Tag Archives: fluoride debate

Why is it so difficult to get an open discussion on fluoridation?

Yes, I know – everyone’s mind is already made up so participants just talk past each other. People’s positions on this and similar issues have become a matter of identity – people are driven by emotions, not information.

But, the information is there – and while I agree many people are driven by emotions they often attempt to use that information to support their positions. In a sense, the information acts as a proxy for their real driving force – their emotions.

Nevertheless, I have always considered a good-faith scientific exchange on issues like this is possible. I believe the exchange I had with Paul Connett, a US anti-fluoride campaigner, four years ago was a good example of what is possible (see Fluoride Debate or download Connett & Perrott (2014) – the pdf document of the exchange).

So, I always look for the chance to repeat that discussion – and I thought that might happen with my recent articles discussing the Mexican maternal prenatal urinary F/child IQ study. Why, because my recent article Paul Connett’s misrepresentation of maternal F exposure study debunked got a response from Mary Byrne, National Coordinator of Fluoride Free New Zealand. I posted her article as Anti-fluoride group coordinator responds to my article.

I responded to that with Mary Byrne’s criticism is misplaced and avoids the real issues and again I offered her a right of reply.

But no response. In fact, she refuses to answer any of my emails.

OK, I can take a hint – but then I see her claiming on Facebook (see image above) that SciBlogs would not allow this discussion! Would not allow “exposure to both sides!” This is patently untrue and she is completely misrepresenting SciBlogs and me.

Note: SciBlogs is a collection of New Zealand science bloggers. My science-oriented blogs usually appear there by syndication.

The email exchange

So it is worth actually looking at the email exchange where Mary requested publication of her article and we responded. Please note the dates and times and excuse the low magnifications. Here are the emails in sequence:

11 March, 12:51 pm: Mary Byrne requests SciBlogs publish her response to my article.
11 March, 1:06pm: After internal passing on the email, Peter Griffin sends it to me.

Pretty quick service. Remember this was a Sunday.

My response was also pretty quick (considering I usually have my daily power nap at that time). I didn’t have to do much thinking about the issue (please excuse my verbosity).

11 March, 2.11 pm

Mary Byrne did not reply so I went ahead anyway and interpreted the original request to mean that a right of reply post on my blog was acceptable. Her article was posted on Tuesday, March 13 (I already posted on Monday and like to spread posts throughout the week) – Anti-fluoride group coordinator responds to my article. I emailed Mary to let her know her article was posted and I would respond to it.

I posted my promised response to her article on Wednesday, March 14th – Mary Byrne’s criticism is misplaced and avoids the real issues and sent Mary an email to let her know – once again offering her another right of reply.

So, Mary’s claim of SciBlogs not allowing exposure from both sides is completely false.

Incidentally, I have emailed Mary asking her to correct that misrepresentation. She has ignored my email, as she ignored all the other emails I have sent her about this issue. The misrepresentation is still on the Fluoride Free NZ Facebook page.

So, I do not expect Mary to continue this exchange, unfortunately. And I do regret she has chosen to misrepresent the situation in the way she has.

But I guess it is just another case of misrepresentation by an anti-fluoridation activist.

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Mary Byrne’s criticism is misplaced and avoids the real issues

Image credit: BuildGreatMinds.Com

First, thanks to Mary Byrne and FFNZ for this response (see Anti-fluoride group coordinator responds to my article). Hopefully, this will help encourage some good faith scientific discussion of the issues involved in my original article (Paul Connett’s misrepresentation of maternal F exposure study debunked). I am pleased to promote such scientific exchange.

I will deal with the issues Mary raised point by point. But first, let’s correct some misunderstandings. Mary claimed I am a “fluoride promoter” and had “sought to discredit the study via his blog posts and tweets.”

  1. I do not “promote fluoride.” My purpose on this issue has always been to expose the misinformation and distortion of the science surrounding community water fluoridation (CWF). I leave promotion of health policies to the health experts and authorities.
  2. I have not “sought to discredit the study.” The article Mary responded to was a critique of the misrepresentation of that study by Paul Connett – not an attack on the study itself. This might become clear in my discussion below of the study and how it was misrepresented.

The study

The paper we are discussing is:

Bashash, M., Thomas, D., Hu, H., Martinez-mier, E. A., Sanchez, B. N., Basu, N., … Hernández-avila, M. (2016). Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6 – 12 Years of Age in Mexico.Environmental Health Perspectives, 1, 1–12.

Anti-fluoride activists have leaped on it to promote their cause – Paul Connett, for example, claimed it should lead to the end of community water fluoridation throughout the world! But this is not the way most researchers, including the paper’s authors, see the study. For example, Dr. Angeles Martinez-Mier, co-author and one of the leading researchers,  wrote this:

1. “As an individual, I am happy to go on the record to say that I continue to support water fluoridation”
2. “If I were pregnant today I would consume fluoridated water, and that if I lived in Mexico I would limit my salt intake.”
3.  “I am involved in this research because I am committed to contribute to the science to ensure fluoridation is safe for all.”

Was the reported association statistically significant?

Mary asserts:

“Perrott claims that the results were not statistically significant but his analysis is incorrect.”

That is just not true. I have never claimed their reported association was not statistically significant.

I extracted the data they presented in their Figures 2 and 3A and performed my own regression analysis on the data. This confirmed that the associations were statistically significant (something I never questioned). The figures below illustrating my analysis were presented in a previous article (Maternal urinary fluoride/IQ study – an update). These results were close to those reported by Bashash et al., (2017).

For Fig. 2:

My comment was – “Yes, a “statistically significant” relationship (p = 0.002) but it explains only 3.3% of the variation in GCI (R-squared = 0.033).”

For Fig 3A:

My comment was – “Again, “statistically significant” (p = 0.006) but explaining only 3.6% of the variation in IQ (R-squared = 0.0357).”

So I in no way disagreed with the study’s conclusions quoted by Mary that:

” higher prenatal fluoride exposure, in the general range of exposures reported for other general population samples of pregnant women and nonpregnant adults, was associated with lower scores on tests of cognitive function in the offspring at age 4 and 6–12 y.”

I agree completely with that conclusion as it is expressed. But what Mary, Paul Connett and all other anti-fluoride activists using this study ignore is the real relevance of this reported association. The fact that it explains only about 3% of the IQ variance. I discussed this in the section The small amount of variance explained in my article.

This is a key issue which should have been clear to any reader or objective attendee of Paul Connett’s meeting where the following slide was presented:

Just look at that scatter. It is clear that the best-fit line explains very little of it.  And the 95% confidence interval for that line (the shaded area) does not represent the data as a whole. The comments on the statistical significance and confidence intervals regarding to the best-fit line do not apply to the data as a whole.

Finally, yes I did write (as Mary quotes) in my introductory summary that “the study has a high degree of uncertainty.” Perhaps I should have been more careful – but my article certainly makes clear that I am referring to the data as a whole – not to the best fit line that Connett and Mary concentrate on. The regression analyses indicate the uncertainty in that data by the low amount of IQ variance explained (the R squared values) and the standard error of the estimate (about 12.9 and 9.9 IQ points for Fig 2 and  Fig 3A respectively).

The elephant in the room – unexplained variance

Despite being glaringly obvious in the scatter, this is completely ignored by Mary, Paul Connett and other anti-fluoride activists using this study. Yet it is important for two reasons:

  • It brings into question the validity of the reported statistically significant association
  • It should not be ignored when attempting to apply these findings to other situations like CWF in New Zealand and the USA.

Paul Connett actually acknowledged (in a comment on his slides) I was correct about the association explaining such small amount of the variance but argued:

  • Other factors will be “essentially random with respect to F exposure,” and
  • The observed relationship will not be changed by the inclusion of these other factors.

I explained in my article Paul Connett’s misrepresentation of maternal F exposure study debunked how both these assumptions were wrong. In particular, using as one example the ADHD-fluoridation study I have discussed elsewhere (see Perrott, 2017). I hope Mary will refer to my article and discussion in her response to this post.

While ignoring the elephant in the room – the high degree of scattering, Mary and others have limited their consideration to the statistical significance and confidence intervals of the reported association – the association which, despite being statistically significant, explains only 3% of the variation (obvious from the slide above.

For example, Mary quotes from the abstract of the Bashash et al., (2017) paper:

“In multivariate models we found that an increase in maternal urine fluoride of 0.5mg/L (approximately the IQR) predicted 3.15 (95% CI: −5.42, −0.87) and 2.50 (95% CI −4.12, −0.59) lower offspring GCI and IQ scores, respectively.”

I certainly agree with this statement – but please note it refers only to the model they derived, not the data as a whole. Specifically, it applies to the best-fit lines shown in Fig 2 and Fig 3A as illustrated above. The figures in this quote relate to the coefficient, or slope, of the best fit line.

Recalculating from 0.5 mg/L to 1 mg/L this simply says the 95% of the coefficient values, or slopes, of the best fit lines resulting from different resampling should be in the range  -10.84 to -1.74 CGI (Fig 2) and -8.24 to 1.18 IQ (Fig 3A).

