters.

It is possible to argue wither way on such issues. This is why I consider anti-fluoride campaigners make a mistake in their concentration on scientific matters which can easily be decided (and which they misrepresent) . If they put more effort into debating the ethical and political aspects they might have more success in winning people to their arguments and in achieving their political demands.

Who has been financing this legal action?

The Supreme Court press release describes New Health NZ, the anti-fluoride group which fronted the legal action, as a “consumer advocacy group.” This is factually wrong. New Health NZ was formed by the NZ Health trust to front such actions but the NZ Health Trust is, in fact, a lobby group for the “natural”/alternative health industry in New Zealand. It is effectively representing big business and not consumers. (Although, strangely, it has registered itself as a charity – perhaps this should be challenged by someone).

In fact, very few consumer advocacy groups could afford such legal action. The cost of defending against this action was substantial. South Taranaki mayor Ross Dunlop said the legal battle had cost the council at least $300,000-$350,000. The Ministry of Health assisted with funding but one can see how the fear of such legal costs has scared councils from making fluoridation decisions in the six years these issues have been before the High Court and then the Supreme Court. Even in this last case, the Supreme Court ordered New Health NZ to pay the Council only $20,000 towards costs.

The New Zealand Health Trust has funded, through New Health NZ, this legal battle to the tune of about $180,000 per year. I described this in my articles  Who is funding anti-fluoridation High Court action?,  Corporate backers of anti-fluoride movement lose in NZ High Court and Anti-fluoridationists go to Supreme Court – who is paying for this?

The financial returns from the NZ Health Trust and New Health NZ clearly show that money is flowing from the “natural”/alternative health industry (which is big business), via the NZ Health Trust (a lobby group for that industry) into New Health NZ which has then used it to find their anti-fluoridation legal activity to the tune of about $180,000 per year ($340,000 in 2017).

This graph shows the correspondence of grants received by New Health NZ with grants paid by the NZ Health Trust.

The size of the grants received by New Health NZ corresponds to payments for consultancy & professional fees. It is most likely this represents the funding used for the legal campaigns against community water fluoridation.

A clear example of big business funding trying to deny a safe and effective social health programme for New Zealanders

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Anti-fluoridation activists buy scientific credibility using a predatory publisher

A group of well-known anti-fluoride activists have just published some new research. Well, this is what their social media publicity will tell us.

In fact, this is not new research. It is simply the republication of a shonky paper from two years ago as a  chapter in a book produced by a predatory open access publisher.

It is a clear example of anti-fluoride activists attempting to buy scientific credibility. This book chapter cost them GBP £1400!

The “new” paper, or book chapter, anti-fluoride people will be promoting is this:

Hirzy, J. W., Connett, P., Xiang, Q., Spittle, B., & Kennedy, D. (2018). Developmental Neurotoxicity of Fluoride: A Quantitative Risk Analysis Toward Establishing a Safe Dose for Children. In J. E. McDuffie (Ed.), Neurotoxins (pp. 115–131). Rijeka: InTech.

In fact, this is simply a slight rehash of the paper published 2 years ago:

Hirzy, J. W., Connett, P., Xiang, Q., Spittle, B. J., & Kennedy, D. C. (2016). Developmental neurotoxicity of fluoride: a quantitative risk analysis towards establishing a safe daily dose of fluoride for children. Fluoride, 49(December), 379–400.

Almost word for word. And the authors acknowledge this at the beginning of the chapter with an introductory statement:

” This work has, in slightly different format, form and content been published in the journal Fluoride, Vol. 49(4 Pt 1):379–400, December 2016.”

I guess that saves me the job of critiquing this new version – my analysis and critique of the original paper was posted as the article  Debunking a “classic” fluoride-IQ paper by leading anti-fluoride propagandists. I also discussed the issues in other articles (see Connett & Hirzy do a shonky risk assessment for fluorideAnti-fluoride authors indulge in data manipulation and statistical porkies, and Anti-fluoridation campaigners often use statistical significance to confirm bias).

I have also submitted for publication a more formal critique of the original Hirzy et al., paper – see Does drinking water fluoride influence IQ? A critique of Hirzy et al. (2016)and  CRITIQUE OF A RISK ANALYSIS AIMED AT ESTABLISHING A SAFE DAILY DOSE OF FLUORIDE FOR CHILDREN.

Perhaps I will just repeat this qualification given by the authors in the first paper (and repeated in the book chapter), as it does call into question the whole campaign against community water fluoridation (CWF). They say:

“However, when comparing a fluoridated area of the USA to an unfluoridated area it would be hard to discern a mean IQ difference, because of the multiple sources of fluoride intake besides drinking water (Table 5). These sources greatly reduce the contrast in total fluoride intake between fluoridated and unfluoridated areas. A very high hurdle is thus created to gaining useful information in the USA, as it was in the New Zealand study [5], via a large, long-range longitudinal epidemiological study of fluoride and IQ.”

They are, in effect, accepting that no study of CWF has shown an IQ effect and argue that such studies will never show an  effect. Because, they argue, there is only a small difference in fluoride dietary intake between children in fluoridated and unfluoridated areas.

The fact that studies show no effect of fluoidation on IQ drives their need to “explain away” these results using dubious estimates of dietary intake. However they are essentially conceding there is no point campaigning against CWF. If they want to stick with their “explaining away” argument then, if anything, they should campaigning against other forms of dietary intake and leave CWF alone.

