Tag Archives: Water fluoridation

Is water fluoridation better than salt fluoridation?

Salt

Discussion of fluoridation here concentrates on community water fluoridation. But some countries (parts of Europe, and Latin America, for example) fluoridate their salt instead of their water.  This could be for a number of reasons – the state of the water reticulation system, or political opposition to water fluoridation, etc.

The effectiveness of community water fluoridation in reducing tooth decay is well established by research, but there has been far less research on the effectiveness of salt fluoridation. Evidence suggests the effectiveness of the two fluoridation methods is similar but new research from Latin  America found water fluoridation significantly better than salt fluoridation.

It’s a very good study, large numbers of subjects and good consideration of possible confounders. But the authors themselves suggest their findings are more relevant to developing countries than developed countries with better oral health systems.

The paper is:

Fabruccini, A., Alves, L. S., Alvarez, L., Alvarez, R., Susin, C., & Maltz, M. (2016). Comparative effectiveness of water and salt community-based fluoridation methods in preventing dental caries among schoolchildren. Community Dentistry and Oral Epidemiology.

The researchers used data from survey of the oral health of 1528 twelve-year-olds in Porto Alegro, South Brazil  (water fluoridated) and 1154 twelve-year-olds in Montevideo, Uruguay (salt fluoridated). Diagnostic procedures were standardised and the data adjusted for gender, maternal education, school type, brushing frequency, use of dentifrice, professional fluoride application, access to dental services and consumption of soft drinks.

Caries prevalence and decayed missing and filled teeth (DMFT) were measured using standard WHO procedures, and modified WHO procedures (which also included noncavitated lesions).

The graphs below show the adjusted data for caries prevalence (%) and DMFT.
Caries water salt

DMFT water salt

Both caries prevalence and DMFT were significantly higher for children from salt-fluoridated Montevideo than similar children from water-fluoridated Porto Alegro.

Apparently this is the first study showing a statistically significant difference between water and salt fluoridated areas. Similar studies in Freiberg, Germany and Dublin, Ireland had shown no signficant differences. The larger sample sizes of the current study may have contributed to the difference. However, the authors also warn that the different situations may also be a factor.

Developing countries have higher prevalence of caries and poorer access to others sources of fluoride than developed countries. Whereas water fluoridation reaches the whole population fluoridated salt may not have such a regular use. In Uruguay the salt fluoridation programme is limited to salt for domestic use. It does not cover public and private canteens, restaurants and bakeries (which the WHO recommends).

So, an interesting study with a clear result – but one that should not be cherry picked to confirm a bias. It indicates community water fluoridation will probably be more effective than salt fluoridation in developing countries – especially if a salt fluoridation programme is not complete. But this should not be used to argue against a good salt fluoridation programme in developed countries.

Similar articles

 

Fluoridation: the hip fracture deception

Warning – this book is deceptive

One of the myths promoted by the anti-fluoride people is that fluoridation is bad for our bones. As with similar myths the evidence used to support the claims usually comes from studies of situations where people have high F intake, often from natural sources.

However, there are studies which anti-fluoridationists can quote which do relate to fluoridated water concentrations.  For example, this is one of the many claims made by Christopher Bryson in his book The Fluoride Deception. This book tends to be used as scripture by anti-fluoridationists today so I thought I would look a bit more deeply into his claim.

Such deeper looks can often show problems of confirmation bias or uncritical evaluation of the literature – it did in this case.

1992

Bryson based his claim solely on work by Joseph Lyon, in particular the paper Hip Fractures and Fluoridation in Utah’s Elderly Population by Christa Danielson; Joseph L. Lyon; Marlene Egger; and Gerald K. Goodenough (1992). However, he does claim  “subsequent studies have found similar associations between fluoride in water and bone fractures.”

Danielson et al. concluded:

“We found a small but significant increase in the risk of hip fracture in both men and women exposed to artificial fluoridation at 1 ppm, suggesting that low levels of fluoride may increase the risk of hip fracture in the elderly”

2000

Well, it doesn’t take much searching to find papers with contrary conclusions. For example Community water fluoridation, bone mineral density, and fractures: prospective study of effects in older women by
Kathy R Phipps, Eric S Orwoll, Jill D Mason, Jane A Cauley (2000).

They concluded:

“Long term exposure to fluoridated drinking water does not increase the risk of fracture.”

So different conclusions, but why? Well Phipps et al. allude to the causes of contradictory conclusions in their introduction.

“While the benefit of fluoridation in the prevention of dental caries has been overwhelmingly substanti­ated, the effect of fluoridation on bone mineral density and rates of fracture is inconsistent. Ecological studies that compare rates of fracture specific for age and sex between fluoridated and non­fluoridated communities have variously found that exposure to fluoridated water increases the risk of hip fracture, (here they refer to Danielson et al 1992) increases the risk of proximal humerus and distal forearm fracture, has no effect on fracture risk, and decreases the risk of hip fracture. Ecological studies, however, have a major design flaw—they are based on community level data and cannot control for confounding variables at the individual level.” (My emphasis).

In contrast:

“We determined, on an individual level, whether older women with long term exposure to fluoridated water had different bone mass and rates of fracture compared with women with no exposure.” (My emphasis).

And they concluded:

“This is the first prospective study with adequate power to examine the risk of specific fractures associated with fluoride on an individual rather than a community basis. Our results show that long term exposure to fluoridation may reduce the risk of fractures of the hip and vertebrae in older white women. Because the bur­den of osteoporosis is largely due to fractures of the hip, this finding may have enormous importance for public health. If fluoridation does reduce the risk of hip fracture it may be one of the most cost effective meth­ods for reducing the incidence of fractures related to osteoporosis. In addition, our results support the safety of fluoridation as a public health measure for the con­trol of dental caries.”

