Tag Archives: IQ

Debunking a “classic” fluoride-IQ paper by leading anti-fluoride propagandists

epa-meeting-sept5-2014

Three of the paper’s authors – Quanyong Xiang (1st Left), Paul Connett (2nd Left) and Bill Hirzy (far right) – preparing to bother the EPA.

Anti-fluoride groups and “natural”/alternative health groups and websites are currently promoting a new paper by several leading anti-fluoride propagandists. For two reasons:

  1. It’s about fluoride and IQ. The anti-fluoride movement recently decided to give priority to this issue in an attempt to get recognition of possible cognitive deficits, rather than dental fluorosis,  as the main negative health effect of community water fluoridation. They want to use the shonky sort of risk analysis presented in this paper to argue that harmful effects occur at much lower concentrations than currently accepted scientifically. Anti-fluoride guru, Paul Connett, has confidently predicted that this tactic will cause the end of community water fluoridation very soon!
  2. The authors are anti-fluoride luminaries – often described (by anti-fluoride activists) as world experts on community water fluoridation and world-class scientists. However, the scientific publication record for most of them is sparse and this often self-declared expertise is not actually recognised in the scientific community.

This is the paper – it is available to download as a pdf:

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.

bruce-spittle

Co-author Bruce Spittle – Chief Editor of Fluoride – the journal of the International Society for Fluoride Research

I have been expecting publication of this paper for some time – Paul Connett indicated he was writing this paper during our debate in 2013/2014. FAN newsletters have from time to time lamented at the difficulty he and Bill Hirzy were having getting a journal to accept the paper. Connett felt reviewers’ feedback from these journals was biased. In the end, he has lumped for publication in Fluoride – which has a poor reputation because of its anti-fluoride bias and poor peer review. But, at last Connett and Hirzy have got their paper published and we can do our own evaluation of it.

The authors are:

david-c-kennedy

Co-author David C. Kennedy – past president of the International Academy of Oral Medicine and Toxicology – an alternative dentist’s group.

Bill Hirzy, Paul Connett and Bruce Spittle are involved with the Fluoride Action Network (FAN), a political activist group which receives financial backing from the “natural”/alternative health industry. Bruce Spittle is also the  Chief Editor of Fluoride – the journal of the International Society for Fluoride Research Inc. (ISFR). David Kennedy is a Past President of the International Academy of Oral Medicine and Toxicology which is opposed to community water fluoridation.

Quanyong Xiang is a Chinese researcher who has published a number of papers on endemic fluorosis in China. He participated in the 2014 FAN conference where he spoke on endemic fluorosis in China.

xiang-Endemic fluorosis

Much of the anti-fluoridation propaganda used by activists relies on studies done in areas of endemic fluorosis. Slide from a presentation by Q. Xiang to an anti-fluoride meeting organised by Paul Connett’s Fluoride Action Network in 2014.

Critique of the paper

I have submitted a critique of this paper to the journal involved. Publication obviously takes some time (and, of course, it may be rejected).

However, if you want to read a draft of my submitted critique you can download a copy from Researchgate – Critique of a risk analysis aimed at establishing a safe dose of fluoride for children.  I am always interested in feedback – even (or especially) negative feedback – and you can give that in the comments section here or at Researchgate.

(Please note – uploading a document to Researchgate does not mean publication. It is simply an online place where documents can be stored. I try to keep copies of my documents there – unpublished as well as published. It is very convenient).

In my critique I deal with the following issues:

The authors have not established that fluoride is a cause of the cognitive deficits reported. What is the point in doing this sort of risk analysis if you don’t actually show that drinking water F is the major cause of cognitive deficits? Such an analysis is meaningless – even dangerous, as it diverts attention away from the real causes we should be concerned about.

All the reports of cognitive deficits cited by the authors are from areas of endemic fluorosis where drinking water fluoride concentrations are higher than where community water fluoridation is used. There are a whole range of health problems associated with dental and skeletal fluorosis of the severity found in areas of endemic fluorosis. These authors are simply extrapolating data from endemic areas without any justification.

The only report of negative health effects they cite from an area of community water fluoridation relates to attention deficit hyperactivity disorder (ADHD) and that paper does not consider important confounders. When these are considered the paper’s conclusions are found to be wrong – see ADHD linked to elevation not fluoridation, and ADHD link to fluoridation claim undermined again.

The data used by the Hirzy et al. (2016) are very poor. Although they claim that a single study from an area of endemic fluorosis shows a statistically significant correlation between IQ and drinking water fluoride that is not supported by any statistical analysis.

The statistically significant correlation of IQ with urinary fluoride they cite from that study explains only a very small fraction of the variability in IQ values (about 3%) suggesting that fluoride is not the major, or maybe not even a significant, factor for IQ. It is very likely that the correlation between IQ and water F would be any better.

Confounders like iodine, arsenic, lead, child age, parental income and parental education have not been properly considered – despite the claims made by Hirzy et al. (2016)

The authors base their analysis on manipulated data which disguises the poor relations of IQ to water fluoride. I have discussed this further in Connett fiddles the data on fluorideConnett & Hirzy do a shonky risk assessment for fluoride, and Connett misrepresents the fluoride and IQ data yet again.

Hirzy et al. (2016) devote a large part of their paper to critiquing Broadbent et al (2014) which showed no evidence of fluoride causing a decrease in IQ  using data from the Dunedin Multidisciplinary Health and Development Study. They obviously see it as a key obstacle to their analysis. Hirzy et al (2016) argue that dietary fluoride intake differences between the fluoridated and unfluoridated areas were too small to show an IQ effect. However, Hirzy et al (2016) rely on a motivated and speculative estimate of dietary intakes for their argument. And they ignore the fact the differences were large enough to show a beneficial effect of fluoride on oral health.

Conclusion

I conclude the authors did not provide sufficient evidence to warrant their calculation of a “safe dose.” They relied on manipulated data which disguised the poor relationship between drinking water fluoride and IQ. Their arguments for their “safe dose,” and against a major study showing no effect of community water fluoridation on IQ, are highly speculative and motivated.