Scientific credibility

Anti-fluoridationists often argue that they have science on their side – and many of them seem to honestly believe it. Of course, when one is singing to the choir it is easy to delude oneself. The facts are that most claims made by anti-fluoride activists do not stand up to scientific scrutiny and when they cite scientific reports they are usually misrepresenting them.

I just wish these campaigners would sit down and actually read the papers they keep touting – very often they just do not say what is claimed for them.

On the other hand a small number of scientifically dubious papers do make their way into the scientific literature and these get used as “proof” by activists. Usually these are published in poor quality journals (like “Fluoride” where Hirzy et al., originally published their paper) and this is especially true when the authors are known anti-fluoride activists.

So, a combination of misrepresentation of the scientific literature and citation of poor quality papers get churned out again and again by campaigners to give scientific credibility to their arguments.

Shonky publishers

In my article Anti-fluoridation propagandists promoting shonky “review”, I discussed the use of shonky journals by anti-fluoride activists. These are usually open access journals which charge authors for publication and have very poor or non-existent peer review standards. I quoted one commenter as describing these journals as “bottom feeders,” but they, and their publishers, are often simply described as “predatory.”

bottom feeder

Some “peer-reviewed” journals really are “bottom-feeders.”

Predatory because these publishers scam researchers and exploit young or naive scientists, often from third world countries, who are impressed by the ease of publication and apparent distinction. An ease which is lubricated by author payments and little or no proper peer review.

Prospective authors can search lists identifying such predatory publishers and journals. So I did my own search and was not surprised to find that the IntechOpen publishers of the Hirzy et al., (2018) book chapter are on such lists. However, even a search of the IntechOpen website and their information for authors showed the signs typical of such predatory publishers. This is what IntechOpen will give you for your money (GBP – see Open Access Publishing Fees):

  • £1400 gets you a book chapter;
  • £4000 will get you a compact monograph, and
  • £10,000 will give you a long form monograph.

So, it looks like Bill Hirzy, Paul Connett, Quanyong Xiang, Bruce Spittle, and David Kennedy had a whip around (probably digging into the Fluoride Action Network funds) and produced £1400 to buy themselves some apparent “scientific credibility.”

I say apparent because more and more readers of scientific literature are becoming aware of the problem of poor quality journals and predatory open access publishers. Rather than providing scientific credibility, publication in such outlets may in fact leave a bad mark on a scientist’s reputation and credibility.

But I guess the politically motivated activists looking to confirm their biases will not care.

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Not just another rat study

A new high-quality study of the effect of fluoride on the memory and learning behaviour of rats has produced definitive results. Anti-fluoride campaigners had great hopes this study would bring an end to community water fluoridation (CWF) – but their hopes have been dashed.

The study showed no effect of fluoride on the memory, learning and motor skills of rats thus reinforcing the consensus that CWF is safe

Animal experiments are commonly used to investigate possible health effects of chemicals like fluoride. This enables strict research protocols without the ethical problems faced by human studies. Consequently, there have been a large number of investigations of the effect of fluoride on animals. Some of these have suggested harmful effects. The US anti-fluoride activist organisation, the Fluoride Action Network (FAN) lists 45 studies “where mice or rats treated with fluoride were found to suffer impairments in their learning and/or memory abilities” (see FLUORIDE AFFECTS LEARNING & MEMORY IN ANIMALS).

FAN claims these and similar studies as irrefutable evidence that CWF is harmful – particularly in their major campaign claiming CWF lowers IQ and should be stopped. However, a more scientific assessment is far less dogmatic.

The US National Toxicity Program (NTP) examined published research of potential neurological effects from fluoride exposures in experimental rodent animals in a systematic review published in 2016 (see Systematic literature review on the effects of fluoride on learning and memory in animal studies). They found many of the studies had limitations due to confounding in the learning and memory assessments and there was a lack of discrimination between motor and learning skills. Very few of the studies were made at drinking water concentrations relevant to CWF and the evidence for adverse effects was “low to moderate,” and weakest for animals during their developmental phase.

The NTP concluded further research was needed and undertook laboratory studies with rodents to fill the research gaps it had identified. Those studies are now complete and have been published in a research paper:

McPherson, C. A., Zhang, G., Gilliam, R., Brar, S. S., Wilson, R., Brix, A., … Harry, G. J. (2018). An Evaluation of Neurotoxicity Following Fluoride Exposure from Gestational Through Adult Ages in Long-Evans Hooded Rats. Neurotoxicity Research. Neurotoxicity Research.

The laboratory experiment

The authors used four treatments for the rats:

  • G1: Fed standard rodent chow;
  • G2: Fed low-fluoride chow;
  • G3: Fed low-fluoride chow + drinking water with 10 ppm F;
  • G4 Fed low-fluoride chow + drinking water with 20 ppm F.

Effects of drinking water F were determined by comparing results for G3 and G4 with G2.

The drinking water fluoride concentrations still seem high (compared with the recommended level of 0.75 ppm for CWF) but are lower than used in most earlier studies (often around 100 ppm). However, the basis for these choices was the use of the US secondary drinking water standard (2 ppm) and US UPA maximum contaminant level (4 ppm) and “the conventional wisdom that a 5-fold increase in dose is required to achieve comparable human serum levels.” However, this “wisdom” is debated as blood serum levels fluctuate.

