Tag Archives: fluoride

If at first you don’t succeed . . . statistical manipulation might help

Anti-fluoride campaigners are promoting yet another new study they claim shows community water fluoridation lowers children’s IQ. For example, the Fluoride Free NZ (FFNZ) press release Ground Breaking Study – Fluoridated Water Lowers Kid’s IQs which claims the study confirms“our worst fears, linking exposure to fluoridated water during pregnancy to lowered IQ for the developing child.”

Yet the study itself shows no significant difference in children whose mothers lived in fluoridated or unfluoridated areas during pregnancy. Here is the relevant data from Table 1 in the paper:

Mean IQ of children whose mothers drank fluoridated or unfluoridated water during pregnancy (SD =  11.9 – 14.7)

Nonfluoridated Fluoridated
All children 108.07 108.21
Boys 106.31 104.78
Girls 109.86 111.47

The differences between fluoridated and nonfluoridated are not statistically significant.

The paper has just been published and is:

Green, R., Lanphear, B., Hornung, R., Flora, D., Martinez-Mier, E. A., Neufeld, R., … Till, C. (2019). Association Between Maternal Fluoride Exposure During Pregnancy and IQ Scores in Offspring in Canada. JAMA Pediatrics, 1–9.

Surprisingly the authors do not discuss the data in the table above. Its as if the data didn’t exist, despite being given in their Table 1. I find this surprising because their discussion is aimed at finding a difference – specifically, a decrease in child IQ due to fluoridation – and surely these mean values must be relevant. Were the authors embarrassed by these figures because they did not show the effect they wanted?

So how did they manage to find an effect they could attribute to fluoride, or fluoridation, despite the mean values above? They basically resort to statistical manipulation – and this has opened up an intense controversy about the paper.

An unprecedented “Editor’s Note”

The journal editor, Dimitri A. Christakis, published a note alongside the paper (see Decision to Publish Study on Maternal Fluoride Exposure During Pregnancy), together with a piece in the Opinion section by David C. Bellinger (see Is Fluoride Potentially Neurotoxic?). This opinion piece is described as an editorial although Bellinger is not an editor of the journal or on the Editorial Board.

This is, in my experience, completely unprecedented. Editor’s don’t comment on the quality of papers or the refereeing process and I can only conclude that within the journal editorial board and those who reviewed the paper there were sharp differences about its quality and whether it should be published. While an editorial may sometimes bring attention to an article, in this case, it is likely that Bellinger was one of the reviewers of the paper and he is expressing his viewpoint on it and supports its publication.

Christakis writes “The decision to publish this article was not easy.” He goes on to imply the journal supports publication “regardless of how contentious the results may be.”  But surely there is no need to defend a good quality paper in this way just because the results may be “contentious.”

Interestingly, FFNZ interpreted the publication of the Editor’s note as making the publication of the paper more “impactful” not realising that the Note is probably not positive for the paper as it reveals controversy over the paper’s quality and whether it was worthy of publication. FFNZ also chose to describe Bellinger’s comments in his opinion piece as representing the views of the authors. However, it would be inappropriate for an editor to make such comments.

I think Bellinger has his own biases and preferences which lead him to advocate for papers like this. I commented on Bellinger’s role in the review of another paper promoting an anti-fluoride perspective in my articles Poor peer-review – a case study and Poor peer review – and its consequences.

A large amount of controversy

I am surprised at the degree of controversy around this paper – and it’s loudness. The fact that it started on the same day the paper was made public reveal various actors have had access to the paper and have been debating it for some time.  This could have been stoked by the unorthodox statistical analysis used and contradictions in the findings.

But it appears this controversy had gone far wider than the journal editors and reviewers of the paper because of the immediate reactions from anti-fluoride organisations like the Fluoride Action Network (see BREAKING: GOVERNMENT-FUNDED STUDY LINKS FLUORIDATED WATER DURING PREGNANCY TO LOWER IQS IN OFFSPRING), some leading Newspapers,  professional bodies (see AADR Comment on Effect of Fluoride Exposure on Children’s IQ Study) and the UK Science Media Centre which published a reaction from experts article (see expert reaction to study looking at maternal exposure to fluoride and IQ in children).

