Tag Archives: fluoridation

Facts about fluorosis – not a worry in New Zealand

This sort of serious dental fluorosis does not occur in New Zealand

A recent issue of the Fluoride Exposed Newsletter gives us the facts about dental fluorosis – a subject very often misrepresented by opponents of community water fluoridation.

Fluoride Exposed also explores what U.S. Surgeon Generals have done to promote prevention of both tooth decay and fluorosis in an article on their website, Is fluoride good for your teeth?:


Ever notice how words ending with “-osis” sound a bit scary?  That’s because “-osis” is a suffix (from the Greek) commonly used to describe disorders or abnormal states. Tuberculosis, multiple sclerosis…no fun. Those are serious.

Dental fluorosis is one of those things that sounds scarier than it actually is… at least if you live in a country like the good old U.S. of A., where public health and environmental protection agencies and organizations have made the scary kind of dental fluorosis (severe dental fluorosis) exceedingly rare.

Dental fluorosis is a little like blood pressure.  When it’s low, you’re good – in fact, mild dental fluorosis can protect your teeth from cavities.  Moderate dental fluorosis describes the appearance of tooth enamel when kids get exposed to a bit too much fluoride.  Changes range from barely visible white spots or streaks (in most cases) to white spots that are a cosmetic concern.  Severe forms involve staining and pitting.  These severe forms of fluorosis are super rare in the U.S. – because we have those protections we mentioned. In the States, we make sure fluoride isn’t too low or too high in drinking water.  It’s only in regions such as rural India, China, and the African Rift Valley, where severe dental fluorosis commonly reaches an actual disease state and affects tooth health and function.  But in the U.S., fluorosis is one of those things that’s not as scary as it sounds.

As you may already know, fluoride gets into your tooth enamel during the remineralization process and forms a super compound called fluoroapatite that resists decay.  For this reason, our dentists want us to get fluoride, ideally through drinking water and fluoride toothpaste.  Or if you’re in a community without fluoridated water, there are dental treatments and dietary supplements you can get.

But if a child who’s still developing teeth gets too much fluoride, dental fluorosis can occur while the teeth are still forming under the gums.  Data from the National Health and Nutrition Examination Survey (1999-2004) tells us that less than one-quarter of persons aged 6-49 in the United States had some form of dental fluorosis.

They even made a chart that shows the severity level of those affected:

Note: One interesting factoid: In this study, the rate of fluorosis for teenagers aged 12-15 was forty percent! That’s significantly higher than the rate for all age groups taken together.  It’s a data point we’ll be keeping an eye on in future studies.

According to the American Dental Association (ADA), the mild and moderate forms of dental fluorosis we have in the U.S. do not negatively affect the health of your teeth. It’s actually even correlated with some good things.  For example, rates of dental fluorosis are higher in kids whose teeth are more resistant to tooth decay.  Makes sense, right?

That said, we can make sure a child’s amount of fluoride is “just right” – enough to provide cavity protection, but not enough to cause visible changes in the tooth enamel.
5 ways to prevent kiddos from ingesting too much fluoride:

    1. Don’t give kids fluoride supplements if your drinking water is already at or above the recommended fluoride concentration of 0.7 mg/L.  You can find out if your water system fluoridates and at what level from this cool site from the CDC: https://nccd.cdc.gov/DOH_MWF/Default/Default.aspx.  Or call your water utility provider.
    2. If your drinking water contains greater than 2 mg/L of fluoride, children 8 years and younger should use an alternative source of drinking water.  A little less than 1% of Americans on public water systems have fluoride above this level.
    3. If you have well water, have it tested for fluoride levels, and again, use an alternative source for kids if fluoride is more than 2 mg/L.  Use an alternative source for everyone in the family if it tests at or above 4 mg/L.
    4. Use only a rice-grain-sized amount of fluoride toothpaste to brush kids’ teeth if they’re younger than 3.
    5. For kids who are 3-6 years old, use a pea-size amount of fluoride toothpaste, and supervise these preschool kids when they brush so they don’t swallow too much fluoride toothpaste.

So that’s it! Dental Fluorosis: it’s a scary name, but not a big worry in the U.S.

Whew! One less “-osis” to freak out about!

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What’s with the anti-fluoridationist promotion of dental health programmes?

“Healthy Teeth, Happy Smile” leaflet promoting dental health programme in Leicester, UK

Anti-fluoride campaigners often promote dental health programmes which they argue are alternatives to community water fluoridation. But seem not to understand that these programmes usually include fluoride dental treatments.

It’s probably a result of some tactical thinking – “let’s promote a positive message to overcome the publicly perceived negativity associated with our opposition to a social health policy like fluoridation.” In fact, some New Zealand anti-fluoride activists have specifically expressed it this way.

But the sting in the tail of this tactic is their promotion of the idea these programmes are an alternative to community water fluoridation (CWF). In reality, they are not genuine about their positive support of a social health policy – they still want to convey a message of opposition to CWF by pretending these policies are successful alternatives.

These programmes may be successful – but they are not alternatives to CWF.  Health authorities promoting them usually see them as complementary to CWF  – certainly not substitutes or alternatives. In fact, these dental health programmes usually include fluoride varnish treatment for children’s teeth.

An example is the “Healthy Teeth, Happy Smile” programme reported as being very successful in the UK city of Leicester. See  City with worst tooth decay in children sees marked improvement). It aims to improve the dental health of young children and includes exercises like supervised tooth brushing in nurseries and linking families up with dentists. The image above shows the first page of a leaflet about the scheme. Notice that it encourages fluoride varnishing of the teeth of young children and offers this free (the image below shows the relevant detail from the leaflet) and yet Fluoride Free New Zealand, the local anti-fluoride group, is promoting it!

The Leicester City Council in its promotion of the scheme lists the following actions for parents:

  • take your child to see the dentist before they are one and go regularly
  • brush your child’s teeth as soon as the first tooth appears
  • brush at least twice a day
  • don’t rinse after brushing just spit the toothpaste out
  • use a fluoride toothpaste
  • ask your dentist about fluoride varnish
  • limit sugary drinks and snacks to meal times only.

The scheme is based on the Oral Health Promotion Strategy for pre-school children which describes its objectives as:

 Optimising exposure to fluoride
 Gain multi-partnership support in order for everyone to play a role in
improving oral health
 Improve preventive and routine dental attendance
 Improve parental skills on caring for children’s oral health

So hardly an alternative to fluoride or CWF.

I have written about other dental health programme which anti-fluoride activists misleadingly promote as alternatives to CWF before.

For example:

The Nexo programme on Sweden – Fluoridation: Open letter to Democrats for Social Credit;

The Scottish ChildSmile programme – ChildSmile dental health – its pros and cons and ChildSmile – a complement, not an alternative, to fluoridation.

I have also made the point that in New Zealand the different District Health Boards often have dental health programmes which incorporate elements of all the three programmes discussed here. They are not run as alternatives to CWF – although some health boards do put extra resources, such a fluoride tooth varnishing into the non-fluoridated areas. For obvious reasons.

Examples are the Mighty Mouth Dental programme run by Counties Manukau District Health Board and the Healthy Smile, Healthy Child programme run by the Ministry of Health and the New Zealand Dental Association.

Whether or not health authorities choose to give their dental health programmes catchy titles such programmes are important. CWF is not a magic bullet and oral health is also served by complementary programmes like these which incorporate education, early training in the use of toothbrushes, connecting families with dentists and use of fluoride varnishes.

Just don’t be fooled into thinking such programmes are substitutes or alternatives to CWF. Especially don’t be fooled by activists who are not seriously promoting dental health but simply attempting to fool people by pretending such programmes could be used instead of CWF.

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Fluoridation not associated with ADHD – a myth put to rest

Fluoridated water is NOT associated with ADHD: Photo by mtl_moe

The myth of community water fluoridation causing attention deficit hyperactivity disorder (ADHD) is just not supported by the data. I show this in a new paper accepted for publication in the British Dental Journal. This should remove any validity for the claims about ADHD by anti-fluoride campaigners.

Mind you, I do not expect them to stop making those claims.

The citation for this new paper is (will be):

Perrott, K. W. (2017). Fluoridation and attention hyperactivity disorder – a critique of Malin and Till. British Dental Journal. In press.

The Background

The fluoridation causes ADHD myth was initially started by the publication of Malin & Till’s paper in 2015:

Malin, A. J., & Till, C. (2015). Exposure to fluoridated water and attention deficit hyperactivity disorder prevalence among children and adolescents in the United States: an ecological association. Environmental Health, 14.