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More nails in the coffin of the anti-fluoridation myths around IQ and hypothyroidism

thyroid_fluoride

Large Canadian study finds no effect of fluoridation on thyroid health

A new Canadian study shows no relationship of cognitive deficits or diagnosis of hypothyroidism with fluoride in drinking water. This work is important because it counters the claims made by anti-fluoride campaigners. While the campaigners cite scientific studies to support their claims, those studies are usually very weak, or irrelevant because they involve areas of endemic fluorosis where drinking water fluoride concentrations are much higher than in situations where community water fluoridation (CWF) is used.

The study is reported in:

Barberio, A. M. (2016). A Canadian Population-based Study of the Relationship between Fluoride Exposure and Indicators of Cognitive and Thyroid Functioning; Implications for Community Water Fluoridation. MSc Thesis, University of Calgary

This new study is important as it has the advantages of using a large representative sample of the Canadian population, with extensive data validation and quality control measures. It also uses individual-level estimates of fluoride exposure on the one hand, and thyroid health and cognitive problems on the other.

Fluoride exposure was measured both by concentration in tap water for selected households and concentration in urine samples from individuals.

Thyroid health

The Canadian study found:

“Fluoride exposure (from urine and tap water) was not associated with impaired thyroid functioning, as measured by self-reported diagnosis of a thyroid condition or abnormal TSH level.”

This contradicts the conclusions from the population-level study of Peckham et al., (2015) which reported that fluoridation was correlated with the prevalence of hypothyroidism. That study is quoted extensively by anti-fluoridation activists but has been roundly criticised because it did not include the influence of confounders – particularly iodine which is known to influence thyroid health.

Barberio (2016) also suggests that the different recommended fluoride concentrations used for CWF in Canada and the UK, and the fact that the Peckham et al (2015) study did not involve individual measures, could also be factors in the different findings.

Cognitive functioning

The Canadian study reported:

“Fluoride exposure (from urine and tap water) was not associated with self-reported diagnosis of a learning disability.”

Barberio (2016) did also investigate a more detailed diagnosis for cognitive problems and found:

“Higher urinary fluoride was associated with having ‘some’ compared to ‘no’ cognitive problems . . . . however, this association:

  • Was weak;

  • Was not dose-response in nature; and

  • Disappeared when the sample was constrained to those for whom we could discern fluoride exposure from drinking water.”

I guess anti-fluoride activists might latch on to this last point regarding urinary fluoride but, at least as far as tap water fluoride is concerned, there was no relationship with learning difficulties.

Conclusion

So – yet another large-scale study contradicts anti-fluoridationist claims. It shows that CWF has no influence on cognitive problems or thyroid health.

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Anti-fluoride IQ claims are false

false-claims
Anti-fluoridation campaigners’ claims that community water fluoridation reduces IQ are simply false. That is the conclusion of  Alex Kasprak – and he says why in his new Snopes.com article (see Fact Check -Fluor-IQ).

These days anti-fluoridation activists use this claim as their main argument – and they often cite scientific articles to back it up. But, Kasprak says, this claim  is based on “either willful or negligent misreading of actual science.” The claim that  studies have “linked” fluoride to reduced intelligence “is a textbook-ready case of bait-and-switch:”

” the topic has surreptitiously been shifted from the act of water fluoridation as a public health measure to the broader concept of fluoride toxicity in children. Many otherwise benign chemicals can also be harmful in high concentrations. Thiocyanate, a chemical found in kale, may kill you at high doses, for example.”

Scale and context

Kasprak critiques the way anti-fluoride campaigners so often use and cite the Choi et al., (2012) study. This was a meta-analysis of 27 mostly poor quality Chinese studies from areas of endemic fluorosis where drinking water fluoride levels are much higher than that used in community water fluoridation.

Citing neuroscientist Steven Novella Kasprak points out:

“There was a lot of variability across the studies, but generally the high fluoride groups were in the 2-10 mg/L range, while the reference low fluoride groups were in the 0.5-1.0 mg/L range […]”

In other words – fluoridated water in the US has the same level of fluoride as the control or low fluoride groups in the China studies reviewed in the recent article, and the negative association with IQ was only found where fluoride levels were much higher – generally above EPA limits.

Note: The optimum level of fluoridated water in the US is 0.7 mg/L.

Anti-fluoride campaigners sometimes concentrate on those studies in the meta-review which did focus on concentrations close to that considered optimum. But:

“Of those eight studies, half of them co-investigated fluoride and iodine together (Lin et al 1991, Xu et al 1994, Yang et al 1994, Hong et al 2001) making it hard or in some cases impossible to separate out the combined effects, and two of those four studies reached conclusions that are counter to the hypothesis that fluoridation levels alone are the main driver of a lower IQ.”

And:

“Two of those eight studies use a control group with fluoride values that are literally the same or higher than the target range of fluoridation efforts in the United States (Xu et al 1994, Hong et al 2001), seemingly ceding the point that those levels do not affect children’s IQ.”

So, as far as scale is concerned, Kasprak concludes:

“Collectively, this demonstrates that most of the IQ variance presented in the Harvard study still stems from exposures to extremely high levels of fluoride that would already be considered dangerous in the US, and those studies finding effects on a smaller scale are not sufficient to demonstrate the effects those groups opposed to fluoridation claim they demonstrate.”

As far as context is concerned none of these 27 studies were relevant to community water fluoridation:

“Literally none of the studies involved tested populations of individuals exposed to drinking water that was artificially supplemented with fluoride as a public health measure. Instead, all of the studies come from China or Iran, both of which have areas of naturally occurring (endemic) high fluoride pockets of groundwater.

That means that studies utilized in its analysis are wholly irrelevant to the question that advocates claim they are answering. This is significant, as the use of these very specific studies introduces a veritable Homerian epic of confounding details, some of which came up in our analysis of the eight low-level fluoride studies discussed above. Among the most pressing of these are a lack of information on other confounding variables and the quality of the studies they utilized. These issues are noted by the authors of the Harvard study themselves”

The authors of the Choi et al (2012) meta-review also:

“explicitly state that the results cannot be used to estimate the possible limits of fluoride exposure with respect to developmental damage, due to lack of data – ‘Our review cannot be used to derive an exposure limit, because the actual exposures of the individual children are not known.'”

