Tag Archives: SciBlogs

Dental health – it’s not all about fluoride

cross-section-of-tooth

Fluoride is not the only element involved in preventing decay. See Fluoridation – topical confusion  for a description of how fluoride, calcium and phosphate react at the tooth surface.

Fluoride is not the only factor in oral health. But it is generally the only element in drinking water considered for its effect on our teeth.

Drinking water fluoride benefits existing teeth by chemically reacting with the tooth surface. Involvement of fluoride in the apatite structure at the tooth surface helps prevent demineralisation, due to acid attack, and also encourages remineralisation – tooth enamel repair.

But fluoride is not the only chemical species in drinking water and food that promotes this reaction at the tooth surface. Calcium and phosphate must also be involved. (Bioapatites in teeth and bones are chemical compounds of calcium, phosphate and fluoride). However, these other ions have generally been neglected in studies of the effects of drinking water composition on dental health.

I recently came across a scientific paper which helps overcome this deficiency:

Bruvo, M., Ekstrand, K., Arvin, E., Spliid, H., Moe, D., Kirkeby, S., & Bardow, A. (2008). Optimal Drinking Water Composition for Caries Control in Populations. Journal of Dental Research, 87(4), 340–343.

It compared the dental health of Danish children with the most significant drinking water characteristics. Data for the decayed missing and filled tooth surfaces (DMF-S) of 15 year old schoolchildren were used.  The drinking water characteristics included the concentration of a range of cations and anions, organic carbon, hardness, pH, ionic strength and residue content.

Statistical analysis identified calcium and fluoride as having the major effect and the authors used their data to produce a model relating DMF-S to both calcium and fluoride. The figure below give some idea of predictions from this model.

Ca and F

The model explains about 45% of the variance – better than when fluoride is considered alone (Ekstrand et al., 2003 were able to explain 35% of the variance using fluoride alone).

Community water fluoridation is not used in Denmark but the natural concentration of fluoride in the drinking waters reported in this study ranged from 0.06 – 1.61 (mean 0.33) mg F/L. The concentration of calcium ranged from 31.4 – 162.3 (mean 83.5) mg Ca/L.

So, a result that is hardly surprising for chemists familiar with the surface chemistry of apatites. But it does suggest that perhaps health authorities should consider the calcium concentration of drinking waters as well as fluoride.

According to the authors optimal drinking water should contain medium concentrations of both ions – about 90 mg Ca/L and 0.75 mg F/L. I suspect our drinking water calcium concentrations in New Zealand tend to be lower than this.

Perhaps this is something to think about. And perhaps those anti-fluoride fanatics who use distillation or reverse osmosis to remove fluoride are also forgoing the oral health benefits of calcium. A case of throwing out two babies with the bath water.

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Are you really right?

Great explanation of our different thinking processes by Julia Galef. Readers who listen to the Rationally Speaking podcast will recognise her.

She describes the two different mindsets we have when approaching problems – calling them the “Warrior mindset” and the “Scout mindset. Motivated reasoning which is so widespread is a strong feature of the “Warrior mindset.” While this may spur people to action it is not a good way of solving problems.

I like the way Julia brings out the fundamental role of emotions in determining mindsets – and the way different people approach problems.

So some good advice from her is to encourage emotions related to curiosity, the desire to understand and the ability to be proud about changing one’s mind and not defensive about retaining beliefs.

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June ’16 – NZ blogs sitemeter ranking

 

Blog June

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

Every month I get queries from people wanting their own blog included. I encourage and am happy to respond to queries but have prepared a list of frequently asked questions (FAQs) people can check out. Have a look at NZ Blog Rankings FAQ. This is particularly helpful to those wondering how to set up sitemeters. Please note, the system is automatic and relies on blogs having sitemeters which allow public access to the stats.

Here are the rankings of New Zealand blogs with publicly available statistics for June 2016. Ranking is by visit numbers. I have listed the blogs in the table below, together with monthly visits and page view numbers. Meanwhile, I am still keen to hear of any other blogs with publicly available sitemeter or visitor stats that I have missed. Contact me if you know of any or wish help adding publicly available stats to your bog.

You can see data for previous months at Blog Ranks

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A cynical take on effective speakers

This video is a parody of a TED talk – you know, those talks which often come across very impressively but may not have much in the way of real content.

Or is this just me getting cynical in my dotage? I certainly feel I have an excuse for that.

Source: This Parody Of Every TED Talk Ever Is Absolutely Perfect – Digg

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Richard Dawkins – speech to Reason Rally, 2016

This was Richard Dawkins’ speech to the 20116 Reason Rally in Washington DC last week.

Richard suffered a mild stroke earlier this year and this video shows he is still not fully well. Anyway, too unwell to travel so he presented the speech as a video.