This suggests to me a large degree of lobbying. Not only from activists and anti-fluoride scientists or reviewers. But also from authors and their institute. I am not really surprised as I have often seen how politics, activism, commercial interests, and scientific ambitions will coordinate in these situations.

How to discover an effect from a nonsignificant difference

So how do we get from the data in the table above – showing no statistically significant difference between fluoridated and unfluoridated areas – to a situation where the authors (who don’t refer to that data in their discussion) say:

“higher levels of fluoride exposure during pregnancy were associated with lower IQ scores in children measured at age 3 to 4 years. These findings were observed at fluoride levels typically found in white North American women. This indicates the possible need to reduce fluoride intake during pregnancy.”

In their press releases and statements to media, where they are not constrained by a journal’s need for evidence and objectivity, they come out even more vocally against community water fluoridation.

Well, it appears to me, by statistical manipulation. One of the Science Media experts referred to above, Prof Thom Baguley, wrote:

“First, the claim that maternal fluoride exposure is associated with a decrease in IQ of children is false. This finding was non-significant (but not reported in the abstract). They did observe a decrease for male children and a slight increase in IQ (but non-significant) for girls. This is an example of subgroup analysis – which is frowned upon in these kinds of studies because it is nearly always possible to identify some subgroup which shows an effect if the data are noisy. Here the data are very noisy.”

It appears the authors found a significant effect of child sex on IQ so made a decision to do a subgroup analysis – of boys and girls – and this produced a significant association of IQ with maternal urinary fluoride for the boys. This resort to subgroup analysis may have, in itself, produced a misleading significant relationship.

Adam Krutchen, Biostatistics PhD student at the University of Pittsburgh, also illustrates how the relationship with child sex has confused the analysis. He comments on the data that he managed to extract from the paper’s Figure 3:

“There were drastic sex-specific IQ differences in the children, which is of course strange. We shouldn’t expect anything like that to happen. This difference is very significant. There’s also some outlier extremely low IQ values among the male children.”

He is saying that his regression analysis showed a strong effect of child sex on IQ. This is quite irrespective of maternal urinary F or drinking water F. However, once that effect of child sex is taken into account he found no relationship of child IQ with maternal urinary F. He says:

“with such a significant effect of sex on IQ, does fluoride have any remaining relationship? The answer is a resounding no in the digitized data.”

It appears that including child sex difference in the regression analysis produces the finding that there is no significant relationship of fluoride to child IQ after taking into account the significant relationship of IQ with child sex. But when the data is divided into subgroups and analysed separately (a technique statisticians “frown on” “because it is nearly always possible to identify some subgroup which shows an effect if the data are noisy”) a significant relationship of IQ with maternal urinary fluoride can be produced for boys (but not girls).

Interestingly, a second part of the Green et al., (2019) study investigated a relationship of child IQ with unverified estimated fluoride intake by the pregnant mothers. The estimation method was not verified so may be questionable). No sex difference appeared in that data set.

How strong are the reported relationships

Perhaps it is not necessary to go any further. Perhaps the data for mean IQ in the table above is sufficient to show there is no effect of fluoride on IQ. Or perhaps the critique of the analysis of subgroups used is sufficient to make the reported conclusions suspect.

However, perhaps a comment on the weakness of the relationships reported by Green et al is useful – if only because I took the trouble to digitally extract the data from the figures in the paper and do my own regression analyses on the data.

Of course, digital extraction does not get all the data – even if only because the points may merge. In this case, I managed to extract 410 data points from Figure 3A which showed the relationships of child IQ with the maternal urinary F concentrations during pregnancy. This is quite a bit smaller than the 512 data pairs the authors reported in their Table 1 and suggests to me they had not plotted all their data. However, the values for means and coefficients obtained by my own regression were very similar to those reported by Green et al., (2019).

The authors reported a significant (p=0.02) negative relationship of boy’s IQ with maternal urinary F. They do not discuss how strong that relationship is – although the wide scatter of data points in the figures suggest it is not strong. My regression analysis showed the relationship explained only 1.3% of the variance in IQ. I do not think that is worth much. With such low explanatory power, I think the authors overstate their conclusions.