Other mechanisms

Kasprek disagrees with the unsubstantiated claim of Choi et al., (2012) that other neurotoxicants are unlikely to be present in the groundwater of the studied areas. Rightly so because all those studies suffer from insufficient consideration of confounding factors. As Choi et al., (2012) said: “Most reports were fairly brief and complete information on covariates was not available.” 

In fact, statistical analysis of the data in one of the better papers the anti-fluoride campaigners rely on shows that fluoride can explain only about 3% of the measured variance in IQ. It is extremely likely that inclusion of sensible confounders in the statistical analysis would have shown any relationship of IQ with fluoride is not statistically signficant (see Connett misrepresents the fluoride and IQ data yet again).

Kasprek briefly considered arsenic as a possible confounder but with subjects like cognitive ability or IQ there are many other physical and social factors that could be imnportant.contaminants. Parental income and education as well as the psychological consequences of deformities resulting from dental and skeletal fluorosis. I discussed this last aspect in my peer-reviewed article Perrott (2015), Severe dental fluorosis and cognitive deficits and my post- Severe dental fluorosis the real cause of IQ deficits?

Fallacy of publication journal

I think Kasprek’s argument about the journal used for publishing some of these papers is fallacious:”

“Finally, four of these eight papers (Yang et al 1994, Lu et al 2000, Hong et al 2001, Xiang et al 2003a) are either published (or republished) in the allegedly peer-reviewed journal Fluoride, a publication of the “International Society for Fluoride Research Inc.” — an anti-fluoridation group whose editor-in-chief is a psychiatrist in private practice, with no academic background on the topic of fluoride toxicity.”

I am very much opposed to using the place of publication as an argument against the scientific veracity of a paper. True, Fluoride is a very poor quality journal. True, is has an ant-fluoride agenda. And true, it shows no evidence of proper peer review. However, it is disingenuous to use these facts to argue against the scientific content of these papers. Critique of the papers should rest on an analysis of their scientific content – not the place of publication.

This lazy approach is doubly worse because it carries the implication that if these papers had been published in a reputable journal with good peer review then that would be sufficient to guarantee the veracity of the science. It is not.

On the fluoride issue, there are plenty of examples of papers involving poor science that are published in reputable journals. I have discussed some of these in my articles – for example ADHD linked to elevation not fluoridationAnti-fluoride hypothyroidism paper slammed yet againPoor peer review – and its consequencesDoes community water fluoridation reduce diabetes prevalence?, The Harvard study and the Lancet paperControversial IQ study hammered in The Lancet and Repeating bad science on fluoride.

The lazy judgmentalism based on place of publication, and not content, is particularly relevant at the moment with the public concern about “false news” and efforts to introduce mechanisms of “fact checking.” Some people are advocating reliance on websites like Snopes.com – yet this site can be blatantly biased on political matters. And its bias can rest on the lazy approach of condemning a news article by its place of publication.

[A recent example was a Snopes.com article which cast aspersions on an independent journalist, Eva Bartlett, because – “She is also a contributor at RT, a news site funded by the Russian government.” OK, you may not see how lazy that argument is but try replacing the words RT and Russian by “Al Jazeera” and Qatar” or “BBC” and “British.” And, I also think describing the fact that Bartlett had been interviewed by an RT reporter, and participated in a debate aired by RT, as being a “contributor” shows a bias]

The good science

Despite delving into the details of the poor quality papers the anti-fluoride IQ argument relies on Kasprak is quite right to stress:

“This should not function as a distraction from the larger point that studying naturally occurring pockets of high fluoride and the assessing the risks of supplementing public drinking water in an effort to have it reach a concentration of 0.7 mg/L are two completely different beasts.”

So, my other criticism of Kasprak’s article is that he could have said more about the studies which are relevant to community water fluoridation.  He does briefly refer to the New Zealand study of Broadbent et al (2014) in a quote from  Ireland’s Health Research Board:

“There was only one study carried out in a non-endemic or CWF [community water fluoridation] area that examined fluoride and IQ. This was a prospective cohort study (whose design is appropriate to infer causality) in New Zealand. The study concluded that there was no evidence of a detrimental effect on IQ as a result of exposure to CWF.”

However, he missed the 2016 study of  Aggeborn & Öhman (perhaps it was too recent for him) which I discussed in my article Large Swedish study finds no effect of fluoride on IQ. The results of this study were so precise and the sample numbers used are so large it should be seriously considered by anyone looking at this issue.

Conclusion

Kasprak’s article is useful in exposing the false claim of activists that fluoride lowers IQ – especially when used in arguments against community water fluoridation. But he could have said more – and he could have avoided the fallacious argument based on place of publication which is so easily reversed to support poor quality science in reputable journals.

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Large Swedish study finds no effect of fluoride on IQ

sweden-f

Fluoride levels in Swedish drinking water (mg/L). Variation between municipalities. Source: Aggeborn & Öhman (2016)

A significant new Swedish study shows fluoride in drinking water, at the concentrations used for community water fluoridation, has no effect on IQ or other measures of cognitive ability. Similarly, it has no effect on diagnosis or prescription of medicines for ADHD, depression, psychiatric illnesses, neurological illnesses or muscular or musculoskeletal diseases.

On the other hand, the study showed positive effects of fluoride on income and employment status – most probably because better dental health is beneficial in the labour market.

This work is reported in:

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

The study covers most of the health effects that anti-fluoride campaigners complain about. It really should put all these complaints to rest as the quality of this new study is much better than anything the campaigners rely on for the following reasons:

  • It involved a much large sample. Over 700,000 individuals were involved. The numbers included in specific measurements varied but they were much greater than those used in the studies cited by anti-fluoride campaigners. For example, almost 82,000 were involved in the cognitive ability comparisons – compared with a few hundred at the most in the comparable studies cited by anti-fluoride campaigners.
  • Estimates of effects were much more precise (as expected with large numbers of subjects) than for previous studies. The effect of fluoride on cognitive ability was always close to zero and for practical purposes was zero.
  • Statistical analyses were based on continuously varying fluoride levels – a much better approach than the simple comparison of data for low and high fluoride villages used in the studies cited by anti-fluoride campaigners.

