Category Archives: New Zealand

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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Did business interests interfere with Hamilton’s fluoride tribunal process?

Oldfield-Poster-2015

 Source: Abuse of democratic process in Hamilton Tribunal?. (Click to enlarge).

Early results from a Waikato University research project show that around 2/3 of all the written submissions to the Hamilton City Council’s fluoride tribunal process were directly or indirectly provided by parties associated with the ‘natural health’ lobby.

This is interesting as it raises the question of links between this lobby and the anti-fluoride movement. I showed in When politicians and bureaucrats decide the science  how the submission process in this case was dominated by the anti-fluoride movement and how their misrepresentation of the science fooled the local body politicians and bureaucrats. In Who is funding anti-fluoridation High Court action? I showed how big money from the “natural” health industry was financing legal action against fluoridation.

This research is not yet complete so we look forward to further details on this relationship and on how such corporate interests and activists groups cooperate in submissions to local body councils.

The research project is “Public Integrity and Participatory Democracy: Hamilton City Council’s Water Fluoridation Decision“. Waikato University student Luke Oldfield is carrying out the work financed by the grant. He recently displayed a poster(above) to an audience of academic faculty sharing some preliminary results of his research.

Interestingly spokespeople for the anti-fluoride groups have opposed this research from the moment of the announcment of the grant (see Anti-fluoride activists unhappy about scientific research).

Something to hide, perhaps?

Thanks to Abuse of democratic process in Hamilton Tribunal? at the new Making Sense of Fluoride web page.

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Download report analysing anti-fluoride attacks on NZ Fluoridation Review

CWF-safe-report

The NZ Fluoridation review, Health Effects of Water Fluoridation: a Review of the Scientific Evidence, is an authoritative and up-to-date review on water fluoridation in New Zealand. The anti-fluoridation activist organisation Fluoride Free NZ (FFNZ) attempted to discredit the review with their report Scientific and Critical Analysis of the 2014 New Zealand Fluoridation Report.

In this report, Fluoridation is Safe and Effective, I analyse the FFNZ critique and show it was written, and “peer-reviewed” by well know anti-fluoridation activists

This report analyses the three main articles in the FFNZ document showing that the critique is based on misinformation commonly promoted by anti-fluoride propagandists.

I point out a small mistake in the executive summary of the Fluoridation review and describe how it arose. The concept was explained correctly in the body of that report. The mistake, little more than a typo, has now been corrected.

Fluoridation is Safe and Effective is a slightly edited version of a number of articles posted on this blog. It is now available to download in pdf format.

I hope this report will be useful wherever Fluoride Free NZ use their own document in an attempt to discredit the NZ Fluoridation Review. If FFNZ use their misleading document in their campaigns to local body councils, or in presentations to the media and public meetings this report can provide the material which debunks their claims.

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January ’15 – NZ blogs sitemeter ranking

Social-Media-Statistics-You-Need-to-Know1

Credit: 10 Social Media Facts, Figures and Statistics You Need to Know

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

Every month I get queries from people wanting their own blog included. I encourage and am happy to respond to queries but have prepared a list of frequently asked questions (FAQs) people can check out. Have a look at NZ Blog Rankings FAQ. This is particularly helpful to those wondering how to set up sitemeters.

Please note, the system is automatic and relies on blogs having sitemeters which allow public access to the stats.

Here are the rankings of New Zealand blogs with publicly available statistics for January 2015. Ranking is by visit numbers. I have listed the blogs in the table below, together with monthly visits and page view numbers.

Meanwhile I am still keen to hear of any other blogs with publicly available sitemeter or visitor stats that I have missed. Contact me if you know of any or wish help adding publicly available stats to your bog.

You can see data for previous months at Blog Ranks

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Hypocrisy

tin foilCredit: The Skeptics’ Guide to the Universe

This cartoon reminded me of some of the local campaigners against fluoridation. They almost all are either strongly connected to the “natural” health movement and its businesses, or, because of their beliefs, are customers of that industry. Yet they often argue that genuine scientific and health experts are in the pay of “big pharma” or similar businesses and are acting as “shills” for industry! That is plain hypocrisy. Similar articles

Fluoride Free NZ report disingenuous – conclusion

This is the third and last article 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 (hereafter refered to as the Royal Society Review).

My first article, Peer review of an anti-fluoride “peer review” discussed Kathleen Theissen’s contribution. (It also discussed a draft contribution by Chris Neurath which does not appear in the final version). The second article, Cherry-picking and misinformation in Stan Litras’s anti-fluoride articlecritiques Stan Litras’s contribution. This one discusses H. S. Micklem’s contribution.

See The farce of a “sciency” anti-fluoride report for an analysis of the close relationships between the authors and peer reviewers of the Fluoride Free NZ report and anti-fluoride activist groups.

There are a few smaller articles by Paul Connett and Mark Atkins. They do not deal with the contents of the Royal Society Review so I will not comment on them here.

This article below completes my critique of the Fluoride free NZ report.


H. S. Micklen, who wrote the second article in the Fluoride Free NZ report, is one of the coauthors, together with Paul Connett, of the book  The Case against Fluoride which anti-fluoride activists treat as gospel. His article was “peer-reviewed” by James Beck, the other co-author of the book.

In my comments I use the section headings used by H. S. Micklem.

Dental fluorosis

I think Micklen’s comments on dental fluorsis are quite muddled. He confuses the relevance of the different grades of dental fluorosis and unfairly attributes the more severe forms to community water fluoridation (CWF). Consequently he calculates a cost of dental treatment which is wrong.

Recently I put dental fluorosis, its different grades and its contribution to oral health satisfaction into context with the image below (see Water fluoridation and dental fluorosis – debunking some myths):

Dental fluorosis of grades none, questionable, very mild and mild are common in countries suitable for CWF – in both fluoridated and unfluoridated areas. Fluoridation may cause a small increase in mild grades. But these first 4 grades (none – mild) are judged purely “cosmetic. In fact children and parents often judge the grades “questionable – mild” more highly than “none.” Research finds these milder forms of dental fluorosis often improve dental health related quality of life (Do and Spencer, 2007; Chankanka et al., 2010; Peres et al., 2009; Biazevic et al., 2008; Büchel et al., 2011; Michel-Crosato et al., 2005).