I think this is another case of placing far too much reliance on p-values and ignoring other results of the statistical analysis. I discussed this in a previous article – see Anti-fluoride activists misrepresent a new kidney/liver study).

Conclusions

I think this paper has been overblown. It has problems with its statistical analyses as well as other limitations referred to in the paper. I do not think it should have been published in its present form – surely reviewers should have picked up on these problems. I can only conclude that intense arguments occurred within the journal’s editorial board and amongst reviewers – and most probably more widely amongst institutes and activist groups. In the end, the publication decision was most likely political.

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Anti-fluoride activists misrepresent a new kidney/liver study

Image Credit: Wild Rose College

A new study reporting the ranges of values for kidney and liver parameters in a healthy population is being actively misrepresented by anti-fluoride campaigners. The Fluoride Action Network’s (FAN) latest bulletin claims the study shows “that fluoride at commonly experienced doses can damage the kidneys and livers of adolescents.”

The study shows nothing of the sort. How could it – individuals suffering liver or kidney disease were specifically excluded from the study population. The reported parameter values are all for healthy individuals.

Readers can check for themselves – there is a free download. The paper is:

Malin, A. J., Lesseur, C., Busgang, S. A., Curtin, P., Wright, R. O., & Sanders, A. P. (2019). Fluoride exposure and kidney and liver function among adolescents in the United States: NHANES, 2013–2016. Environment International,

It is important to understand what this study really found. Not only is it being misreported by anti-fluoride activists. The University (The Mount Sinai Hospital/Mount Sinai School of Medicine) press release also appears to attribute more to the study’s findings than is warranted. This is a common problem with university public relations departments. (Readers are warned – the press release includes the disclaimer:

“AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system”

Below I list some information on the study

This is not a study about kidney or liver disease

Individuals showing such disease were specifically excluded. The study reports values for kidney and liver parameters in “generally healthy” subjects. The authors make this very clear in the discussion saying:

“this study did not aim to determine whether fluoride exposure is associated with clinical decrements in kidney function among U.S. adolescents. Rather, this study aimed to examine subclinical changes in kidney or liver parameters associated with fluoride exposure among a generally healthy population. For example, the lowest GFR estimated in this study was 84 mL/min/1.73m2, and therefore none were below the<75 mL/min/1.73m2 value considered reflective of
abnormal kidney function. Future prospective studies including participants with and without kidney disease are needed to assess clinical changes in kidney or liver function.”

So, this study just could not have identified factors causing kidney and liver disease, let alone confidently attribute a cause to the disease. So we can reject the anti-fluoride activist’s claims and their misrepresentation of the study results.

But why all this fuss about fluoride?

Because the authors have a preoccupation with fluoride they used statistical analyses to see if they could find any association between drinking water fluoride or blood plasma fluoride and the measured kidney and liver parameters. They did find a small number of very weak associations.

They do not support the claims made by anti-fluoride activists so details of their results and a critique of their results are irrelevant to the main arguments. But I do have a hangup about the way statistical analyses are used, and the way they are over-interpreted to support pet biases so will discuss their data below.

Very few associations found

The study included nine kidney and liver function test parameters. Only one of these (Blood Urea Nitrogen [BUN]) had a statistically significant relationship with water fluoride (Uncorrected p <0.001) – see figure below.

The relationship of BUN with blood plasma F was also statistically significant (Uncorrected p <0.001) – see figure below.

The Standard Reference Range of BUN for this adolescent population is 6–23 mg/dL. Only a few data points are outside that range and they mainly occur for low water F or plasma F concentrations.

The authors also reported statistically significant associations of estimated glomerular filtration rate (eGFR) and Serum uric acid (SUA) with blood plasma F. However, once adjustments were made for plasma cotinine levels (a biomarker of tobacco smoke exposure) associations were not statistically significant (uncorrected p=0.18 for eGFR) or only “marginally” statistically significant (uncorrected p=0.06 for SUA).

In effect, statistically significant associations with either water F or plasma F occurred for only one. It is not credible for FAN to use these associations as indicators “that fluoride at commonly experienced doses can damage the kidneys and livers of adolescents.”