So, if we compare the results from the two studies we see that while Danielson et al (1992) reported an increase in the risk of hip fracture for women drinking fluoridated water, Phipps et al (2000) actually reported a decrease in the risk. The difference being that Phipps et al (2000) removed confounding factors such as  medical history, drugs and supplements, reproductive history, menopause, alcohol consumption, exercise, smoking, caffeine intake, height and weight.

hip-fract

Relative risk of hip fracture for women with fluoride exposure compared to women with no fluoride exposure

2013

While preparing this I noted a new paper on this subject just published – Näsman et al (2013) “Estimated Drinking Water Fluoride Exposure and Risk of Hip Fracture:A Cohort Study

The abstract reports:

“Estimated individual drinking water fluoride exposure was stratified into 4 categories: very low, < 0.3 mg/L; low, 0.3 to 0.69 mg/L; medium, 0.7 to 1.49 mg/L; and high, ≥ 1.5 mg/L. Overall, we found no association between chronic fluoride exposure and the occurrence of hip fracture. . . . fluoride exposure from drinking water does not seem to have any important effects on the risk of hip fracture, in the investigated exposure range.”

So extra support for the conclusion that fluoridation does not lead to increased risk of hip fracture.

Motivated cherry picking

I think this shows the danger of cherry picking studies to support a preconceived position. And of relying on individual sources, or ideologically motivated sources like  The Fluoride Deception, for information.

There is a large amount of research on fluoride which to the uninitiated must seem contradictory. Proper review of this literature requires skills in critical thinking, and background in the field. The sort of thing that activist groups, and local body councils, don’t have.

Of course, I have no special background in this area either – and I don’t pretend that my summary here is at all definitive. However, it does show how misinformation can easily be promoted, with an apparent respectability conferred by  scientific references, when motivated people cherry pick.

See also:

Similar articles on fluoridation
Making sense of fluoride Facebook page
Fluoridate our water Facebook page
New Zealanders for fluoridation Facebook page

Anatomy of an anti-fluoridation myth

The internet seems to nurture and promote myths. Consequently it’s a great place for the ideologically motivated person desiring a  bit of  “evidence” for their confirmation bias. They can even get a bit pretentious and call their googling “research.”

Phil Evans on the New Zealand Fluoride Free Facebook page, provides an example of just such a myth. He is also someone who claims to have “been researching fluoride” for “many years.”

Europe has banned fluoridation?

Phil’s article is a hatchet job on the Ministry of Health’s new website on Community Water Fluoridation. He has produced what he claims is a  “long list of factually incorrect information” on that site. I will just deal with one issue here – his promotion of the myth that Europe has banned fluoridation of public water supplies. Partly because it is a popular myth for anti-fluoridation activists – but also because it illustrates the nature of the “research” done by many activists – and the unreliability of relying on any old link that Google throws up in that “research.”

He rips into Robyn Haisman-Welch, Chief Dental Officer from the Ministry of Health:

“She is not being honest about the reason fluoridation was removed in Europe, which is a European Court ruling banning the practice because it was illegal to force medication on the public.”

He also makes this claim about the European Court in his second paragraph. Taking issue with references to the use of milk and salt fluoridation or use of other alternative methods in Europe he claims:

“The actual reason is that the European Court ruled some years ago that using fluoridation chemicals was medical intervention, and was therefore illegal. It has nothing to do with practicalities.”

The myth

So there it is – the anti-fluoridation myth. Europe has banned community water fluoridation. The European Court has called the practice “illegal.”

banner-web

Fluoridation banned in Europe – a common anti-fluoridationist claim

The point is that using Google and confirmation bias as your “research” tools it is easy to find support for the claim. Do a search for “European Court” and “fluoride” and you have all the “evidence” you need to confirm your bias (but none from a primary source like the European Court). It’s there on Fluoride Alert, Fluoride Action Network of NZ (FANNZ) and any number of  political, alternative lifestyle, alternative health or diet, and conspiracy theory websites.

Statements like:

“The European Court of Justice has defined fluoridation as a medication and has refused to sanction its implementation.”

“… the European Court of Justice recently determined that fluoride is a medicine, and therefore water fluoridation is a form of forced medication.”

Now, the trouble with this “research” is the difficulty of checking with any primary source. If the claims are referenced, they cite similar articles from similarly unreliable sources, not primary sources. (Fluoride Alert and FANNZ have made an art form out of circular citations – they very often just cite themselves).

However, I did find what appears to be the origin of this myth, because it is very frequently quoted – an article by Doug Cross at the UK Campaign Against fluoridation website. He claims:

“Fluoridated water must be treated as a medicine, and cannot be used to prepare foods! That is the decision of the European Court of Justice, in a landmark case dealing with the classification and regulation of ‘functional drinks’ in member states of the European Community. (HLH Warenvertriebs and Orthica (Joined Cases C-211/03, C-299/03, C-316/03 and C-318/03) 9 June2005)”

Often the quote marks used when this is quoted give the impression they are quoting from the actual European Court of Justice ruling. Which is wrong – the document does not refer to fluoridation at all!

Also, while the title of the Court judgement is often given it is never linked to the document itself.

The Court decision

The specific ruling referred to in the Doug Cross’s often quoted  article is easily found by searching on the European Court of Justice web site – providing you don’t use “fluoride” or “fluoridation” in the search.” Those words just don’t occur in the document.  In fact “water” only shows up a few times.

So here is the judgement – JUDGMENT OF THE COURT In Joined Cases C-211/03, C-299/03 and C-316/03 to C‑318/03.

The judgement refers to a conflict between the Netherlands and Germany over trade in a few food items. The codes in the title refer to these items. They are:

  • C-211/03, Lactobact omni FOS in powdered form; one gram of powder contains at least 1 000 000 000 organisms from the following bacterial strains: lactobacillus acidophilus, lactococcus lactis, E. faecium, bifidobacterium bifidum, lactobacillus casei and lactobacillus thermophilus; the recommended consumption is approximately 2 g per day, dissolved in half a glass of water or with yoghurt, although the dose is doubled where the need is greater and during the first four weeks of taking it;
  • C-299/03, C 1000 in tablet form containing, in particular, 1 000 mg of vitamin C, 30 mg of citrus bioflavonoids, hesperidin rutin complex and other ingredients; the recommended consumption is one tablet per day;
  • C-316/03, OPC 85 in tablet form containing, in particular, 50 mg of extract of bioflavonol – oligomere procyanidine; the recommended consumption is one tablet per day;
  • C-317/03, Acid Free C-1000 in tablet form containing, in particular, 1 110 mg of ascorbate of calcium – 1 000 mg of vitamin C and 110 mg of calcium; the recommended consumption is one tablet per day;
  • C-318/03, E-400 in tablet form, containing 268 mg of vitamin E; the recommended consumption is one tablet per day.