Micklem is straw-clutching to take one reference used by the Royal Society Review out of context to imply that these studies are wrong because “subjects liked the appearance of a complete set of artificially white teeth.” He says “they did not like the whiteness associated with fluorosis.”  But the authors actually say:

“The ranking of images of teeth with a fluorosis score of TF 1 may lead to the inference this sample of 11 to 13 year olds do not consider milder presentations of fluorosis to be aesthetically objectionable. The very white teeth represented an unnatural presentation that could only be achieved by cosmetic procedures. . . . This is consistent with previous work related to dental aesthetics [18,19] whereby teeth with mild forms of fluorosis (TF 1, TF2) were rated similarly.”

Micklem raises the bogey of the cost of veneers (up to $1750 per tooth) but this is just scaremongering as veneers would not be used for teeth with these mild grades of fluorosis.

Moderate and severe grades of dental fluorosis are common in areas where fluorosis is endemic, but relatively rare where CWF is used. Occurences in the later 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.

Treatment of moderate and severe cases of dental fluorosis using veneers may well be appropriate for a very few young people in countries like New Zealand and the US but it is misleading to attribute this to CWF. Interestingly, Micklem’s misattribution mirrors that of Ko and Thiessen (2014). They also assumed all moderate and  severe dental fluorosis was caused by CWF thereby enabling them to declare no cost benefit to CWF because of the required dental treatments.

Micklem has simply continued the anti-fluoride propagandist tradition of confusing data for the relative amounts of different grades of dental fluorosis and attributing problems with the rare moderate and severe forms to the more common questionable and mild forms.

Neurotoxicity and IQ

In this section Micklem attempts to contrast the Choi et al (2012) metareview with the Broadbent et al (2014) study. He erroneously refers to both as being relevant to CWF and “the case that water fluoridation poses a development risk to human intelligence.”

Let’s make this clear. The Choi et al (2012) review did not include studies of CWF. The authors made clear that their results should not be seen as relevant to CWF. Most of the brief reports they reviewed studied areas of endemic fluorosis and Xiang (2014) (one of the authors of an included study) gives some idea of how this is manifested in a title slide to a recent talk.

The only study Micklem comments on that involved CWF was that of Broadbent at al (2014).  Micklem describes this as “inconclusive” but does not say why. Do I detect some bias there?

Given the available studies I think the Royal Society review was justified in concluding “that on the available evidence there is no appreciable effect on cognition arising from CWF.”

Passing on to the question of the Choi et al (2012) metareview, which is not relevant to CWF. Micklen concedes that included studies were individually  “not strong” but argues “the existence of so many studies almost all saying the same (important) thing” should be treated with attention and respect. I agree – but lets not allow that attention and respect to be blind. Let’s be aware of the limitations and attempt to understand what the results might mean.

The authors of that metareview have extended their work to making their own measurements in a pilot study (Choi et al., 2014). In this new paper they did not find a significant relationship between cognitive deficit measurements and drinking water fluoride. We need to accommodate this finding in our assessment of the metareview.

Choi et al (2014) did find a significant association of cognitive deficits with severe dental fluorosis.  Perhaps we need to respect that finding and give it some attention. Rather than the assuming the mechanism of such cognitive deficits is the speculated but unproven neurotoxic activity of fluoride we should be open to other possible mechanisms (Perrott 2015)..

I have done so with my article  and would welcome any feedback Micklem could give on this. I feel that the effects of a physical deformity like severe dental fluorosis on learning is a more realistic mechanism (for which there is a lot of published evidence) than some sort of vague chemical toxicity which has never been noted at these low concentrations.

Incidentally, Micklem attempts to discredit the Royal Society’s understanding of the Choi et al (2012) saying it suggested that the measured IQ reduction was “arguably negligible.” The Royal Society review actually said:

“Setting aside the methodological failings of these studies, Choi et al. determined that the standardised weighted mean difference in IQ scores between “exposed” and reference populations was only -0.45. The authors themselves note that this
difference is so small that it “may be within the measurement error of IQ testing”.[172]”

Choi et al., (2012) said:

“The estimated decrease in average IQ associated with fluoride exposure based on our analysis may seem small and may be within the measurement error of IQ testing.”

And their abstract reported the “standardized weighted mean difference in IQ score between exposed and reference populations was –0.45 (95% confidence interval: –0.56, –0.35).”

There has been some confusion because Choi et al., (2012) used a standardised weighted mean difference to accommodate the different IQ scales used in the studies they reviewed. But their warning about the small size of the calculated difference and its relationship to measurement errors in IQ testing is relevant.

The Royal Society Review did indeed make a mistake in the executive summary where it referred to a claimed IQ shift of “less than one IQ point” when it should have said “less than one standard deviation.” I discussed this in Did the Royal Society get it wrong about fluoridation? and noted that even Harvard University made the same mistake in its inital press release of the Choi et al (2012) work.

I think the Authors of the Royal Society Review should correct that mistake, as Harvard University did – but it does not change the fact there is no mistake in the review’s evaluation of the Choi et al (2012) paper.

Lead

In this section Micklem attempts to cast doubt on the Royal Society Review’s comments on the form of fluoride in drinking water and a possible role of fluoride in releasing lead from pipe fittings.

The hydrolysis of fluorosilicic acid when diluted during water treatment may not be completely understood (nothing ever is) but recent high quality research (Urbansky & Schock 2000; Urbansky 2002; Finney et al., 2006) has confirmed the review’s statement it is “effectively 100% dissociated to form fluoride ion under water treatment conditions.” Despite acknowledging the need for more and better research Urbansky (2002) concluded “all the rate data suggest that equilibrium should have been achieved by the time the water reaches the consumer’s tap if not by the time it leaves the waterworks plant.”

This debate only exists among anti-fluoride propagandists because of selective and motivated reliance on old and poor quality research, together with confirmation bias. For example, the report by Crosby (1969) that “evidence from specific-ion electrode and conductivity measurements at 25° confirms that sodium fluorosilicate, at the concentration normally present in public water supplies, is dissociated to at least 95%” is interpreted by Coplan et al., (2007) as “proof” the fluorosilicate is 5% unhydrolysed!

Micklem relies on then papers of Master et al., (2000), Copelan et al 2007 and Mass et al., (2007) to argue that fluoride treatment chemical enhances lead release from pipes. However, I think an objective assessment of these paper would conclude the authors argue determinedly for a preconceived hypothesis and that many of their arguments are irrelevant and faulty. This is not to dismiss their finding on lead levels in drinking water – but as Masters et al., (2000) themselves point out – “statistical association should not be confused with causation.” 