There is nothing new here – he has made all these points before. But these points are well worth repeating, and he makes them so well.

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Chemophobic scaremongering: Much ado about absolutely nothing

much-ado

Sometimes anti-fluoride propagandists end up shooting themselves in the foot. This always seems to happen when they produce “evidence’ that fluoridating chemicals are loaded with toxic heavy metals.

It feels like shooting fish in a barrel to debunk their use of analytical figures because the data they produce always shows them to be completely wrong. I wrote about this before in Fluoridation: emotionally misrepresenting contamination. So, I am effectively repeating myself by discussing the meme image below that Fluoride Free NZ is currently circulating in social media.

Hill lab

Still, this time, I will show how insignificant these analytical figures by comparing the calculated final concentrations in tap water – due to addition of the chemical – with measured concentrations for these contaminants in Hamilton tap water.

Added contaminants as percentage of MAVs

But first – what contribution would this sample of fluorosilicic acid make to the contaminant levels in Hamilton’s tap water – and how do these levels compare with the maximum acceptable values (MAVs) defined in New Zealand’s Drinking Water Standards? The values for the MAVs are published in:

Ministry of Health. (2008). Drinking-water Standards for New Zealand 2005 ( Revised 2008 ) (Vol. 2005). Wellington.

In this table, the “Tap water (mg/L)” data are the calculated final concentrations after addition of the fluoridating agent in the meme. The “%age of MAV” data are these values expressed as a percentage of the maximum acceptable values (MAVs) for the contaminants.

Impurity MAV (mg/L) Tap water calculated (mg/L) %age of MAV
Aluminium 0.1 8.69E-05 0.0869
Antimony 0.02 < 3.56E-07 <0.0018
Arsenic 0.01 1.26E-05 0.1264
Barium 0.7 4.27E-06 0.0006
Cadmium 0.004 2.37E-07 0.0059
Chromium 0.05 4.74E-06 0.0095
Copper 1 1.19E-06 0.0001
Iron 0.2 1.62E-04 0.0810
Lead 0.01 2.37E-07 0.0024
Manganese 0.04 3.56E-06 0.0089
Mercury 0.007 < 1.98E-07 <0.0028
Molybdenum 0.07 < 3.56E-07 <0.0005
Nickel 0.08 3.95E-06 0.0049
Selenium 0.01 < 1.98E-07 <0.0020
Uranium 0.02 2.05E-06 0.0103

Sorry, I have had to use scientific formating for some numbers because the final calculated concentrations in tap water are so low. On average, the calculated concentration  of these contaminants due to the fluoridating agent is about 0.02% of the MAV.  The largest relative contribution is for arsenic – just over 0.1%.

Regulations require that the contribution of contaminants from fluoridating agents should always be less than 10% of the MAV . The actual level of contaminants in this particular sample is well below those regulated maxima.

The Fluoride Free NZ meme is just promoting naive chemophobic scaremongering about absolutely nothing. These activists just haven’t bothered calculating what the analytical data means for the final concentrations in tap water. Or even bothered comparing the data with the regulated maximum amounts allowed for fluoridating chemicals. These values are available in Standard for the Supply of Fluoride for Use in Water Treatment.

Added contaminants as a percentage of concentrations in inlet water and treated water.

Let’s now compare the estimated contribution from contaminants in this sample of fluorosilicic acid to the levels of the very same contaminants in the Hamilton water. I have taken data from this document issued by the Hamilton City Council:

Waikato River and Treated Drinking Water Comprehensive Analysis Report 2013/14

The next table is for samples taken on 18th July 2013 at the intake to the treatment plant (that is the source water before treatment). The “Added FSA%” is the calculated level of impurity resulting from fluoridation expressed as a percentage of the impurity naturally present in the source water.

Impurity Intake (mg/L) Added FSA%
Aluminium 1.68E-01 0.05
Antimony 8.50E-04 <0.04
Arsenic 1.96E-02 0.06
Barium 1.88E-02 0.02
Berylium <1.10E-04 0.18
Cadmium <5.30E-05 0.45
Chromium <5.30E-04 0.89
Copper <5.30E-04 0.22
Iron 2.94E-01 0.06
Lead 1.18E-04 0.20
Manganese 2.15E-02 0.02
Mercury <8.00E-05 <0.25
Molybdenum 3.80E-04 <0.09
Nickel <5.30E-04 0.75
Selenium <1.10E-03 <0.02
Tin <5.30E-04 0.22
Uranium <2.10E-05 9.78
Zinc 8.13E-01 0.00

Now, a similar calculation and comparison – this time “Added FSA%” is the calculated level of impurity resulting from fluoridation expressed as a percentage of the impurity already present in the “treated water” – which is the final tap water. (At this time the Hamilton water supply was not fluoridated).