These drinking water concentrations are still far higher than the recommended optimum level for CWF (0.75 ppm) so the results should be seen as more related to the defined upper limits than to CWF itself.

Behavioural assessments

A range of behavioural assessments was made. These included:

“motor, sensory, or learning and memory performance on running wheel, open-field activity, light/dark place preference, elevated plus maze, pre-pulse startle inhibition, passive avoidance, hot-plate latency, Morris water maze acquisition, probe test, reversal learning, and Y-maze.”

The purpose of using such a wide range was to overcome deficiencies of the measurements made in earlier studies and to fill in gaps. Animals at the developmental stage were included as most earlier studies had been made with adult rats.

“No significant differences observed”

One of the most commonly used phrases in this paper as the results are presented and discussed is that there were “no significant differences observed across groups.”

The authors note in their abstract that they “observed no exposure-related differences” in any of the behavioural tests listed above.

This result is important. The study is authoritative. The chosen experimental protocols resulted from an extensive systematic review of the earlier work which identified gaps and deficiencies. A very wide range of behavioural tests was used. And the experimental plans were discussed very widely before the experiments began.

We can conclude, therefore, that rodent experiments are unlikely to show behavioural effects related to fluoride exposure at the concentrations which, the authors argue, are relevant to the recommended maximum drinking water standard (2 ppm) and maximum contaminant level (4 ppm) for humans. The argument that this result is relevant to humans is strengthened by the possibility that ““the conventional wisdom that a 5-fold increase in dose is required” to make results relevant for humans may be inflated.

The argument is further strengthened for humans as the recommended drinking water fluoride concentrations for humans is even lower than the maximum drinking water standard and the maximum contaminant level.

Other assessments

The researchers also analysed thyroid hormones and examined collected tissues. They reported:

“No exposure-related pathology was observed in the heart, liver, kidney, testes, seminal vesicles, or epididymides.”

And:

No evidence of neuronal death or glial activation was observed in the hippocampus at 20 ppm F.”

In fact, the only statistically significant effects they found were a “mild inflammation in the prostate gland” and “evidence of mild fluorosis in adults” at 20 ppm F (treatment G4). Remember this level corresponds to the maximum contaminant level for humans and dental fluorosis has also been reported for humans at that concentration.

The anti-fluoride spin

Several years ago I discussed the planned NTP work and the reaction of anti-fluoride campaigners to it in my article Fluoride and IQ – another study coming up.

These campaigners seemed ecstatic about the planned NTP work, although I did comment:

“You wouldn’t think the anti-fluoride crowd would welcome such a careful analysis of the poor-quality articles they promote”

However, Fluoride Free NZ revealed the spin they placed on the NTP document describing the systematic review and the planned work in their press release at the time (see Fluoride-Brain Studies Set to Expose Fluoridation Damage):

“Results could mean the end to fluoridation world-wide, and definitely should put a halt to any plans to start fluoridation in places not currently fluoridated.

Because it is now well established that fluoride affects the brain, the NTP plans to conduct new animal studies to determine the lowest dose at which this damage occurs. They also plan to do a systematic review of all the existing scientific literature. To date, there have been 314 studies that have investigated fluoride’s effects on the brain and nervous system. These include 181 animal studies, 112 human studies, and 21 cell studies.”

I commented on this:

“The confirmation bias and dogmatic agenda stick out like a sore thumb – don’t expect these people to accurately report this study’s findings.”

Well, it seems that these campaigners are still stuck in dumb shock of the denial phase as they have yet to make any comment on these research results. When they do get around to overcoming their speechlessness they are going to be hard put to reconcile this denial with their earlier hopes for the research findings.

There is no way this study can be used to argue for “the end to fluoridation worldwide” or that there “definitely should” be “a halt to any plans to start fluoridation in places not currently fluoridated.

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Anti-fluoridationist Paul Connett misrepresents NZ data

Slide 110 from Paul Connett’s presentation prepared for his planned meeting at Parliament Buildings last February

Here is another post in my series critiquing a PowerPoint presentation of Paul Connett – a leading US anti-fluoridation activist.

Paul prepared this for a meeting in New Zealand Parliament buildings last February. Although only three MPs turned up his presentation is important as it summarises almost all the arguments used by anti-fluoridation activists.

Connett claims NZ data shows fluoridation ineffective

Connett argues the evidence community water fluoridation (CWF) is effective in reducing tooth decay is weak. He covers this in slides 96-110 but in this post I will deal only with the New Zealand evidence he uses (slides 108-110).  Paul’s presentation can be downloaded for those wishing to look at it in detail – see Prof Paul Connett Power Point Presentation to Parliament 22nd Feb 2018.

The total New Zealand evidence Connett presents for this is a graphic obtained from his NZ offsiders, Fluoride Free NZ (FFNZ):

We know how unreliable FFNZ is as a source and the data is obviously cherry-picked. But what is the truth? What do the NZ School Dental statistics really say about the oral health of children in NZ?

I have covered this before – FFNZ misrepresentation of the MoH data is an annual event occurring each time the Ministry of Health adds its annual summary of the data to their web pages.

For a change, here is a breakdown and discussion of the 2016 data prepared by Environmental Health Indicators NZ in association with Massey University:

“Children in fluoridated areas generally have better oral health”

“Children living in communities with fluoridated drinking-water generally had better oral health than children living in non-fluoridated communities.