[Note – these are close to the CIs produced in my regression analyses described above – an exact correspondence was not expected because digital extraction of data from an image is never perfect and a simple univariate model was used]

The cited CI figures relate only to the coefficient – not the data as a whole. And, yes, the low p-value indicates the chance of the coefficient, or slope, of the best-fit line being zero is extremely remote. The best fit line is highly significant, statistically. But it is wrong to say the same thing about its representation of the data as a whole.

This best-fit line explains only 3% of the variance in IQ – and a simple glance at the figures shows the cited confidence intervals for that line simply do not apply to the data as a whole.

The misrepresentation

That brings us back to the problem of misrepresentation. We should draw any conclusions about the relevance of the data in the Bashash et al., (2017) study from the data as a whole – not just from the small fraction with an IQ variance explained by the fitted line.

Paul Connett claimed:

“The effect size is very large (decrease by 5-6 IQ points per 1 mg/L increase in urine F) and is highly statistically significant.”

But this would only be true if the model used (the best-fit line) truly represented all the data. A simple glance at Fig 2 in the slide above shows that any prediction from that data with such a large scatter is not going to be “highly statistically significant.” Instead of relying on the CIs for the coefficient or slope of the line, Connett should have paid attention to the standard error for estimates from the data as a whole given in the Regression statistics of the Summary output. – For Fig. 2, this is 12.9 IQ points. This would have produced an estimate of “5-6 ± 36 IQ points which is not statistically significantly different to zero IQ points,”  as I described in my article

Confusion over confidence intervals

Statistical analyses can be very confusing, even (or especially) to the partially initiated. We should be aware of the specific data referred to when we cite confidence intervals (CIs).

For example, Mary refers to the CI values for the coefficients, or slopes, of the best fit lines.

Figs 2 and 3A in the Bashash et al., (2017) paper include confidence intervals (shaded areas) for the best fit lines (these take into account the CIs of the constants as well as the CIs of the coefficients). That confidence interval describes the region of 95% probability for where the best-fit line will be.

Neither of those confidence intervals applies to the data as a whole as a simple glance at Figs 2 and 3A will show. In contrast, the “prediction interval” I referred to in my article, does. This is based on the standard error of the estimate listed in the Regression statistics. Dr. Gerard Verschuuren demonstrated this in this figure from his video presentation.

Mary is perfectly correct to claim “it is the average effect on the population that is of interest” – but that is only half the story as we are also interested in the likely accuracy of that prediction. The degree of scatter in the data is also relevant because it indicates how useful this average is to any prediction we make.

Given the model described by Bashash et al., (2017) explained only 3% of the IQ variance, while the standard error of the estimate was relatively large, it is misleading to suggest any “effect size” predicted by that model would be “highly significant” as this ignores the true variability in the reported data. When this is considered the effect size (and 95% CIs) is actually “5-6 ± 36 IQ points which is not statistically significantly different to zero IQ points,”

Remaining issues

I will leave these for now as they belong more to a critique of the paper itself (all published papers can be critiqued) rather than the misrepresentation of the paper by Mary Byrne and Paul Connett. Mary can always raise them again if she wishes.

So, to conclude, Mary Byrne is correct to say that the model derived by Bashash et al., (2017) predicts that an increase of “fluoride level in urine of 1 mg/L could result in a loss of 5-6 IQ points” – on average. But she is wrong to say this prediction is relevant to New Zealand, or anywhere else, because when we consider the data as a whole that loss is “5-6 ± 36 IQ points.”

I look forward to Mary’s response.

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Anti-fluoride group coordinator responds to my article

Image credit: Debate. The science of communication.

My recent article Paul Connett’s misrepresentation of maternal F exposure study debunked got some online feedback and criticism from anti-fluoride activists. Mary Byrne, National coordinator Fluoride Free New Zealand, wrote a response and requested it is published on SciBlogs “in the interests of putting the record straight and providing balance.”

I welcome her response and have posted it here. Hopefully, this will satisfy her right of reply and help to develop some respectful, good faith, scientific exchange on the issue.

I will respond to Mary’s article within a few days.


Perrott wrong. New US Government study does find large, statistically significant, lowering of IQ in children prenatally exposed to fluoride

By Mary Byrne, National coordinator Fluoride Free New Zealand.

While the New Zealand Ministry of Health remains silent on a landmark, multi-million-dollar, US Government funded study (Bashash et al), and the Minister of Health continues to claim safety based on out-dated advice, fluoride promoter Ken Perrott has sought to discredit the study via his blog posts and tweets.

Perrott claims that the results were not statistically significant but his analysis is incorrect.

The conclusion by the authors of this study, which was published in the top environmental health journal, Environmental Health Perspectives, was:

In this study, higher prenatal fluoride exposure, in the general range of exposures reported for other general population samples of pregnant women and nonpregnant adults, was associated with lower scores on tests of cognitive function in the offspring at age 4 and 6–12 y.”

Perrott states the study has “a high degree of uncertainty”. But this contrasts with the

statistical analysis and conclusion of the team of distinguished neurotoxicity researchers from Harvard, the University of Toronto, Michigan and McGill. These researchers have written over 50 papers on similar studies of other environmental toxics like lead and mercury.

RESULTS: In multivariate models we found that an increase in maternal urine fluoride of 0.5 mg/L (approximately the IQR) predicted 3.15 (95% CI: −5.42, −0.87) and 2.50 (95% CI −4.12, −0.59) lower offspring GCI and IQ scores, respectively.

The 95% CI is the 95% Confidence Interval which is a way of judging how likely the results of the study sample reflect the true value for the population. In this study, the 95% CIs show the results are highly statistically significant. They give a p-value of 0.01 which means if the study were repeated 100 times with different samples of women only once could such a large effect be due to chance.

Perrott comes to his wrong conclusion because he has confused Confidence Intervals with Prediction Intervals and improperly used Prediction Intervals to judge the confidence in the results. A Prediction Interval is used to judge the confidence one has in predicting an effect on a single person, while a Confidence Interval is the proper measure to judge an effect on a population. In epidemiological studies, it is the average effect on the population that is of interest, not how accurately you can predict what will happen to a single person.

Despite the authors controlling for numerous confounders, Perrott claimed they did not do a very good job and had inadequately investigated gestational age and birth weight.

Once again Perrott makes a fundamental mistake when he says that the “gestational period < 39 weeks or > 39 weeks was inadequate” and “The cutoff point for birth weight (3.5 kg) was also too high.”

Perrott apparently did not understand the Bashash paper and mistook what was reported in Table 2 with how these covariates were actually treated in the regression models. The text of the paper plainly states:

“All models were adjusted for gestational age at birth (in weeks), birthweight (kilograms)”

Thus, each of these two variables were treated as continuous variables, not dichotomized into just two levels. Perrott’s criticism is baseless and reveals his misunderstanding of the Bashash paper.

Perrott states that the results are not relevant to countries with artificial fluoridation because it was done in Mexico where there is endemic fluorosis. But Perrott is wrong. The study was in Mexico City where there is no endemic fluorosis. Furthermore, the women’s fluoride exposures during pregnancy were in the same range as found in countries with artificial fluoridation such as New Zealand.

The study reports that for every 0.5 mg/L increase of fluoride in the urine of the mothers there was a statistically significant decrease in average IQ of the children of about 3 IQ points. It is therefore correct to say that a fluoride level in urine of 1 mg/L could result in a loss of 5 – 6 IQ points. This is particularly relevant to the New Zealand situation where fluoridation is carried out at 0.7 mg/L to 1 mg/L and fluoride urine levels have been found to be in this range2.

There is no excuse for Health Minister, David Clark, to continue to bury his head in the sand. This level of science demands that the precautionary principle be invoked and fluoridation suspended immediately.

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New fluoride debate falters

Characters debate the “fluoride conspiracy” in Kubrick’s Dr Strangelove

What is it with these anti-fluoride campaigners – and particularly their leaders? They make a song and dance about having “science on their side.” They will heavily promote the latest research and papers if they can argue that they confirm their bias. And they will email politicians or make submissions to local bodies making scientific claims – often with citations and long lists of references.

But we simply can not get them to enter into a good faith scientific discussion of the sort I suggested in Do we need a new fluoride debate?

I thought this was going to happen. Bill Osmunson, the current Direct of the Fluoride Action Network (FAN), had agreed and even produced an initial article for posting. But he has now pulled out and asked me not to post his article. Apparently, my critique of a recent paper by him and his colleagues from FAN (see Flaw and porkie in anti-fluoride report claiming a flaw in Canadian study) was the straw that broke the camels back as far as he was concerned.

Talk about tiptoeing around a discussion partner. How can one have a discussion with someone this sensitive?

Excuses, excuses!

This is the explanation he gives for his withdrawal from the planned exchange:

“I have second thoughts about a discussion with you.  Do not publish my comments.*

After reading your comments in response to Neurath, it became obvious that you have no interest in discovering the truth or protecting the public.  Nor do you have reasonable judgment to evaluate research.