Reported associations may be “a pure act of will”

The authors appear to place a lot of reliance, in my opinion far too much reliance, of p values as somehow providing a causal mechanism behind the reported associations. This reliance has been strongly criticised by statisticians. Recently Briggs (2019) (Everything Wrong with P-Values Under One Roof) concluded:

“P-values should not be used. They have no justification under frequentist theory; they are pure acts of will. Arguments justifying p-values are fallacious. P-values are not used to make all decisions about a model, where in some cases judgment overrules p-values. There is no justification for this in frequentist theory. Hypothesis testing cannot identify cause. Models based on p-values are almost never verified against reality. P-values are never unique. They cause models to appear more real than reality.”

He goes on to elaborate:

“a small p-value has no bearing on any hypothesis . . . Making a decision about a parameter or data because the p-value takes any particular value is thus always fallacious . . . . Decisions made by researchers are often likely correct because experimenters are good at controlling their experiments, . . . . . ., but if the final decision is dependent on a p-value it is reached by a fallacy. It becomes a pure act of will.”

I believe Malin et al., (2019) place too much reliance on the p values they obtained and should have provided more complete results from the statistical analyses. Citing and relying on p values alone is, I believe, a major deficiency in this paper.

To their credit, while not providing full statistical analysis results the authors did display individual data points in their figures 1 and 2. This enables careful readers to make some judgments about the statistical analyses which would not be possible if the figures had not been provided.

Problems with outliers

The figures show a small number of outlying data points with some of the parameters. One has to be very careful that any association found only has a low p-value because of the influence (or leverage) of these outliers. The figures above for the BUN parameter illustrate the problem – particularly for water F where 2 data point greater than 6 mg/L clearly have a lot of influence.

This problem should stand out to any informed reader of the paper. The authors claim “Cook’s distance estimates were used to test for influential data points; none were identified.” However, this does not seem credible (particularly for Water F) so it is understandable that I should ask to see the results of these estimates so I can make up my own mind. They were not provided.

The associations were extremely weak

There is a huge scatter in the data points obvious in the figures above. This tells us that the reported associations can explain only a small amount of the variance. This is one reason why p-values alone can be misleading. A low p-value for an association (or fitted line) explaining only a few percent of the variance is meaningless. Concentration on such associations means that more important ones (explaining more of the variance) may be ignored. It also ignores the fact that the risk-modifying factor (in this case water F or plasma F) may simply be acting as proxies for more important factors (see Perrott 2018 for an example of this).

Malin et al., (219) should have provided more complete statistical analyses results to help readers judge the strength of the reported association. however, the figures themselves enable us to conclude the associations are very weak.

It is misleading to use the statistical result predictively

Malin et al., (2019) appear to “predict” the effect of fluoride on liver and kidney parameters, particularly BUN. They write in their abstract:

“A 1 mg/L increase in water fluoride was associated with a 0.93 mg/dL lower blood urea nitrogen concentration (95% CI: −1.44, −0.42; p=0.007)”

And

“1 μmol/L increase in plasma fluoride was associated with . . . . . a 1.29 mg/dL lower blood urea nitrogen concentration (95%CI: −1.87, −0.70; p < 0.001).”

But consider going from 0 to 1 mg/L in the image above for water F. The fitted line suggests that BUN would drop from about 11 to about 10 mg/dL. Taking the 95% CI interval into account the line “predicts” a value in the range of about 9.56 to 10.58 mg/dL. But only a small number of the points scattered at about 1 mg/L F have values in that range.

[Yes, I know. The authors only refer to associations, but reports of this work in the alternative health media are using these statements as predictions and that is how activists are suing the information.]

All that the best fit line can predict are values which fit the line. As the association represented by the best-fit line explains only a very small percentage of the variance (despite the small p-value) these “predictions” are meaningless. Unfortunately, the authors do not make this clear in their paper and this deficiency only contributes to the ability of anti-fluoride activists to misrepresent the findings.