Yes, a key issue in the case was whether some of these products should really be classified as medicines and not foods, or that they contained genetically modified or novel organisms, and therefore trade in them is not permitted under food regulations. But how the hell this judgement can be used to claim that the court had ruled “fluoridated water must be treated as a medicine, and cannot be used to prepare foods” is beyond me.

What has this to do with fluoridation?

I know I am not a lawyer. I can understand how a lawyer for FANNZ might use this case as an argument in their own attempts to make fluoridation illegal. And they are welcome to attempt this – although I suspect they won’t get very far by relying on that judgement.

But one thing is abundantly clear to anyone with basic comprehension skills. This judgment did not rule that fluoridated water is a medicine. Or that it cannot be used to prepare foods. And it did not rule that trade in foodstuffs from New Zealand would be banned by Europe as some of these sources were claiming.

So another anti-fluoridation myth hits the dust. Except it won’t. It will be repeated ad nauseum by anti-fluoridation activists. They will even give links to “prove” their claims. And those activists will claim they are doing “research.”

unfortunately, like many other stories told by anti-fluoridation activists, a bit of critical thinking and deeper searching proves the myth to be based on a complete lie.

The lesson

Something to remember when using Google for research – the rubbish, as in other situations, usually rises to the top. It is the easiest to find and gets the most hits. Oh, yes – be careful with that confirmation bias – it will trip you up.

See also:

Similar articles on fluoridation
Making sense of fluoride Facebook page
Fluoridate our water Facebook page
New Zealanders for fluoridation Facebook page

NZ experts deplore anti-fluoridation misrepresentation of science

I usually abhor the concept of science by petition. But I have had a gutsful of devoted anti-fluoridationists assuring me that they have scientific and other experts on their side. And the last straw was the attempt by a local supporter of Fluoride Free Hamilton to get the Waikato University Chemistry Department staff to stop discussing the science of fluoridation. He wanted scientists to opt out of discussing science!

So it was nice to see medical, scientific and technical people respond a little to this. The last issue of Hamilton’s free paper Hamilton News included a list of New Zealand experts who disagree with the anti-fluoridationist claims. The list was whipped up in short time and is not restricted to local people.

The supported statment reads:

“The following medical, scientific and technical experts deplore the misrepresentation of science to support the beliefs of the anti-fluoridation lobby.

The true science of water fluoridation has:

SHOWN that drinking water fluoridation reduces the incidence of tooth decay
NOT SHOWN that drinking water fluoridation has any ill-effects on general health”

bfp5lg

Download a sharper version if you wish to check names.

See also:

Similar articles on fluoridation
Making sense of fluoride Facebook page
Fluoridate our water Facebook page
New Zealanders for fluoridation Facebook page

When politicians and bureaucrats decide the science

The current seperation of responsibility for water treatment (local body councils) and community health policy (District Health Boards) is a problem when considering fluoridation. This was illustrated by the Hamilton City Council’s suspension of  fluoridation of the city’s water supply. In the end the City Council neglected its real responsibility (to find out and reflect the views of its citizens) and instead took over the health Board’s responsibility for public health policy.

The council set itself up as a “tribunal” to make judgements on the science – a task they were clearly not equipped for.

The “tribunal” process

Tegan McIntyre, the Hamilton City Council’s Strategy and Research Unit manager, recently revealed a little of the process used by the council in its judgment of the science around fluoridation. She released “a list of the key research papers referenced during the submission and tribunal process.” She also described the “in-house evaluation” of that research. This evaluation appeared to find the research acceptable if it was “validated (peer reviewed) and/or published in an acknowledged peer-reviewed journals.”

You can download Tegan’s list –Scientific research supporting the stopping of fluoridation. The research seems to have been chosen using some sort of popularity index – she says “Please note, this list does not cover all the reports referred as this was extensive but focuses on the ones most frequently cited.”

So, the unrepresentative nature of submissions is a bit of a problem to start with – the summary of submissions says – ”

“Of the 1,557 submissions received 1,385 (89%) seek Council to stop the practise of adding fluoride to the Hamilton water supply. 170 (10.9%) seek Council to continue the practise of adding fluoride and 2 (0.1%) submitters did not indicate a stance.”

submissions

This in a city which showed 70% support for fluoridation at its 2006 referendum!

The validity of scientific research determined by this sort of popularity contest. Or by the way the councillors and council bureaucrats kept referring to “experts on both sides” as if it was simply a matter of weighing the submissions without any proper evaluation of the validity of claims made by the “experts.”

This approach is not acceptable for scientists who are used to critical consideration and in depth analysis of published research.

However, maybe it’s a natural way for bureaucrats without the scientific background necessary to make sense of a large number of submissions. I am sure the anti-fluoridation activist organisations realise this and I can understand why they use the approach of swamping such hearings with unrepresentative numbers of submissions, basically repeating the same message.

I will comment below on the documents in the list and the validity of the Council’s assessments. Sorry for the inevitable length of these comments. You can download a pdf to read at your leisure.

1: Public Health Investigation of Epidemiological data on Disease and Mortality in Ireland related to Water Fluoridation and Fluoride Exposure by Declan Waugh.

Declan Waugh is a darling of the anti-fluoridation movement. He also made presentations (written and by Skype from Ireland) to the “tribunal” so I am not surprised to find it top of the list. Apparently the Council evaluated the document highly because it was a “literature review collated by environmental scientist/consultant.”