You do have good mechanical skills, but not judgment.

You correctly take weaker arguments and point out they are weak.  But you do not comment or appreciate the main more powerful issues.  Your comments make it sound like there is no value because some points have lower value.  Only a person who carefully rereads McLaren and Neurath, and then your comments understands some of your points are valid and you have missed others which are powerful.

In addition, you use derogatory, unprofessional mocking terms to attack the person instead of the issues.  I’m not interested in being your porky or sparky or pimp.

You are unprofessional and are not worth the time.”

  • The “comments” Bill refers to are a 55-page pdf file he sent me as the first post in our exchange. We were discussing a shorter form more suitable for a blog post when he decided to back out.

Mind you, in a previous email he had acknowledged that his mates (presumably in FAN) were unhappy about him participating in this good-faith scientific exchange. He wrote:

“Several people have told me not to respond to you, because you are unprofessional with your statements and comments.  You attack the messenger instead of the message and you have such severe bias and faith in fluoride that you must have worked for the tobacco companies to learn your strident blind bias.  
OK, I gave you a try once before and found you to be violent with your personal attacks and lack of judgment.”
 Sounds like “excuses, excuses,” to me. Surely I am not such a horrible person? I asked Bill to identify anything in my exchange with Paul Connett (see The Fluoride Debate) where I had behaved in the way he charged. He couldn’t. And I challenge anyone else to identify such behaviour on my part in that exchange.

Bill Osmunson and his mates claim I behaved badly in this exchange with Paul Connett – but they refuse to give a single example

 I can only conclude that the people at FAN are unable to provide good scientific arguments to support their case. They may well produce documents with lists of citations and references with “sciency” sounding claims. But they will not allow their claims to undergo the sort of critique normal in the scientific community.
Still – I am willing to be proven wrong. if Bill feels that he doesn;t have the scientific background for this sort of exchange perhaps Chris Neurath, Harvey Limeback or one of the other authors from FAN of the article I critiqued in Flaw and porkie in anti-fluoride report claiming a flaw in Canadian study) could take his place.
The offer is open.

Do we need a new fluoride debate?

I think we do. Something like the good faith scientific exchange I had with Paul Connett four years ago (see Connett & Perrott, 2014 – The Fluoride Debate).

After all, there have been a number of important scientific reports since then. They may have been thrashed out (and thrash is sometimes the operative word) in one of the “anti-fluoride” or “pro-fluoride” internet silos but there has yet to be a proper discussion.

I have been trying to get one going for a while. Paul Connett is no longer interested and everyone else on the “anti-fluoride” side seems unwilling. However, Bill Osmunson who recently replaced Paul Connett as director of the Fluoride Action Network has been contributing to the discussion on several of the posts here. He seems to be the obvious choice for a discussion partner and I  asked him if he is willing to participate in another scientific exchange of the sort I had with Connett.

So far he has not responded – but as he has made some relevant critiques of several recent scientific papers in these discussion contributions I think it is relevant to bring that discussion into the formal blog posts. Otherwise, some important points will just be lost because they are buried deep in the discussion threads.

Here I respond to criticisms Bill makes of two recent studies which looked for evidence of the influence of community water fluoridation (CWF) on IQ and cognitive deficits in general. I urge Bill Osmunson to respond to my points in a format which can be presented as a blog post here.

Community water fluoridation and IQ

The two studies were published after my exchange with Paul Connett and are:

Broadbent, J. M., Thomson, W. M., Ramrakha, S., Moffitt, T. E., Zeng, J., Foster Page, L. A., & Poulton, R. (2014). Community Water Fluoridation and Intelligence: Prospective Study in New Zealand. American Journal of Public Health, 105(1), 72–76.

And

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), 229.

Broadbent et al., (2014)

This study used data from the Dunedin  Multidisciplinary Health and Development longitudinal study and found no difference in IQ of people in fluoridated and unfluoridated areas or any effect of fluoridated toothpaste or fluoride supplement use.

I hope I represent Bill correctly but his criticisms of this study are vague – I can’t help feeling he is succumbing to the general hostility anti-fluoride campaigners have had about this study.

Let’s deal with his last criticism:

” I have previously presented my reservations about the NZ study and Broadbent’s comparing fluoridation with fluoride supplements, which lacked power to evaluate IQ.”

It more or less encapsulates anti-fluoride criticisms of the study and does contain an element of validity in reference to the study’s “power.” However, Bill’s reference to “power” is far too vague. It needs to be quantified.

Is Bill claiming that there are declines in IQ caused by CWF but they are too small to be detected in a study like Broadbent et al., (2014)? Or was there something about that study which made it incapable of detecting a reasonable IQ decline? Or does it matter – after all someone who is ideologically committed to believing fluoride is bad for IQ can always fall back on this argument when experimental results don’t go their way. No study will realistically have the ability to detect an extremely small IQ change that they might argue for. And such a small change is more in the eye of the (biased) observer than a reality.

Fellow FAN members Hirzy et al., (2016) also argued that the “power” of the Broadbent et al.,  (2014) study was too low to detect their assumed change in IQ. They argued this case on the basis of total dietary intake of fluoride claiming that there was very little difference of total dietary intake between fluoridated and fluoridated areas.  Osmunson et al., (2016) made the same argument – appearing to give up completely on the contribution of CWF (as it “likely represents less than 50% of total fluoride intake”) and directing attention to total fluoride intake instead. However, their arguments are very subjective as they pull dietary data “out of a hat” and don’t deal with the real situation where the study occurred.

Osmunson mentioned the importance of fluoride supplements and fluoride toothpaste to fluoride intake but seemed to have missed the fact that Broadbent et al., (2014) had also included these as factors in their statistical analysis. Neither these factors nor CWF exhibited a statistically significant effect on IQ.

The apparent fallback position of Hirzy et al., (2016) and Osmunson et al., (2016) that the relatively small dietary F intake meant their assumed IQ differences were too small for the study to detect comes across as straw-clutching. Especially as oral health differences between fluoridated and unfluoridated areas were detectable See Evans et al., 1980 and Evans et al., 1984).

The “power” of a study

The “element of validity” I referred to in Bill’s complaint about the “power” of the experiment is one every practical researcher faces – especially when dealing with an existing programme rather than designing, from the ground up, a laboratory experiment. Numbers of participants, or samples, are always limited and researchers rarely have the luxury of the large number they would wish for to provide more “power.”

The “power” of a study is often represented by the  95% confidence interval (CI). This means that if the same population is sampled on numerous occasions and interval estimates are made on each occasion, the resulting intervals would bracket the true  population parameter in approximately 95 % of the cases.” Usually, more sample numbers mean a smaller CI and therefore more confidence in the value of the result.

Broadbent et al (2014) reported a 95%CI of -3.22 to 3.20 IQ points for the effect of community water fluoridation with children of 7 -13 years. (The equivalent CIs for the effects of fluoride toothpaste and fluoride tablets were -1.03 to 2.43 and -0.38 to 3.49 respectively). The observed effects were not statistically different to zero. Their study used just 990 children. If more participants had been available the 95%CI could have been reduced to less than the range of 6.4 IQ points actually found for the effect of CWF.

In a very large Swedish study, Aggeborn & Öhman (2016) included between 20,000 and 80,000 participants and estimated a confidence interval of -0.23 to 0.89 IQ units when fluoride is increased by 1 mg/L. (They were able to consider a continuous measure of fluoride and not simply fluoridated or unfluoridated treatments). This study has far more “power” than that of Broadbent et al., (2014), and therefore a smaller CI value. But the conclusion was the same – fluoride at these concentrations had “a zero-effect on cognitive ability.”

Barberio et al., (2017)

This is a Canadian study with a large representative sample and individual estimates of fluoride exposure and reported learning disability diagnosis. Overall it concluded there was no “robust association between fluoride exposure and reported learning disability diagnosis.”

Bill Osmunson argues that this study “has limitations” and that the “conclusions overstate their data.”

I agree with Bill that diagnosis of learning disability based on a household questionnaire is not the same as a proper professional diagnosis, although presumably the question aimed at finding out if a professional diagnosis had been made – and what it was in some cases. The authors acknowledge that weakness but argue that more objective assessments are probably only feasible in small-scale studies.

Interestingly Bill and his fellow anti-fluoride campaigners did not raise this problem of reliance on parental answers to a questionnaire when they considered and argued strongly for, the Malin and Till (2015) ADHD study. (See  Perrott 2017 – Fluoridation and attention deficit hyperactivity disorder – a critique of Malin and Till (2015)for more details of this study and its problems.

Of course, these are the real-world problems faced by researchers attempting to extract useful data from large-scale surveys. One of the reasons why readers should not consider single studies as definitive and should consider each one critically and sensibly.

However, I think Bill is straw-clutching when he quotes the authors:

“When Cycles 2 and 3 were combined, a small but statistically significant effect was observed such that children with higher urinary fluoride had higher odds of having a reported learning disability in the adjusted model (p = 0.03).” [Cycles 1 and 2 are two separate parts – 2009-20011 and 2012-2013 respectively – of the Canadian Health Measures Survey]

And then argues:

“Barberio could have concluded they found harm. Instead, they focused on data which did not show harm.”