In 2016, around 60 percent of 5-year-olds were caries-free in their primary teeth. Rates were similar in fluoridated communities (60 percent) and non-fluoridated communities (60 percent) (Figure 1).

More Māori and Pacific Island 5-year-olds were caries-free in fluoridated communities than in non-fluoridated communities in 2016. The largest difference can be seen for Māori children.

5-year-olds had on average 1.8 decayed, missing or filled primary teeth in 2016. Children living in fluoridated communities had less decayed, missing or filled teeth than children living in non-fluoridated communities (Figure 2).

This difference is particular large for Māori children. 5-year old Māori children had on average 2.5 decayed, missing or filled teeth in fluoridated communities compared to 3.3 decayed, missing or filled teeth in non-fluoridated communities in 2016.”

I am unable to embed the Environmental Health Indicators NZ graphs, but they are essentially the same I presented in my article Anti-fluoridationists misrepresent New Zealand dental data – an annual event so I reproduce that section of the article below:


What does the new data really say?

Let’s look at a summary of the data – for 5-year-olds and year 8 children – and for the different ethnic groups listed – Māori, Pacific Island and “other”(mainly Pakeha and Asian).  You can download the spreadsheets contain the data from the MoH web page – Age 5 and Year 8 oral health data from the Community Oral Health ServiceWe will look at the % of these children that a free from caries as well as the mean decayed, missing and filled teeth (dmft and DMFT) for each group.

5-year-olds

Notice the FFNZ cherry picking? Yes, the “Total” figures show very little difference but if they had dared look at different ethnic groups their argument would not have looked so great. Fluoridation appears to be associated with an improvement of dental health from about 6% (for “Other”) to 23% (for Māori)

Year 8 children

You can see why  FFNZ chose the 5-year-olds instead of year 8 children. Even the misleading data for the “Total” group suggests an almost 20% improvement of dental health in fluoridated areas.  Fluoridation appears to be associated with an improvement of dental health from about 18% (for “Other”) to 30% (for Māori).


What’s the problem with the 2009 Oral Health Survey?

Anti-fluoride activists love to hate this survey because it concluded:

“Overall, children and adults living in fluoridated areas had significantly lower lifetime experience of dental decay (ie, lower dmft/DMFT) than those in non-fluoridated areas. There was a very low overall prevalence of moderate fluorosis (about 2%; no severe fluorosis was found), and no significant difference in the prevalence of moderate fluorosis (or any of the milder.

“These findings support international evidence that water fluoridation has oral health benefits for both adults and children. In addition, these findings should provide reassurance that moderate fluorosis is very rare in New Zealand, and that the prevalence of any level of fluorosis was not significantly different for people living in fluoridated and non-fluoridated areas.”

Yes, it covers only the period up to 2008 and it would be good to get more recent high-quality data from a similar study.

But Connett’s accusation of “cherry-picked data” is simply wrong – and dishonest. In fact, scientific principles were used to obtain a representative sample for the survey – recognising that oral health is strongly influenced by ethnic, regional and fluoridation differences.

The methods used are explained in 22 pages of the report –  MoH. (2010). Our Oral Health Key findings of the 2009 New Zealand Oral Health Survey

In contrast, the annual School Dental Data is simply a record of overall findings. There is no attempt to standardise diagnostic and reporting methods to the standard of the Oral Health Survey or scientific studies.

But, of course, it provides a lot of data which can be cherry-picked to support a specific argument or confirm a bias. FFNSZ and Paul Connett have ignored all the known ethnic, social and regional differences in their cherry-picking. Consequently, their reported “findings” do not have credibility.

Conclusion

I think it is somewhat disrespectful of Paul Connett to include such a shonky bit of misrepresentation in a presentation prepared for members of parliament. It is also disrespectful in that he relies on his scientific qualifications, his Ph. D. to give “respectability” to a scientific argument which is so easily shown to be false.

Surely our members of parliament deserve something better than this.

Although, even with members of parliament, I guess the old adage “reader (or listener) beware” applies. Sensible MPs will not accept such assurances at face value and will seek out adive=ce on such matters from their officials and experts.

I guess we should feel pretty confident that most of our MPs are sensible in this repect. The fact they did not turn up to a meeting to hear someone well-known for misrepresenting the science is telling – and this despite the fact that anti-fluoride activists were exerting strong pressure on MPs to attend.

Politicians have experienced, and learned from, excessive lobbying, pressuring and untruthful submissions precisely because of their targeting by anti-science activist groups like FFNZ. They know this is why local councils wanted the central government to take over fluoridation decisions.

I suspect our parliamentary politicians are a little more mature than our local body politicians and now  treat such organised campaigns like water off a duck’s back.

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Anti-fluoridationists rejection of IQ studies in fluoridated area.

US anti-fluoride activist Paul Connett claims studies cannot detect an IQ effect from fluoridated water because total fluoride intake is the real problem – but still campaigns against community water fluoridation. Image credit: MSoF “Activist Spouts Nonsense – The Evidence Supports Fluoridation”

This is another article in my critique of the presentation Paul Connett prepared to present to a meeting at Parliament in February.

I deal with his coverage of the studies of IQ effects where community water fluoridation (CWF) is used. There are now actually three such studies (Broadbent et al. 2015, Barberio et al. 2017  and  Aggeborn & Öhman 2016), but Connett pretends there is only one – the Broadbent et al. (2015) New Zealand study.