Conclusions

Anti-fluoride activists are misrepresenting the finding reported in this paper. The authors themselves stress that their study was not designed to determine if fluoride exposure is associated with, or causes, declines in kidney or liver health. The FAN claim that the study shows“that fluoride at commonly experienced doses can damage the kidneys and livers of adolescents” is completely incorrect.

That is all we need to know regarding the way activists are misrepresenting the study. However, a closer look at the data suggests that the associations with fluoride for healthy individuals reported in the paper are extremely weak.

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Preempting the annual misrepresentation of NZ dental health data by anti-fluoride activists

Dental therapist Heather Dalton examines an Avondale College student in Auckland in 2010. Image credit: Te Ara: The Encyclopedia of NZ.

The latest NZ school dental service data again confirms that community water fluoridation is effective.  The data show benefits of up to about 30% improvement in oral health. But, anti-fluoride activists will, once again,  reject this evidence and instead cherry-pick the data to support their claims.

The NZ Ministry of Health (MoH) has posted the latest summary of child dental health collected by the dental health service. So it is time for local anti-fluoride activists to indulge in their annual activity of cherry-picking and misrepresentation to claim the data “proves” community water fluoridation (CWF) is ineffective (see my comment on last year’s misrepresentation – Anti-fluoridationists misrepresent New Zealand dental data – an annual event).

I haven’t seen this year’s expected press release from Fluoride Free NZ. I may have missed it or perhaps they haven’t got their A into G yet (although there is a bit of notice on their Facebook page). Nevertheless, I will post here my annual analysis of the data.

My comments are much the same as last year – the data has not really changed. But first an explanation of how the data should be used

Nature of the MoH dental health data

The published spreadsheets are simply records of dental health (% caries free and mean Decayed, Missing and Filled Teeth (DMFT and dmft) for 5-year-olds and year 8  children. There has been no selection of children to give representative data. Distortion due to ethnic and socioeconomic factors has not been taken into account.

Data are presented for all children – (Total), Maori, Pacific Island and “Other.” I have previously explained that the Total data is distorted by ethnic factors – different ethnic groups have differences in oral health, irrespective of fluoridation. In particular, the predominance of Pacific Island children in fluoridated areas distort the “Total” data – 85% live in fluoridated areas. Pacific Island children comprise about 15.1% of children in fluoridated areas but only about 3.2% of children in non-fluoridated areas.

Because Pacific Island children generally have poorer health they increase the value of dmft/DMFT and lower the value of caries-free % in the fluoridated areas in the Total figures. Therefore the “Other” figures are more reliable than the “Total” figures for interpretation.

The 2017 data

You can download the two spreadsheets, and the spreadsheets for earlier years, from the MoH website – Age 5 and Year 8 oral health data from the Community Oral Health Service). I will just give the overall New Zealand data for Māori and “Other” (this is all except Māori and Pacific Island).

As explained above the “Total” data is misleading because of ethnic effects and the data for Pacific Island is poor because only a small number resided in non-fluoridated areas.

5-Year Old Children

Clearly, the overall data suggest a benefit of fluoridation to Maōri and “other” children – about 14% for “Other” and 25% for Māori children (using the data for mean dmft).

Year 8 Children


Again the data suggests that fluoridation has been beneficial to Māori and “Other” children. The DMFT data suggest a benefit of about 30.5% for Māori and 26% for “Other” children.  Even the %Caries free data indicates benefits of about 16% and 11% for Māori and “Other” children respectively.

Changes over time

It’s worth considering more than one year. This overcomes, to some extent, variations in the data. It may also be helpful in assessing if the effectiveness of CWF is changing.

However, there is a proviso. Let’s not forget this is simply raw data from the school dental service. While I have corrected for ethnic differences I have no way of correcting for other differences. Socioeconomic effects may change over time. Another important factor is that, at least in some regions, dental health authorities are targeting children form non-fluoridated areas with extra treatments like fluoride tooth varnishes. Ideally, a controlled experiment would take all these factors into account.

I will just take one example – the DMFT data for year 8 children.

The table shows the mean values of %Caries free and DMFT of year 8 children over the periods 2005-2017 and 2013-2017.