Bill is aware that a statistically significant effect of fluoride exposure was observed in only a limited case – when data from two cycles were combined and the urinary fluoride data had not been corrected by using either creatine concentration or specific gravity. This correction is necessary as an attempt to overcome the shortcomings of single spot-samples of urine. As the authors point out “spot urine samples used to measure fluoride are vulnerable to fluctuations.” And :

“creatinine-adjusted urinary fluoride or specific gravity-adjusted urinary fluoride . . .  are thought to be more accurate because they help to correct for the effect of urinary dilution, which can vary between individuals and different points in time. Accordingly, these adjusted measures help to offset some of the limitations associated with spot urine samples. The finding that the effect was reduced to non-significance when creatinine-adjusted and specific gravity-adjusted urinary fluoride were used, suggests that the association between urinary fluoride and reported learning disability diagnosis may not be robust.”

So Bill would prefer that the authors had based their conclusions on uncorrected urinary fluoride data and not the more reliable corrected figures? And why? Because that would have confirmed his bias. That is an unfortunate personal foible – our biases often encourage us to go with unreliable conclusions and not allow them to be challenged by the more reliable data.

Conclusions

Here I have simply considered the Broadbent et al., (2014) and Barberio et al.,. (2017) papers because these are the ones Bill Osmunson has responded to. I urge him, to also consider the Aggeborn and Öhman (2016) paper.

I hope Bill Osmunson will respond to this post with his refutations of my points or further arguments about these and other papers. I hope also that he takes up my offer of space here for an in-depth exchange of the sort I had with Paul Connett four years ago.

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), 229.

Broadbent, J. M., Thomson, W. M., Ramrakha, S., Moffitt, T. E., Zeng, J., Foster Page, L. A., & Poulton, R. (2014). Community Water Fluoridation and Intelligence: Prospective Study in New Zealand. American Journal of Public Health, 105(1), 72–76.

Evans, R. W., Beck, D. J., & Brown, R. H. (1980). Dental health of 5-year-old children: a report from the Dunedin Multidisciplinary Child Development Study. The New Zealand Dental Journal, 76(346), 179–86.

Evans, R. W., Beck, D. J., Brown, R. H., & Silva, P. A. (1984). Relationship between fluoridation and socioeconomic status on dental caries experience in 5-year-old New Zealand children. Community Dentistry and Oral Epidemiology, 12(1), 5–9.

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.

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. (20217). Fluoridation and attention deficit hyperactivity disorder – a critique of Malin and Till (2015)).  British Dental Journal, In press.

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Debating science

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

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

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

The Science March

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

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

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

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

Debating science

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

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

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

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

Problems with formal debates

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

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

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

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

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

Good faith discussion

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

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

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

A challenge to anti-fluoridation activists

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

Why do these people ignore such opportunities?

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

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

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

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

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

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NZ Fluoridation review – Response to Micklen

I welcome open and transparent discussion here so am thankful to Dr Micklen for his response (see NZ Fluoridation review – HS Micklen responds to critique). Unfortunately he is the only author or “peer-reviewer” of Fluoride Free NZ’s report criticising the NZ Fluoridation review to accept my offer of a right of reply to my critiques. A pity, as if any of them think I have got things wrong, and they can support this with evidence, I certainly want to know about it. There are three aspects to Dr Micklen’s reply – dental fluorsis chronic kidney disease and his critique of my letter in the journal Neurotoxicology and Teratology –   Perrott (2015). I will deal with these separately.

Dental fluorosis

I appreciate Dr Micklen is unhappy about my criticisms of his article, and my suggestion his comments of dental fluorosis were muddled. I may have been a bit harsh but he has still not responded to my specific criticism that he:

“unfairly attributes the more severe forms [of dental fluorosis] to community water fluoridation (CWF). Consequently he calculates a cost of dental treatment which is wrong.”

The key problem is that Micklen is assuming that all the  medium and severe dental fluorosis can be attributed to CWF, whereas none of it can. Briefly reviewing the argument – the figure below is from the NZ Ministry of Health’s Our Oral Health – the same source Micklen used. My comment on the relevance of the different grades of dental fluorosis was:

“Moderate and severe grades of dental fluorosis are common in areas where fluorosis is endemic, but relatively rare where CWF is used. Occurrences in the latter case, despite the low concentrations of fluoride in treated drinking water, will have other causes – high natural levels in well water, industrial pollution, excessive consumption of toothpaste, etc.”

The important factor is that severe and moderate forms of dental fluorosis are not caused by CWF. CWF can contribute to mild and very mild forms of dental fluorosis but because these are usually judged positively they certainly don’t need expensive veneers – my dentist colleagues advise simple microabrasion usually works. So Micklen was wrong to suggest the cost of cost of veneers (up to $1750 per tooth) should be attributed to CWF because such costs would be encountered in non-fluoridated areas as well. (In fact, if Micklen had calculated costs for such treatment in non-fluoridated areas using the “Oral Health” data in the literal way he did for the fluoridated areas,  he would have found costs to be higher than in non-fluoridated areas! Certainly doesnt’ support his claim but a meaningless result because of the small numbers and large variability).

Chronic kidney disease

Micklen accuses me of  using “a piece of grammatical legerdemain to pretend that I [Micklen] called for CKD sufferers to be warned to avoid tap water, which I did not.” Granted he left himself a way out by actually writing:

“I suspect that most opponents of fluoridation would call for CKD sufferers to be warned to avoid tap water. Possibly the NZ health authorities have done so.”

OK, so its not a direct personal recommendation (perhaps he doesn’t belong to the group of “most opponents of fluoridation”) but a reader could be excused for getting that message and in this context it comes across as “dog whistling.” However I will accept his assurance now that:

” In fact, I am inclined to agree with him [me] that that might be extreme in the present state of knowledge.”

As for questions like: “Does further research on the topic receive any funding priority, for example?” – well this is a round about way of giving the message that it doesn’t. Perhaps he should actually check that out and give some evidence instead of making an unwarranted implication. This tactic of posing unfounded questions to convey an unwarranted message is typical of the approach Micklen and Connett take in their book The Case against Fluoride. I criticised this tactic in my exchange with Paul Connett (see Fluoride Debate). I reject Micklen’s suggestion that:

“Perhaps it would be embarrassing, too, for a government to insist on putting fluoride in the water and then advise a substantial number of people not to drink it – or so one might think.”

That is silly – it is like a conspiracy theory. Why would genuine health authorities refuse to give warnings to a small group of people who might be put at risk from a social health policy that is beneficial to the vast majority? Surely they are used to such situations. I also think he is waxing lyrical with the word “substantial!” The numbers involved would be very small, if any, and such a group would already be advised about a number of risks to them because of their condition and treatments. Micklen also lets his ideological position take over  by drawing the implication from my article that I am saying CWF is “effective and safe – for some.” Far from it. Surely I am saying it is effective and safe for the vast majority (which is what we can expect from a social health policy) and simply recommending (as in all such policies) that the small group of people, if any, who might be at risk should use alternatives. I am actually saying that CWF is effective and safe for at least  the vast majority and that claims to the contrary should be backed up with evidence which should be considered critically

Severe dental fluorosis and cognitive deficits

I thank Dr Micklen for his comments on my letter in the journal Neurotoxicology and Teratology – (Perrott 2015). I am pleased he accepts the hypothesis that severe dental fluorosis could explain observations of cognitive deficits is worth considering and  he agreed with the other reviewers the letter was worth publishing. Influence of age I take his point that the poor appearance of teeth may not influence young children (ages 6-8 as in the small the group Choi et al, (2015) studied). However, this is pure speculation on his part and is surely a detail. A detail that should be considered in any planned research incorporating this hypothesis, but not in itself a reason for rejecting the hypothesis out of hand – surely? Unless, of course, he can give evidence to support his suggestion. I notice that he does not support the idea with any citations so suspect the idea is more one of straw-clutching  than a serious suggestion. Actually most, but not all, of the citation I used did indeed refer to work with older children. Some were review papers and did not limit their review to any age group. Aguilar-Díaz, et al., (2011) considered children from 8 – 10 years old, Do and Spencer, (2007) studied 8-12 year olds and Abanto et al., (2012) 6-14 year old children. Chikte (2001) studied three groups: 6, 12, 15 year olds. However, I found a quick literature search showed reports of negative effects of oral defects like tooth decay on the child’s quality of life. Kramer et al., (2013) reported this for ages 2 – 5, Scarpelli et al., (2013) for 5 year olds and Cunnion et al., (2010) for 2 – 8 year olds. So, I suggest on the available evidence the negative influence of severe dental fluorosis on quality of life (and possibly cognitive deficits) is likely to occur even in younger children who have not “reached an age to be self-conscious about their appearance.” I don’t think young children are as immune to social attitudes and personal appearance as Dr Micklen suggests. Does effect depend on how common dental fluorosis is?  Dr Micklen suggests that:

“Since fluorosis was common in the community [the children studied by Choi el., 2015], having the condition would not appear abnormal.”