Maybe because it was the first one to provide evidence challenging his extrapolation of the fluoride/IQ studies (see The 52 IQ studies used by anti-fluoride campaigners) results in areas of endemic fluorosis to areas where CWF is used. It is also the study which seems to have resulted in the most hostility from anti-fluoride campaigners.

So here I will just be sticking with his criticism of the New Zealand study Broadbent et al (2015):

Slide 76 from Paul Connett’s presentation prepared for his February meeting at  parliament buildings

Broadbent’s findings do not “negate all other human studies”

Paul allows emotion to get the better of him as no one is suggesting this at all. The studies Connett refers to are all from areas of endemic fluorosis (see  The 52 IQ studies used by anti-fluoride campaigners), not from areas of CWF.

Broadbent et al (2015) simply concluded that their “findings do not support the assertion that fluoride in the context of CWF programmes is neurotoxic.”  That is a modest statement and Broadbent et al. (2015) simply do not draw any conclusions about the studies Connett relies on. But, of course, Connett is upset because this and similar studies just do not support his attempt to extrapolate results from areas of endemic fluorosis to areas of CWF.

The health problems suffered by people in areas of endemic fluorosis are real and it is right they should be studied and attempts made to alleviate them. But this has absolutely nothing to do with CWF.

“Fatally flawed” charge is itself fatally flawed

Again, Paul has allowed emotions to get the upper hand. It is possible, and necessary, to critique published papers – but critiques should be evidence-based and realistic. Paul’s “fatally flawed” charge (slides 77 & 78) simply displays how much this paper has put his nose out of joint.

But let’s look at the specific “flaws” Paul (and other critics associated with the Fluoride Action Network) claim.

The two villages mindset: Paul alleges that the Broadbent et al (2015) study “essentially compared two groups.” He is stuck in the mindset of most of his 52  studies from areas of endemic fluorosis (see  Fluoride & IQ: The 52 Studies). The mindset of simply comparing the IQ levels of children in a village suffering endemic fluorosis with the IQ levels of children in a village not suffering endemic fluorosis. This simple approach can identify statistically significant differences between the villages but provides little information on causes. For example, most of these studies used drinking water fluoride as a parameter but there could be a whole range of other causes related to health problems of fluorosis.

Professor Richie Poulton, current Director of the Dunedin Multidisciplinary Health and Development Research Unit

In contrast, Broadbent et al. (2015) used “General Linear models to assess the association between CWF and IQ in childhood and adulthood, after adjusting for potential confounders.” The statistical analysis involved includes accounting for a range of possible risk-modifying factors besides CWF., This was possible because the study was part of the Dunedin Multidisciplinary Health and Development Study. This is a highly reputable long-running cohort study of 1037 people born in 1972/1973 with information covering many areas.

The fluoride tablets argument: Connett and other critics always raise this issue – the fact that “In New Zealand during the 1970s, when the study children were young, F supplements were often prescribed to those living in unfluoridated areas.” Often they will go further to claim that all the children in the unfluoridated area of this study were receiving fluoride tablets – something they have no way of knowing.

But the fact remains that fluoride tablets were included in the statistical analysis. No statistically significant effect was seen for them.  Overlap of use of fluoride tablets with residence in fluoridated or unfluoridated areas will have occurred and their influence would be reflected in the results found. Presumably, the effect would be to increase the confidence intervals. As the critics, Menkes et al. (2014), say “comparing groups with overlapping exposure thus compromises the study’s statistical power to determine the single effect of CWF.”  I agree. But this does not negate the findings which are reported with the appropriate confidence intervals (see below).

The point is that the simplistic argument that effects of fluoride tablets were ignored is just not correct. Their effect is reflected in the results obtained.

Potential confounders: Many poor quality studies have ignored possible confounders, or considered only a few. This is a general problem with these sort of studies – and even when attempts are made to include all that the researchers consider important a critic can always claim there may be others – especially if they do not like the results. Claims of failing to consider confounders can often be simply the last resort of armchair critics.

In this case, there is no actual reported association to be confounded (unlike my identification of this problem with the Malin & Till 2015 ADHD study – see Perrott 2017). However, Osmunson et al. (2016) specifically raised possibilities of confounding by lead, manganese, mother’s IQ and rural vs urban residence. Mekes et al. (2014) also raised the rural vs urban issue as well as a possible effect from breastfeeding reducing fluoride intake by children in fluoridated areas.  In their response, Broadbent et al (2015b & 2016) reported that a check showed no significant effect of lead or distance from the city centre and pointed out that manganese levels were too low to have an effect. Broadbent et al (2015b) also reported no significant breastfeeding-fluoride interaction occurred.

Numbers involved: Connett claims the study was fatally flawed because “it had very few controls: 991 lived in the fluoridated area, and only 99 in non-fluoridated” (Slide 77). But the numbers are simply given by the longer term Dunedin study themselves – they weren’t chosen by Broadbent and his co-workers. That is the real world and is hardly a “fatal flaw.”

The 95% confidence intervals

Yes, statisticians always love to work with the large numbers but in the real world, we take what we have. Smaller numbers mean less statistical confidence in the result – but given that Broadbent et al (2015) provides the results, together with confidence intervals, it is silly to describe this as fatally flawed. These were the results given in the paper for the parameter estimate of the factors of interest:

Factor Parameter estimate 95% Confidence interval p-value
Area of residence -0.01 -3.22 to 3.20 .996
Fluoride toothpaste use 0.70 -1.03 to 2.43 .428
Fluoride tablets 1.55 -0.38 to 3.49 .116

Connett did not refer to the confidence intervals reported by Broadbent et al (2015). However, Grandjean and Choi (2015) did describe them as “wide” – probably because they were attempting to excuse the extrapolation of “fluoride as a potential neurotoxic hazard” from areas of endemic fluorosis to CWF.