I haven’t had time to critically consider this specific document but in the scientific world Declan Waugh’s work is not so highly regarded. The Irish Expert Body on Fluorides and Health evaluated Waugh’s previous report – which he considers his “main Report” – (Human Toxicity, Environment Impact and Legal Implications of Water Fluoridation)  and found it was “not reliable.” That while the “report is expertly produced and is impressive in size and appearance. However, in spite of its presentation, its content is decidedly unscientific” (see Appraisal of Waugh report – May 2012). Among specific points it made are these (see Executive Summary of Appraisal of Waugh report – May 2012):

  • “The allegations of ill health effects are based on a misreading of laboratory experiments and human health studies, and also on an unfounded personal theory of the author’s.
  • There is an absence of reporting of the bulk of the scientific literature which points to the lack of harmful effects from fluoridation.
  • The views of authoritative bodies such as the World Health Organisation, the European Commission and others are significantly misrepresented.
  • There is a misunderstanding of the evidence of benefits to oral health and with regards to enamel fluorosis.
  • The view that there is a build up of fluoride in the environment is unfounded and not supported by the evidence.”

Anyone willing to spend a little time can make their own evaluation of Declan Waugh’s scientific integrity simply by checking his approach to citations.

Two examples:

On page 74 of his “main report” we find the claim:

“Fluoride is known to be an inhibitor of enzymatic activity and research has identified fluoride as an inhibitor of homocysteine hydrolase.363

The cited paper is:

Mehdi S, Jarvi ET, Koehl JR, McCarthy JR, Bey P. The mechanism of inhibition of S-adenosyl-L-homocysteine hydrolase by fluorine-containing adenosine analogs. J Enzyme Inhib. 1990;4(1):1-13.

Waugh is citing work about “fluoride-containing adenosine analogs” to make the claim about the fluoride anion. Extremely sloppy!

On Page 75 he claims:

“Current research has also identified the link between fluoride and atherosclerosis.370

The cited paper is:

Li Y, Berenji G R, Shaba W F, Tafti B, Yevdayev E, Dadparvar S. Association of vascular fluoride uptake with vascular calcification and coronary artery disease. Nucl Med Commun. 2012 Jan;33(1):14-20.

Those familiar with the claims made by anti-fluoridation propagandists will recognise this paper. It concluded “[18F]fluoride PET/CT might be
useful in the evaluation of the atherosclerotic process in
major arteries, including coronary arteries. “ Fluoride does not cause atherosclerosis but because fluoride is associated with calcium containing products of atherosclerosis – fluoride is only along for the ride – the authors proposed the technique for detecting atherosclerosis.

Waugh uses citations like a drunk uses a lamp post – for support rather than illumination. And this causes him to use the citations dishonestly – as evidence for claims that they actually don’t support. Try checking out a few citations yourself.

2:  Ethics of Artificial Water Fluoridation in Australia by Niyi Awofeso

This appears to be an academic discussion of the ethical issues involved and comes out in opposition to fluoridation. Effectively it balances  health equity against individual autonomy – a values/political judgement. The Council evaluated the document highly because it was “Published in a peer-reviewed international journal.”

I could not get the full text of this document so can’t really comment on it – except to conclude from the abstract that no scientific issues seem to be discussed.

3: Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis by Anna L. Choi, Guifan Sun, Ying Zhang,and Philippe Grandjean

If you are familiar with the fluoridation debate you will recognise this paper – it is one of the most quoted by anti-fluoridation commenters on the internet.  The Council evaluated the document highly because it was “Published in a peer-reviewed research and news journal published with support from the National Institute of Environmental Health Sciences.”

The study often seems to be quoted alongside outrageous claims like the Nazis used fluoride in the concentration camps to placate inmates. Or the US government adds fluoride to water to keep the population from revolting (see Fluoridation and conspiracy theories).

Because of the study’s misuse to attack fluoridation the authors warned in a press release:

“These results do not allow us to make any judgment regarding possible levels of risk at levels of exposure typical for water fluoridation in the U.S. On the other hand, neither can it be concluded that no risk is present. We therefore recommend further research to clarify what role fluoride exposure levels may play in possible adverse effects on brain development, so that future risk assessments can properly take into regard this possible hazard.”

One problem is that the effects on IQ were seen at high fluoride intakes (studies were of Chinese localities with a range of fluoride in drinking water from both natural and industrial pollution sources). The “control” ‘low fluoride exposure” groups in this study are often exposed to fluoride concentrations comparable to that achieved by community water fluoridation schemes. Andrew Sparrow illustrated this with the following infogram:

neuro

Another problem is that no causal link between fluoride and IQ levels was sought or found. The fact that some of the locations suffered from industrial and coal pollution means these IQ effects, if real as social factors were not elimated, could have been caused by any number of pollutants.

This work should not have been considered relevant to the question of fluoridation of Hamilton’s water supply – despite its popularity with anti-fluoridation submitters.

4: Critical review of any new evidence on the hazard profile, health effects, and human exposure to fluoride and the fluoridating agents of drinking water by SCHER

The Council evaluated the document highly because it was “Published by one of the independent non-food Scientific Committees which  provides the European Commission with scientific advice.

This review is often cited by both sides. Reasons for anti-fluoridation citing could include the clear assertion that fluoride “is not an essential element for human growth and devlopment.” But the review does make clear the fluoride is beneficial for oral health. Misunderstandings often revolve around precise usage of words like “essential.”

Another reason could be the vague comparsion between “topical fluoride application” and “systemic” intake of fluoride. This could enable anti-fluoridationists to claim fluoridated water is ineffective. However, the report does refer to the effectiveness of maintianing “a continuous level of fluoride in the oral cavity.” Fluoridated water does do this.

Again this illustrates the need for careful and critical evaluation of the scientific literature and the need to avoid simple claims which may incorrectly cite that literature. I just don’t think politicans and bureaucrats can be relied on for that.

5: Estimated Dietary Fluoride Intake For New Zealanders by Peter Cressey, Dr Sally Gaw and Dr John Love

The Council evaluated the document highly because it “was prepared as part of a Ministry of Health contract for scientific services.”

It is a straightforward desktop study of the “dietary fluoride intakes for a range of age and gender sub-populations based on New Zealand data.” There are no surprises in the data, although the interest for anti-fluoridationists was probably their findings for  formula-fed infants:

“The estimates for a fully formula-fed infant exceeded the UL [upper level of intake] approximately one-third of the time for formula prepared with water at 0.7 mg fluoride/L and greater than 90% of the time for formula prepared with water at 1.0 mg fluoride/L. However, it should be noted that the current fluoride exposure estimates for formula-fed infants are based on scenarios consistent with regulatory guidelines, rather than on actual water fluoride concentrations and observed infant feeding practices.”