It was quickly taken up and promoted by anti-fluoride campaigners – becoming one of their most cited papers when claiming harmful psychological effects from fluoridation. Part of the reason for its popularity is that it is the only published paper reporting an association between community water fluoridation (CWF) incidence and the prevalence of a psychological deficit. All other reports on this used by anti-fluoride campaigners are based on studies made in high fluoride regions like China where fluorosis is endemic. Those studies are just not relevant to CWF.

While many critics rejected Malin & Till’s conclusions on the simple basis that correlation does not mean causation I decided to look a bit deeper and test their statistical analyses. This was easy because they used published US data for each US state and such data is available for many factors.

I posted my original findings in the article ADHD linked to elevation not fluoridation. This showed that a number of factors were independently associated with ADHD prevalence (eg., home ownership, poverty, educational attainment, personal income, and % of the population older than 65) and these associations were just as significant statistically as the associaiton reported by Malin & Till.

However, multiple regression of possible modifying factors showed no statistically significant of ADHD prevalence with CWF incidence when mean state elevation was includedd.

The importance of elevation was confirmed by Huber et al. (2015):

Huber, R. S., Kim, T.-S., Kim, N., Kuykendall, M. D., Sherwood, S. N., Renshaw, P. F., & Kondo, D. G. (2015). Association Between Altitude and Regional Variation of ADHD in Youth. Journal of Attention Disorders.

Huber et al., (2015) did not include CWF incidence in their analyses. I have done this with the new paper in the British Dental Journal.

Publication problems

I firmly believe that scientific journals, like  Environmental Health which published the Malin & Till paper, have an ethical obligation to accept critiques of papers they publish (subject to peer review of course). Similarly, it is appropriate that any critique of a published paper is made in the journal where it was originally published. Implicit in this arrangement, of course, is that the authors of the original paper get the chance to respond to any critique and that the response be published by the original journal.

Unfortunately, this was not possible for this paper because the Chief Editor of  Environmental Health,  Prof Philippe Grandjeansimply refused to allow this critique to be considered for publication. No question of any peer reviuew. In his rejection he wrote:

“Although our journal does not currently have a time limit for submission of comments on articles published in EH, we are concerned that your response appears a very long time after the publication of the article that you criticize. During that period, new evidence has been published, and you cite some of it. There are additional studies that would also have to be taken into regard in a comprehensive comment, as would usually be the case after two years. In addition, the way the letter is written makes us believe that the letter is part of a controversy, and our journal is certainly not the appropriate forum for a dispute on fluoride policies.”

My response pointed out the reasons for the time gap (problems related to the journals large publication fee), that no other critique of the Malin & Till paper had yet been published and that any perceived polemics in the draft should normally be attended to by reviewers. This was ignored by Grandjean.

While Grandjean’s rejection astounded me – something I thought editors would consider unethical – it was perhaps understandable. Grandjean is directly involved as an author of several papers that activists use to criticise community water fluoridation. Examples are:

Grandjean is part of the research group that has published data on IQ deficits in areas of endemic fluorosis – studies central to the anti-fluoride activist claims that CWF damages IQ.  He has also often appears in news reports supporting research findings that are apparently critical of CWF so has an anti-fluoridation public standing.

In my posts Poor peer-review – a case study and Poor peer review – and its consequences I showed how the peer review of the original Malin & Till paper was one-sided and inadequate. I also provided a diagram (see below) showing the relationship of Grandjean as Chief Editor of the Journal, and the reviewers as proponents of chemical toxicity mechanisms of IQ deficits.

So, I guess a lesson learned. But the unethical nature of Grandjean’s response did surprise me.

I then submitted to paper to the British Dental Journal. It was peer-reviewed, revised and here we are.

The guts of the paper

This basically repeated the contents of my article ADHD linked to elevation not fluoridation. However, I tried to use Malin &Till’s paper as an example of problems in ecological or correlation studies. In particular the inadequate consideration of possible risk-modifying factors. Malin & Till clearly had a bias against CWF which they confirmed by limiting the choice of covariates that might show them wrong. I agree that a geographic factor like altitude may not have been obvious to them but their discussion showed a bias towards chemical toxicity mechanisms – even though other social factors are often considered to be implicated in ADHD prevalence.

Unfortunately, Malin & Till’s paper is not an isolated example. Another obvious example of confirmation bias is that of Peckham et al., (2015). They reported an association of hypothyroidism with fluoridation but did not include the most obvious example of iodine deficiency as a risk-modifying factor in their statistical analysis

Of course, anti-fluoride campaigners latched on to the papers of Peckham et al., (2015) and Malin & Till (2015) to “prove” fluoridation was harmful. I guess such biased use of the scientific literature simply to be expected from political activists.

However,  I also believe the scientific literature contains many other examples where inadequate statistical analyses in ecological studies have been used to argue for associations which may not be real. Such papers are easily adopted by activists who are arguing for or against specific social policies or social attitudes. For example, online articles about religion will sometimes refer to published correlations of religosity with IQ, educational level or scoio-economic status. Commenters simply select the studies which confirm the bias they are arguing for.

These sort of ecological or corellations studies can be useful for developing hypotheses for future study but it is wrong to use them to support an argument and worse as “proof” of an argument.

Take home message

  1. There is no statistically significant association of CWF with ADHD prevalence. Malin & Till’s study was flawed by lack of consideration of other possible risk-modifying factors;
  2. Be very wary of ecological or correlation studies.Correlation is not evidence for causation and many of these sudues iognore other possible important risk-modifying factors.

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Are fluoride researchers sacked for their findings?

Dr Phyllis Mullenix – employment terminated because of her fluoride research or other reasons? (Image credit: NYC Coalition Against Artificial Fluoridation)

Heard the one about the scientist who was doing excellent research but was sacked by her Institute because her discoveries shattered the prevailing “scientific orthodoxies?”

Yes, it is a common claim. Often made by activists promoting conspiracy theories.  But it is an easy one to make and it is always worth checking the facts in such cases.

Of course, the anti-fluoridation movement is no exception – they claim that a number of “anti-fluoridation scientists” have been sacked for their work. Here I will just look at one of these stories – that of Dr Phyllis Mullenix.

The Mullenix story

A few facts.

Phyllis Mullenix was working for the Forsyth Research Institute in Boston. In her time there, she researched several possible neurotoxicants but made only one study on fluoride which was published in 1995. The paper is:

Mullenix, Phyllis J., DenBesten. Pamela K., Schunior, A., & Kernan, W. J. (1995). Neurotoxicity of sodium fluoride in rats. Neurotoxicology and Teratology, 17(2), 169–177.

This paper has become central to claims made by anti-fluoride campaigners that community water fluoridation lowers IQ in children.

However, this paper is not relevant to community water fluoridation because of the very high concentrations of fluoride used (0, 75, 100, 125 and 175 mg/L in drinking water fed the rats). That such levels are unrealistic was shown by her own report that “the 175 ppm level .  .  . resulted in dehydration and the death of 10 of the exposed animals within 10 days.” Half of the 21 animals exposed died within 10 days!

For comparison, the recommended concentrations for community water fluoridation are usually less than 1 mg/L. But it is interesting that when anti-fluoride campaigners tell Mullenix’s story they rarely mention the concentration she used.

Mullenix did lose her job at Forsyth. A unanimous meeting of senior staff members on April 19, 1994, recommended she not be reappointed to her position. She was a staff associate and employment was usually guaranteed for 12 months at a time. Renewals would have depended on several factors, including the level of funding the employee was able to attract from research grants. Mullenix was informed by letter on May 31, 1994, that the Board of Trustees had approved the recommendation from senior staff members that her appointment would not be renewed.

So, she lost her job – but technically was not sacked – just not reappointed.

Why was her employment not renewed? 

Anti-fluoride campaigners rely on books like “The Fluoride Deception” to support their conspiracy theories

Depends if you believe there was a conspiracy against fluoride research.

Here are some of the conspiracy stories that are floated:

Chris Bryson says in his book The Fluoride Deception:

“PHYLLIS J. MULLENIX. A leading neurotoxicologist hired by the Forsyth Dental Center in Boston to investigate the toxicity of materials used in dentistry. In 1994 after her research indicated that fluoride was neurotoxic, she was fired.”