Sweden is an ideal country for studying effects of fluoride at these low concentrations. It does not have artificial water fluoridation but its drinking water contains naturally occurring fluoride. The fluoride concentration in drinking water depends on the geology of the region so different Swedish communities consume water with different fluoride concentrations.

This graphic from the paper shows the number of people drinking water with various concentrations of fluoride. Note – the steps are 0.1 mg/L and although concentrations above 2.0 mg/L occur they are relatively rare. Sweden makes no attempt to remove excess fluoride until the concentrations exceed 1.5 mg/L – the maximum recommended by the World Health Organisation. For comparison, the recommended optimum concentration in  New Zealand is 0.7 mg/L.

sweden-f-01

Histogram of numbers people drinking water containing naturally occurring fluoride at different concentrations. Source: Aggeborn & Öhman (2016)

Effects of fluoride on dental health

The Swedish data showed positive effects of fluoride on oral health. For example, the share of dentists visits “decreased by approximately 6.6 percentage points if fluoride is increased by 1 mg/l. This should be considered as a large effect.” Tooth repairs are closely related to fluoride. “If fluoride would increase with 1 mg/l, the share of 20-year-olds that had a tooth repaired would be decreased approximately 3.4 percentage points considering the 2013 sample. Again, this effect is large, especially for this cohort.”

Cognitive ability

Relevant data was used from national education tests and psychological tests during the years of the Swedish military conscription. The statistical analysis produced estimates which were all very small and often not statistically significant. The estimates were sometimes negative and sometimes positive. For example, an estimate including covariates showed that “cognitive ability is increased by 0.045 Stanine points [equivalent to about 0.3 IQ points] if fluoride is increased by 1 mg/l (a large increase in fluoride). This should be considered as a zero-effect on cognitive ability.”

Other possible health effects

The authors considered the effects of fluoride on the prescription of medicines for ADHD, depression, and psychoses. They also looked at psychiatric and neurological diagnoses from outpatient and inpatient registers, as well as diagnoses of muscular and skeletal diseases. Anti-fluoride campaigners often claim fluoride has a harmful effect on these health problems.

The was no effect of fluoride on the possibilities of being prescribed any of these medicines.  For example “the probability of receiving ADHD medicines is decreased by 0.2 percentage points if fluoride is increased by 1 mg/l. In economic terms, this effect is a zero-effect.”

It was the same for all the diagnoses considered –  “The estimated effects are small and often statistically insignificant.”

According to the authors:

“In conclusion, we do not find that fluoride has any effects on these health outcomes. This further strengthens our argument that fluoride does not have any negative effects for levels below 1.5 mg/l on human capital development or health outcomes related to human capital development. It is also interesting that we do not find any effects on diagnoses for muscular and skeleton diseases, which has been a question also discussed in connection to fluoride.”

Annual income and employment status

The lack of any effect of fluoride on IQ and other psychological and non-psychological estimates suggest that fluoride would have no effect on long-term outcomes like income and employment status. However, the authors suggested that it could have a positive influence on these outcomes because of better dental health.

And this was the case. Estimates of the effect of fluoride on income were always positive and usually statistically significant. The authors estimated that “income increases by 4.2 percent if fluoride increases by 1 mg/l. This is not a negligible effect and the estimate should be considered as economically significant.”

Similarly for employment status. “If fluoride is increased by 1 mg/l, then the probability that the person is employed is increased by 2 percentage points. This result thus point in the same direction as the results for log income where both these results are significant in economic terms.”

Further analysis indicated “that when dental repairs increases by 1 percentage point, income decreases by 2 percent on the same aggregate level. This effect is clearly economically significant. This indicates that fluoride improves labor market outcomes through better dental health.”

Conclusions

This is an important study. It involved large numbers of people, estimated outcomes were far more precise than in previous studies, it used continuously varying concentrations of fluoride instead of simply comparing high fluoride and low fluoride villages, and it considered possible long-term outcomes like income and employment chances.

The advantages of this study compared with the generally poor quality studies cited by anti-fluoride campaigners should put to rest arguments used by those campaigners. In particular, it should make the current campaigns relying on to IQ and cognitive effects irrelevant.

The authors comment that their data shows there is no need to consider negative health effects on consideration of the cost-effectiveness of community water fluoridation. I wonder if, in fact, these results will encourage policy makers to consider the cost benefits of improved income and employment chances in future calculations of the cost-effectiveness of fluoridation programmes.

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Anti-fluoridationists now scaremonger about silica in your drinking water

orthosilicic-acid

Orthosilicic acid exists in drinking water. This is an idealised presentation because of polymerisation reactions. In practice, analysts measure “reactive silica.”

Well – that’s what we can infer from a new campaign of the Fluoride Action Network (FAN).

But what is the link with fluoride – the whole reason for FAN’s existence? Well, they base this campaign on the well-known hydrolysis of the fluorosilicates used in community water fluoridation to form the hydrated fluoride anion and silica. (Although these campaigners are confused here as they will also often claim fluorosilicates do not hydrolyse and survive to come out of your tap and poison you).

Then they claim that “silicic acid” (silica in solution) dissolves lead from the pipes and fittings and this lead causes brain damage. A double-barreled danger as they also claim the fluoride also damages your brain. What’s more – they also claim that “silicic acid” may dissolve your teeth!

But there are two problems with this:

  1. Your drinking water contains silica whether it is fluoridated or not. So their warnings about the silica in fluoridated water should also be valid for “fluoride-free” water which they promote!
  2. They do not have a viable chemical mechanism for silica dissolving your pipes (and there are plenty of other mechanisms which can result in corrosion of pipes anyway). The same for your teeth. This claim is just not supported by the chemical literature.

I will just concentrate here on the “evils” of silica (or “orthosilicic acid”) that are being promoted by FAN and leave the lead story for another day. These “evils” all come down to concepts being promoted by Richard Sauerheber who FAN describes as “the ultimate citizen chemist.” (OK, he is their ultimate citizen chemist). His argument is presented in Silicic Acid – How Does Fluorosilicic Acid Leach Lead? Why Does Fluorosilicic Acid Leach Lead So Much More Than Sodium Fluoride?