The argument over confidence intervals can amount to straw clutching – a “yes but” argument which says “the effect is still there but is small and your study was not large enough to find it.” That argument can be never ending but it is worth noting that Aggeborn & Öhman (2016) made a similar comment about wide confidence intervals for all fluoride/IQ studies, including that of Broadbent et al. (2015).  Aggeborn & Öhman (2016) had a very large sample (almost 82,000 were involved in the cognitive ability comparisons) and reported confidence intervals of -0.18 to 1.03 IQ points (compared with -3.22 to 3.20 IQ points reported by Broadbent et al 2015). Based on this they commented, “we are confident to claim that we have estimated a zero-effect on cognitive ability.”

The “yes but” argument about confidence intervals may mean one is simply expressing faith in an effect so small as to be meaningless.

Total fluoride exposure should have been used: Connett says (slide 77) “Broadbent et al did not use the proper measure of fluoride exposure. They should have used total F exposure.  Instead, they used only exposure from fluoridated water.” Osmunson et al. (2016) make a similar point, claiming that the study should not have considered drinking water fluoride concentration but total fluoride intake. They go so far as to claim “the question is not whether CWF reduces IQ, but whether or not total fluoride intake reduces IQ.”

This smacks of goalpost moving – especially as the argument has specifically been about drinking water fluoride and most of the studies they rely on from areas of endemic fluorosis specifically used that parameter.

In their response to this criticism Broadbent et al (2016) calculated estimates for total daily fluoride intake and used them in their analysis which “resulted in no meaningful change of significance, effect size, or direction in our original findings.”

It’s interesting to note that Connett and his co-workers appear to miss completely the point about “wide” confidence intervals made by Grandjean and Choi (2015). Instead, they have elevated their argument to the claim that fluoride intake is almost the same in both fluoridated and unfluoridated areas so that any study will not be able to detect a difference in IQ. Essentially they are claiming that we are all going to suffer IQ deficits whether we live in fluoridated or unfluoridated areas.

This is the central argument of their paper – Hirzy et al (2016). However, the whole argument relies on their own estimates of dietary intakes – a clear example where motivated analysts will make the assumptions that fit and support their own arguments. This argument also fails to explain why the Dunedin study found lower tooth decay in fluoridated areas.

Last time I checked the anti-fluoride campaigners, including Connett, were still focusing on CWF – fluoride in drinking water. One would think if they really believed their criticism that they would have given up that campaign and instead devoted their energies to the total fluoride intake alone.

Conclusions

All studies have limitations and of course, Broadbent et al. (2015) is no exception. However, the specific criticisms made by Connett and his fellow critics do not stand up to scrutiny. Most have been responded to and shown wrong – mind you this does not stop these critics from continuing to repeat them and disregard the responses.

I believe the relatively wide confidence intervals could be a valid criticism – although it does suggest a critic who is arguing for very small effects. A critic who may always find the confidence intervals still exclude their very small effect – no matter how large the study is.

In effect, the narrow confidence intervals reported by Aggeborn & Öhman (2016) should put that argument to rest for any rational person.

References

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

Barberio, A. M., Quiñonez, C., Hosein, F. S., & McLaren, L. (2017). Fluoride exposure and reported learning disability diagnosis among Canadian children: Implications for community water fluoridation. Can J Public Health, 108(3),

Broadbent, J. M., Thomson, W. M., Ramrakha, S., Moffitt, T. E., Zeng, J., Foster Page, L. A., & Poulton, R. (2015). Community Water Fluoridation and Intelligence: Prospective Study in New Zealand. American Journal of Public Health, 105(1), 72–76.

Broadbent, J. M., Thomson, W. M., Moffitt, T., Poulton, R., & Poulton, R. (2015b). Health effects of water fluoridation: a response to the letter by Menkes et al. NZMJ, 128(1410), 73–74.

Broadbent, J. M., Thomson, W. M., Moffitt, T. E., & Poulton, R. (2016). BROADBENT ET AL. RESPOND. American Journal of Public Health, 106(2), 213–214. https://doi.org/10.2105/AJPH.2015.302918

Grandjean, P., Choi, A. (2015). Letter: Community Water Fluoridation and Intelligence. Am J Pub Health, 105(4).

Hirzy, J. W., Connett, P., Xiang, Q., Spittle, B. J., & Kennedy, D. C. (2016). Developmental neurotoxicity of fluoride: a quantitative risk analysis towards establishing a safe daily dose of fluoride for children. Fluoride, 49(December), 379–400.

Malin, A. J., & Till, C. (2015). Exposure to fluoridated water and attention deficit hyperactivity disorder prevalence among children and adolescents in the United States: an ecological association. Environmental Health, 14.

Menkes, D. B., Thiessen, K., & Williams, J. (2014). Health effects of water fluoridation — how “ effectively settled ” is the science? NZ Med J, 127(1407), 84–86.

Osmunson, B., Limeback, H., & Neurath, C. (2016). Study incapable of detecting IQ loss from fluoride. American Journal of Public Health, 106(2), 212–2013.