They conclude “the very young appear to be the group at greatest risk of exceeding the UL.” However:

“the rarity of moderate dental fluorosis in the Australia or New Zealand populations indicates that current exceedances do not constitute a safety concern, and indicates that the UL may need to be reviewed.”

Anti-fluoridationist have made some mileage out of this, taking advantage of parent’s’ understandable concerns about their children. They (and the Hamilton City Council in their initial advice to ratepayers) advised parent not to use fluoridated water to make up formulae when infants are  fully formula-fed.

While the current expert advice is a little confusing it does take account of the need for review of current UL’s and considers use of fluoridated water safe for fully formula-fed infants. However, they also advise that if parents are concerned they should use non-fluoridated water for part of the feeding – a peace of mind matter.

Again, I question if the “tribunal” really understood the complexity of the situation for fully formula-fed children. Even though health experts had explained the situation during the hearings they apear to have simply accepted the anti-fluoridationist’s interpretation of this research.

Maybe it was the loudest, or more frequently presented, message which prevailed?

6: Fluoride in Drinking Water: A Scientific Review of EPA’s Standards by National Research Council Of  The National Academies Committee on Fluoride in Drinking Water.

The Council evaluated the document highly because the national research council is a “government funded research entity.”

This report usually get cited by both supporters and opponents of fluoridation – however, it actually does not have direct relevance to fluoridation of water supplies at the concentrations used in New Zealand (0.7 – 1.0 ppm) or in the US (0.7 to 1.2 ppm). “The charge to the committee did not include an examination of the benefits and risks that might occur at these lower concentrations of fluoride in drinking water.”

The NRC’s task was to evaluate the scientific evidence to determine if the Environmental Protection Agency’s maximum recommended levels of 4 ppm F should be lowered. They concluded it should be lowered to below 2 ppm to avoid any severe fluorosis. Anti-fluoride activists very often cite this report because of its thorough discussion of the negative effects of fluoride observed at high concentrations. They rarely admit that these effects are not reported for the concentration range used in public water fluoridation. This sort of scare-mongering often comes up in political debate but I would expect a critical evaluation of the report would have recognised that it is not relevant to the Hamilton situation.

But then again, why should we expect politicians and bureaucrats to be capable of such critical consideration.

7: Water Fluoridation: a Review of Recent Research and Actions by Joel M. Kauffman

The Council evaluated the document highly because although the “journal  is not listed as an academic journal but as a professional association journal. [It]Has a double-blind peer-review process.”

This was published in the Journal of American Physicians and Surgeons which really has no scientific standing. Issuepedia says “the journal does not appear to be considered respectable by the scientific establishment because:

  • It is not listed in the major literature databases ( MEDLINE/PubMed nor the Web of Science).
  • The World Health Organization found that a 2003 article on vaccination published in the journal had “a number of limitations which undermine the conclusions drawn by the authors.” 
  • Quackwatch lists it as an untrustworthy, non-recommended periodical. 

Investigative journalist Brian Deer described the journal as the:

“house magazine of a right-wing American fringe group, the Arizona-based Association of American Physicians and Surgeons, which campaigns against US vaccination policies. The association is also vocal in opposing moves to combat fraud by private doctors, and medical professional efforts to reduce deaths from domestic firearms. In 2005, Time Magazine reported that the association had only 4,000 members. Although cited by Private Eye in stories attacking MMR, the association’s journal – recently renamed from the Medical Sentinel, presumably for the purpose of attempting to give its ideologically slanted material the aura of science – is barely credible as an independent forum for such material. No objective medical scientist with important information of any standard would submit it to such a publication, unless they couldn’t get it published anywhere else.”

So much for the Hamilton City Council high evaluation. But the paper itself is not at all convincing. It’s claims are poorly supported. It relies heavily on citation of sources from anti-fluoridation activists. Much of the citation is to just one book Fluoride: Drinking Ourselves to Death by Barry Groves – a staple anti-fluoridationist manual. Kauffman’s ideological motivation are obvious.

8: Prevention and reversal of dental caries: Role of low level fluoride  by J. D. Featherstone.

The Council evaluated the document highly because it was in a “ranking academic journal.”

This paper is often cited by anti-fluoridationists as support for their claim that the “topical mechanism” of protection of existing teeth means that fluoridated water is ineffective. Yet the paper clearly includes “fluoride in drinking water” (as well as in “fluoride-containing products”) as operating via the topical mechanisms. Featherstone has also stressed drinking water in recent descriptions of the “topical mechanism” (Topical Effects of Fluoride in the Reversal and Prevention of Dental Decay). I can only conclude that some people have the wrong impression through superficial reading and their conclusions have been adopted by others without any checking. The Fluoridation Action network NZ (FANNZ) website even claims, incorrectly, that a topical effect of fluoridated water on teethis contradicted by Featherstone.”

Again, and again, I find this website very misleading in their use of citations.

The Hamilton City Council repeated this incorrect interpretation of topical mechanisms in their information leaflet for citizens (see Topical confusion persists) – a serious mistake which has been strongly criticised by health professionals. Did Council bureaucrats simple take the anti-fluoridationist use of this citation at their word – without any checking?

9: Why I changed my mind about water fluoridation by J. Colquhoun.

The Council evaluated the document highly because it was in a “Peer-reviewed academic journal published by Johns Hopkins. Author: former dental officer in New Zealand during the 1970s and early 1980s”

This is really a memoir, and not a high quality review. I found that it generally gave a lot of emphasis to longitudinal studies which show improvement in oral health over time for both fluoridated and unfluoridated areas. This may have suprised researchers at the time but is well recognised today and, by itself, is not evidence against the effectiveness of fluoridation. He also seems to be very selective, some would say cherry-picking, in referring to studies where comparison have been made between fluoridated and unfluoridated areas. The all appear to show either no effect, or that oral health was better in the non-fluoridated areas! (Anti-fluoridations regularly do such cherry-picking today).