Is silicic acid the bogy Sauerheber claims?

His article is confused and convoluted. But it starts with the assumption that silica in drinking water (silicic acid or orthosilicic acid) is bad. He declares:

“Neither fluoride nor silicic acid are constituents of normal pristine human or mammalian blood, but rather are contaminant materials, . . “

And he states:

“The mass treatment of public fresh drinking water with industrial fluorosilicic acid to produce fluoride ion at 1.0 ppm also produces approximately 6 ppm sodium ion and .7 ppm orthosilicic acid. None of these is found in or belongs in fresh drinking water.”

Let’s stop right there and check out his claim that sodium and “orthosilicic acid” are not found in fresh drinking water.

Here is some data for drinking water in fluoridated and unfluoridated areas of Auckland, New Zealand, taken from the WATERCARE ANNUAL WATER QUALITY REPORT 2013. The data are for 15 unfluoridated treatment plants and 8 fluoridated treatment plants.

silica-sodium

These are average figures over all the plants. But values for silica as high as 64 mg/L in the unfluoridated plants and 44 mg/L in the fluoridated plant were recorded. The corresponding figures for sodium were 140 and 22 mg/L.

So Sauerheber is completely wrong. Unfluoridated water does contain silica and sodium. And at concentrations much higher than could be accounted for by added fluoridating chemicals – he calculated 0.7 mg/L – 0.7 ppm) for silica. In fact, the values are higher for the unfluoridated treatment plants in these examples.

Fluoridation makes a minuscule contribution to the concentration of these chemical species in drinking water.

Forget about fluoridation. If silica (and sodium) are such problems then Sauerheber should be campaigning against unfluoridated water as well. Even the “pristine” water in his local river or spring – silica is a normal and natural component of surface and bore waters.

But Sauerheber is also wrong about the dangers of silica in drinking water. Of course silica is present in “normal pristine human or mammalian blood” because it is part of our diet (Bisse et al 2005). It is a component of many of our foods. Sauerheber is simply attempting to confuse the issue because of the current lack of knowledge about the role of silica in the body.

But Jugdaohsingh et al., (2015) say:

“Silicon (Si) is a natural trace element of the mammalian diet and although it has not been demonstrated unequivocally that mammals have a requirement for Si there is increasing evidence to suggest that it may be important for the normal health of bone and the connective tissues. Indeed, severe dietary Si deprivation in growing animals appears to cause abnormal growth and defects of the connective tissues”

Given that silica appears to be important the presence of it in our drinking water is as an advantage. According to Jugdaohsingh (2007):

“Drinking water and other fluids provides the most readily bioavailable source of Si in the diet, since silicon is principally present as Si(OH)4, and fluid ingestion can account for ≥ 20% of the total dietary intake of Si.”

One trick Sauerheber uses is to cite reports of the danger of inhaled silica dust – which can cause cancers and silicosis. Completely irrelevant because of its different chemical form. This is equivalent to the trick often used by anti-fluoride campaigners of citing reports of results of industrial pollution or studies from areas of endemic fluorosis to support their attacks on community water fluoridation.

Will silica dissolve your teeth?

This claim is completely unsupported – no citations and purely a figment of Sauerheber’s imagination. He claims:

“Orthosilicic ‘weak’ acid has been long used in agriculture to break down solid calcium phosphate Ca3(PO4)2, thereby releasing soluble phosphate ion in soils even at neutral pH, for uptake by plant life. The reaction of silicic acid with calcium phosphate under neutral pH conditions is:

H4SiO4 + Ca3(PO4)2 →  HPO4-2 + 3Ca2+ + PO4-3+ H3SiO4.

This reaction occurs at a pH where any strong acid would have been neutralized. Orthosilicic acid is reluctant to dissociate and can break down calcium phosphate. This reaction is relevant not only to calcium phosphate in soil but also to calcium phosphate in teeth enamel. By means of orthosilicic acid, enamel is subject to slow and progressive degradation. “

This is a new one on me – and I spent many years researching the dissolution of apatite (the natural calcium phosphate) in soil and the factors influencing that. This arose because unacidulated phosphate rocks were being used in New Zealand agriculture. These material contain insoluble phosphate – in contrast to superphosphate which contain soluble phosphate.

The phosphate rocks used are mainly apatites and are complex (because of isomorphous substitution). A specific chemical equation for their dissolution depends on composition and environmental pH. But, in general, acid (H+) reacts with the apatite to produce Ca2++ H2PO4, H2O, F, Cl, CO2, etc.

H+ + Ca10(PO4)6(OH,F,Cl)2 → Ca2+ + H2PO4 + H2O + Cl + F + CO2

Dissolution is promoted by the presence of acid (H+) and removal of dissolution products (particularly Ca2+). The calcium in soil solution can inhibit apatite dissolution – it drives the equation above to the left. The later is important because New Zealand agricultural soils have relatively high levels of calcium. On the other hand, our research showed that when soils are leached to remove calcium this can promote dissolution of the natural fluorapatite in the soil. (Perrott and Kear 2004). Removal of calcium from solution drives the above equation to the right.

Apatite particle size, fluoride content and substitution of other species in the apatite structure can also influence the dissolution rate of these materials in soil. But silica, or silica in soil solution – that is a new one on me!

Pity Sauerheber didn’t give a citation to support his claim that silica “has been long used in agriculture to break down solid calcium phosphate Ca3(PO4)2, thereby releasing soluble phosphate ion in soils even at neutral pH, for uptake by plant life.” I would be very interested to see the evidence – but I cannot find anything in the scientific literature to support Sauerheber’s statement. It appears to be a figment of his imagination and anti-fluoride bias.

In the same unsupported manner, Sauerheber is suggesting silica (“orthosilicic acid”) may be dissolving our teeth. He even provides a chemical equation for it:

2H4SiO4 + Ca3(PO4)2 → 2HPO4-2 + 2H3SiO4 + 3Ca2+

First,  the primary mineral in teeth is a bioapatite (Ca10(PO4)6(OH,F,Cl)2) not Ca3(PO4)2. And H3SiO4 is not stable at the pH of drinking water or saliva so his idea is destroyed by the immediate reaction:

H+ + H3SiO4→ H4SiO4

In other words, Sauerheber’s equation above is driven to the left at the neutral and acid pH values of saliva and drinking water.