This claim has been repeatedly presented in articles and submissions by anti-fluoride activists. For example:

She went from being a leading neurotoxicologist at a Harvard affiliated research institute to an industry pariah. This assignment and her findings ruined her career as a grant-funded research scientist.”

Dr Phyllis J Mullenix should be a household name. She was sacked for her work proving Aluminium and Fluoride act synergistically to damage your brain and that of your unborn child.”

Within days of learning that her study was accepted for publication, Dr [Phyllis] Mullenix was fired from the Forsyth Dental Center.  She has received no grants since that time to continue her research.”

Dr Phyllis Mullenix was sacked from the Forsyth Dental Center, where she was head of the toxicology department, for publishing research in Neurotoxicology and Teratology showing that fluoride can adversely affect brain function. She had been warned: “If you publish this information, we won’t get any more grants from NIDR” (from which the institute got most of its money).

And I could go on. And on. There is no shortage of such claims promoted as arguments against community water fluoridation.

But here are some facts.

I have gone to the legal document presented to the US District Court, D, Massachusett on November 13, 1996. These relate to a case brought by Mullenix against Forsyth claiming discrimination and retaliation for her legal actions.

Mullenix’s complaint:

“alleges that Forsyth discriminated against Dr. Mullenix on the basis of her sex, denied her equal pay and one or more promotions and retaliated against her for seeking legal redress during her employment at Forsyth as a Staff Associate from 1982 to 1994.”

The document, Mullenix v. Forsyth Dental Infirmary for Children, is quite long and full of legalese which I would never pretend to understand. But it certainly makes clear that the complaint by Mullenix and the response by Forsyth have nothing to do with fluoride or fluoridation.

Fluoride is mention only a few times:

“Dr. Mullenix asseverates that no one at Forsyth ever questioned the quality of her work or that her fluoride research did not lie within Forsyth’s mission. (Docket Entry # 102, Mullenix Affidavit).”

And:

“Dr. Mullenix contends that Dr. Taubman “called Dr. Mullenix `hysterical’ because he disagreed with her research.” (Docket Entry # 102, p. 18). Dr. Mullenix recites Dr. Taubman’s alleged statement while explaining what she said to Dr. Hay during a conversation a few days after giving a seminar on fluoride research. According to Dr. Mullenix, Dr. Hay mentioned that “Marty Taubman in particular was very irate about the data that was presented …” and that “Marty Taubman had indicated that I was hysterical in my reporting.” (Docket Entry # 98, Mullenix Deposition).”

It appears Mullenix made the complaint about use of the word “hysterical” together with apparently sexist remarks made by colleagues (relating to clothing and the employment rights of women who had husbands) as evidence of a hostile and sexist work environment.

This document outlines the various complaints made by Mullenix – and clearly, they did not relate to fluoride or, directly, to her findings about fluoride. In fact, it says:

“Dr. Mullenix asserts that the only reason other than gender which explains Forsyth’s actions is that it acted in retaliation for Dr. Mullenix’ seeking legal redress.”

Mullenix took her initial legal action because she had been denied a promotion and subsequently claimed Forsyth had retaliated against her because of her initial threat of legal action if her promotion was declined (it was and she did take legal action) and then the actual legal action.

I have focused on Mullenix’s version here because they do make clear that her fluoride research and findings were not involved in any retaliation by Forsyth. The institute’s version, of course, seeks to justify their actions. While there is some reference to her research interest not coinciding strongly with the Institute’s interests, their evidence relates almost completely to salaries for male and female staff members, the responsibilities of the staff associate position that Mullenix occupied, and the extent of funding Mullenix was able to attract.

I have no idea of the legitimacy of Phyllis Mullenix’s complaints or the legitimacy of Forsyth’s rebuttals. Nor do I know what the final outcome of her legal action was.

Mullenix’s complaints could very likely have been genuine. Even today women do get discriminated against in employment and salaries. Their complaints are often disregarded or treated in a sexist way. “Uppity” women can face retaliation. And things are better now than they were in the 1980s and 1990s. It is very likely Mullenix was granted an out-of-court settlement.

But one thing I am sure of – she was not “sacked’ for her fluoride research or publication of her fluoride paper. Any complaint made by colleagues about that work would have been perfectly normal and expected – and she herself, at the time, did not attribute any retaliatory action to her fluoride research.

So, yet another case where it pays to check the claims made by anti-fluoride activists.

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Fluoridation and cancer

Yes, you have. And one lie is the claim that fluoridation causes cancer. Image credit: Have You Been Lied to About Fluoride?

We all know the phrase “Lies, damned lies, and statistics.” If nothing else, this should warn us not to take on faith arguments which rely on statistical analysis for their credibility. Wikipedia uses this phrase to illustrate the “persuasive power of numbers, particularly the use of statistics to bolster weak arguments.”

Unfortunately, the scientific literature is full of weak arguments bolstered by statistics. It’s another case of “reader beware.” Do the statistical analyses used really support the argument? And how good was the statistical analysis anyway?

Unfortunately, scientific papers with poor or inappropriate statistical analyses often get used to bolster arguments in the political field. Anti-fluoride campaigners do this all the time. I illustrated this for the “fluoridation caused ADHD” argument in my articles ADHD linked to elevation, not fluoridation and ADHD link to fluoridation claim undermined again.

Another paper often used by anti-fluoride campaigners is that of Takahasi et al., (2001). They cite this to support their “fluoridation causes cancer” argument. For example, the prominent anti-fluoride activist Karen Favazza Spencer did this recently in a Facebook post quoting from Tkahashi et al., (2001):

“Cancers of the oral cavity and pharynx, colon and rectum… were positively associated with ‘optimally’ fluoridated drinking water.”

Well, how justified is that quote? How reliable was the statistical analysis used by these authors to arrive at that claim?

Takahashi et al., (2001)

In fact, their statistical analysis was poor. They considered only fluoridation as a factor. When we consider other likely factors the statistical analyses show no significant association between these cancers and fluoridation.

Let’s have a look at the paper and the statistical analysis.

The paper is:

Takahashi, K., Akiniwa, K., & Narita, K. (2001). Regression Analysis of Cancer Rates and Water Fluoride in the USA based Incidence on IACR / IARC ( WHO ) Data ( 1978-1992 ). Journal of Epidemiology, 11(4), 170–179.

Briefly, it searched for possible statistically significant associations between the incidence rates for a whole range of cancers and the extent of fluoridation. It used fluoridation extent and cancer incidence data for three US states and six US cities. Other factors were considered only for lip cancer where sunshine extent was included in the analyses.

I set out to repeat their statistical analysis, including some other relevant factors. However, the data they used for cancer incidence in 1978-1992 is not available on-line. But there are data sets available for more recent years.

Here I use the cancer incidence data for 1993-1997 taken from the WHO, International Agency for Research on Cancer publication Cancer Incidence in Five Continents Vol. VIIIThis lists cancer incidence for 58 body sites but I restricted my analysis to eight of the body sites for which Takahashi et al., (2001) reported significant associations with fluoridation.

Are any of these cancers significantly associated with the extent of fluoridation?

Well, yes, two are at the 5% level (p < 0.05) – cancers of the rectum and bladder. The table lists values for the probability p value produced by linear regressions. The p values for cancers at all the body sites considered is also significant – but only for females.

Cancer site p – Male p – Female
Lip 0.750 0.825
Oesophagus 0.427 0.285
Colon 0.090 0.146
Rectum 0.037* 0.048*
Bone 0.784 0.147
Prostate 0.639
Bladder 0.015* 0.031*
Thyroid 0.806 0.519
All sites 0.250 0.020*

Takahashi et al., (2001) found significant associations for rectum and bladder. But also for Colon, bone (male), oesophagus (female), prostate (male) and lip. This difference is not too surprising as I used a different, more recent, data set. Also, correlations do not mean causation, they can occur by chance (1 in 20 samples) and other factors are more than likely involved (see below).

Another difference is that I used simple linear regressions. Takahashi et al., (2001) transformed both fluoridation extent and cancer incidence to logarithms but their explanation for this is inadequate.  Such transformations are not normally applied unless there is evidence that a relationship is nonlinear.  Takahashi et al., (2001) did not give any evidence for this and there was no evidence for it in the data set I used.  Neither was there any evidence of patterns in the residual values from the regression analysis – another sign that simple linear regression was valid.

What about the influence of other factors?

One of the biggest complaints I have about the use of regression analysis in studies like this is that very often other factors are ignored. Takahashi et al., (2001) considered only sun shine extent – and then only for lip cancer.