Again I think he is indulging in straw-clutching, or special pleading. special-pleading-fallacy Clearly medium and severe dental fluorosis is far more common in this Chinese group than in countries like New Zealand which use CWF. In the graph below I compare their data with that for New Zealand and USA. Incidentally, this figure shows why the data from Choi et al., (2012, 2015) should not be used as an argument against CWF – yet that is what Micklen did in his original article. DF---good-and-bad But this does not mean that those children with more severe forms will not stand out against the children with less severe forms. There is always a range of appearances of such defects in a group of children. Some will obviously suffer more than others because of their appearance. If Choi et al., do continue to include detailed analysis of dental fluorosis in their future work on this issue then it will be possible to compare cognitive deficit measurements with dental fluorosis indices in a larger group. Such data will be interesting. However, discussion of details like this is premature. My letter simply raised to idea as an alternative worth considering and encouraged the group to continue including detailed dental fluorosis measurements in future work. I was also concerned that they were not being sufficiently open-minded in their choice of a working hypothesis. I concluded my letter with:

Researchers need to be careful not to limit their possible hypotheses or research approaches. Unfortunately Choi et al. (2014) appear to be doing just this with their plans for a larger scale study targeted only at “fluoride’s developmental neurotoxicity.”

Unfortunately none of this group have yet responded to my letter. So, again, I thank Dr Micklen for his feedback on that letter – and his acceptance of the right-of-reply to my article critiquing the FFNZ report. See also:

References

Abanto, J., Carvalho, T. S., Bönecker, M., Ortega, A. O., Ciamponi, A. L., & Raggio, D. P. (2012). Parental reports of the oral health-related quality of life of children with cerebral palsy. BMC Oral Health, 12, 15. doi:10.1186/1472-6831-12-15 Aguilar-Díaz, F. C., Irigoyen-Camacho, M. E., & Borges-Yáñez, S. A. (2011). Oral-health-related quality of life in schoolchildren in an endemic fluorosis area of Mexico. Quality of Life Research : An International Journal of Quality of Life Aspects of Treatment, Care and Rehabilitation, 20(10), 1699–706. Chikte, U. M., Louw, A. J., & Stander, I. (2001). Perceptions of fluorosis in northern Cape communities. SADJ : Journal of the South African Dental Association = Tydskrif van Die Suid-Afrikaanse Tandheelkundige Vereniging, 56(11), 528–32. Choi, A. L., Sun, G., Zhang, Y., & Grandjean, P. (2012). Developmental fluoride neurotoxicity: A systematic review and meta-analysis. Environmental Health Perspectives, 120(10), 1362–1368. Choi, A. L., Zhang, Y., Sun, G., Bellinger, D., Wang, K., Yang, X. J., … Grandjean, P. (2015). Association of lifetime exposure to fluoride and cognitive functions in Chinese children: A pilot study. Neurotoxicology and Teratology, 47, 96–101. Cunnion, D. T., Spiro, A., Jones, J. a, Rich, S. E., Papageorgiou, C. P., Tate, A., … Garcia, R. I. (2010). Pediatric oral health-related quality of life improvement after treatment of early childhood caries: a prospective multisite study. Journal of Dentistry for Children, 77, 4–11. Do, L. G., & Spencer, A. (2007). Oral Health-Related Quality of Life of Children by Dental Caries and Fluorosis Experience. Journal of Public Health Dentistry, 67(3), 132–139. Kramer, P. F., Feldens, C. A., Ferreira, S. H., Bervian, J., Rodrigues, P. H., & Peres, M. A. (2013). Exploring the impact of oral diseases and disorders on quality of life of preschool children. Community Dentistry and Oral Epidemiology, 41(4), 327–35. NZ Ministry of Health. (2010). Our Oral Health Key findings of the 2009 New Zealand Oral Health Survey. Perrott, K. W. (2015). Severe dental fluorosis and cognitive deficits. Neurotoxicology and Teratology. Scarpelli, A. C., Paiva, S. M., Viegas, C. M., Carvalho, A. C., Ferreira, F. M., & Pordeus, I. A. (2013). Oral health-related quality of life among Brazilian preschool children. Community Dentistry and Oral Epidemiology, 41(4), 336–44.

NZ Fluoridation review – HS Micklen responds to critique

I have posted several articles in a series critiquing contributions to the Fluoride Free NZ report Scientific and Critical Analysis of the 2014 New Zealand Fluoridation Report which is aimed at discrediting the recent review Health Effects of Water Fluoridation: a Review of the Scientific Evidence produced by the Royal Society of NZ together with the Office of the Prime Minister’s Chief Science Advisor. The articles in this series are collected into a pdf document which can be downloads from Download report analysing anti-fluoride attacks on NZ Fluoridation Review.

In an attempt to encourage a discussion on the fluoridation review and the FFNZ report I offered all the authors and “peer-reviewers” of the FFNZ report the right of reply to my critiques. So far Dr H. S. Micklen (whose article I critiqued in Fluoride Free NZ report disingenuous – conclusion), is the only one to take up this offer.

Here is his reply. 


I thank Dr Perrott for reproducing my notes on the NZ Fluoridation Review and appreciate his comments. My appreciation would be warmer had he spent less time using his imagination and paid more attention to what I actually wrote.  He has me bustling around, agenda in hand, clutching at straws here, raising bogeys there, scaremongering, relying on this, calling for that, and getting confused about different grades of fluorosis (as if..,). All nonsense.  If I “distort the science” as Perrott’s headline proclaims, he does a great job of distorting the distortion.

Most of my short piece merely commented on a few places where, in my opinion, the NZ report failed – through error, omission or incompetence – to reach proper standards of objectivity and impartiality and exhibited ill-founded complacency. Since the NZ report was highly biased in favour of fluoridation, any criticisms of it are likely to have an anti-F flavour. Too bad; I was dealing with the report’s view of the science, not pushing my own. I avoided speculating on the outcome of issues that I consider unresolved, dental fluorosis (where Perrott makes nonsense of what I wrote) being the only exception.

Most of these issues have been argued over ad nauseam and I shall not try to unscramble Perrott’s lucubrations. The question of chronic kidney disease and its possible cardiovascular consequences is perhaps an exception. I gave credit to the Review for discussing the paper by Martin-Pardillos. Agreeing with the Review’s opinion that the results needed to be confirmed, I remarked “The interesting question is, what should happen meanwhile?” That is not a rhetorical question. What does, or should, happen when an alarm bell sounds over a long-established procedure? Does further research on the topic receive any funding priority, for example?  Perrott uses a piece of grammatical legerdemain to pretend that I called for CKD sufferers to be warned to avoid tap water, which I did not. In fact, I am inclined to agree with him that that might be extreme in the present state of knowledge. Perhaps it would be embarrassing, too, for a government to insist on putting fluoride in the water and then advise a substantial number of people not to drink it – or so one might think. But Perrott concludes “Any patients who are particularly worried can then take steps like using filtered water for their own peace of mind. This seems more appropriate than denying the rest of the population access to a simple, effective and safe (for them at least) social health policy like CWF.”  So that’s all right then, thanks to the patients, whom Perrott doubtless consulted, being willing to promote the alleged greater good. He has pricked a hole in the old mantra, though: “effective and safe – for some”.

Perrott asked for my feedback on his idea about the possible effect of dental fluorosis on IQ.  Since then his paper has appeared online as a short article in Neurotoxicology and Teratology. Perhaps the best thing I can do at this stage is pretend that it had arrived on my desk for peer review. I would have commented as follows.

“This communication refers to a recent paper by Choi et al (2014) that reports certain cognitive defects in young children affected by moderate-severe dental fluorosis. Choi et al suggest that this is due to an adverse effect of fluoride on the developing brain. The present author proposes an alternative explanation, namely that fluorosis itself, and the stress of living with it, can affect learning and general quality of life and result in poor performance in certain types of cognitive test. This appears to be a novel idea and, as such, is suitable in principle for publication as a short communication. There is, however, a fundamental question that the author should be invited to address and clarify with a view to possible resubmission.

“The paper is somewhat discursive and lacking in focus and in the course of it the author seems to lose track of what age group he is talking about. Surprisingly, he does not mention the age of Choi’s (2014) subjects, which averaged 7 years  (range 6-8). When he finally presents evidence that moderate-severe fluorosis is aesthetically displeasing and likely to impair quality of life, all of it relates to older children, mainly teenagers, who have reached an age to be self-conscious about their appearance and have been living with fluorosis for several years. In contrast, 16% of Choi’s (2014) subjects had no erupted permanent teeth at all and in the remainder eruption of the first permanent teeth would have been very recent. Since fluorosis was common in the community, having the condition would not appear abnormal. The crucial question is whether the author is proposing that the quality of life of these young children is so compromised by fluorosis as to impair their performance in cognitive tests. Apparently the answer is a tentative affirmative: It is just possible that the negative quality of life associated with oral defects like severe dental fluorosis contribute to cognitive deficits reported by Choi et al. (2012, 2014)’

“The author needs to discuss this issue in a transparent fashion so that readers can judge for themselves whether the proposal is plausible. Conversely, if he is not making such a proposal, that too should be made clear.