Incidentally, it is the presence of Ca2+, H2PO4 and F in our saliva (derived from food and drink) that drives the dissolution equation for apatite to the left. It prevents dissolution (acid attack or demineralisation) and promotes remineralisation. This the surface or “topical” mechanism that reduces decay in existing teeth when fluoridated water is used.

Sauerheber’s confusion

Sauerheber’s arguments are chemically confused – probably because he is driven by a wish to find anything connected with fluoride to be bad. He is confused by terminology because the silica in solution is often called orthosilicic acid, or silicic acid. But the point is that this species (whatever it is – the chemistry of silica in water is very complex) is not dissociated at neutral pH values near 7.  (more correctly only 0.18% of it is – Belton et al., 2012). It is a very weak acid -significant dissociation to form the anion only occurs at higher pH values according to the equation:

OH + H4SiO4 → H3SiO4 + H2O

Enamel attack is caused by acid (H+) not an unionized silica species or silicate anion. At these high pH values, dissociation of silicic acid at high pH does not produce H+. It actually removes OH.

The same confusion is behind Sauerheber’s assertion that leaching of lead from pipes and plumbing is caused by “orthosilicic acid.” He says:

“it is the intact orthosilicic acid, the predominant form present over the pH range 7-10 (sic) that is leaching lead or lead salts from pipes and plumbing fixtures.”

In fact, acid in drinking water is one of the causes of lead leaching. The chemical species responsible is H+ and that is why treatment plants adjust pH levels to reduce acidity. Silica in  solution does not make a contribution to the (H+) concentration.

But if it did then we should be concerned about all water as fluoridating chemicals make only a minuscule contribution to silica in water.

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Once more on the IQ and fluoride myth – why ignore other factors?

The “fluoride damages IQ” myth won’t go away – mainly because it is avidly promoted by campaigners against community water fluoride (CWF). This is despite the fact that no link has even been drawn between CWF and IQ (the only relevant study shows no connection). But that doesn’t stop ideologically driven campaigners who rely on poor quality studies from areas of endemic fluorosis where dietary fluoride intake is higher than in areas using CWF.

There are plenty such studies, but a more recent one illustrates their problems – and the role  confirmation bias seems to play in these studies. It is:

Kundu, H., Basavaraj, P., Singla, A., Gupta, R., Singh, K., & Jain, S. (2015). Effect of fluoride in drinking water on children′s intelligence in high and low fluoride areas of Delhi. Journal of Indian Association of Public Health Dentistry, 13(2), 116.

It’s another study where the IQ values of children from a “high fluoride” area were compared with those for children from a “low fluoride area.” There was a statistically significant difference and the paper goes on to claim:

“High F concentration in the drinking water was found to have marked systemic effects on the IQ of children. Though the precise mechanism by which F crosses the blood brain barrier is still not clean‑cut; enough evidence survives for the influence of F intake via drinking water and low IQ of the child.”

However they do acknowledge:

“Apart from fluoride there are other factors which also affect IQ of children. In the present study, mothers diet during pregnancy also significantly affected the IQ of the children.”

The supporting data is poorly presented and described – for example, no indication is given of the fluoride concentration in the drinking water of the “high fluoride and “low fluoride” areas used. Although they do cite areas in Delhi (where the study was located) with fluoride concentration as high as 32.5 ppm!. And I cannot find any details on “mothers diet during pregnancy” (except perhaps division into two groups – “routine” or “special diet as suggested by the doctor during pregnancy”).

Those confounding factors

These sorts of studies almost always rely on finding a statistically significant difference in the IQ values of children in two different areas or villages. But that statistical significance says nothing about the causal factors involved – it may have nothing to do with differences in fluoride levels.

Kundu et al., (2015) do at least include some data on confounding factors which is often missing from such studies. These show significant difference between the groups from the “high fluoride” and “low fluoride” areas which have no connection with fluoride in drinking water – such as father’s occupation, mother’s education and father’s education) – or only an indirect connection (dental fluorosis).

Here is a summary of the data for the various factors. I have selected the data so to show as two values – equal to “high fluoride” and “low fluoride.”

Kundu

You get the picture. The areas were chosen according to the concentrations of fluoride in drinking water (whatever they were), but they could equally have been chosen on the basis of parental education, father’s occupation or prevalence of the more severe forms of dental fluorosis.

In fact, rather than concluding drinking water fluoride has a “marked systemic effects on the IQ of children” we could equally have concluded:

  • “The father’s occupation has a marked effect on the IQ of children with the children of unskilled fathers having a lower IQ.”
  • “The mother’s and father’s education has a marked effect on the IQ of children with the children of parents with a higher education having a higher IQ.”
  • “Diet of mothers during pregnancy has a marked effect on the IQ of children.” (The paper did not include data suitable for plotting for this.)

The dental fluorosis factor interests me as I have suggested that, in areas of endemic fluorosis, the physical appearance of defective teeth could lower quality of life and cause learning difficulties which are reflected in lower IQ values (see Severe dental fluorosis the real cause of IQ deficits?Severe dental fluorosis and cognitive deficits – now peer reviewed and Free download – “Severe dental fluorosis and cognitive deficits”).

I think that this is more reasonable as a mechanism than the chemical toxicity mechanism that almost all authors of these sorts of papers assume – but never support with any evidence. Even when dental fluorosis is considered it is usually treated as an indicator of lifetime intake of fluoride (which it is) rather than and independent cause of low IQ.

Conclusions

Most studies like this seem to be motivated by confirmation bias. Despite the possibility of a range of factors being involved, and some of these such as parental education being a more obvious cause, there appears to be an urge to interpret data as evidence of a chemical toxicity mechanism involving fluoride. And there is never any experimental work to confirm this preferred mechanism.

To my mind, if fluoride is implicated in the low IQ values the mechanism involving effects of dental fluorosis on quality of life and learning difficulties appears more credible than an unproven chemical toxicity.