I think the restriction to consideration of only fluoridation is naive. In fact, probably indicating a bias and a desire to confirm it. It is extremely unlikely that all, or even most, of the specific cancers considered have a single cause – fluoride. And it is unlikely that a single factor would explain all the variability in the cancer incidence data.

Also, fluoride could be acting as a proxy for more relevant factors. The ADHD relationship with the extent of fluoridation is an example. In my paper Attention deficit hyperactivity disorder prevalence associated with altitude but not exposure to fluoridated water*, I showed that fluoridation extent is significantly correlated with mean altitude. When altitude was included in a multiple regression there was no significant association of ADHD with fluoridation.  This suggests that, in fact, the fluoridation data was really a proxy for something else – in this case, altitude – which Huber et al (2015) reported is associated with ADHD prevalence.

I am not intending here to narrow down the most likely factors which are associated with cancer at all these body sites. I simply want to check how significant any association with fluoridation is when other possible factors are included.

Geographic factors are worth considering – not because they necessarily have a direct influence. But because they may act as proxies from environmental, population density and industrial concentration factors which could be important. So I included data for mean elevation, mean latitude and mean longitude together with the extent of fluoridation in multiple regressions of the eight cancers above as well as for all the body sites data.

Using adjusted R square values to test for a fluoridation contribution

Rather than attempting to identify significant correlations with different factors for different cancers, I used the method of judging what effect inclusion of fluoridation extent had on the explanatory power of regression models which included the geographic factors. Jim Frost describes this approach in his article Multiple Regression Analysis: Use Adjusted R-Squared and Predicted R-Squared to Include the Correct Number of Variables

Briefly, he describes problems with the R squared value:

“Every time you add a predictor to a model, the R-squared increases, even if due to chance alone. It never decreases. Consequently, a model with more terms may appear to have a better fit simply because it has more terms.”

Include more factors and you could simply be modelling random noise in the data.But the adjusted R-squared  overcomes this because it adjusts for the number of predictors in a model:

“The adjusted R-squared increases only if the new term improves the model more than would be expected by chance. It decreases when a predictor improves the model by less than expected by chance. The adjusted R-squared can be negative, but it’s usually not.  It is always lower than the R-squared.”

These examples below of multiple regression output including fluoridation and excluding fluoridation in the models illustrate where adjusted R square values are reported:

The table below lists the adjusted R square values for multiple regressions:

  • +Fl included fluoridation extent, mean elevation, mean latitude and mean longitude, and
  • -F included only mean elevation, mean latitude and mean longitude.

Comparing the adjusted R square values for +Fl and -Fl tells us about the effect of including fluoridation extent on the models:

  • Where the value for +Fl is larger than for -F then the extent of fluoridation improves to model more than would be expected by chance.
  •  Where the value of +Fl is smaller than for -F then the extent of fluoridation improves to model less than would be expected by chance.

Male

Female

Cancer site + Fl – Fl + Fl – Fl
Lip 0.170 0.242 0.685 0.649
Oesophagus 0.809 0.842 0.558 0.612
Colon 0.842 0.771 0.681 0.659
Rectum 0.357 0.455 0.616 0.692
Bone 0.451 0.527 0.625 0.700
Prostate -0.350 0.130
Bladder 0.860 0.863 0.530 0.606
Thyroid 0.434 0.544 0.801 0.824
All sites 0.622 0.676 0.846 0.865

The table shows that adjusted R square values are greater (red) when fluoridation extent is not included in the regression model for all cancer sites except the colon and female lip. That indicates that these cancers are not associated with fluoridation extent. That the simple regression results alone  for fluoridation extent in the case of rectum and bladder cancer (and all sites female cancer) are misleading.

The colon and female lip cancer are exceptions – but the fact no significant association was found for fluoridation extent alone (first table) suggests something more complex is occurring here. It could be that the selected geographic factors have very little role in these cancers and inclusion of more relevant factors is needed.

Conclusion

The associations of fluoridation extent with various cancers reported by Takahashi et al., (2001) disappear when we consider other more relevant factors. Therefore, the use of this study by anti-fluoride campaigners to claim fluoridation is responsible for cancer is misleading. Not that I expect, from their past record, they will stop doing this.

More generally this is yet another example showing that readers should beware of putting too much faith in simple statistical analyses reported in scientific papers – even those published in respectable journals. It is just too easy to use statistical analysis to confirm a bias.

We should all keep in mind the phrase  “Lies, damned lies, and statistics” and treat such reports critically. If possibly checking out the extent to which other factors have been considered. Even where significant correlations are reported we should check how useful such correlations are at explaining the variations in the data.


*The full text of this paper is not yet available as it is undergoing journal peer review. However, the full text of CRITIQUE OF A RISK ANALYSIS AIMED AT ESTABLISHING A SAFE DAILY DOSE OF FLUORIDE FOR CHILDREN, the first draft from which this paper was taken, is available.

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Local anti-fluoride activists tell porkies yet again

FFNZ confuses lack of low fluoride studies on rats with human studies

Well, I suppose that’s not news. A bit surprising, though, because they are claiming the absence of research on fluoridation and IQ – which sort of conflicts with the previous attempts to actually condemn and misrepresent the actual research on fluoridation and IQ.

Fluoride Free NZ’s (FFNZ) face book page is claiming:

Would you be interested to know that no studies have been conducted on fluoridated water at 0.7ppm to determine whether there is IQ reduction? The National Toxicology Program are currently completing research to fill this gap. You would have thought that they would have done this in the 1950s before starting the fluoridation program wouldn’t you?

There have actually been three recent studies from three different countries which have specifically investigated the claim of an effect of fluoridation on IQ – and, unsurprisingly, all threes studies showed there was no effect.

Here are those studies:

New Zealand

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

In fact, anti-fluoride activists in the US, as well as New Zealand, have campaigned against this study. Their major criticism is that the study also included the effect of fluoride tablet use. They argue that this makes the unfluoridated control group useless because many participants will have consumed fluoride tablets. However, they ignore the fact that the statistical analysis corrected for this but still found no statistically significant difference in IQ of children and adults from fluoridated and unfluoridated areas.

Sweden

Other critics of the Broadbent et al. (2014) study have raised the issue of experimental power because of the numbers of people in the study. This could be a valid issue as it would determine the minimum effect size capable of being detected. Aggeborn & Öhman (2016) made that criticism of Broadbent et al., (2016) and all other fluoride-IQ studies. Their study is reported at:

Aggeborn L, Öhman M. (2016) The Effects of Fluoride in the Drinking Water. 2016.

Aggeborn & Öhman (2016) used much larger sample size than any of the other studies – over 81,000 observations compared with around 1000 or less for the commonly cited studies. It was also made on continually varying fluoride concentrations using the natural fluoride levels in Swedish drinking waters (the concentrations are similar to those in fluoridated communities), rather than the less effective approach of simply comparing two villages or fluoridated and unfluoridated regions. The confidence intervals were much smaller than those of other cited fluoride-IQ studies. This makes their conclusion that there was no effect of fluoride on cognitive measurements much more definitive. Incidentally, their study also indicated no effect of fluoride on the diagnosis of ADHD or muscular and skeleton diseases.

Canada

Another recent fluoridation-IQ study is that of Barbario (2016) made in Canada:

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

This study also had a large sample size – over 2,500 observations. This reported no statistically significant relationship of cognitive deficits to water fluoride.

Incidentally, Barberio (2016) also found there was no evidence of any relationship between fluoride exposure and thyroid functioning. That puts another pet claim of anti-fluoride campaigners to rest.

Animal studies

So much for NZFF’s claim that “no studies have been conducted on fluoridated water at 0.7ppm to determine whether there is IQ reduction.” But, just a minute, they are quoting the National Toxicology Program (NTP):

“No studies evaluated developmental exposure to fluoride at levels as low as 0.7 parts per million, the recommended level for community water fluoridation in the United States. Additional research is needed.”

But they omit the next sentence from the quote:

“NTP is conducting laboratory studies in rodents to fill data gaps identified in the systematic review of the animal studies.”

The NTP is discussing the research with animals, mainly rats, where effects of fluoride on the cognitive behaviour of the test animals have been reported but the fluoride concentrations are very high. And NTP’s assessment base on the review of the literature found only “a low to moderate level of evidence that the studies support adverse effects on learning and memory in animals exposed to fluoride in the diet or drinking water.” Hence the need for more research.