Perrott, K. W. (2017). Fluoridation and attention deficit hyperactivity disorder – a critique of Malin and Till ( 2015 ). Br Dent J.

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A conference paper on the maternal neonatal urinary fluoride/child IQ study has problems

Image credit: Do new mothers doing a Ph.D. get enough support?

The anti-fluoride movement has certainly mobilised over the neonatal maternal urinary fluoride study which reported an association with child IQ. They see it as the best thing since sliced bread and believe it should lead to the end of fluoridation worldwide.

They also seem to be putting all their eggs in this one basket and have started a campaign aimed at stopping pregnant women from drinking fluoridated water (See Warning to Pregnant Women: Do Not Drink Fluoridated Water).

So I was not surprised to see a newsletter this morning from the Fluoride Action Network reporting another output from this study – a conference paper (most likely a poster) presented at the  3rd Early Career Researchers Conference on Environmental Epidemiology. The meeting was in Freising, Germany, on 19-20 March 2018.

I had been aware of the poster for the last week so had expected FAN to gleefully jump on it and start promoting it in their campaigns.

Here is a link to the abstract:

Thomas, D., Sanchez, B., Peterson, K., Basu, N., Angeles Martinez-Mier, E., Mercado-Garcia, A., … Tellez-Rojo, M. M. (2018). Prenatal fluoride exposure and neurobehavior among children 1-3 years of age in Mexico. Occupational and Environmental Medicine, 75(Suppl 1), A10–A10.

It’s only an abstract and it may be some time before a formal paper is published, if at all. Posters do not get much in the way of peer review and often not followed by formal papers.  So I can’t say much about the poster at this stage as I never like to make an assessment of studies on the basis of abstracts alone.

But, in this case, I have Deena Thomas’s Ph.D. thesis which was the first place the work was reported. If you are interested you can access it from this link:

Thomas, D. B. (2014). Fluoride exposure during pregnancy and its effects on childhood neurobehavior: a study among mother-child pairs from Mexico City, Mexico. University of Michigan.

I will wait for a formal paper before properly critiquing the poster, but at the moment I find a big discrepancy between the Thesis conclusions and the conclusions presented in the poster abstract.

Thesis conclusions

In her work, Deena Thomas used the Mental Development Index (MDI) which is an appropriate way of determining neurobehavioral effects in young children.

She concluded in her thesis (page 37):

“Neither maternal urinary or plasma fluoride was associated with offspring MDI scores”

And (page 38):

“This analysis suggests that maternal intake of fluoride during pregnancy does not have a strong impact on offspring cognitive development in the first three years of life.”

And further (page 48):

“Maternal intake of fluoride during pregnancy does not have any measurable effects on cognition in early life.”

So – no association found of child MDI score with maternal neonatal urinary F concentrations.

Poster conclusions

But the poster tells a different story.

The abstract concluded:

“Our findings add to our team’s recently published report on prenatal fluoride and cognition at ages 4 and 6–12 years by suggesting that higher in utero exposure to F has an adverse impact on offspring cognitive development that can be detected earlier, in the first three years of life.”

So her conclusions reported in her thesis are exactly the opposite of the conclusions reported in her conference poster!

What the hell is going on?

The data

Obviously, I do not have access to the data and she does not provide it in her thesis. But from her descriptions of the data in her thesis and her poster perhaps we can draw some tentative conclusions.

The table below displays the data description, and a description of the best-fit line determined by statistical analysis, in her thesis and her poster.

Information on data Thomas Ph.D. Thesis Conference abstract
Number of mother/child pairs 431 401
Maternal Urinary F range (mg/L) 0.110 – 3.439 0.195 – 3.673
Mean maternal urinary F (mg/L) 0.896 0.835
Model β* -0.631 -2.40
Model p-value 0.391 – Not significant
95% CI for β -4.38 to -0.40

*β is the coefficient, or slope, of the best-fit line

Conclusions

Apparently at least 30 data pairs have been removed from her thesis data to produce the dataset used for her poster. Perhaps even some data pairs were added (the maximum urinary F value is higher in the smaller data set used for the poster).

This sort of change in the data selected for the statistical analysis could easily swing the conclusion from no effect to a statistically significant effect. So the reasons for the changes to the dataset are of special interest.

Paul Connett claims this poster “strengthens” the findings reported in the Bashash paper.  He adds:

“This finding adds strength to the rapidly accumulating evidence that a pregnant woman’s intake of fluoride similar to that from artificially fluoridated water can cause a large loss of IQ in the offspring.”

But this comes only by apparently removing the conflicting conclusions presented in Deela Thomas’s Ph.D. thesis. We are still left with the need to explain this conflict and why a significant section of the data was removed.

To be clear – I am not accusing Thomas et al. (2018) of fiddling the data to get the result they did. Just that, given the different conclusions in her thesis and the poster,  there is a responsibility to explain the changes made to the dataset.

From the limited information presented in the poster abstract, I would think the scatter in the data could be like that seen in the Bashash et al. (2017) paper. The coefficient of the best fit line (β) is relatively small and while the 95% CI indicates the fit is statistically significant its closeness to zero suggest that it is a close thing.

However, let’s look forward to getting better information on this particular study either through correspondence or formal publication of a research paper.