Colquoun presented the “topical” mechanism as an argument that fluoridated water is ineffective – a suprising interpretation for someone familiar with the literature. However, I guess his committment to the anti-fluoridationist cause when he wrote this memoir might explain the faulty interpretation.

10: The mystery of declining tooth decay by Mark Diesendorf

The Council evaluated the document highly because it was published in “Nature [which] is a prominent interdisciplinary scientific journal. Ranked the world’s most cited. “

Although Diesendorf is an environmental scientist he is also an anti-fluoridation activist. In this paper he relies heavily on longitudinal studies, where oral health was found to improve in both fluoridated and unfluoridated areas over time. This is a well accepted observation, explained by improvements in diet and care of teeth, as well as availability of fluoridated toothpaste. I believe some of this improvement is also due to changes in dental practice involving less fillings.

Such research does not invalidate the also well recorded difference in oral health between fluoridated and unfluoridated areas observed in many good studies. However, the longitude observations still get trotted out as evidence against fluoridation by the anti-fluoridation activists.

Despite the high standing of Nature, this paper does come across as somewhat one-sided, maybe partly because of its age (1986).

Conclusions

The mistaken approach of the Hamilton City Council in its “tribunal” judgement of the science behind fluoridation illustrates the problems of the current situation where councils effectively make decisions about fluoridation because they manage water supplies. This can force them into a role for which they have neither the skills nor the training – making scientific and health judgements. Anti-fluoridation activists have taken advantage of this anomaly with a certain amount of success.

The Medical Association has called the debate on fluoridation to be raised to a national level. “Medical Association chairman Dr Mark Peterson says it’s not ideal for it to be discussed at a regional level and not nationwide.” This could be a way of avoiding the problems illustrated by the actions of some councils – including the Hamilton City Council.

The way scientific research was evaluated by the Hamilton City Council and its bureaucrats shows what can happen when such evaluations are not done critically by people with expertise in research and some understanding of the issues involved. Discussion and decision of the fluoridation issues at the natioanl level could help ensure such evaluations are done by bodies better equipped for the job.

See also:

Similar articles on fluoridation
Making sense of fluoride Facebook page
Fluoridate our water Facebook page
New Zealanders for fluoridation Facebook page

Welcome counter to scientific and health misinformation

Anti-fluoridation activists work very hard to propogate their misinformation. Letters to the editor, Facebook, Twitter and blog comments. At times their material will dominate google searches. No wonder the layperson can be confused, or even influenced by some of this information.

So I welcome the announcement of a new website dedicated to correcting the misinformation. This will provide New Zealanders a place to go for information on fluoride and fluoridation when they or their communities are faced with questions or even decisions. Interestingly, it is probably fairly unique in New Zealand – on-line action by authorities to counter misinformation about science and health.

Here is the media release about the new website from the Minister of Health Tony Ryall.


CWF

A new website, www.fluoridefacts.govt.nz will help local communities make informed decisions on water fluoridation, Health Minister Tony Ryall says.

The most recent nationwide New Zealand survey into oral health showed 40 percent less tooth decay on average for children living in fluoridated areas compared with non-fluoridated areas, Mr Ryall says.

“Some information circulating about community water fluoridation is either confusing or misleading. This website, which is supported by the Ministry of Health, district health boards and the New Zealand Dental and Medical Associations, contains evidence-based information, backed-up by research.”

New Zealand’s Chief Science Advisor, Professor Sir Peter Gluckman is among the several health professionals, scientists and community leaders who feature in a video series on fluoride also on the website. Professor Gluckman says: “It’s absolutely clear that the levels of fluoride that are put into New Zealand’s water supply – and are clearly regulated – are safe. They have real health benefits and there are no health risks.”

Mr Ryall noted that fluoride occurs naturally in water but New Zealand, like several other countries, has low levels. “Many countries in similar situations supplement fluoride to optimum levels for dental health benefit by adding it to the community water supply, or in some cases milk or salt.”

In New Zealand the levels of fluoride used in community water fluoridation are carefully monitored and within the guidelines of the World Health Organization and other public health agencies.

Mr Ryall says tooth decay, which is less likely in individuals when fluoride is added to the water supply, is painful and costly when fillings are needed to treat it. Community water fluoridation is effective, safe and an affordable way to provide the dental health benefits to everyone in a community.”

“People should refer to www.fluoridefacts.govt.nz  and come to their own conclusions when deciding to support community water fluoridation.”

For further information, including videos from Chief Science Advisor, Professor Sir Peter Gluckman, Chief Medical Officer of Health Dr Don Mackie, Chief Dental Officer Dr Robyn Haisman-Welsh and Children’s Commissioner Dr Russell Wills, along with other health experts and community leaders, see: www.fluoridefacts.govt.nz.


Further information also available from www.Health.govt.nz and www.nfis.org.nz the National Fluoride Information Service.
In New Zealand community water fluoridation is endorsed by the following organisations:

Ministry of Health
District Health Boards
New Zealand Dental Association
New Zealand Medical Association
Public Health Association of New Zealand
New Zealand Nurses Organisation
Te Ao Marama – the Māori Dental Association
Toi Te Ora – Public Health Service
Office of the New Zealand Children’s Commissioner
New Zealand College of Public Health Medicine
NZ Dental and Oral Health Therapists Association
NZ Society of Hospital and Community Dentistry
NZ Oral Health Clinical Leadership Network Group
Royal New Zealand Plunket Society
Cancer Society of New Zealand
The Royal Australasian College of Physicians
Royal Australasian College of Dental Surgeons

See also:

Similar articles on fluoridation
Making sense of fluoride Facebook page
New Zealanders for fluoridation Facebook page

Dentists you can trust?

billboard2

Credit: Making Sense of Fluoride Facebook page.

Looks like the Fluoride Free Hamilton activists have managed to find 3 dentists who they agree with. None of them work in Hamilton – one is from Northland, one from Wellington and the other is from Dunedin. So they literally searched far and wide to locate them.

Never mind, Fluoride Free Hamilton and its network is trusted by the Hamilton City Council when it comes to health matters. So they can continue to ignore the advice from local and national health experts. However, it might be harder for the incoming council to ignore the advice coming from voters during the upcoming local body elections and fluoridation referendum in the city.