As part of the NTP’s research, which is currently underway, there are plans to extend studies to low fluoride concentrations more typical of that used in community water fluoridation.

The high concentrations used in animal studies is a major flaw in the anti-fluoride activist use of them to oppose community water fluoridation. For example, Mullinex et al (1995) (very commonly cited by anti-fluoride campaigners) fed test animals drinking water with up to 125 mg/L of fluoride (concentrations near 0.8 mg/L of fluoride are used in community water fluoridation).

While it is unlikely that the NTP research will find any significant effects of fluoride on the cognitive behaviour of rats at the low concentrations used in community water fluoridation the anti-fluoride campaigners have their fingers (and probably toes as well) crossed.

NTP will begin publishing the results of their new research next year (see Fluoride and IQ – another study coming up).

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Fluoridation: Open letter to Democrats for Social Credit

The only New Zealand political party opposing community water fluoridation relies on false information

The only political party in New Zealand campaigning against community water fluoridation is the Democrats for Social Credit. It is a minor party, nor represented in Parliament and of little influence. However, it does have connections with Fluoride Free NZ, the main anti-fluoride activist group, and its members have imposed anti-fluoridation policies on some groups they belong to. Two examples are Grey Power and the Hamilton Residents & Ratepayers Association – both of which presented anti-fluoride submissions to the recent parliamentary health committee hearings.

I wish to promote an open discussion with the Democrats for Social Credit about their anti-fluoridation policy so have sent them this Open Letter. If they are open to a good-faith discussion I am happy to provide space on this blog for an exchange of views on their policy.


David Trantor, Health Spokesperson for Democrats for Social Credit

Dear David Tranter,
Health Spokesman,
Democrats for Social Credit

You wrote an open letter to the Minister of Health critiquing the government’s policy on community water fluoridation (CWF) and posing some questions about dental health programmes, documented evidence relating to CWF and human rights aspects you consider relevant.

Here I take issue with some of your claims – particularly about dental health in Denmark and the scientific evidence supporting CWF. I believe the evidence does not support the anti-fluoridation policy of your party and your party should reconsider that policy.

If you believe my arguments here are mistaken or otherwise wish to defend the current anti-fluoride policy of your party I am open to a good-faith exchange of opinions and offer you the right of reply and the opportunity for a further discussion on this blog.

Natural fluoridation in Denmark

You point to the good dental health in Denmark and assert “they have never fluoridated their water.” This is true – but you ignore the fact that much of the Danish population benefits from natural levels of fluoride in their drinking water.

Unlike New Zealand parts of Denmark have drinking water fluoride concentrations similar to the optimum concentrations recommended for CWF. Map 1 from Kirkeskov et al., (2010) shows the distribution of different drinking water fluoride concentration ranges.  Map 2 shows the population distribution. We can see a significant fraction of the Danish population does have access to drinking water containing fluoride.

Map 1: Distribution of natural drinking water fluoride concentrations in Denmark. The town of Nexo is on the Baltic island of Bornholm – shown in the top left-hand rectangle.

Map 2: Population distribution in Denmark.

These natural levels of drinking water fluoride are beneficial to oral health in Denmark. Here is some data from Kirkeskov et al., (2010) illustrating this. The following graph compares the dental decay (numbers with more than 2 decayed, missing or filled teeth surfaces – dmfs) at various drinking water fluoride concentrations for 5 year-olds born in 1989 and 1999.

As we can see, the extent of decay declines with fluoride concentration.

There is a similar pattern for 15-year-olds born in 1979 and 1989. This figure shows the relative numbers with more than 2 decayed missing or filled teeth surfaces, DMFS, for 15-year-olds.

And the same pattern for 15-year-olds with more than 6 decayed, missing or filled tooth surfaces.

Danish dental health programmes

You refer to a “Nexux” programme and argue that this could be an alternative to CWF in New Zealand.

I think you are referring to the programme run in Nexo – a town on the east coast of the Baltic island of Bornholm, Denmark. It is a successful local dental health programme, but only one of several in Denmark. Nexo was in an area of very low socio-economic status and introduced a dental programme at the end of 1987 aimed at improving the dental health fo children.  Ekstrand & Christiansen, (2005) give this description of the programme:

“Since 1992, the program has been offered to children from the age of 8 months. It is based on three closely interrelated principles applied according to the individual child’s needs: (1) education of parents, children and adolescents in understanding dental caries as a localized disease, (2) intensive training in home-based plaque control and (3) early professional, non-operative intervention, including professional plaque removal, local application of 2% NaF and application of sealants. In the period when the children have erupting permanent first or second molars, the parents and children are instructed in using a tooth brushing technique specially designed for erupting molar teeth.”

As you can see it is a rather intensive programme and is not a Denmark-wide programme. It has been successful in Nexo, where 15-year-olds had DMFS (decayed, missing and filled tooth surfaces) values in 1986 (before introduction of the programme)  slightly higher than the Danish average. The equivalent values of DMFS for Nexo were the third lowest for all municipalities in 1993 and the lowest in 1999 (Ekstrand & Christiansen, 2005).

Elements of the Nexo programme will be used in other parts of Denmark, and in other countries. Especially where school-based programmes exist.

Incidentally, Map 1 indicates the concentration of natural fluoride in the drinking water on the island where Nexo is situated is similar to that recommended for community water fluoridation. Ekstrand et al., (2005) reports that the fluoride concentration in the Nexo drinking water is 0.8 mg/L.

Nexo is a complement to, not a substitute for, CWF

Each country and region adopt health programmes appropriate to their circumstance. In New Zealand, we have programmes which include some aspect of the Nexo programme or similar programmes like the ChildSmile programme in Scotland (see ChildSmile dental health – its pros and cons and ChildSmile – a complement, not an alternative, to fluoridation). For example the use of fluoride varnish treatments, especially in non-fluoridated areas.

New Zealand can learn from the experience of other countries and in practice, we may introduce some aspects of other programmes. But blanket transfer of full programmes is rare.

The important aspect, though, is none of these programmes is considered an alternative to fluoridation. They are considered as complementary to CWF, and not substitutes for CWF.  The Danish Dental Association has supported fluoridation for areas of low natural fluoride concentrations. Similarly, the British Dental Association in Scotland supports both ChildSmile and CWF and has publicly called for communities to move towards introducing water fluoridation.

In fact, we can consider that the programme used in Nexo (where the drinking water contains fluoride at 0.8 mg/L) actually complements the effect of natural community water fluoridation.

“Documented evidence”

You ask the Minister:

“Why do you ignore all the documented evidence against fluoridation instead of applying positive dental health policies such as the Denmark example?”

The “Denmark example” is dealt with above and it is not what you suggest. Similarly, I suggest the “documented evidence” you refer to really doesn’t give the viable argument “against fluoridation” you imply.

Unfortunately, you do not present any of this “documented evidence” for discussion. Perhaps, if you respond positively to my suggestion of a right of reply and an ongoing discussion, you can give this evidence.

“Informed consent”

You refer to the “H&D Commissioner’s Code of Rights” asserting that:

“no-one can be medicated without giving their informed consent” and “people have the right to give – or refuse – their INFORMED consent when fluoridation is applied to public water supplies?”

Well, I am all for people being properly informed and providing consent to the treatments used for their water supply. I see this as a democratic issue and I support democracy.

But you destroy your argument by suggesting fluoridation is a “medication” when it clearly is not – either legally or rationally. The legal argument was surely settled by the High Court decision in 2014 (see Corporate backers of anti-fluoride movement lose in NZ High Court) where Justice Rodney Hansen concluded:

“[80] In my view, fluoridation cannot be relevantly distinguished from the addition of chlorine or any other substance for the purpose of disinfecting drinking water, a process which itself may lead to the addition of contaminants as the water standards themselves assume. Both processes involve adding a chemical compound to the water. Both are undertaken for the prevention of disease. It is not material that one works by adding something to the water while the other achieves its purpose by taking unwanted organisms out.

[81] The addition of iodine to salt, folic acid to bread and the pasteurisation of milk are, in my view, equivalent interventions made to achieve public health benefits by means which could not be achieved nearly as effectively by medicating the populace individually. . . . All are intended to improve the health of the populace. But they do not, in my view, constitute medical treatment for the purpose of s 11″ [the relevant section of the NZBORA].”