Similarly, I suggest that Micklen’s reliance on Sawan et al., (2010) to support Copelan’s hypothesis amounts to special pleading as those workers used drinking water concentration of 100 mg/L of fluoride and 30 mg/L of lead.

Osteosarcoma

Micklem uses the old anti-fluoride activist trick of fixating on a cherry-picked paper which fits his agenda and downplaying or attempting to discredit papers which don’t. He concentrates on Bassin et al (2006), despite its description by its authors as “an explanatory study” requiring “further research” to “confirm or refute” its conclusions. That paper fits Micklem’s agenda because it found a statistically increased risk of osteosarcomas in male boys exposed to water fluoridated at 1.2 mg/L F.

In such a complex area, for a cancer with such a low incidence, a balanced overall consideration of research reports is necessary. All papers have their advantages and drawbacks so conclusions should be derived from proper consideration of the total research findings – as the Royal Society review appears to have done.

The Bassin (2006) findings have not been confirmed by any later work – despite a range of such studies (Kim et al., 2011; Comber et al., 2011; Levy and Leclerc 2012; Blakey et al., 2014). The Royal Society Review pointed out previous reviews had all concluded that “based on the best available evidence, fluoride could not be classified as carcinogenic in humans.” And that “more recent studies have not changed this conclusion.”

Micklem hasproduced nothing to counter that conclusion.

Cardiovascular and renal effects

Micklen attempts to use the paper, Martín-Pardillos et al., (2014), cited by the Royal Society Review, against the reviews conclusions. The review presents the paper this way:

“A number of studies indicate that fluoride may reduce aortic calcification in experimental animals and humans.[199] This preventive effect was recently confirmed by in vitro experiments, but in vivo findings from the same studies showed the opposite result – that phosphate-induced aortic calcification was accelerated following exposure of uremic rats to fluoride in water at around 1.5 mg/L.[200] The authors suggested that chronic kidney disease could be aggravated by relatively low concentrations of fluoride, which (in turn) accelerates vascular calcification. However, further studies are required to test this hypothesis.”

Martín-Pardillos et al., (2014) proceeded from the hypothesis that fluoride did not initiate calcification but because it is attracted to calcified deposits it may influence subsequent crystallisation of the calcified material.

Their in vitro results indicated a protective effect against calcification. While the opposite was observed with the 5/6 nephrectomised rats with induced calcification they still concluded:

“The direct inhibition of ectopic calcification could still occur in vivo when the renal function is correct, such as during aging or even the initial stages of diabetes, and this possibility deserves further research.”

This is relevant to healthy humans without chronic kidney disease (CKD).

The acceleration of induced vascular calcification with the 5/6 nephrectomised rats does raise the need for further studies, and monitoring the situation with humans suffering CKD. But let’s not forget the rat model was extreme. Rats had all of one kidney and 2/3 of the other kidney removed. They were also fed a phosphate enriched diet and the induced CKD was clearly indicated by urea and creatine blood concentration.

Of course these findings are relevant when considering ongoing research and monitory the situation of CKD human patients. As the authors say “the effects of fluoride on renal function and vascular health are more complicated than expected.”

However, the current advice of the National Kidney Foundation is that:

“Dietary advice for patients with Chronic Kidney Disease (CKD) should primarily focus on established recommendations for sodium, calcium, phosphorus, energy/calorie, protein, fat, and carbohydrate intake. Fluoride intake is a secondary concern.”

Given that such patients are already monitory their diet and more advanced cases also probably regularly monitory blood indicators  any possible effect of fluoride for individuals should be detected. It is likely that by the time any problem with fluoride in drinking water is indicated other problems will also have occurred and patients will be taking steps such as water filtering and careful dietary management to handle their situation.

In fact individually directed management of food and drinking water appears to be a sensible way of handling problems if they do occur with a few people.

Micklem’s “call for CKD sufferers to be warned to avoid tap water” is too extreme and alarmist. Already the advice is that persons with CKD should be notified of the potential risk of fluoride exposure and be kept up to date with new research. 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 policy like CWF.

Conclusions

This completes my critique of the Fluoride Free NZ report.

The original Royal Society review, Health Effects of Water Fluoridation: a Review of the Scientific Evidence, was prepared in response to a request from councils for a summary of the current science on CWF. This is because over the last few years activists political groups, like Fluoride Free NZ (and its international associate Fluoride Action Network) have bombarded New Zealand councils with misinformation and distortion of the science in campaigns to prevent CWF or get it removed

Councils do not have the expertise to critical consider claims made by such activist groups and have adopted a policy of requesting central government take over their responsibilities on the issue. Until that happens, however, councils will continue to have such decisions forced upon them.

The Royal Society review provides a timely and authoritative source of information for councils. Understandably Fluoride Free NZ feels somewhat trumpted by the review. So it is understandable this activist groups, and the international associate will use their media influence to try to discredit it.

This report is an attempt to fool councils by pretending to be objective and international. Yet, as my articles in this series show, it is simply a put-up job. It is not objective – all the authors and “peer reviewers” are working for or associated with the Fluoride Action Network or its associates. The articles follow the typical cherry-picking and confirmation bias of such activist organisations.

See The farce of a “sciency” anti-fluoride report for an analysis of the close relationships between the authors and peer reviewers of the Fluoride Free NZ report and anti-fluoride activist groups.

The Fluoride Free report is simply disingenuous – a sham aimed at fooling councils.

References

Bassin, E. B., Wypij, D., Davis, R. B., & Mittleman, M. a. (2006). Age-specific fluoride exposure in drinking water and osteosarcoma (United States). Cancer Causes & Control : CCC, 17(4), 421–8.

Biazevic, M. G. H., Rissotto, R. R., Michel-Crosato, E., Mendes, L. A., & Mendes, M. O. A. (2008). Relationship between oral health and its impact on quality of life among adolescents. Brazilian Oral Research, 22(1), 36–42.

Blakey, K., Feltbower, R. G., Parslow, R. C., James, P. W., Gómez Pozo, B., Stiller, C., … McNally, R. J. (2014). Is fluoride a risk factor for bone cancer? Small area analysis of osteosarcoma and Ewing sarcoma diagnosed among 0-49-year-olds in Great Britain, 1980-2005. International Journal of Epidemiology, 43(1), 224–34.

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.

Büchel, K., Gerwig, P., Weber, C., Minnig, P., Wiehl, P., Schild, S., & Meyer, J. (2011). Prevalence of Enamel Fluorosis in 12-year-Olds in two Swiss Cantons. Schwiz Monatsschr Zahnmed, 121(7/8), 652–656.