The activist’s claim that their 3 dentists are the informed ones carries the implication that all other New Zealand dentists are uninformed! In fact Grant et al (2013) survey New Zealand dentists on the opinions of fluoridation (see New Zealand dentists’ views on community water fluoridation). Their finding were that:

“Most practitioners (93.5%) reported supporting community water fluoridation; the other 6.5% either were unsure or did not support it. Higher proportions of more recent graduates supported CWF. Some 85.6% of practitioners thought that drinking fluoridated water was a harmless way to prevent dental caries, but 6.2% felt that fluoridated water may cause other health problems.”

And they concluded:

“Most New Zealand dental practitioners support community water fluoridation, although a very small proportion believe that it is harmful and/or does not prevent caries.”

The fluoridation issue is turning out like the controversy around scientific issues like climate change and biological evolution. Just as scientists supporting creationism or climate change denial turn out to be a very small fraction of the numbers on those fields, dentists opposing community water fluoridation are also a very small fraction of all dentists.

Mind you – Fluoride Free Hamilton seems to be making a virtue out of that embarrassingly small support for their views. I am expecting to hear them come out with the Galileo Gambit some time soon.

Thanks to Dan from Making Sense of Fluoride for bringing my attention to the paper.

See also:

Similar articles on fluoridation
Making sense of fluoride Facebook page
New Zealanders for fluoridation Facebook page

Cherry picking fluoridation data

Anti fluoridationists certianly go in  for picking cherries when the produce “evidence” to discredit fluoridation. Two anti-fluoridatioon actvists, Bruce Spittle and Russel McLean, did this in there opinion piece in the Otago Daily Times recently (see No consent given for fluoridation). In particular, they carefuly selected data from the Ministry of Health’s database on the oral health of children.

How to “prove” fluoridation ineffective

They claimed:

The efficacy of water fluoridation is modest.The Dental School staff referred to the 2009 New Zealand Oral Health Survey which noted that in 2008, for all of New Zealand, the 5-year-olds in fluoridated areas had a percentage caries-free rate of 58.7% compared to the rate of 55.0% for those in non-fluoridated areas. However, the 2011 figures show little difference, with the rate for fluoridated areas being 59.91% and that for non-fluoridated areas being 59.18%.

In this case, while they chose the total data set, they selected just 2 years (2008 and 2011), selected only one age group, considered just “percentage caries-free” and ignored the data for “decayed, missing and filled teeth,” and also ignored the data for Maori (important because these show the influence of social and economic deprivation).

I looked at the whole data set in my article Fluoridation – it does reduce tooth decay. So I will just repeat a few of my data plots from that article toi show the effect of cherry picking. The plots of the data below give an idea of variability and trends. They also show the influence of social and economic deprivation is long-term. (Click on the graphs to enlarge for details).

% CARIES FREE

Fluor-3

MEAN DECAYED, MISSING AND FILLED TEETH

Fluor-4

There could well be some story in the apparent reduction of the effect of fluoridation shown by the % caries free of 5 year olds but that has to be put into the context of the whole data set. It is dishonest to just select the small samples Spittle and McLean did – but of course you can see why they did select those years and restricted their comments to just 5 year olds and “% caries free.”.

How to prove fluoridation damages oral health

The Fluoride Free New Zealand Facebook page provides another example of cherry picking (see Waikato Dental Health Stats). In this case their “findings” were so ludicrous that you might have thought they would blush at presenting them. There are some mistakes in their data, but it tends to show that children had better teeth in the non-fluoridated areas than the fluoridated areas!

Well, they achieved this by cherry picking data for one year (2011) and one region (the Waikato). If we look at some of the data over the availabke time period (2002 – 2011) for Waikato, we can see why they cherry picked this region and year.

Waikato1

But, comparing the Waikato data with the total data in the previous figures we can see a greater variability from year to year. This variability makes any honest comparison very difficult – but it does give opportunities for creative cherry picking. (Yes, I have just “cherry-picked” the caries free data for 5 years old in this graph – but I am making a point).

Be careful of variation and cherry picking

The opportunities for cherry picking in a field like this are everywhere because of the variability. This is not like the data one gets in a carefully controlled laboratory experiment. We are dealing with a biological system – which introduces biological variability. But on top of that, it is also a social system which introduces an extra set of variability.

As an example, I was recently discussing with my granddaughter her new school in Hamilton. She told me that all her friends actually lived out-of-town. But the dental data will have recorded them as being from a fluoridated area because, at the time, Hamilton was fluoridated. Then there are problems of getting consistent evaluation from a large number of dental nurses. Differences in dietary intake, drinking of bottled water, etc., – the list goes on.

Some of this variation “evens out” when the data set is large (and of course has more influence when only part of the data set is chosen. Yes, it would be nice to control for all these social effects but in the real world one rarely gets the opportunity.

However, my point is that the variability introduced into this sort of data by biological and social effects provides ample opportunity for political activists to cherry pick data to support their own story – confirmation bias if innocent and dishonest misrepresentation if not.

So, it is easy to make claims one way or the other in the fluoridation controversy – and to find data to support these claims. But serious assessment of the claims requires critical evaluation of the data – something many people have no experience with.

This seems to have been the case with the Hamilton City Council who concluded from presentations heavily biased toward anti-fluoridationists that fluoridation of water supplies is not effective. But why should we expect city councillors to have the critical evaluation skills required to assess such data? They should never be put in the position of being asked to make scientific judgements in this way.

See also:

Similar articles on fluoridation
Making sense of fluoride Facebook page
New Zealanders for fluoridation Facebook page

Anti-fluoride activists attempt to silence science

Roger Stratford, a local aspiring politician, wants scientist to shut up. He is campaigning against the fluoridation of Hamilton’s water supply (we have a referendum coming up) and is a member of Fluoride Free Hamilton. He is also campaigning for a seat on the Hamilton City Council.