Is scientific knowledge  really “one-sided” propaganda

You also weaken your argument by claiming:

“the one-sided propaganda used to support fluoridation is not informing people”

Describing objective scientific research and findings as “one-sided” simply displays your own bias – and willingness to discredit or ignore the science. Again, you do not give specific examples of the science you consider “one-sided propaganda” – hopefully, you will do so if you take up my offer of a right of reply and a continued discussion.

Democratic rights

You assert:

“when fluoridation is forced upon people it is nothing less than mass medication concerning which people have no opportunity to give – or refuse – their consent.”

The common anti-fluoride claim that people are having fluoridated water forced upon them always raises the picture in my mind of a person being held down and water being forced down their throat as in force-feeding.

Of course, that is ridiculous – for a number of reasons.

  • In New Zealand, there has usually been a democratic public consultation of some sort before the introduction of CWF – or even after its introduction. Local bodies have surveyed residents or used referenda. They have also used a consultation procedure relying on submissions from the public.The opportunity “to give – or refuse – their consent” has in most cases been far greater than for most decisions made by our representatives in this democracy of ours. Some voters find it annoying when asked for such consent (preferring their representatives decide) but I firmly believe it important to include the public in controversial decisions – even where the controversy results from scaremongering rather than facts (as it does with CWF).
  • There are alternatives for the minority. This means that democratic decisions made by a community can actually be a win-win situation. The majority get the social policy they want and have voted for. the minority have access to alternatives. In fact, most anti-fluoride activists already use alternatives – they filter their tap water or source a different supply. Some cities already provide “fluoride-free” water sources to help this. Sometimes I think the real motivation of these ideologically driven activists is to deny this social health policy to others rather than any real concern they have for their own access to water.
  • Some activists will acknowledge there is no evidence of any harmful side effects from CWF but invoke a “precautionary principle” to argue against it. They should be mollified by the fact that CWF is one of the most extensively researched topics. In a sense, we must thank the ideologically and commercially motivated anti-fluoride campaigners for this. Their activity is rarely successful in preventing CWF or fooling most of the public. But it does mean that researcher keep an eye on the arguments and are continually checking them out.

Conclusion

David, I believe you are mistaken, or misinformed, about the dental health programmes in Denmark. You ignore completely the availability of effective natural levels of fluoride in much of Denmark’s drinking water and seem unaware of the nature of the Nexo programme or its limited area of operation.

Expert opinion considers programmes like Nexo and the Scottish ChildSmile are effective complements to CWF – not substitutes for, or alternatives to, CWF. I support our health officials considering use of similar programmes in New Zealand but it is misleading for the Democrats for Social Credit to advocate for such programmes simply as a way of preventing or opposing CWF – which is  an effective, beneficial and safe social health measure.

I appreciate you may not accept my arguments or the facts I have presented here. If that is the case I urge you to accept my offer of a right of reply and ongoing good-faith discussion and am happy to help this by making space available on this blog.

I look forward to your response.

References

Ekstrand, K. R., & Christiansen, M. E. C. (2005). Outcomes of a non-operative caries treatment programme for children and adolescents. Caries Research, 39(6), 455–467.

Kirkeskov, L., Kristiansen, E., Bøggild, H., Von Platen-Hallermund, F., Sckerl, H., Carlsen, A., … Poulsen, S. (2010). The association between fluoride in drinking water and dental caries in Danish children. Linking data from health registers, environmental registers and administrative registers. Community Dentistry and Oral Epidemiology, 38(3), 206–212.

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Fluoridation: What’s happening with the New Zealand legislation?

The second reading of the fluoridation bill is now on the order paper for the current parliament. Public submissions have been heard, the Health Committee has reported back to the House and the Ministry of Health (MoH) has provided its own responses to submissions.

Of course, we don’t know yet what the final Act will be like exactly. But the submissions, the committee report, and the MoH responses give us some idea of likely changes to the original bill.

Submissions

I have described before how the anti-fluoride activist groups organise to deluge consultation processes with their submissions. This was certainly the case here and their submissions accounted for most of those opposed to the Bill.

However, because the legislation is about the decision-making process and not the scientific or ethical validity of social health policies simple opposition to fluoridation was irrelevant  – outside the scope of the bill. This was true of most submissions (85%) and these should be considered a waste of every bodies time.

I am surprised the anti-fluoride organisations organising this submission campaign chose to take such an irrelevant approach. Surely if they had put a bit of thought into their efforts they could have directed their submission at relevant aspects such as the consultation process, the decision-making body and the question of referenda.

That said, a small number of the anti-fluoride submissions did address aspects of the bill and these were considered by the Health Committee and the MoH.

Putting aside the anti-fluoride submissions which did not address the bill, 20% percent supported the Bill and 80% opposed to the Bill as currently drafted. Most supported extending fluoridation cover, but disagreed with specific parts of the Bill and suggested changes.

The legislation does not mandate fluoridation

This is a common misunderstanding promoted by anti-fluoride campaigners – obviously attempting to use scare-mongering to motivate their supporters. For example, Fluoride Free NZ formally names the legislation the Mandatory Fluoridation Bill which is dishonest – the correct name of the bill is Health (Fluoridation of Drinking Water) Amendment Bill.”

The bill transfers decision-making from local bodies to District Health Boards (DHBs) – but it does not require DHBs to make a decision about fluoridation. That is up to local DHBs and local conditions such as dental health, likely advantages and establishment costs.

Consideration of other health factors

A number of submitters expressed concern that while the bill requires DHBs to consider dental health effects, consideration of other possible health issues is not provided for. However,  the response from the MoH to this is:

“While DHBs are required to consider the evidence in relation to oral health, DHBs are not prevented from considering other factors, including the effect of fluoridation on overall health. However, officials do not consider it necessary for the Bill to require DHBs to consider these other factors.”

So, consideration of other health factors will depend on specific situations, the board members or public interest. Importantly, DHB’s are not prevented from considering wider health aspects.

Considering the science

I was interested to see that:

” The Ministry of Health is currently exploring options for the ongoing monitoring and assessment of research on fluoridation within the Ministry to align with the implementation of the Bill.”

The MoH sees this as carrying on the role formerly played by the now disbanded National Fluoridation Information Service. But this also goes some way to satisfying a suggestion in my own submission that the assessment of research on fluoridation is carried out by some sort of central expert body (see Fluoride, coffee and activist confusion). My concern was that the DHBs are not really suitable bodies for making expert reviews of the literature and evaluating the current state of the science. Handing this over to a central body could also prevent boards being deluged with misinformation and unsupported claims about the science – a feature of local body consultation which caused so much trouble to councils.

It was the pressure of submission campaigns including misrepresentation and false claims about the science which drove local bodies, who do not have the expertise to consider the science, to request a change to the legislation. DHBs will confront the same situation unless they can direct scientific consultation to a central expert body.

Community consultation

Many submitters (12%), both for and against fluoridation, suggested the bill should specifically require DHBs to consult the community about fluoridation decisions. While the bill did not make such specific requirements it also did not prevent such consultation.

In practice, public consultation will depend on the level of demand for it. It is up to DHBs to decide when consultation is appropriate and there is already a regulatory requirement for DHBs “to foster community participation in health improvement” which could cover that.

There is also provision for the Minister to describe a fluoridation decision as a “significant service change” which would require DHBs to undertake community consultation on regional service plans including fluoridation.

So, the anti-fluoride activist claims of denial of community consultation is wrong. While consultation is not specifically required it is not prevented by the bill and will depend on the level of public interest.

Engagement with local authorities

The health committee is recommending the bill be amended to explicitly require DHBs to consider the views of the drinking water supplier. This accommodates suggestions made by some local bodies who feared the imposition of decisions without considering their local situations.

However, the committee also suggested an amendment to make clear that engagement with local authorities does not require them to consult communities. The DHB which makes the ultimate decision would have that responsibility where necessary.

The Committee also suggested “the Government consider whether
it intends to contribute funding towards the costs of establishing fluoridated water supplies” because there is a “moral hazard arising from the DHBs making a decision that will impose costs on local authorities and ratepayers.”  It looks like the Government has accepted this point as they have already made $12 million dollars available to local bodies setting up new fluoridation systems (see Government commits $12m to help councils cover costs of fluoridation in water supplies.).

Provision of non-fluoridated alternatives

Some local bodies have already introduced “fluoride-free” taps at the request of local anti-fluoride campaigners., The MoH is suggesting an amendment to the bill to make clear that “DHBs can direct local government water supplies in their region on a supply by supply basis if they wish.”