Note: None of this is directly relevant to areas where CWF is used. The prevalence of more serious forms of dental fluorosis is very small in these areas and not related to CWF. Also, no study has yet found an effect of CWF on IQ. Given the higher levels of fluoride used in the studies from areas of endemic fluorosis, and the higher levels of serious forms of dental fluorosis, extrapolation of the results to areas where CWF is used is completely unwarranted.

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Cultural and ideological bias in scientific literature reviews

 

The scientific community is international but it is surely dominated, and influenced by, something less international – the overwhelming predominance of  the use of the English language.

In the past when that dominance was less extreme scientists were more aware of the need to use non-English sources. Scientific degree courses often had a requirement for a degree of scientific fluency in an alternative language. I learned German and Russian and have often needed to translate scientific papers in both these languages. In fact, several times I can trace a breakthrough in my research to a Russian or German paper I translated.

So, I was often disappointed when searching the literature to come across papers in a less dominant language like Mongolian, Ukrainian, Byelorussian, Arabic, etc. Very often these were published in unattainable obscure journals or periodicals. While I was aware that such papers were perhaps of poor quality I still lamented my inability to check that out for myself. I felt I  might be missing something useful.

I can’t help thinking that scientific reviews, even systematic ones, may suffer from such omissions. After all the problems of expense and the probably poor quality of obscure papers usually mean that even systematic reviewers will not be able to obtain obscure papers and their translations.

But there is the other side. What happens if ideologically motivated groups able to make the financial investment obtain and translate obscure papers which fit their political or commercial biases? Can that not result in the “skewing” of readily available literature? Could it result ion the wider availability and influence of poor quality research?

One would hope scientific reviewers critically and intelligently appraise the papers they review. This would help prevent promotion of poor science. But not all scientific reviewers may be that objective. And certainly, such poor quality science can be promoted in the popular literature and used for political and ideological campaigns.

Bad science promoting the fluoridation/IQ myth

This is what has happened with the promotion of the fluoride/IQ myth by anti-fluoride campaigners. Several years ago the Fluoride Action Network (the main activist group campaigning against community water fluoridation internationally) paid for the searching out, and translation into English, obscure articles (mainly Chinese) suggesting a link between fluoride in drinking water and child IQ. These articles represented in almost all cases poor quality research mostly published in obscure journals, newsletters and conferences. Given the bias of FAN, preference was clearly given to articles supporting their party line.

The result is that these articles have now entered into English language scientific literature – via publication of the translations in the journal Fluoride – a poor quality, English language journal, linked organisationally and financially to FAN. This has introduced an ideologically promoted skewing of the available literature – on top of the well-understood publication bias (negative results are rarely published). Such skewing is important for reviewers such as those in the US  National Toxicology Program considering a new systematic review on (see Fluoride and IQ – another study coming up).

Don’t get me wrong. Despite the biases of this translation process I like to see such obscure studies, even poor quality one, made available to researchers. And sensible, conscientious reviewers will take the poor quality into account. But less objective researchers can opportunistically use such material to support their preferred hypothesis. This has happened with the fluoridation issue, for example, with the paper of Grandjean & Landrigan (2014) which is continually used by anti-fluoride campaigners (see Repeating bad science on fluoride). This is a secondary effect where the poor quality research that is selected, translated and published in a poor quality journal like Fluoride can then make its way into more reputable journals (like The Lancet) without any further evidence. Adding to the skewing of the available scientific literature.

And all of this provides ammunition to the unscrupulous ideologically motivated campaigners. Critical assessment of the research is the last thing on their minds and they are certainly not in  the habit of even reading, let alone critically understanding, the papers they promote in  their arguments.

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Fluoride and IQ – another study coming up

Well, eventually.

It’s basically a systematic review of published scientific literature on fluoride-IQ effects in humans. It’s just at the planning stages and don’t expect anything for a few years – peer review and public consultation of the findings are not planned until 2018.

NTP

The review is planned by National Toxicology Program (NTP) which is part of the US National Institute of Environmental Health Sciences. It’s a special project developed in response to requests from the public (guess who?).

Some might question whether such a review will add anything – after all this question has been included in several reviews of possible health effects of community water fluoridation (eg NRC and NZ review), although it has just been one component of most of these reviews. An exception is the review by the Bazian Company

Bazian. (2009). Independent critical appraisal of selected studies reporting an association between fluoride in drinking water and IQ (Vol. 44).

This considered in detail the specific publications used by campaigners against CWF to argue there is a problem (the reviewers found there wasn’t).

But, on the positive side, this will most likely be one more review by a reputable body showing how poor the evidence used by anti-fluoride campaigners is. On the negative side the process and findings will be misrepresented again and again by anti-fluoride campaigners. That has already started – see the press release by Fluoride Free NZ –  Fluoride-Brain Studies Set to Expose Fluoridation Damage. Talk about counting chickens before they hatch!

Here is an extract from the Summary of the NTP proposal (Proposed NTP Evaluation on Fluoride Exposure and Potential for Developmental Neurobehavioral Effects):

“The National Toxicology Program (NTP) proposes to conduct an evaluation of the published literature to determine whether exposure to fluoride is associated with effects on neurodevelopment, specifically learning, memory, and cognition. This evaluation will use systematic review methods and include an examination of data from human (epidemiological), experimental animal, and mechanistic studies. Previous evaluations have found support for an association between fluoride exposure and impaired cognition; however, many of the studies included exposure to high levels of fluoride. Most of the human evidence was from fluoride-endemic regions having high background levels of fluoride, and the animal studies typically included exposure during development to relatively high concentrations of fluoride (>10 mg/L) in drinking water. Thus, the existing literature is limited in its ability to evaluate potential neurocognitive effects of fluoride in people associated with the current U.S. Public Health Service drinking water guidance (0.7 mg/L).” [My emphasis].