Chankanka, O., Levy, S. M., Warren, J. J., & Chalmers, J. M. (2010). A literature review of aesthetic perceptions of dental fluorosis and relationships with psychosocial aspects/oral health-related quality of life. Community Dentistry and Oral Epidemiology, 38(2), 97–109. x

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., Grandjean, P., Sun, G., & Zhang, Y. (2013). Developmental fluoride neurotoxicity: Choi et al. Respond. Environmental Health Perspectives, 121(3), A70.

Choi, A. L., Zhang, Y., Sun, G., Bellinger, D., Wang, K., Yang, X. J., … Grandjean, P. (2014). Association of lifetime exposure to fluoride and cognitive functions in Chinese children: A pilot study. Neurotoxicology and Teratology, 47, 96–101.

Comber, H., Deady, S., Montgomery, E., & Gavin, A. (2011). Drinking water fluoridation and osteosarcoma incidence on the island of Ireland. Cancer Causes & Control : CCC, 22(6), 919–24.

Coplan, M. J., Patch, S. C., Masters, R. D., & Bachman, M. S. (2007). Confirmation of and explanations for elevated blood lead and other disorders in children exposed to water disinfection and fluoridation chemicals. Neurotoxicology, 28(5), 1032–42.

Crosby, N. T. (1969). Equilibria of fluorosilicate solutions with special reference to the fluoridation of public water supplies. Journal of Applied Chemistry, 19(4), 100–102.

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.

Eason, C., & Elwood, JM. Seymour, Thomson, WM. Wilson, N. Prendergast, K. (2014). Health effects of water fluoridation : A review of the scientific evidence. Royal Society of New Zealand and Office of the Prime Minister’s Chief Science Advisor, Wellington.(p. 74).

Finney, W. F., Wilson, E., Callender, A., Morris, M. D., & Beck, L. W. (2006). Reexamination of hexafluorosilicate hydrolysis by 19F NMR and pH measurement. Environmental Science & Technology, 40(8), 2572–7.

Kim, F. M., Hayes, C., Williams, P. L., Whitford, G. M., Joshipura, K. J., Hoover, R. N., & Douglass, C. W. (2011). An assessment of bone fluoride and osteosarcoma. Journal of Dental Research, 90(10), 1171–6.

Ko, L., & Thiessen, K. M. (2014). A critique of recent economic evaluations of community water fluoridation. International Journal of Occupational and Environmental Health

Levy, M., & Leclerc, B.-S. (2012). Fluoride in drinking water and osteosarcoma incidence rates in the continental United States among children and adolescents. Cancer Epidemiology, 36(2), e83–e88.

Maas, R. P., Patch, S. C., Christian, A.-M., & Coplan, M. J. (2007). Effects of fluoridation and disinfection agent combinations on lead leaching from leaded-brass parts. Neurotoxicology, 28(5), 1023–31.

Martín-Pardillos, A., Sosa, C., Millán, A., & Sorribas, V. (2014). Effect of water fluoridation on the development of medial vascular calcification in uremic rats. Toxicology, 318C, 40–50.

Masters, RD; Coplan, MJ; Hone, BT; Dykes, J. (2000). Association of silicofluoride treated water witrh elevated blood lead. NeuroToxicology, 21(6), 1091–1100.

Michel-Crosato, E., Biazevic, M. G. H., & Crosato, E. (2005). Relationship between dental fluorosis and quality of life: a population based study. Brazilian Oral Research, 19(2), 150–155.

Peres, K. G., Peres, M. a, Araujo, C. L. P., Menezes, A. M. B., & Hallal, P. C. (2009). Social and dental status along the life course and oral health impacts in adolescents: a population-based birth cohort. Health and Quality of Life Outcomes, 7, 95.

Perrott, K. W. (2015). Severe dental fluorosis and cognitive deficits. Neurotoxicology and Teratology. In press.

Sawan, R. M. M., Leite, G. A. S., Saraiva, M. C. P., Barbosa, F., Tanus-Santos, J. E., & Gerlach, R. F. (2010). Fluoride increases lead concentrations in whole blood and in calcified tissues from lead-exposed rats. Toxicology, 271(1-2), 21–6.

Urbansky, E. T. (2002). Fate of fluorosilicate drinking water additives. Chem. Rev., 102, 2837–2854.

Urbansky, E. T., & Schock, M. R. (2000). Can Fluoridation Affect Water Lead Levels and Lead Neurotoxicity ? In American Water Works Association Annual Conference (pp. 1–31).

Xiang, Q. (2014) Keynote Address on IQ studies published in China. Fluoride Action network.

December ’14 – NZ blogs sitemeter ranking

2015 Happy New Year Strands Line Glow Dark Background

 


PLEASE NOTE: Sitemeter is still playing up but far fewer blogs are effected. It was still impossible to get the stats for a the blogs that I list below. Maybe more bloggers will shift to StatCounter or other counter.

No stats could be found for these blogs:

Science Behind the Curtain Grumpollie

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

Every month I get queries from people wanting their own blog included. I encourage and am happy to respond to queries but have prepared a list of frequently asked questions (FAQs) people can check out. Have a look at NZ Blog Rankings FAQ. This is particularly helpful to those wondering how to set up sitemeters.

Please note, the system is automatic and relies on blogs having sitemeters which allow public access to the stats.

Here are the rankings of New Zealand blogs with publicly available statistics for December 2014. Ranking is by visit numbers. I have listed the blogs in the table below, together with monthly visits and page view numbers.

Meanwhile I am still keen to hear of any other blogs with publicly available sitemeter or visitor stats that I have missed. Contact me if you know of any or wish help adding publicly available stats to your bog.

You can see data for previous months at Blog Ranks

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Cherry-picking and misinformation in Stan Litras’s anti-fluoride article

This is the second article in a series critiquing contributions to the Fluoride Free NZ report Scientific and Critical Analysis of the 2014 New Zealand Fluoridation Report.”

My first article Peer review of an anti-fluoride “peer review”  discussed Kathleen Theissen’s contribution. (It also discussed a draft contribution by Chris Neurath which does not appear in the final version).

I will shortly post a 3rd article discussing H. S. Micklem’s contribution.

See The farce of a “sciency” anti-fluoride report for an analysis of the close relationships between the authors and peer reviewers of the Fluoride Free report and anti-fluoride activist groups.


There is a lot in Stan Litras’s article to criticise – there is a lot which is misleading or outright wrong. I hope Stan will seriously consider my criticisms and respond to them, especially where he thinks I am wrong.