Other articles on the Mexican study

Fluoride, pregnancy and the IQ of offspring,
Maternal urinary fluoride/IQ study – an update,
Anti-fluoridation campaigners often use statistical significance to confirm bias,
Paul Connett “updates” NZ MPs about fluoride?
Paul Connett’s misrepresentation of maternal F exposure study debunked,
Mary Byrne’s criticism is misplaced and avoids the real issues

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The 52 IQ studies used by anti-fluoride campaigners

Slide number 30 from Paul Connett presentation prepared for a talk at NZ Parliament buildings in February 2018.

Continuing my critique of the presentation prepared by Paul Connett for his much-publicised meeting at Parliament Building in February. The meeting attracted only three MPs but his presentation is useful as it presents all the arguments anti-fluoride campaigners rely on at the moment.

My previous articles on this presentation are Anti-fluoride activist commits “Death by PowerPoint” and Paul Connett’s misrepresentation of maternal F exposure study debunked.

In this article, I deal with the argument presented in the slide above. it is an argument repeated again and again by activists. Connett has posted a more detailed list of these studies and his description of them in Fluoride & IQ: The 52 Studiesat the Fluoride Action Network website.

Studies in areas of endemic fluorosis

All the 52 studies comment refers to are from regions of endemic fluorosis in countries like India, China, Mexico and Iran where dietary fluoride intake is above the recommended maximum level. People in these areas suffer a range of health problems and studies show cognitive deficits as one of them. However, a quick survey of Google Scholar shows this concern is well down the list (See Endemic fluorosis and its health effects). Only 5% of the Google Scholar hits related to health effects of endemic fluorosis considered IQ effects.

People in high fluoride areas where fluorosis is endemic suffer a range of health problems. Credit: Xiang (2014)

In, most, but not all, cases the major source of fluoride in the diet is drinking water with high fluoride levels (above the WHO recommended 1.5 mg/L). Paul Connett’s logic is simply to extrapolate to low drinking water fluoride concentrations typical of community water fluoridation (CWF). However, we do not see the other health effects like severe dental fluorosis, skeletal fluorosis, etc., where CWF is used.

His logic also ignores the possibility that cognitive deficits may result from other health problems common in areas of endemic fluorosis. Problems such as premature births and low birth weight, skeletal fluorosis or even the psychological effect of unsightly teeth due to severe dental fluorosis.

Comparing “high” fluoride villages with “low” fluoride villages

This approach is simplistic as it simply compares a population suffering fluorosis with another population not. Yes, the underlying problem is the high dietary intake (mainly from drinking water) in the high fluoride villages – but that does not prove fluoride in drinking water is the direct cause of a problem. The examples discussed above, eg., low birth weights or premature births, could be the direct cause.

It is easy to show statistically significant differences of drinking water fluoride and a whole host of fluorosis related diseases between two villages but that, in itself, does not prove that drinking water fluoride is the direct cause. Nor does it justify extrapolating such results to other low concentrations situations typical of CWF.

Paul Connett’s logic ignores the fact that in most of these studies the “low” fluoride villages (which the studies were treating as the control or normal situations where IQ deficits did not occur) had drinking water fluoride concentrations like that used in CWF. It also ignores, or unjustly attempts to dismiss) studies which show no cognitive deficits related to CWF.

A low fluoride concentration study showing an IQ effect

After making a big thing about the large numbers of studies and being challenged by the high fluoride concentrations involved Connett normally goes into a “yes, but” mode and attempts to transfer that credibility of “large numbers” to the very few studies which report effects at low fluoride concentrations.

He usually makes a big thing of the study by Lin et al (1991):

Lin Fa-Fu, Aihaiti, Zhao Hong-Xin, Lin Jin, Jiang Ji-Yong, M. (1991). THE RELATIONSHIP OF A LOW-IODINE AND HIGH- FLUORIDE .ENVIRONMENT TO SUBCLINICAL CRETINISM lN XINJIANG. Iodine Deficiency Disorder Newsletter, 24–25.

Connett claims this study shows a lower IQ when the drinking water F concentration was 0.88 ppm, but the areas suffered from iodine deficiency which is related to cognitive deficits.

The study I reviewed recent by Bashash et al (2017) (see Paul Connett’s misrepresentation of maternal F exposure study debunked) is also on Connett’s list. He doesn’t mention, however, that while an association of child IQ with prenatal maternal urinary fluoride was reported the paper also reported there was no observed association of child IQ with child urinary fluoride concentrations.

Studies not showing an effect

Connett lists 7 studies which showed no effect on IQ. One of these was the well-known Broadbent et al., (2014) study from New Zealand, which he, of course, proceeds to debunk in an irrational and not very truthful manner.

He does not mention the studies from Canada (Barberio et al. 2017 ) and Sweden (Aggeborn & Öhman 2016) which also show no effect of CWF on IQ.

The 6 other studies listed are all Chinese, and not translated. Interesting because Connett’s Fluoride Action Network invested money and time into translating obscure Chinese papers that could support their argument of harm. They obviously did not bother translating those papers which did not confirm their bias.

Conclusion

So, Connett’s 52 studies are rather a waste of time. Based in areas of endemic fluorosis their findings are not transferable to areas where CWF is used. The quality of most papers is low and, usually, the studies are simply a comparison of two villages, one where fluorosis is endemic and the “control” village where it isn’t but drinking water concentrations are like that used in CWF.

Connett simply is not able to properly evaluate, or in some cases even consider, studies which show no effect of fluoride on IQ or were made in areas where CWF exists and no effects are shown.

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