Year 8 Children Māori “Other”

%Caries Free

Mean 2005-2017 24.2 13.4
Mean 2013-2017 15.6 8.8

MDFT

Mean 2005-2017 31.3 24.7
Mean 2013-2017 30.1 22.2

This data shows that the oral health of both Māori and “Other” children have improved over time irrespective fluoridation. But there is still a difference between fluoidated and unfluodiated areas indicating fluoridation is having a benefit over and above other factors contributiong to oral health improvement.

The differences due to fluoridation seem to be diminishing. However, my comments above are relevant here. This could be due to extra fluoride treatments targeting children from non-fluoridated areas.

It’s obviously a factor for health authorities to consider but limitations in this data should be kept in mind and other sources of information also considered.

Conclusions

Once again the MoH school dental service data show benefits from CWF. But don’t expect anti-fluoride activists to accept this. I expect they will indulge in their usual cherry-picking of the data to confirm their biases.

Fluoridation: Another study shows stopping fluoridation bad for child tooth decay

Stopping community water fluoridation in Alaska’s capital city, Juneau, caused an increase in child tooth decay

In the last week, Windsor in Ontario, Canada, voted to reinstate community water fluoridation (CWF) 5 years after it was stopped because of opposition. This time the City Council was swayed by the Windsor-Essex County Health Unit’s Oral Health 2018 Report which found the percentage of children with tooth decay or requiring urgent care increased by 51 per cent since fluoridation had stopped.

Now a new study reports similar increases in child tooth decay after stopping CWF in the Alaskan capital, Juneau. This paper reports the study results for Juneau:

Meyer, J., Maragaritis, V., & Mendelshon, A. (2018). Consequences of community water fluoridation cessation for Medicaid-eligible children and adolescents in Juneau, Alaska. BMC Oral Health, 18:215

Juneau – an ideal community for the study

Juneau maintains all the modern conveniences and standards expected of a capital city but has little in-and-out migration or travel from neighboring countries as it is accessible only by plane or sea. This reduces confounding effects due to population changes, only about 0.006% per year during the study period.

Use of fluoridated toothpaste is widespread and CWF was available to 96% of residents before it was stopped in January 2007.

The researchers compared child oral health data in 2003 (when children were exposed to optimum levels of fluoride: 0.7 – 1.2 mg/L) with that in 2012, 6 years after CWF ceased. During those six years, exposure to fluoride was suboptimum: <0.065 mg/L.

The data used for the study was from Medicaid dental claims records. This means the study population was made up of residents living at near poverty conditions. This limited confounding effects from higher-income groups.

Cessation of CWF resulted in increased child tooth decay

The findings were clear and statistically significant. The number of caries-related dental procedures increased after cessation of CWF.

For all children and adolescents (ages 0 – 18 years) the number of procedures increased by 16%. But binary logistic results indicated “the odds of a child or adolescent undergoing a dental caries procedure in 2003 was 25.2% less than that of a child or adolescent in the suboptimal CWF group.”

The effects of CWF were even greater for children aged 0 – 6 years who had never experienced the advantages of exposure optimum fluoride levels. The number of caries-related dental procedures in this group increased by 63%. However,  binary logistic results indicated “the odds of undergoing dental caries procedures under optimal CWF conditions was 51% less than that for a child of the same age in 2012 under suboptimal conditions.”

CWF cessation increased dental treatment costs

The researchers obtained dental costs from the Medicaid dental claims records so were able to make estimates of the effects of CWF on the financial costs to the community. After adjusting for inflation this data showed that the increased annual cost per person of ages 0 – 18 years due toi cessation of CWF increased by $162, a 47% increase. The corresponding increase for children 0 – 6 years was %303, a 111% increase.

Conclusions

While this study had several advantages over similar studies because of reduced confounding effects due to migration and socioeconomic factors this may also be seen as a limitation when trying o extend to findings to more socially heterogeneous communities. However the authors conclude it does provide stong evidence supporting:

“current evidence that even in modern conditions with widely available fluoride toothpaste, rinses, and professionally applied prophylaxis, CWF is associated with population benefits, including cost effectiveness and caries prevention.”