This could make it possible for specific local supplies, like Petone in the Hutt region or some supplies in Christchurch to remain unfluoridated if their communities demand it even if a decision is made to fluoridate a region.

The DHB or the director general of health?

Many of the submitters opposed to the bill in its present form suggest that the decision-maker should not be the DHBs but the Director-General of Health or central government. This is because of the likely low expertise of DHB members, low voter turnout for DHB elections and concerns of legal challenges to DHB decisions. There was also the expressed belief that the anarchic and dishonest coordinated submission campaigns previously experienced by local bodies would simply be transferred to the DHBs.

Some submitter proposed that fluoridation be mandatory thereby removing the need for an elected body to be responsible for the decision making.

The committee report and response from the MoH show that parliament will probably stick with the DHBs as the decision maker. There are some advantages in this (the DHB have responsibilities in health areas) and the proof of the pudding will be in the eating. Will the DHB approach to consultations be able to successfully give more credence to credible and peer-reviewed science than the misinformation and distortions of science promoted by anti-fluoride campaigners?

Possibly. I hope so.

Conclusions

Despite the anti-fluoride campaigns and the resulting deluge of misinformed or misleading submissions, the submission process has been successful. Problems in the current wording of the bill were identified and reasonable solutions to these problems have been advanced.

We should now see how MPs react to the bill and the recommended changes in the second reading. Anti-fluoride activists have carried on an intensive campaign of emails, letters and representations aimed at MPs. On the whole, this will have been counterproductive as MP are surely aware this bill is not about the science or ethics of fluoridation but simply the decision-making process.

I am picking that these campaigns have produced more heat than light and will have little influence on the progress of the bill. However, I do expect a lot of teeth-grinding, hairpulling, garment rending, lamentations that democracy doesn’t work or that various MPs should be shot or otherwise disposed of from anti-fluoride campaigners. This is already happening and will no doubt intensify when the final bill is passed into law.

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Anti-fluoridationists commonly misrepresent Ministry of Health data

Anti-fluoride activists tell porkies about the Ministry of Health’s data on child dental health. They cherry-pick the data to make it appear that community water fluoridation is ineffective. And when challenged to discuss the issue they run away.


I am currently dealing with family issues so am reposting this article, “A challenge to anti-fluoridationers to justify their misrepresentation of New Zealand research”  from April 2016.  It shows how local anti-fluoride activists are misrepresenting the Ministry of Health’s data on child oral health


One of the frustrations I have with the fluoridation issue is the refusal of anti-fluoride activists to engage on the science. They will pontificate, but they won’t engage in discussion.

On the surface, one would think there is a difference of opinion or interpretation of scientific issues and that could be resolved by discussion. Yet local anti-fluoride campaigners refuse to enter into discussion. Again and again, I have offered space here to local anti-fluoride campaigners so that they could respond to my articles and they have inevitably rejected the offer. They have also blocked me, and other people discussing the science, from commenting on any of their social media pages or web sites. Even when they, themselves, call for a debate they reject specific responses I have made accepting that call.

So I am left with the only alternative of responding to their claim with an article here – or on a friendly web or blog site. At least that gives me space to present my argument – I just wish I could get some intelligent responses enabling engagement on the issues.

Misrepresentations repeated

The latest misrepresentation of the science is a claim by the Auckland Fluoride Free NZ Coordinator, Kane Titchener, that recent research proves fluoridation [is] not needed.

It repeats the same misrepresentation made by Wellington Anti-fluoride campaigner, Stan Litras, which I discussed in my article Anti-fluoridation cherry-pickers at it again. Kane has either ignored my article, chosen to ignore it or possibly not even understood it.

So here we go again.

Kane claims:

“A New Zealand study published in Bio Medical Central Oral Health last month shows dental health improved the greatest extent for children in non-fluoridated areas. There is now no difference in dental decay rates between non-Maori children who live in fluoridated areas and non-Maori children who live in non-fluoridated areas, proving that fluoridation is not needed for children to obtain good dental health.”

Although he doesn’t cite the study (wonder why), his use of two figures from the study show he is writing about the paper:

Schluter, P. J., & Lee, M. (2016). Water fluoridation and ethnic inequities in dental caries profiles of New Zealand children aged 5 and 12–13 years: analysis of national cross-sectional registry databases for the decade 2004–2013. BMC Oral Health, 16(1), 21.

His claim relies on the comparison of data for “non-Māori” children in fluoridated and fluoridated areas. No – he doesn’t misrepresent the data – he just ignores the discussion by these authors of problems with simple interpretation of the data for non-Māori because of the fact it is not ethnically uniform. In particular, he ignores the qualifications they place on the data because of the inclusion in non-Māori of data for Pacifica who have poorer dental health than the rest of this group and live predominantly in fluoridated areas. This, in effect, distorts the data by overestimating the poor oral health for “non-Māori” in the fluoridated areas.

The apparent convergence

The data used in this study were taken from the Ministry of Health’s website. This divides the total population of children surveyed into the ethnic groups Māori, Pacific and “Other.” While the “other’ group will not be completely uniform (for example including Pakeha, Asian, other groups) it becomes far less uniform when combined with the Pacific group to form the non-Māori group.

So, Kane salivates over this figure from the paper especially the plots for  non-Māori ethnicities in fluoridated (F) and non-fluoridated (NF) areas.

12903_2016_180_Fig1_HTML

Fig. 1 No obvious decay experience (caries-free) percentages and mean dmft for 5-year old children over years 2004 to 2013, partitioned by Māori and non-Māori ethnicities and fluoridated (F) and non-fluoridated (NF) areas

Yes, that convergence is clear and I can see why Kane is clinging to it – who can blame him. But he completely ignores the warning from the paper:

“It is likely that a substantial driver of this convergence was due to significant changes within the dynamic and heterogeneous non-Māori groups both within and between DHB regions. In effect, the ecological fallacy – a logical flaw whereby analyses of group data are used to draw conclusions about an individual – may be operating within the non-Māori group.”

When the Pacific data is removed (as is the case for the “other” group effectively made up from non-Māori and non-Pacifica) we get the plots below.

Other

Comparison of data for “other” (non-Māori/non-Pacifica) children in fluoridated (F) and unfluoridated (UF) areas.

Nowhere near as useful for Kane’s confirmation bias and the message he wants to promote. OK – there is still some evidence of convergence from about 2007 on between fluoridated and unfluoridated children. But the graphs do show that community water fluoridation is still having  a beneficial effect. And this apparent convergence could be explained by things like the introduction of “hub and spoke” dental clinics after 2004. One problem with this raw data is that children are allocated according to the fluoridation status of the school – rather than their residence. This will lead to incorrect allocation in some cases.

Some data for Pacifica

Just to underline the problems introduced by inclusion of Pacific in the non-Māori group of the study consider the data for Pacifica shown below.

other-pacifica

Data for 5-year-old children. dmft = decayed, missing and filled teeth. The “other” group is non-Māori and non-Pacifica

The oral health of Pacifica is clearly poorer than that of the “other” group.

Also, Pacifica make up about 20% of the non-Māori fluoridated group. So they will influence the data for the non-Māori fluoridated group by reducing the % caries free and increasing the mean dmft.

So Kane, like Stan, is blatantly cherry-picking. He is misrepresenting the study – and its author – by ignoring (or covering up) the qualifications regarding the influence of inclusion of pacific in the non-Māori fluoridated group.

The challenge

Now, I repeat the offer I have made in the past to give a right of reply to both Kane Titchener and Stan Litras. They are welcome to comment here and if they want more space I am happy to give space for separate articles for them in the way I did for the debate with Paul Connett. Now I can’t be fairer than that, can I?

So what about it Stan and Kane? What are your responses to my criticisms of the way you have cherry-picked and misrepresented this New Zealand paper?


NOTE: I have sent emails to both Kane and Stan asking them to respond and offering them right of reply.

UPDATE 1: Great minds and all that – Stan Litras sent out a press release today calling for a nation-wide debate on this issue (see FIND calls for a national debate on fluoridation). However, the seriousness of his request is rather compromised by his reply to my offer of a right of reply to the above article. He did respond to my email very quickly. This is what he wrote:

“Thanks for the offer, Ken, but I have not visited your blog site for a long time, as I object to the way you attempt to defame and discredit me.

You play the man and not the ball, which is not the mark of a reasonable person.