“The author might wish to refresh his memory of the paper by Hilsheimer and Kurko (1979), which really is of virtually no relevance to his argument.”

I hope this helps.

H S M 12 February 2015

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Fluoride debate: Second response to Rita Barnett-Rose – Daniel Ryan

Here is Daniel Ryan’s second response to Rita Barnett-Rose’s defence of here unpublished paper Compulsory water fluoridation: Justifiable public health benefit or human experimental research without informed consent“. That defence was posted yesterday at Fluoride debate: Response to Daniel Ryan’s critique – Rita Bartlett-Rose.

Daniel’s second response is available to download as a pdf.


Compulsory water fluoridation: second response to Rita Barnett-Rose

Dan Ryan 2

Daniel Ryan from the Making Sense of Fluoride group

Written by Daniel Ryan

5/10/2014

Introduction

This is my second response to Associate Professor Rita Barnett-Rose to her paper “Compulsory water fluoridation: justifiable public health benefit or human experimental research without informed consent”. It is a response to her document “RE: CWF Working Paper Article” (hereafter referred to as “Rita’s reply.”). I wish to thank Rita for acknowledging in that papers should be referenced accurately by using citations to the original sources rather than simply referencing activist sources. I am also pleased she is getting experts to review the science in her paper and am interested to know who the independent reviewers are.
In this this response I have collected a number of comments to consider under separate headings.

Objectively looking at the science.

Rita’s reply:

“…you object to my failure to include contrary studies that reaffirm the (English speaking countries’) public health agencies’/dental lobby positions on the safety and benefits of compulsory water fluoridation.”

“…with respect to your complaint or desire that I cite to contrary (i.e., pro-fluoridation) studies in addition to (or in lieu of) the published studies that I cite that tend to weigh against fluoridation”

“It is not meant to be an exhaustive examination of all studies on fluoridation and is specifically and accurately identified for what it is”

“…you are just as guilty of ‘cherry picking’ your sources and your studies as you suggest I am.”

“I am not interested in a battle of the studies debate”

“These reasons would remain even if compulsory water fluoridation were proven to be entirely safe, which it most definitely has not, despite the presumed “majority” view in the English speaking countries”

My reply:
Rita implies I only use ‘pro-fluoridation’ or ‘English speaking countries’ papers. This is incorrect – I cite papers which provide the best weight in regards to evidence. Science doesn’t take sides (good papers are neither “anti-fluoridation” nor “pro-fluoridation”, they present data and reasoning) and these are international. To clarify, my issue is not that Barnett-Rose (2014) was not using ‘pro-fluoridation’ papers, it was the quality of the studies themselves. Reviewers of the science should attempt to understand and evaluate the quality of the research.

I also look at the quality of journal. And I try to cite papers which are in high quality journals more as those journals attract the best scientific papers. Journals use a metric called “impact factor” that basically states how many times an average paper is cited by other papers. It is an independent, objective method to judge the quality of published research.
The hierarchy of scientific evidence in the literature is also important I illustrate this in the image below.

cm-evidence-listed-medicines-05-01
Secondary reviews published in peer-reviewed, high-impact journals and high quality randomised controlled trials with definitive results should be the preferred sources. For consideration of human health effects I consider that animal studies would be placed above “expert opinion” in this hierarchy.
Overall one needs to approach the literature intelligently and critically – considering the evidence provided in the individual papers and also considering other published material.

Instead I saw that Barnett-Rose (2014) did not evaluate the evidence well, only selecting evidence of harm in order to persuade the audience to accept her position. There is no reason to use low validity papers when there is plenty of high quality papers but unfortunately this happens when trying to “price” a preconceived idea.

An example of this is Barnett-Rose (2014) used an opinion article from the Scientific American many times as her source. This is not a scientific paper, it is not peer reviewed or in a research journal; furthermore the writer is not a scientist and definitely not an expert on the subject. This type of evidence would come below “expert opinion” on the image above. I hope such problems would be given as feedback from the independent reviewers.
Rita accuses me of cherry picking but fails to back this up. I do try to use only the best sources of evidence – usually systematic reviews. A systematic review is a literature review focused on a research question that tries to identify, appraise, select and synthesize all high quality research evidence relevant to that question.

The evidence shows

Rita’s reply:

“However, what I do believe is that the burden of proving safety and effectiveness lies with the pro-fluoridation side”

“It also appears to me that the pro-fluoridation side is playing “whack a mole” with the studies weighing against CWF – often trying to hammer down/marginalize the opposition each time a negative study pops up, rather than trying to consider the evidence objectively.”

“However, to me, if even one strong study exists, then the entire compulsory practice must be re-evaluated.”

My Reply:
The scientific consensus is that fluoridation works, it is safe and it is cost effective. We have evolved with fluoride and had it adjusted in our water for over 60 years in some countries. Developed countries where natural fluoride levels are low but choose not to use community water fluoridation (CWF) generally use other methods such as milk and salt fluoridation, which again are both safe and effective, or have very effective public health and dental systems. Over 5,500 papers have been systematically reviewed and no consistent association between fluoridation and illness has been found that has been confirmed through later research.

Using the latest evidence: Public Health England just released their water fluoridation review this month – Water fluoridation Health monitoring report for England 2014 and it concluded:

“This monitoring report provides evidence of lower dental caries rates in children living in fluoridated compared to non-fluoridated areas. Similarly, infant dental admission rates were substantially lower. There was no evidence of higher rates of the non-dental health indicators studied in fluoridated areas compared to non-fluoridated areas. Although the lower rates of kidney stones and bladder cancer found in fluoridated areas are of interest, the population-based, observational design of this report does not allow conclusions to be drawn regarding any causative or protective role of fluoride; similarly, the absence of any associations does not provide definitive evidence for a lack of a relationship.”

Last month a reviewHealth effects of water fluoridation: A review of the scientific evidence written on behalf of the Royal Society of New Zealand and the Office of the NZ Prime Minister’s Chief Science Advisor concluded:

“Councils with established CWF schemes in New Zealand can be confident that their continuation does not pose risks to public health, and promotes improved oral health in their communities, reducing health inequalities and saving on lifetime dental care costs for their citizens. Councils where CWF is not currently undertaken can confidently consider this as an appropriate public health measure, particularly those where the prevalence and severity of dental caries is high. A forthcoming study from the Ministry of Health is expected to provide further advice on how large a community needs to be before CWF is cost-effective (current indications point to all communities of 1000+ people). It is recommended that a review such as this one is repeated or updated every 10 years – or earlier if a large well-designed study is published that appears likely to have shifted the balance of health benefit vs health risk.”

Looking at the many other systematic reviews you will find a similar pattern. CWF is shown to be safe and effective. So the “burden of proof” really is on those claiming evidence of harm. They need to produce well supported and peer-reviewed studies which back up their claims.

If there is a strong evidence for health risks of fluoridation then I totally agree with Rita that it needs to be re-evaluated. Every year many studies are written on fluoridation and continued monitoring of the scientific findings occurs in many countries with the precautionary principle of being alert to any possible negative effects.

Health organisations

Rita’s reply:

“Please also note that any and all of your cites to the ADA lobby, or to the CDC (which, though its oral health division, works hand in hand with the ADA promoting fluoridation and thus has a serious conflict of interest/credibility problem) are unpersuasive to me – as they should be to anyone conducting even a minimum level of research into the history of and politics behind fluoridation (some of which is chronicled in my article, including the story of the EPA’s NTEU battle).”

“it does not take long to discover how politically motivated many “public health agencies” and “professional dental associations” are — or how willing they are to obscure, minimize, or bury contrary evidence or to marginalize the anti-fluoridation messengers, regardless of the evidence or the credentials of those messengers (e.g., Waldbott, Taylor, Marcus, Mullenix, Bassin, Hirzy).”

My reply:
I think Rita is placing her own bias on these judgments. One could equally say:

“It does not take long to discover how politically motivated Dr Paul Connett and FAN are — or how willing they are to obscure, misinform, or bury contrary evidence or to marginalise the pro-science messengers, regardless of the evidence or the credentials of those messengers.”

If Rita has a specific problem with the CDC or the ADA, I can use some of the many other hundreds of health organisations around the world. They all have similar conclusions about fluoridation. As I said in my first response, there is not one reputable health organisation that is against fluoridation. We already have Dr Paul Connett suggesting a massive conspiracy, I hope you do not agree with his accusations as this is generally the last resort for people who cannot find reasonable faults in the evidence but still refuse to believe it.

NRC Report

Rita’s reply:

“However, I believe that its review of fluoride toxicology is highly relevant to exposures from fluoridated water (and its exposure data itself suggests that some people drinking fluoridated water can, indeed, receive doses that can cause adverse health effects, including severe dental fluorosis and bone fractures).”