They also conclude from their results that:

“CWF cessation promoted a marked increase in the number of caries-related procedures and treatment costs for Medicaid-eligible children and adolescents aged 0–18 years. Additionally, the results indicated that children in the younger age group cohorts underwent more dental caries procedures than the older age group cohorts, who had benefited from early childhood exposure to optimal CWF.”

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Protection of teeth by fluoride confirmed – yet again

 

Fluoride protects teeth from the attack of acid and microbes. Figure from Faidt et al., (2018)

The protective role of fluoride in teeth has been confirmed, yet again. A new study nicely demonstrates how incorporation of even a small amount of fluoride into the surface layer of teeth protects them from the acid attack which leads to tooth decay.

Researchers measured the ablation, or loss of surface material from hydroxyapatite before fluoridation and after fluoridation. It showed a clear difference due to inhibition of ablation by fluoride.

The research findings are published in:

Faidt, T., Friedrichs, A., Grandthyll, S., Spengler, C., Jacobs, K., & Müller, F. (2018). Effect of fluoride treatment on the acid-resistance of hydroxyapatite. Langmuir

Measuring ablation

Samples were etched with a sodium acetate buffer at pH 4.5 which simulated the effect of an acid attack on teeth resulting from the formation of acid when sugars are microbiologically decomposed in the mouth. The degree of ablation was measured using atomic force microscopy (AFM). Part of the sample surface was coated with a gold layer to prevent acid attack and give a reference surface.

Fluoridated surfaces, submerged for five minutes in a sodium acetate buffer at ph 6.0 cotnaining 500 mg/L of sodim fluoride, were compared with unfluoridated surfaces.

Results

Interestingly, the AFM height images showed there were two different areas of the hydroxyapatite surface when it came to ablation – a fast etching area and a slow etching area. The authors attributed this to the different orientations of crystallites in the hydroxyapatite sample. The image below is for an unfluoridated sample

Ablation of  fluoridated samples was quite different – no ablation occurred until after 330 seconds – the image below is for a fluoridated sample

The paper summarises the results for the fluoridated and unfluoridated surfaces and the different ablation rates due to crystallite orientation in this figure:

The crystallites that etched slowly (Z2) in the unfluoridated sample did not etch at all in the fluoridated sample. The more rapidly etching crystallites (Z1) did etch in the fluoridated sample but only after a delay.

The authors concluded that some of the fluoride in the surface layer of the fluoridated samples could eventually be removed by soaking in the acid buffer – but only after a delay. This was confirmed by an analysis of the surface concentrations of Ca, P, O and F using X-ray photoelectron spectroscopy (XPS) – see below:

Thickness of the fluoridated surface layer

The authors recall:

“In a former study, we revealed that the thickness of the HAp layer that can be loaded with fluoride is in the range of only a few nanometers (24, 25), even if loaded under optimal conditions (25). “

So – a very thin layer. One that some anti-fluoridation commenters claimed insufficient to give any protection. As the authors say

” the question arose whether such a thin layer would actually be capable of protecting the surface against acid attacks. “

But, their results definitely show that this thin layer does offer protection. I am sure critics will quickly point to the fact that the experimental study showed the removal of some of the fluoride after about 400 seconds. But this removal should be seen in the light of the dynamic system in the oral cavity where the pH of saliva is changing, dropping due to sugar decomposition and then rising again. The presence of fluoride, together with phosphate and calcium in saliva also leads to repair of areas where acid attack has occurred.

Conclusions

This experimental work confirms the protective role of fluoride in saliva for existing teeth – despite the fact that the fluoridated layer may be extremely thin – of the order of a few nanometers. While some of the fluoride in the surface layers is eventually removed the presence of fluoride in saliva helps replenish these layers and repair areas of acid attack.

The authors conclude their results provide:

“evidence that already thin and low concentrated fluoridated layers have a large effect on the acid resistance of HAp [hydroxyapatite]”

They combine these finding with results from a previous study of theirs showing fluoridation reduced adhesion forces of bacteria on hydroxyapatite (HAp) to finally conclude:

“the caries-preventive effect of fluoride is an interplay of at least two mechanisms: a reduction of the solubility and a reduction of the bacterial adhesion force.”

Hence the figure at the top of this article.

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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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