I hope to address that in due course as time permits, but for now I must leave you to indulge yourself without my company.”

So much for his wish for a “national debate” when he will not front up to a critique of his claims about the science.

UPDATE 2: Kane Titchener today also posted a press release today which was the text of the article I discuss in this post (see NZ research proves fluoridation not needed). He also responded quickly to my e-mail. The full text of his response was:

Who is this?”

Rather strange – considering he often pesters me with emails.

So I guess both of them have turned down my offer.

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ChildSmile – a complement, not an alternative, to fluoridation

Childsmile-Hebrides-Today

New Zealand Health Boards already run elements of the Scottish ChildSmile dental health programme and do not see it as an alternative to community water fluoridation


I am currently dealing with family issues so am reposting this article,ChildSmile dental health – its pros and consfrom September 2015.  Local antifluoride activists are busy presenting ChildSmile and similar programmes as alternatives to fluoridation. They aren’t – and New Zealand District health Boards alreeayd operate elements of these programmes where they consider them effective.


There is some local interest in the Scottish ChildSmile dental health programme. Partly because anti-fluoride campaigners are promoting it to local bodies as an alternative to community water fluoridation (CWF). Their interest is possibly due to the opt-in nature of the programme which they see as satisfying their demands for “freedom of choice” (in this case the choice means excluding their own children from the programme which, after all, does include fluoride treatments).

However, health professionals in the UK are more balanced in their opinions. While welcoming ChildSmile they do not see it as an argument against CWF – rather as “the next best thing – a rather expensive substitute for the fluoridation schemes that have never been introduced.”

I have written about the ChildSmile programme before (see Fluoride debate: Ken Perrott’s closing response to Paul Connett?). But here is some more detail I have picked up from discussion online with health professionals.

What is the ChildSmile programme?

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On the surface, the ChildSmile programme supplies children with toothbrushes and toothpaste:

“The core programme involves supervised daily toothbrushing for all Scottish three and four year olds attending nursery schools (but not those who don’t attend nurseries). This has been extended to five and six year olds in primary schools in those areas (not necessarily across entire local authorities) counted as being among the 20% most deprived in Scotland.”

Data suggest that about 82% of three and four-year-olds are participating. The children who do not take part do not benefit.

ChildSmile also includes twice-yearly application of fluoride varnish to children’s teeth.  The programme 2013/2014 targets included this:

“At least 60% of 3 and 4 year old children in each SIMD quintile to receive at least two applications of fluoride varnish per year by March 2014.”

In addition to toothbrushing and varnishing, Childsmile involves health education initiatives based principally on public health nurses and health visitors attaching themselves to particular schools in order to give oral health advice to children and parents. Subject to parental consent, they also arrange for children who are not registered with a dentist to undergo check-ups and, if necessary, treatment.

Is it a substitute for CWF?

Not really, but health professionals see it as the “next best thing.” Appropriate for situations where there is no CWF. But it only covers children – and then only those children whose parents give consent (many don’t). In contrast, CWF benefits adolescents and adults, as well as children. Families can, of course, “opt out” od CWF (by using water filters or different sources), but numbers will be lower than those excluded by “opt-in” procedures.

It is wrong to see such programmes as alternatives to, or separate from, CWF. Elements of the ChildSmile programme were already present before ChildSmile was introduced. Similar elements will also be common in countries like New Zealand.

Is it effective?

Childsmile was introduced in 2008 so it is a little early to judge its effectiveness. Scottish children’s dental health has improved and the programme most likely has assisted that.

For example, 58% of five-year-olds were free of decay in 2008, compared with 68% in 2014. The average decayed, missing and filled teeth (dmft) score for this age group has fallen over that period from 1.86 to 1.27.

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However, there does not seem to have been a reduction in dental health inequalities between children from different social groups in Scotland. In 2008, 42% of children from the most socially deprived quintile of Scottish five-year-olds were free of decay compared with 73% of those from the least deprived quintile. In 2014, 53% of five-year-olds in the most deprived quintile were free of decay compared with 83% of those from the least deprived quintile.

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According to the Scottish National Dental Inspection programme the absolute inequality between the most and least deprived children remains at 30% (comparing percentages of children without tooth decay), according to surveys conducted in 2008, 2010, 2012 and 2014.

Another concern is that children in the most deprived quintile of five-year-olds have not reached the national target set in 2010 that 60% of them should be free of decay.

Of course, the ChildSmile programme has no effect on the oral health of  current adolescents and adults.

What about the cost?

ChildSmile is far less cost-effective than CWF. Let’s compare the cost of CWF in England with the costs for the ChildSmile programme in Scotland

CWF serves 6 million people in England, costs around £2.1 million a year and is benefiting everyone with natural teeth, regardless of age, education or socioeconomic status. It benefits all children. So the cost per person of is around 35 pence per annum, although if we exclude people with no natural teeth it is likely to be a little higher than that – an average cost of about 40 pence per person benefiting.

If we take a narrow view and assume only children and adolescents aged 0 to 17 (21% of the population in England ) benefitted from CWF the cost would apply to around 1.26 million out of the 6 million supplied with fluoridated water. On that basis, the cost of CWF would be £1.67 per year for each child benefitting.

In contrast:

The total national ChildSmile budget for 2013/14 was £14,956,000, according to a statement by the Minister responsible to the Scottish Parliament in July 2013. This covers everything attributable to Childsmile – the toothbrushing programme, plus targeted varnish applications and associated oral health education initiatives.  Assuming that around 120,000 Scottish children aged between three and six are benefiting, it works out at a cost of around £125 per child per annum.

Compare the Childsmile costs of around £125 per child per annum with the CWF costs of about 40 pence per person per annum or even £1.67 per year for each child benefitting. CWF is obviously many times less expensive that ChildSmile.

What is the attitude of Scottish dentists?

The British Dental Association supports CWF and in Scotland has come out publicly to call for communities to move towards introducing water fluoridation. That position undermines the arguments of New Zealand anti-fluoridation groups claiming that Childsmile is an adequate substitute for water fluoridation. The professional body representing dentists in Scotland does not see it that way.

The BDA in Scotland points out that CWF would be beneficial to children and elderly people. It argues that water fluoridation “would complement the Childsmile programme” by helping cut the overall burden of tooth decay and reducing dental health inequalities in the elderly. We could look at it another way and see that a Childsmile programme could complement water fluoridation. After all, we must remember that initiatives such as Childsmile rely on personal compliance and that they benefit only those taking part. They give no benefit for the rest of the population, unlike CWF.

CWF and ChildSmile are are not mutually exclusive. Children in fluoridated areas should be encouraged to brush their teeth regularly with a fluoride toothpaste and to receive dental check-ups. Bear in mind, also, that components of a ChildSmile programme, such as supervised toothbrushing, were in use in parts of Scotland before the introduction of the full programme. Elements of the ChildSmile programme will also be in current use in New Zealand.

Conclusions

Despite claims of anti-fluoride propagandists, the ChildSmile programme is not a simple alternative to CWF. And it is wrong to see it as such in New Zealand.

It is far less cost-effective – the Scottish programme costs around £125 per child per annum compared with 40 pence per person per annum (or £1.67 per year for each child benefitting when benefits to adults are excluded) and therefore far less likely to be put in place as an alternative to CWF.

ChildSmile is an “opt-in” programme so its coverage is far lower than CWF which is an “opt-out.” This is important when social differences in oral health are important.

However, the contact between children and their families on the one hand and public health nurses, health visitors and dentists on the other, is very valuable and may have wider benefits than oral health alone. (I am thinking of problems caused by child neglect and abuse).

I think these sort of programmes are socially very helpful and strongly support them. The cost is, of course, a limiting factor. However, elements of such social programmes may be possible within budget constraints that health authorities face.

Health programmes like ChildSmile, or elements of that programme, can be very effective even in areas where CWF exists. They can give that extra boost to the oral health of children and can, therefore, complement CWF.

There are many areas where CWF is not feasible because of low population density, lack of suitable water reticulation systems or local political opposition to CWF. I believe that programmes like ChildSmile, or parts of that programme, can be very helpful in those situations. Northland and particularly NZ’s Far North are obvious examples.

Finally, let’s not be diverted by the programme name. I am sure that elements of the Scottish ChildSmile programme are already in place in New Zealand, or parts of New Zealand. Given the costs of such programmes, and budget limitations, these programmes do have the advantage that they can be targeted to regions or social groups where the need is the greatest.

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