My criticisms should also be considered by Bruce Spittle and Hardy Limeback who Fluoride Free NZ listed as “peer reviewers” of Stan’s article. They must bear some responsibility for allowing the article to go ahead without the necessary corrections.

Litras makes many of his criticisms of community water fluoridation (CWF) in passing – without argument or evidence. But he declares:

“My comments will focus on the gross over statement of the purported benefits of fluoridation in our society, New Zealand, 2014.”

So, I will start with the claims he makes on this.

“Overseas studies” – The WHO data

Central to this are Stan’s assertions:

“The “elephant in the room” is that while decay rates fell in areas where fluoridation was implemented, it also fell in areas that weren’t, often at a faster rate. (8)”

And

“Globally, fluoridation is seen to make no difference to reduced decay rates, there being no difference between the few countries which use artificial fluoridation, and those that don’t. (8,7)”

His only evidence for this is a figure prepared by Chris Neurath from the Fluoride Action Network – using data from the World Health Organisation (WHO). Here it is in a slightly simpler version to the one used by Stan.

I am amazed that anti-fluoride propagandists keep using this graphic as “proof” that fluoride is ineffective. But they do – which can only mean they haven’t thought it through.

While the plots do show improvements in oral health for countries independent of fluoridation they say nothing about the effect of fluoride. Simple comparison of countries obscures all sorts of effects such as differences in culture, history, social and political policies, etc. Such plots are also influenced by changes and differences in dental treatment and measurement techniques.

Robyn Whyman in his report Does delayed tooth eruption negate the effect of water fluoridation? exposes the little trick Stan is trying to pull with the WHO data:

“Studies that appropriately compare the effectiveness of water fluoridation do not compare poorly controlled inter-country population samples. They generally compare age, sex, and where possible ethnicity matched groups from similar areas. Inter-country comparisons of health status, including oral health status, are notoriously difficult to interpret for cause and effect, because there are so many environmental, social and contextual differences that need to be considered.”

There are some within country data within the WHO data set Neurath used which can give a better idea of the beneficial effects of fluoridation. This plot shows the results for the WHO data for Ireland. A clear sign that fluoridation plays a beneficial role.

Neurath covered up evidence for the benefits of CWF by simply using the mean of fluoridated and unfluoridated areas for countries like Ireland and New Zealand. Also, the straight lines in Chris Neurath’s plots are a real give away to the poor quality of the data used. Two data points for each country!

New Zealand – Cherry-picking the MoH data

I have criticised Stan’s misrepresentation the Ministry of Health (MoH) data before. At the time he was using and misrepresenting some of my own graphics on his business website. He has since removed the offending article but now he returns with a vengeance – with tables and figures of his own.

This has given him free hand to cherry-pick and misrepresent to his heart’s content.

He claims:

“Ministry of Health figures recorded every year in 5 year olds and year 8s (12-13 year olds) consistently show minimal or no differences between fluoridated and nonfluoridated areas of NZ.”

stan_1

Cherry-picked data from Stan Litras

And he backs this up with a graph.

That looks about right. The data for 2011 shows 59.9% of 5 year olds in fluoridated areas were caries-free while 59.2% were carries free in non-fluoridated areas. No real difference.

But come on! A single data point, one year, one of the age groups for the fluoridated and unfluoridated areas! That is blatantly cherry-picking – as I mentioned in my article Cherry picking fluoridation data. In that I presented all the data for 5 year olds and year 8s, and for the total population and Maori, and for % caries free and decayed, missing and filled teeth (DMFT).

I have reproduced this data here in a simpler form using several figures.

caries-freeConsidering the % caries free data there are several points:

1: These do not “consistently show minimal or no differences between fluoridated and nonfluoridated areas” as Stan claims.

2. They do show a decline in differences between fluoridated and non-fluoridated areas in recent years.

3: This trend is less obvious for Maori but still present.

4: Stan has blatantly cherry-picked the  data points for 5 year-olds in 2011 to give him the least possible difference (see red circle in figure).

dmft

The data for decayed, missing and filled teeth (DMFT) shows similar trends.

Presumably both measures (% caries free and DMFT) are useful indicators of oral health but they probably convey complementary and not exactly the same information.

I discussed features of the graphs and their trends in in my articles Cherry picking fluoridation data and Fluoride debate: Response to Paul’s 5th article where I also discussed limitations in the data.

We need to appreciate this is just normal school clinic data, without technique standardisation for those making the measurements or proper recording of place of residence. The latter effect probably shows up more strongly after 2004 when a “hub and spoke” dental clinics system was introduced further confusing proper records of likely fluoride intake. One school dental clinic could serve a number of areas – both fluoridated and non-fluoridated. This mixing is a likely explanation for the apparent decline of the effectiveness of fluoridation after 2006.

So, yes, the MoH data is not straightforward. But this means it should be considered sensibly, taking into account its limitations and the social factors involved.  Instead, Stan has leapt in – found the data points which best fit his own biases and then tried to claim those data  are representative when they aren’t.

Stan presented another self-prepared graphic using data for the 4 different regions for 5 year olds (see his page 27). He appears not to have used the correct data – at least for the Northern and Southern regions.  My own graphic for this shows differences to his. (Of course, the mistake may be mine – if Stan can show I am wrong I will happily delete this part from my critique).

region-correct

Again, that data should also not just be considered at face value – or selected to confirm a bias. It has limitations. For example in this case there were only 55 children in the fluoridated Southern region compared with 7568 in the non-fluoridated area. A footnote on the data sheet says:

“2. Excludes Southern DHB because data were not reported for 1 Jan-20 Feb 2012, and fluoridation status was not captured for most children throughout 2012, due to transition to a new data system. “

Proper consideration of such data must take these sort of limitations into account. But of course all Stan Litras did was select data to support his assertions and ignore the rest. Any limitations in the data did not concern him.

Lifetime benefit

Stan has a thing about the “lifetime benefits,” or lack of benefits, of CWF. Most studies of CWF have used data for children – data for adults is less common but there is still research literature on this available.