The proposal also says:

“A 2015 systematic analysis of the human literature conducted for the Republic of Ireland’s Department of Health (Sutton et al. 2015) concluded that there was no evidence of an association with lowered IQ in studies of community water fluoridation areas based primarily on an analysis of a prospective cohort study in New Zealand (Broadbent et al. 2015). For fluoride-endemic areas, there was a strong suggestion that high levels of naturally occurring fluoride in water (> 1.5 ppm) may be associated with negative health effects, including lowering of IQ. In general, these studies were considered of low quality because they did not fully account for other factors that could also cause a lowering of IQ e.g., nutritional status, socioeconomic status, iodine deficiency, other chemicals in the ground water (arsenic or lead). The conclusions of Sutton et al. (2015) are consistent with findings of a 2012 meta-analysis of 27 epidemiology studies that “supported the possibility of an adverse effect of “high” fluoride exposure on children’s neurodevelopment, specifically for lowered IQ; although the 2012 meta-analysis also identified study quality limitations, mostly related to reporting quality, that limited the strength of conclusions that could be reached (Choi et al. 2012).

The anti-fluoride spin

You wouldn’t think the anti-fluoride crowd would welcome such a careful analysis of the poor-quality articles they promote – but you can get some idea of how they will spin this study over the next few years from the comments in the above press release:

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

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

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

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Connett misrepresents the fluoride and IQ data yet again

The video clip below shows how local body politicians can be fooled by people misrepresenting the science. The culprit (unsurprisingly for the fluoride issue) is Paul Connett, Executive Director of the anti-fluoride propagandist group Fluoride Action Network (FAN). He relies on his PhD to provide authority – and the fact that few people in his audiences have the time or background to check out his claims.

At the moment, Connett is putting a lot of effort into promoting the myth that fluoridation causes a decrease in IQ. In this very short video clip (just over 1 minute) of a recent presentation to the Denver Water Board Connett massages data reported by Xiang et al., (2003a) to pull the wool of the Board’s eyes..

The innocent victims in his audience, including the Denver Water Board members, were no doubt impressed by this graph Connet used.

It looks pretty convincing, doesn’t it? There appears to be a statistically very significant decrease in IQ with an increase in drinking water fluoride above about 1 ppm F? (Community water fluoridation [CWF] usually uses a concentration of about 0.7 ppm). All the data points are lined up in a row.

That is until you look at the original data.

This figure is from Xiang et al., (2003a).  Not so convincing, eh? Clearly, with such a wide scatter of the data,  fluoride is only part of the story – if it has any effect at all. But this is the sort of graph one needs to consider when looking at correlations. Connett obtained his figure by breaking the data up into ranges. It looks prettier – but is misleading.

One should always look at the original data.*

Although the correlation is statistically significant, urinary fluoride explains only 3% of the variance in IQ! This tells us that fluoride has very little effect on IQ and it is very likely that it would have no explanatory role at all once other factors were considered in the statistical analysis!

I think it is inhumane to make the claims Connett does on such a flimsy correlation. His biased advocacy is, in effect, denying any efforts to find the real causes of the IQ variation.

What about confounding factors?

Connett’s claim that data was “controlled for” confounding factors is just not true. Xiang did not include any of these other factors in the statistical analysis of the data in Figure 2.

He only compared average values of these factors for the two villages in the study. There were no proper correlations across all the data. Xiang reported no differences between villages for urinary iodine, family income, and parent’s education level. However, there was an average age difference between the villages and he reported that IQ was influenced by age. The drinking water arsenic concentrations were higher in the low fluoride village than the high fluoride village (Xiang et al., 2013).

Incidentally, in a later paper (Xiang et al., 2003b) presents data for blood lead. This time he did check for a correlation across all samples and found there was no statistically significant correlation with IQ. But this was separate and not incorporated into a statistical analysis together with fluoride concentrations.

There was no real checking for the effect of confounding factors on the correlation of IQ with fluoride.

Connett asks a silly question

Connett goes on to make an emotional appeal for scientists to produce convincing data showing that fluoride does not decrease IQ:

This question is disingenuous as science can never prove something can never happen – it can only consider the evidence for it happening. Evidence of the sort presented by Xiang et al. (2003a). Scientific reviews look at the evidence, consider its reliability, compare it with evidence from other studies and draw conclusions.

Connett is disparaging about scientific reviews of the fluoride literature because he does not understand that such literature requires critical and intelligent analysis. Things like the high concentrations and doses used in animals studies he refers to. And looking below surface claims to see what the data really says – as I have done here. This is what reviewers of the scientific literature do all the time.

All Connett has relied on here is his own confirmation bias – and his emotions. Policy makers should beware of such advocacy.

See also:

Connett fiddles the data on fluoride
Connett & Hirzy do a shonky risk assessment for fluoride

*Note: Observant readers might note the second figure compares IQ with urine fluoride concentration. Unfortunately, he did not give a similar figure for fluoride concentration in drinking water. However, this is well correlated with urine fluoride. And, as urine concentration is a better indicator of fluoride intake that drinking water concentration, this figure does give a useful picture of the variance in the data Xiang used.

Incidentally, I have made several attempts without success, to get the original water fluoride concentrations from Xiang (who has so far not replied to several emails) and Connett (who told me that he does not want me contacting him again!).

References

Xiang, Q; Liang, Y; Chen, L; Wang, C; Chen, B; Chen, X; Zhouc, M. (2003a). Effect of fluoride in drinking water on children’s intelligence. Fluoride, 36(2), 84–94.

Xiang, Q.; Liang, Y.; Zhou, M. . and Z. H. (2003b). BLOOD LEAD OF CHILDREN IN WAMIAO–XINHUAI INTELLIGENCE STUDY. Fluoride, 36(3), 198–199.

Xiang, Q., Wang, Y., Yang, M., Zhang, M., & Xu, Y. (2013). Level of fluoride and arsenic in household shallow well water in wamiao and xinhuai villages in jiangsu province, china. Fluoride 46(December), 192–197.

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Free download – “Severe dental fluorosis and cognitive deficits”

S08920362Anyone interested in my article on this subject in Neurotoxicology and Teratology can now download a pdf version:

Perrott, K. W. (2015). Severe dental fluorosis and cognitive deficits. Neurotoxicology and Teratology, 48, 78–79.

The publishers tell me that anyone who clicks on the link until May 3, 2015, will be taken to the final version of on ScienceDirect for free. No sign up or registration is needed – just click and read!

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