“In addition, in a number of health risk areas, the NRC panel concluded that there was not enough data, and/or that more research needed to be conducted, before definitive statements could be made with respect to other potential adverse health effects due to excess exposure to fluoride.”

My reply:
I will not repeat what I said in my earlier reply. The review itself said that it was not relevant to exposures to concentrations used for fluoridated water and to say it is “highly relevant” is spreading misinformation. The NRC report furthered shows the safety of fluoridation. As for the “more research needed”, that is always the case with science. That is why responsible public health agencies continue to monitor research findings.

Ethics

Rita’s reply:

“I would genuinely be interested in knowing why you feel so strongly that imposing this practice on everyone is ethically justifiable.”

“Thus, I am very curious as to why there appears to be such an aggressive campaign on the pro fluoridation side to impose this practice on the world – and why anyone believes that personal liberties and rights to bodily integrity should be sacrificed for a public health practice addressing a non-contagious disease.”

“I would also be interested in understanding where you personally believe compulsory public health practices should begin and end (e.g., do you believe governments should mandate compulsory flu shots? What about the HPV vaccine that the Governor of Texas tried to mandate for girls? Where should the personal right to bodily integrity begin and end, in your opinion? And how comfortable are you with public health officials mandating what is good for you?…)”

My reply:
I don’t see how you conclude that I “feel so strongly that imposing this practice on everyone”. I, myself, could say I am strongly against misinformation. The MSoF society is here to help explain what the actual scientific evidence shows to the public, not to advocate for CWF at any cost. It is up to the communities if they want to use CWF and we, the MSoF Society, support their democratic right to decide.

But regarding ethical aspects, you might be interested in what the Nuffield Council on Bioethics decided. It:

  • Rejected the prohibition of water fluoridation based on the argument of mass medication and restricting personal rights.
  • Affirmed that water fluoridation should be accepted based on the quantified risks and benefits, the potential alternatives, and, where there are harms, the role of consent.

They also used a ‘stewardship mode’ to analyse the acceptable degree of state intervention to improve population health, concluding that water fluoridation can be justified based on its contribution to the goals of stewardship: the reduction of health inequalities, the reduction of ill health, and the concern for children, who represent a vulnerable group.

The New Zealand High Court this year ruled that fluoridation of the water supply:

  • is not a medical treatment,
  • does not violate the right to refuse medicine,
  • is not in breach of the Bill of Rights, And that
  • the Council was thoughtful and responsible in making their decision to begin fluoridation, and had no obligation to consider “controversial factual issues” (anti-fluoride propaganda).

You could say there is an aggressive campaign on both sides, but people are pushing for fluoridation simply because it works – reducing up to 40% of caries over a whole population.

Dental caries is a serious chronic disease, it makes no difference if it is contagious or not. The Royal Society Review pointed out that:

“…tooth decay (dental caries) remains the single most common chronic disease among New Zealanders of all ages, with consequences including pain, infection, impaired chewing ability, tooth loss, compromised appearance, and absence from work or school. Tooth decay is an irreversible disease; if untreated it is cumulative through the lifespan, such that individuals who are adversely affected early in life tend to have pervasive decay by adulthood, and are likely to suffer extensive tooth loss later in life. Prevention of tooth decay is essential from very early childhood through to old age”.

The Royal Society Review also suggested that removing fluoridation would have direct and indirect costs to society.

“Tooth decay is responsible for significant health loss (lost years of healthy life) in New Zealand. The ‘burden’ of the disease – its ‘cost’ in terms of lost years of healthy life – is equivalent to 3/4 that of prostate cancer, and 2/5 that of breast cancer in New Zealand. Tooth decay thus has substantial direct and indirect costs to society.”

I am all for protecting the vulnerable. If individuals do not consent, they can simply choose not to partake of the community water supply (bottled water, filters, rain water, etc.). I feel this is starting to head slightly off-topic but to answer your question, if the vaccine given out is safe and effective for the general public then I have no problems with compulsory shots for children. While choice is nice thing to have, you cannot always get it, especially if it is going to lower the quality of life in children.

The New Zealand High Court summarised some ethical aspects in the decision I referred to above:

“Provided it does not have consequences for public health a person has the right to make even the poorest decisions in respect of their own health. But where the state, either directly or through local government, employs public health interventions, the right is not engaged. Were it otherwise, the individual’s right to refuse would become the individual’s right to decide outcomes for others. It would give any person a right of veto over public health measures which it is not only the right but often the responsibility of local authorities to deliver.”

The World Health Organization

Rita’s reply:

“Data published by the WHO suggests that the decline in dental caries is similar in both fluoridated and unfluoridated countries, and I have heard of no massive outbreak of a worldwide dental carie epidemic that has been attributed to a lack of fluoridated water (rather than to poverty, poor nutrition, or a lack of access to proper dental care).”

My reply:
Petersen & Lennon (2004), a WHO funded study showed dental caries remain a major public health concern, affecting 60–90% of schoolchildren and the vast majority of adults. While fluoride is not a silver bullet, it is just part of the problem, it should not be ignored when it can clearly help very effectively. Their study goes into a number of suggestions for alleviating tooth decay, one being fluoridation.

“Water fluoridation, where technically feasible and culturally acceptable, has substantial advantages particularly for subgroups at high risk of caries. Alternatively, fluoridated salt, which retains consumer choice, can also be recommended. WHO is currently in the process of developing guidelines for milk fluoridation programs, based on experiences from community trials carried out in both developed and developing countries.”

As for the similar DMFT decline between fluoridated and unfluoridated countries Rita claims this needs to be considered critically. Fluoride occurs naturally everywhere and it is very hard to compare one country to others because of the many other contributing factors such as; history, culture, ethnic differences, as well as differences in health services, dental practice and assessments. The graphical evidence FAN promotes on their website and elsewhere they do not account for naturally occurring fluoride or other programs (fluoride vanish, mouth rinse programs, etc.) and different history and social practices. Their graphs also use only 2 data points for each country. There is no consideration of also changing fluoridation amounts over time and their graph is very confusing. It does not enable proper consideration of different DMFT declines in different countries. The stats show Denmark having the lowest DMFT and FAN marked them as not fluoridated, but they actually have high levels of naturally occurring fluoride.

Irish-2
If you look at the WHO data in more detail (graph left does this for the Irish Republic using the same WHO data) you will find that fluoridated areas show faster declines in DMFT than unfluoridated areas.

Making Sense of Fluoride

Rita’s reply:

“…you complain about FAN not being a legitimate source of credible scientific information, but your organization is also a political advocacy (pro-fluoridation) group”

“I urge you to conduct such a battle with a more appropriate sparring partner, such as FAN-NZ.”

My reply:
Like yourself, I am not a scientist – I am a software developer; my responses get checked by scientists but I would always look into the evidence in scientific studies. I avoid political or activist organisations (legitimate or not). The Making Sense of Fluoride society is not a pro-fluoridation group, we are a pro-science group. We will go with what the scientific consensus says and will spread warnings, if for example: some time in the future, CWF was really found to be harmful.

The objectives of the MSoF incorporated society are:

a) To foster awareness and dispel misinformation regarding fluoride with a focus on CWF.
b) Use the scientific method as the foundational platform upon which this awareness is promoted.

FANNZ, now known as Fluoride Free NZ (and a close partner of FAN), will always be anti-fluoride no matter what the evidence shows. For that reason it is usually not fruitful debating them. Their incorporated society main purposes make clear their opposition to CWF irrespective of the science:

a) To bring about the permanent end to public water fluoridation (“fluoridation”) in New Zealand.
b) To provide resources, both personal and material, to others opposing fluoridation in New Zealand.
c) To provide a central contact point for those opposing fluoridation in New Zealand.

Apology

Rita’s reply:

“This statement about “mounting scientific evidence” at the start of my paper (near fn. 2) actually references an entire section of my article – (“See discussion infra Sec. II-B”) — and not an opinion piece by Colquhoun, which is only referenced – appropriately – at footnote 65 (referring to “formerly avid fluoride proponents” who have changed their minds). I have no desire to engage with insincere zealots, so I hope that you simply made a mistake there.”

My reply:
I apologise for my mistaking you and any offense it may have caused you. It was clearly a simple mistake that anyone could have made and I had no intention to twist your words.

Wrapping up

Rita’s reply:

“After this exchange, however, I am only interested in a private discussion with you, which is something you may not be interested in as it may not advance your organization’s agenda”
“However, your Facebook posting has generated some contact to me by a few rude (and seemingly unbalanced) pro fluoridation folks”

My reply:
MSoF is always happy to have private discussions if you are willing to listen to our feedback. A lot of our work is outside of what the public sees but we always up for public exchanges to share to our followers.

You will find that your paper got sent all over Facebook and the media; because it was publicised in a press release from FAN. That is how I found out about it.
It is a pity you were subjected to insults because of that publicity. That said I was also hit with insults on Fluoride Free NZ Facebook pages because of my response to you. These insults are common and something I have gotten used too; in either case it is a shame that people feel it best to engage in debate in disrespectful ways. Fluoridation is an emotional topic for some – personally I do my best to stick with the science and keep my emotions out.