But all Stan did on this was to cherry-pick a graphic (Figure 53) from the NZ Oral Health Survey showing no significant change in DMFT for 65-74 year olds between the years 1976, 1988 and 2009. He then claims:

“Data from the NZOHS 2010 do not support statements of a lifetime benefit, indicating that the action of fluoride is simply to delay the decay. (13)”

But he has had to work hard to avoid other data like that in Figure 49 below which do show a significant improvement in the number of retained teeth of that age group. The Oral Health Survey report itself says:

“In dentate adults aged 65–74 years, the mean number fell from 17.1 to 12.1 missing teeth per person on average from 1976 to 2009.”

mising-teeth

Again, instead of cherry-picking, searching for an image to fit his story, Stan should have considered the data and figures critically and intelligently. Perhaps the DMFT data does not show what he claims because more teeth have been retained in recent years. The decline in missing teeth could have been balanced by increases in fillings due to increase in remaining teeth. The lack of a significant difference in DMFT actually suggests the opposite to what he claims.

Litras also misrepresent the York review on the question of benefits from CWF for adults. He says:

“The York Review found there was no weight of evidence to support benefit in adults or in low SES groups, or increase of decay in cessation studies. (7)”

Just not true. The York report says:

“One study (Pot, 1974) found the proportion of adults with false teeth to be statistically significantly greater in the control (low-fluoride) area compared with the fluoridated area.”

Sheiham and James (2014) stressed that a proper assessment of oral health problems should include data for adults as well as children. Recent research is starting to take up this issue. For example O′Sullivan and O′Connell (2014) recently showed that water fluoridation provides a net health gain for older Irish adults.

Systemic vs topical

Stan promotes the common mythology of the anti-fluoridation propagandist that any mechanism for a beneficial effect of fluoride in restricting tooth decay is purely “topical.” He claims:

“It has been widely accepted since the 1990s that any effect on tooth decay from swallowing fluoride is insignificant or non-existent. To quote: CDC 1999: “the effect of Fluoride is topical “ (5); J Featherstone 1999: “the systemic effect is, unfortunately, insignificant” (6).”

Let’s consider what the sources Stan cites actually do say. I will quote from the 2001 edition of Stan’s citation 5 which he (partly) cites on page 36:

“Fluoride works to control early dental caries in several ways. Fluoride concentrated in plaque and saliva inhibits the demineralization of sound enamel and enhances the remineralization (i.e., recovery) of demineralized enamel (12,13 ). As cariogenic bacteria metabolize carbohydrates and produce acid, fluoride is released from dental plaque in response to lowered pH at the tooth-plaque interface (14 ). The released fluoride and the fluoride present in saliva are then taken up, along with calcium and phosphate, by demineralized enamel to establish an improved enamel crystal structure. This improved
structure is more acid resistant and contains more fluoride and less carbonate (12,15–19 ) (Figure 1). Fluoride is more readily taken up by demineralized enamel than by sound enamel (20 ). Cycles of demineralization and remineralization continue throughout the lifetime of the tooth.”

topical-mechanism

And

“Saliva is a major carrier of topical fluoride. The concentration of fluoride in ductal saliva, as it is secreted from salivary glands, is low — approximately 0.016 parts per million (ppm) in areas where drinking water is fluoridated and 0.006 ppm in nonfluoridated areas (27 ). This concentration of fluoride is not likely to affect cariogenic activity. However, drinking fluoridated water, brushing with fluoride toothpaste, or using other fluoride dental products can raise the concentration of fluoride in saliva present in the mouth 100-to 1,000-fold. The concentration returns to previous levels within 1–2 hours but, during this time, saliva serves as an important source of fluoride for concentration in plaque and for tooth remineralization (28 ).”

(Note: Stan simply quotes the first part of this statement (in red) in his article (page 36) and completely omits the second part (in black) – presumably because he wants to deny a role for fluoridated water in influencing the saliva fluoride concentrations. This cherry-picking of the CDC statement is typical for anti-fluoride propagandists – see Fluoridation – topical confusion).

There is an attempt to confuse a “topical” or “surface” mechanism with a “topical” application (eg toothpaste or dental treatments). However, fluoride is transferred to saliva from food and drink during ingestion so that ingested fluoride also contributes to the “topical” or “surface” mechanism.

However Stan wants to deny a “topical” role for ingested fluoride and claims (page 36):

“The required elevation of baseline levels only occurs after using fluoridated toothpaste or mouth rinse, a concentration of 1,000 ppm or more instead of 1 ppm from water.(24)”

His citation 24 is to Bruun (1984) and he misrepresents that paper which actually said:

“It was concluded that direct contact of the oral cavity with F in the drinking water is the most likely source of the elevated whole saliva fluoride and that the increased availability of fluoride in the oral fluids has an important relationship to the reduced caries progression observed in fluoridated areas.”

Systemic role.

Featherstone does say:

“Fluoride works primarily via topical mechanisms which include (1) inhibition of demineralization at the crystal surfaces inside the tooth, (2) enhancement of remineralization at the crystal surfaces (the resulting remineralized layer is very resistant to acid attack), and (3) inhibition of bacterial enzymes. Fluoride in drinking water and in fluoride-containing products reduces tooth decay via these mechanisms. Low but slightly elevated levels of fluoride in saliva and plaque provided from these sources help prevent and reverse caries by inhibiting demineralization and enhancing remineralization. The level of fluoride incorporated into dental mineral by systemic ingestion is insufficient to play a significant role in caries prevention. The effect of systemically ingested fluoride on caries is minimal.”

There is some debate over the role of systemic fluoride exuded by salivary glands. Many feel the concentration is too low – but because its effect is also determined by the presence of calcium, phosphate, organic species and pH it is best not to be dogmatic about this. It is, anyway, difficult to separate salivary fluoride derived from transfer from food and beverage in the oral cavity from that exuded by the salivary glands from systemic sources.

Stan is determined to deny a role for systemic fluoride during tooth development asserting:

“the erroneous theory that fluoride incorporated into children’s developing tooth enamel would make teeth more resistant to decay.”

While often neglected because of the concentration on surface mechanisms with existing teeth the theory that fluoride is incorporated into the developing teeth of children and confers a degree of protection is far from erroneous.

Newbrun (2004), for example, stressed in a review of the systemic role of fluoride and fluoridation on oral health:

“The role of systemic fluoride in caries prevention is neither “minimal” nor “of borderline significance.” On the contrary, it is a major factor in preventing pit and fissure caries, the most common site of tooth decay. Maximal caries-preventive effects of water fluoridation are achieved by exposure to optimal fluoride levels both pre- and posteruptively.”

Cho et al (2014) presented data showing that children exposed to CWF during teeth development retained an advantage over those never exposed to it even after fluoridation ceased.

Let’s stop confusing the issue. Systemic fluoride may not play a role with existing teeth but it does during tooth development – even if the relative contributions of systemic fluoride and “topical” or surface fluoride to lasting oral health are difficult to determine.