But Roger seems to have a King Canute-like (or is it Walter Mitty-like) perception of his own powers. The Waikato Times this morning reports he wrote to the University of Waikato’s Chemistry Department requesting that it’s staff stop communicating their science (see Anti-fluoride campaigner tries to silence science). He objects to:

“the degree of casual support emanating from the chemistry department in local papers in support of the practice [of fluoridating water] . . . At Fluoride Free Hamilton we intend to limit the debate to the social science and public health aspects of fluoridation. . . . It would be appreciated if we could receive some confirmation from the chemistry department that it will remain publicly neutral on the matter. . . . Fluoride Free Hamilton does not have any issues with the chemistry department academically, it is the implications of modern science in which we differ.”

What a cheek – Fluoride Free Hamilton and Roger Stratford want a deal! They will talk only about social science and the chemists can STFU. Well, we all know that most of the issues around fluoridation are scientific, and mostly chemical. And the anti-fluoridation activists are spreading misinformation about that chemistry as fast and as widely as they possibly can.

What was Roger thinking?

My first whiff of Roger’s stupidity came with a comment of his on the Fluoride Free Hamilton Facebook page:

Facebook-before-2I contacted him asking if he had in fact written to the Chemistry Department. He Assured me in his reply:

“In my experience as a student the chemistry department doesn’t negotiate on anything, it was just a throwaway line of mine to get that Archer fellow from blogging. There is no reason to be alarmed.”

Well, I guess that’s a political answer – an implied but not a factual denial. Mind you, very quickly the comments on the Fluoride Free Hamilton Facebook page changed – see if you can guess what was deleted:

Facebook-after-2

Well, I suppose that is politics. It is really a bit much to expect honesty and integrity from politicians, or from political activists like the Fluoride Free groups.

But I object very strongly to politicians, and political activists, who will do their earnest best to spread misinformation about science – and then tell scientists they have no right to comment on the issues.

See also:

Similar articles on fluoridation
Making sense of fluoride Facebook page
New Zealanders for fluoridation Facebook page

Experts speak out on fluoridation

How Fluoride Works

This is a letter to Dunedin City Councillors from 21 senior School of Dentistry staff. They believe that fluoridation of Dunedin’s water supply should be retained and expanded. As the Otago Daily Times headline puts it – Better oral health largely due to fluoridation.

I think it is a good summary which should be read more widely than in Dunedin. In the upcoming local body elections there will be referenda deciding on local fluoridation in Hastings, Whakatane and Hamilton. There are also campaigns against fluoridation in Auckland and Wellington with declared intentions to spread the campaigns even wider.

Here is the letter:


In 1958, the Faculty of Dentistry requested the council to fluoridate the water supply of our city.

The Otago Branch of the Dental Association pledged its support of this request.

Our position remains unchanged after 55 years.

A debate surrounding community water fluoridation has recently surfaced again in Dunedin, and has received some coverage by local and national media.

We would, therefore, like to remind councillors of the strong case for fluoridation to continue in our city, and be expanded wherever feasible, including to unfluoridated areas of Mosgiel and areas covered by the Northern Water Scheme.

The New Zealand Ministry of Health has commissioned extensive reviews, which have led to development of ministry guidelines and statements on fluoridation.

These guidelines and statements are clear: community water fluoridation is effective and safe, and community water supplies should be fluoridated at 0.7-1.0 parts per million (ppm) wherever feasible.

The Australia New Zealand Food Safety Authority also approves the addition of fluoride to bottled drinking water, as it believes this is important for public health.

The US Centers of Disease Control estimate that for every $1 spent on water fluoridation, $38 is saved on tooth decay treatment, and named water fluoridation as one of the greatest public health improvement measures of the 20th century.

The World Health Organisation considers access to fluoride to be a human right.

Scientific evidence shows that there remains a very strong public health case for continuing and expanding the use of community water fluoridation, because it improves New Zealanders’ oral health and quality of life.

While the extent of tooth decay has reduced in recent decades, the disease remains more prevalent than other significant health conditions in New Zealand (such as asthma), particularly in unfluoridated areas and among disadvantaged New Zealanders.

The recent New Zealand Oral Health Survey found much less tooth decay in fluoridated than in non-fluoridated areas.

The argument that water fluoridation is no longer necessary due to better oral health in New Zealand is not correct.

In fact, the improved oral health we now enjoy in New Zealand compared to the past is in no small way a direct result of water fluoridation.

We forget that very few New Zealanders are affected by water-borne diseases, thanks to water chlorination.

If chlorination was not used, we would have more water-borne diseases.

If community water fluoridation ceased, the severity of tooth decay would increase again, back towards historical levels.

Fluoride is a naturally occurring substance which is present at varying concentrations in water.

It is even detectable at 0.1ppm in the water of the Rattray St ”Speight’s” spring.

Community water fluoridation is not just a matter of fluoride addition; rather, it is the adjustment of fluoride levels up (or even down) to an optimal effective level for the prevention of tooth decay.

Adjusting the background fluoride level (which is generally about 0.3ppm) to 0.7-1.0ppm has a significant effect of reducing tooth decay among people of all ages.

This is particularly important in New Zealand, as we are a country with very little in the way of a publicly funded ”safety net” for adults who cannot afford dental care.

We also now know that, rather than being a disease of childhood only, tooth decay continues through life.

We respectfully request that when councillors consider the fluoridation issue, they be aware of current Ministry of Health guidelines and statements on fluoride, and that when formulating strategy they consult relevant experts at the University of Otago and the Southern District Health Board who are familiar with the relevant peer-reviewed literature.

The opinions of those experts are strongly endorsed by the Otago Branch of the New Zealand Dental Association, the New Zealand Dental Hygienists’ Association and the New Zealand Dental and Oral Health Therapists’ Association.

The Otago Branch unequivocally supports the national Dental Association’s 2012 statement on water fluoridation.

We also advise councillors that anti-fluoridation arguments are often based on un-refereed internet resources or books that present a highly misleading picture of water fluoridation, rather than being based on objective science.

With this letter, we have included copies of an excellent Australian article from the journal Australia and New Zealand Health Policy, and the Victorian government publication Water fluoridation helps protect teeth through life.

Both are short, and are written for the benefit of public health officials.

We trust that the council will make the sensible public health decision to retain and expand community water fluoridation in our city.

See also

Other articles on fluoridation
Making sense of fluoride Facebook page.