Thank you Rita for making time in reading our feedback and responding to us.

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Fluoride debate: Response to Daniel Ryan’s critique – Rita Bartlett-Rose

Rita F. Barnett

Rita Barnett-Rose, author of Compulsory water fluoridation: Justifiable public health benefit or human experimental research without informed consent” has replied to Daniel Ryan’s critique of her paper. Daniel’s critique was posted yesterday at Fluoride debate: A response to Rita Barnett-Rose – Daniel Ryan.

Rita’s reply is available to download as a pdf


RE: CWF Working Paper Article

Dear Daniel,
I have now had a chance to consider your comments to my draft article. In some respects, I am flattered that you have devoted so much time to an unpublished working paper, and I thank you for giving me some of your opinions. I absolutely want to make sure that I have cited to sources accurately and have not mischaracterized any particular study I reviewed. To that end, I have now engaged independent review of my article from several highly-qualified scientists/researchers with the specific request that they review my article for scientific accuracy. After I have received their comments, I will revise my draft accordingly.

Unfortunately (or fortunately for me), I did not find in your review any specific places where I actually mischaracterized any cited study. Instead, your primary points of contention seem to be twofold: (1) you object to my use of Fluoride Action Network’s (“FAN”) website as a cited source; and (2) you object to my failure to include contrary studies that reaffirm the (English-speaking countries’) public health agencies’/dental lobby positions on the safety and benefits of compulsory water fluoridation.

First, with respect to my reliance on FAN. Of the 209 footnote references in my article, I believe only 17 of them are cites to FAN. Of those 17 cites, I am citing to the FAN website primarily as an easy way to get to the primary source material (e.g., studies or newspaper articles from around the world). For example, in footnotes 85-87, I could have listed the primary source studies, but I have found that many of these studies are hard to get on the internet for those who do not have paid subscriptions to the various science databases. I myself had to order a number of the primary sources from my University intra-library loan system and felt that it would be better to simply provide a link so that the reader could see the names of the studies and determine for himself/herself how to get to those primary sources. Nevertheless, your point is well-taken that I should not give the appearance of relying upon an advocacy group (including yours), and I will review those 17 cites to see if I should instead cite to primary sources.

Second, with respect to your complaint or desire that I cite to contrary (i.e., pro-fluoridation) studies in addition to (or in lieu of) the published studies that I cite that tend to weigh against fluoridation, as I have already indicated to you on two occasions: I am not interested in a battle of the studies debate, and I urge you to conduct such a battle with a more appropriate sparring partner, such as FAN-NZ. Specifically: you complain about FAN not being a legitimate source of credible scientific information, but your organization is also a political advocacy (pro-fluoridation) group, and, from your critique, you are just as guilty of “cherry picking” your sources and your studies as you suggest I am. Moreover, and in stark contrast to you, the section of my article where the studies are discussed is specifically entitled: “Scientific Evidence Against Compulsory Water Fluoridation.” It is not meant to be an exhaustive examination of all studies on fluoridation and is specifically and accurately identified for what it is. I am well aware of many of the pro-fluoridation studies — as well as the criticisms of many of those studies (in terms of who funded them, flaws in methodology, conflicts of interest, etc.) by those opposed to fluoridation. I do not believe either side has definitively proved their case with respect to safety/benefits or lack thereof. However, what I do believe is that the burden of proving safety and effectiveness lies with the pro-fluoridation side, as it is your side that is insisting on imposing this “public health measure” on everyone else, even in the face of substantial objection and despite existing studies suggesting serious risks of harm. It also appears to me that the pro-fluoridation side is playing “whack a mole” with the studies weighing against CWF – often trying to hammer down/marginalize the opposition each time a negative study pops up, rather than trying to consider the evidence objectively. I note throughout your critique that you often refer to studies that weigh against fluoridation as “flawed” or “debatable” or as somehow lacking in proper control mechanisms – while studies that support fluoridation are “quality studies.” (p.8). You also minimize any existing evidence weighing against fluoridation by qualifying it: “there is no quality research” (p. 4) “there is no robust evidence” (p. 4), “there is no strong evidence” (p. 6). However, to me, if even one strong study exists, then the entire compulsory practice must be reevaluated.

Please also note that any and all of your cites to the ADA lobby, or to the CDC (which, though its oral health division, works hand in hand with the ADA promoting fluoridation and thus has a serious conflict of interest/credibility problem) are unpersuasive to me – as they should be to anyone conducting even a minimum level of research into the history of and politics behind fluoridation (some of which is chronicled in my article, including the story of the EPA’s NTEU battle). Incidentally, as someone who did not have a pony in this race before doing the actual research (i.e., I am not a long-time anti-fluoridation advocate), it does not take long to discover how politically motivated many “public health agencies” and “professional dental associations” are — or how willing they are to obscure, minimize, or bury contrary evidence or to marginalize the anti-fluoridation messengers, regardless of the evidence or the credentials of those messengers (e.g., Waldbott, Taylor, Marcus, Mullenix, Bassin, Hirzy).

With respect to the NRC Report, I agree with you that it did not specifically address compulsory water fluoridation. However, I believe that its review of fluoride toxicology is highly relevant to exposures from fluoridated water (and its exposure data itself suggests that some people drinking fluoridated water can, indeed, receive doses that can cause adverse health effects, including severe dental fluorosis and bone fractures). In addition, in a number of health risk areas, the NRC panel concluded that there was not enough data, and/or that more research needed to be conducted, before definitive statements could be made with respect to other potential adverse health effects due to excess exposure to fluoride. This is hardly a ringing endorsement of the safety of fluoride or fluoridation. Nor is the NRC Report irrelevant to the fluoridation debate.

I see no point in going through your critique page by page to point out various flaws in it, as mostly you seem to be trying to persuade me with contrary evidence rather than identifying any mischaracterizations of the studies I did cite. I will, however, point out that your opening accusation on p. 2 that my “paper starts off by saying there is mounting scientific evidence against fluoridation” and that I used an opinion piece by John Colquhoun as my “evidence” to support this statement is outrageously incorrect, and it almost prompted me not to respond to you at all, as I do not appreciate my words being twisted or my cites misused to inflate your argument. This statement about “mounting scientific evidence” at the start of my paper (near fn. 2) actually references an entire section of my article – (“See discussion infra Sec. II-B”) — and not an opinion piece by Colquhoun, which is only referenced – appropriately – at footnote 65 (referring to “formerly avid fluoride proponents” who have changed their minds). I have no desire to engage with insincere zealots, so I hope that you simply made a mistake there.

As I said to you privately, I am more than willing to revise my article where I have misstated any of the cited scientific evidence. However, I disagree with you that a discussion on the legal and ethical aspects of CWF would be “confusing” or “pointless” at this point and I would genuinely be interested in knowing why you feel so strongly that imposing this practice on everyone is ethically justifiable. Data published by the WHO suggests that the decline in dental caries is similar in both fluoridated and unfluoridated countries, and I have heard of no massive outbreak of a worldwide dental carie epidemic that has been attributed to a lack of fluoridated water (rather than to poverty, poor nutrition, or a lack of access to proper dental care). Thus, I am very curious as to why there appears to be such an aggressive campaign on the pro-fluoridation side to impose this practice on the world – and why anyone believes that personal liberties and rights to bodily integrity should be sacrificed for a public health practice addressing a non-contagious disease. I would also be interested in understanding where you personally believe compulsory public health practices should begin and end (e.g., do you believe governments should mandate compulsory flu shots? What about the HPV vaccine that the Governor of Texas tried to mandate for girls? Where should the personal right to bodily integrity begin and end, in your opinion? And how comfortable are you with public health officials mandating what is good for you? Do you contend that they haven’t been wrong on a public health issue before?).

As for me, I remain convinced that CWF is legally and ethically unjustifiable. My article sets forth my reasons, so I won’t repeat those arguments here. These reasons would remain even if compulsory water fluoridation were proven to be entirely safe, which it most definitely has not, despite the presumed “majority” view in the English speaking countries. You will also find many of my reasons articulated by dissenting justices in fluoridation cases over the last 60+ years, when presumably even less “science” was available to support their nevertheless valid legal/ethical objections to CWF. I include some of these cases and dissenting opinions in my article.

Daniel, I thank you for your (heretofore) civilized exchange with me and I do welcome your thoughts if you have any on the legal and ethical justifications of CWF. After this exchange, however, I am only interested in a private discussion with you, which is something you may not be interested in as it may not advance your organization’s agenda. However, your facebook posting has generated some contact to me by a few rude (and seemingly unbalanced) pro-fluoridation folks, and I have no interest in entertaining their rants (which certainly do nothing but convince me that the pro-fluoridation side has something to hide). In any event, I do thank you for reaching out and for your interest in my article. I hope to ensure that my final draft will address any legitimate criticisms/issues.
Sincerely,
Rita


Daniel Ryan’s response to Rita’s reply will be posted tomorrow. See Fluoride debate: Second response to Rita Barnett-Rose – Daniel Ryan.

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