Tooth eruption delays

Stan resorts to special pleading when he claims with reference to NZ MoH data:

“Small apparent differences could be accounted for by other factors such as delayed eruption of teeth in fluoridated communities, therefore less time in the mouth exposed to plaque acids, ethnic distribution and urban/rural differences.”

He relies on the “York review” (McDonagh et al., 2000) to back up his “delayed tooth eruption” excuse:

“Importantly, the York Review noted that the variation of tooth eruption times between fluoridated and unfluoridated areas was not taken into account. (7)”

But that review actually said on this subject:

“It has been suggested that fluoridation may delay the eruption of teeth and thus caries incidence could be delayed as teeth would be exposed to decay for a shorter period of time. Only one study compared the number of erupted teeth per child. The difference was very small and in opposite directions in the two age groups examined, however no measure of the statistical significance of these differences was provided. Only one of the studies attempted to control for confounding factors using multivariate analysis (Maupomé 2000).”

Robyn Whyman has gone into this claim in more detail in his report Does delayed tooth eruption negate the effect of water fluoridation?Here he critiques Paul Connett’s reliance on this excuse and concludes from his review of the literature:

“The studies and reports cited by Professor Connett to try and validate an argument for delayed tooth eruption either do not make the claims he suggests, or do not have direct relevance to trying to assess the issue. The claimed association is at odds with the published literature which indicates minimal variation in eruption time of permanent teeth by exposure to fluoride. A rational explanation exists for the minimal variations that have been reported based on the relationship between fluoride exposure, caries experience in the primary teeth and emergence timing for the permanent teeth.”

The “delayed tooth eruption” excuse is nothing more than special pleading and straw clutching.

Socio-economic factors

Stan again misrepresented the York review regarding socio-economic effects on oral health and the effectiveness of CWF when he claimed “there was no weight of evidence to support benefit in adults or in low SES groups.” The York review actually said:

“Studies should also consider changes in social class structure over time. Only one included study addressed the positive effects of fluoridation in the adult population. Assessment of the long-term benefits of water fluoridation is needed.”

And

“Within the UK there is a strong social gradient associated with the prevalence of dental caries. This is found both in adults and in children. Those who are more deprived have significantly greater levels of disease. There is also geographical variation with the northwest of England, Scotland and Northern Ireland most severely affected. (Pitts, 1998; Kelly, 2000)”

There have been a range of studies internationally showing that fluoridation can aid in reducing differences in oral health due to socio-economic effects. See for example Cho, et al., (2014).

What happens when fluoridation is stopped

Stan briefly refers to this issue, citing (as anti-fluoridation activists always do) Künzel and·Fischer (2000). I will simply refer him, and interested readers to my article What happens when fluoridation is stopped? This boils down to the need to read the scientific literature properly as usually the anti-fluoridation activists ignore the details referring to fluoride treatments and procedures which replaced CWF.

There are a number of other points mentioned briefly by Stan Litras which could be discussed but this article is already too long so I will leave that to the comments section.

Conclusions

Stan Litras has simply indulged in blatant cherry-picking of data, and misrepresentation of the literature, in his critique of 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. Perhaps we shouldn’t expect better from a political activist in the anti-fluoride movement but he, and Fluoride Free NZ, attempt to present this, and other articles in the collection, as objective and scientifically credible. It is neither – such cherry-picking and misrepresentation violates any scientific ethics and needs to be exposed for what it is. The Fluoride Free NZ claimed “peer reviewers,” Bruce Spittle and Hardy Limeback, must share responsibility because, by their endorsement, they signal their approval of such behaviour.

Note

I offered Stan Litras a right of reply to this post, or even an ongoing exchange with him along the lines of my debate with Paul Connett. He replied:

“I look forward to your comments on my review, as a lay person, but I cannot engage in a serious dialogue with someone who is not a peer with the same level of knowledge as myself in the dental field. “

Hopefully this means he will at least comment here, take issue with me where he thinks I am wrong and correct me where I am mistaken. I also hope than Bruce Spittle and Hardy Limeback will also take advantage of their right to comment here.

References

Bruun, C., & Thylstrup, A. (1984). Fluoride in Whole Saliva and Dental Caries Experience in Areas with High or Low Concentrations of Fluoride in the Drinking Water. Caries Research, 18(5), 450–456.

Centers for Disease Control and Prevention. (2001). Recommendations for Using Fluoride to Prevent and Control Dental Caries in the United States (Vol. 50, p. 50).

Cho, H.-J., Jin, B.-H., Park, D.-Y., Jung, S.-H., Lee, H.-S., Paik, D.-I., & Bae, K.-H. (2014). Systemic effect of water fluoridation on dental caries prevalence. Community Dentistry and Oral Epidemiology.

Cho, H.-J., Lee, H.-S., Paik, D.-I., & Bae, K.-H. (2014). Association of dental caries with socioeconomic status in relation to different water fluoridation levels. Community Dentistry and Oral Epidemiology.

Fluoride Free New Zealand. (2014). Scientific and Critical Analysis of the 2014 New Zealand Fluoridation Report.

Künzel, W.;·Fischer, T. (2000). Caries Prevalence after Cessation of Water Fluoridation in La Salud, Cuba. Caries Res, 34, 20–25. Retrieved from http://www.karger.com/Article/Fulltext/16565

McDonagh, M., Whiting, P., Bradley, M., Cooper, J., Sutton, A., & Chestnutt, I. (2000). A Systematic Review of Public Water Fluoridation.

Ministry of Health. (2010). Our Oral Health Key findings of the 2009 New Zealand Oral Health Survey. Wellington, Ministry of Health.

Ministry of Health (2014) Age 5 and Year 8 oral health data from the Community Oral Health Service. http://www.health.govt.nz/nz-health-statistics/health-statistics-and-data-sets/oral-health-data-and-stats/age-5-and-year-8-oral-health-data-community-oral-health-service.

National Fluoridation Information Service (2011): Does Delayed Tooth
Eruption Negate The Effect of Water Fluoridation? National Fluoridation Information Service Advisory June 2011, Wellington, New Zealand.

O′Sullivan, V., & O′Connell, B. C. (2014). Water fluoridation, dentition status and bone health of older people in Ireland. Community Dentistry and Oral Epidemiology.

Sheiham, A., & James, W. P. T. (2014). A reappraisal of the quantitative relationship between sugar intake and dental caries: the need for new criteria for developing goals for sugar intake. BMC Public Health, 14(1), 863.

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The farce of a “sciency” anti-fluoride report

F network

Click for a larger image

I came up with the image above after a quick glance at a “report” promoted by the local Fluoride Free groups and Paul Connett’s Fluoride Alert organisation. (Scientific and Critical Analysis of the 2014 New Zealand Fluoridation Report). It illustrates the incestuous network of authors and “peer reviewers” involved in producing the “report.” I have also illustrated connections of these people to a number of anti fluoride organisations and 2 publications.

The first column lists the authors in red, and their claimed peer reviewers in green. The third column lists the anti-fluoride organisations and several publications these people are connected to.

The middle column lists some other people who are also connected to these organisations and publications. I have already reviewed Kathleen Theissen’s article (see Peer review of an anti-fluoride “peer review”) and will get around to reviewing the other 2 articles (by H.S. Miclen and Stan Litras) later.

Meanwhile, lets just consider the connections between these authors, “peer reviewers” and anti-fluoride organisations.

Taking in each other’s laundry

Most of these names are familiar to anyone who has followed the anti-fluoride movement. That fact in itself shows how this report can in no way be seen as “expert,” “independent” or at all credible. Some details on the illustrated people, organisations and publications.

NRC Review minority: There were several disagreements on the 12 member panel which produce the 2006 NRC report “Fluoride in drinking water. A scientific review of EPA’s standards” because 3 members were anti-fluoride. They were Robert Issacson, Hardy Limeback and Kathleen Theissen. Hardy Limeback is involved in several anti-fluoride activist groups.

Kathleen Theissen appears not to be organisationally involved but regularly makes anti-fluoridation submissions when the issue is debated.

UPDATE: Steve Slott has reminded me of this example of Theissen’s lack of credibility as a peer reviewer of fluoridation-related papers:

“In July 2013, Douglas Main, that freelance reporter and bastion of “objectivity”, interviewed Thiessen to get her opinion on Hirzy’s study on which he based his petition to the EPA.

From the article:

“Experts not involved with Hirzy’s study agreed with its findings.”

“I think this is a reasonable study, and that they haven’t inflated anything,” said Kathleen Thiessen, a senior scientist at SENES Oak Ridge Inc., a health and environmental risk assessment company.”

When the EPA reviewers looked at Hirzy’s study they found that he had made a 70-fold miscalculation in his study. When corrected for that error, the EPA reviewers found that Hirzy’s data actually demonstrated the exact opposite of what he had concluded.

Seems Thiessen either didn’t bother to read Hirzy”s study prior to commenting on it, or she overlooked his glaring error, too.”

Fluoride/ISFR: The International Society for Fluoride Reasearch (ISFR) publishes the journal Fluoride and organises regular conferences. They provide an avenue for authors to publish anti-fluoride articles, and generally poor quality research from areas where endemic fluorosis is common which may not be acceptable in the normal scientific journal.

The Society is based in New Zealand and is registered here as a charity. Bruce Spittle is the treasurer and journal managing editor.

FTRC/Second look: The anti-fluoride organisation and web site Second Look as set up the Fluoride Toxicity Research Collaborative (FTRC). It appears to be a weak attempt to provide a front “scientific institute” for anti-fluoride activists who want to present themselves as scientific experts.

This reminds me of the creationist Biologic Institute set up by the intelligent design creationists at the Discovery Institute. Actually, the Intelligent Design “pretend” scientific journal Bio-complexity also reminds me of the anti-fluoride journal Fluoride.

The FTRC lists the following staff:

  • Russell Blaylock, M.D., FTRC Medical Director
  • Hardy Limeback, Ph.D., D.D.S, FTRC Principle Investigator
  • Phyllis J. Mullenix, PhD., FTRC Research Program Director
  • Aliss Terpstra, RNCP, FTRC Research Coordinator

So far they claim to have sponsored (financed?) 2 research papers only by Phyllis Mullinex. Have a read of them and make up your own mind about their quality.

Case Against Fluoride: This is Paul Connett’s book The Case against Fluoride: How Hazardous Waste Ended Up in Our Drinking Water and the Bad Science and Powerful Politics That Keep It There. It is usually treated as a holy scripture in the anti-fluoridation movement. His co-authors were H. S. Micklen and James Beck.

Connett is very proud of this book and relies on it to support his claim to be a “world expert” on fluoridation.

Fluorine in Medicine: This is the sole scientific paper that Paul Connett can claim authorship (actually co-authorship) to:

Strunecká, A. ., & Patočka, J.; Connett, P. (2004). Fluorine in medicine. Journal of Applied Biomedicine, 2, 141–150.

The senior author Anna Strunecká is also part of the anti-fluoride network illustrated above. I am personally very suspicious of the quality of the journal which published this paper – anti-fluoride people have a history of placing poor quality papers in suspect journals purely to attain some sort of scientific credibility. DonQuixoteJune2011

FIND: The Fluoride Information Network for Dentists is one of the local Fluoride Free’s astroturf organisations claiming about 8 members but only Stan Litras is active. Stan uses his FIND hat for his anti-fluoride press releases – such as the one promoting the “report” considered here.

NZ Tour of Don Quixote & Sancho Panza: Sorry, can’t help thinking of these two when the upcoming NZ tour of Paul Connett and Bill Hirzy is mentioned. They do seem to be charging local fluoridation windmills with meetings in Taupo and Auckland.

William Hirzy: He is Paul Connett’s wingman on the Don Quixote & Sancho Panza Tour. Unlike Paul’s sole co-authorship he actually has 2 published scientific papers related to fluoridation where he appears as senior author. (See Comparison of hydrofluorosilicic acid and pharmaceutical sodium fluoride as fluoridating agents—A cost–benefit analysis and Corrigendum to “Comparison of hydrofluorosilicic acid and pharmaceutical sodium fluoride as fluoridating agents—A cost–benefit analysis” [Environ. Sci. Policy 29 (2013) 81–86]“)

The “credibility” of his “expertise” on the subject is shown by the fact his second paper was necessary to correct the huge arithmetic mistake he made in the first paper!

Perhaps you can see why the Connett/Hirzy act brings Done Quixote and Sancho Panza to my mind.

Conclusion

The “report” is discredited even before addressing the arguments presented – simply because of the well-known anti-fluoride stance of all the authors and “peer-reviewers.” The diagrammatic network shows just how incestuous the “report” is. It is simply an attempt to put a “sciency” face on their political stand and their attack on the Royal Society Review.

As a scientific presentation it is a farce.

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