Impurity Treated (mg/L) Added FSA%
Aluminium 2.04E-02 0.43
Antimony 8.00E-04 <0.04
Arsenic <1.10E-03 1.15
Barium 1.26E-02 0.03
Berylium <1.10E-04 <0.18
Cadmium <5.30E-05 0.45
Chromium <5.30E-04 0.89
Copper 8.00E-04 0.15
Iron <2.10E-02 0.77
Lead 4.82E-04 0.05
Manganese 1.75E-03 0.20
Mercury <8.00E-05 <0.25
Molybdenum 3.70E-04 <0.10
Nickel 3.52E-03 0.11
Selenium <1.10E-03 <0.02
Tin <5.30E-04 0.22
Uranium <2.10E-05 9.78
Zinc 4.82E-03 0.14

The extremely low levels of contaminants – both calculated and already in the intake water and final treated water – mean some of the calculations are rather meaningless. Especially as some of the analysed values are given as less than the detection limit.

However, the very low calculated contribution of contaminants from this fluorosilicic acid sample – usually < 1% of that naturally present – shows how ridiculous the Fluoride Free NZ claims about contamination introduced by fluoridating agents is.

Never trust anti-fluoride campaigners

Fluoride Free NZ is simply scaremongering – relying on naive chemophobia where just the chemical name and analytical data (even where the “<” symbol indicates below the level of detection) seem to scare people.

This example illustrates, once again, that the claims made by anti-fluoride and similar activists should never be accepted at face value. They should always be checked against reliable sources.

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Fluoridation: News media should check press releases from anti-fluoridationists

A recent ruling from the New Zealand Press Council warns against news media  publishing press releases from biased groups without providing context or seeking comment from any other party. The ruling resulted from a complaint  by Toi Te Ora Public Health Service against the coverage of the fluoridation issue by The Whakatane Beacon. For the full ruling see Source: TOI TE ORA PUBLIC HEALTH SERVICE AGAINST WHAKATANE BEACON.

Specifically, the ruling relates to two articles:

  • “Dentist group dispels dire warning message” provided by Stan Litras, spokesman for Fluoride Information Network for Dentists (an anti-fluoridation group). It asserted the Bay of Plenty DHB claims that increased tooth decay would result from removal of fluoride were not supported by reliable metadata studies.
  • “No Fluoride commonsense to campaigner” gave the views of Jon Burness, Fluoride Free Whakatane spokesman. He claimed reports that Ministry of Health figures show no justification for adding fluoride.

The Press council concludes:

“Importantly both published articles were effectively press releases from interest groups with a particular point of view. As the Council has had cause to comment in two recently upheld complaints (Cases 2478 and 2483) running a press release, without seeking comment from any other party, does not make for a balanced piece of journalism. There are significant dangers in simply regurgitating a Press Release and it does not accord with best journalistic practice unless it is clearly spelt out as a Press Release.”

Media should be wary of misrepresentation

Stan Litras’s press release criticised evidence used by Dr de Wit from the District Health Board and medical officer of Health. It misrepresented de Wet, yet the newspaper failed to put the criticisms and allegations to him. The Press council described this as “a simple failure of journalistic principles.” It added that it “is the obligation of the publication to allow an individual to comment if mentioned or quoted indirectly in an article.”

The Press Council made a similar observation with Jon Burgess’s press release, pointing out that the claims in the article were not put to the Ministry of Health (whose data Burgess was misrepresenting). The council put this specific complaint to one side as it did not have a direct complaint from the Ministry. It did comment, though, “that again this was not the best journalistic practice.”

Anti-fluoridation groups like Litras’s  Fluoride Information Network of Dentists (an astroturf group for Fluoride Free New Zealand) are constantly providing press releases misrepresenting studies and experts. These manufactured press releases are circulated within the international anti-fluoride network and the tame websites and magazines run by the “natural”/alternative health industry. Occasionally they end up being published in more reputable mainstream media outlets where they can do more damage.

It would be nice to think the mainstream news media was sufficiently responsible to actually check out the claims being made by such obviously biased groups. It seems a simple principle to actually check with the experts or organisation whose data is being used in the press release (the Whakatane Beacon slipped up there). But it would also be nice to think that responsible news media attempts to provide balance when they are producing articles critical of scientific findings – even when provided by a maverick scientist into self-promotion. It surely doesn’t take much to work out which expert or institution should be asked for a balancing viewpoint.

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May ’16 – NZ blogs sitemeter ranking

blogging-success-2013-green-wood-1t4tkvs

Image credit: Blogging Discussion with Students 

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

Every month I get queries from people wanting their own blog included. I encourage and am happy to respond to queries but have prepared a list of frequently asked questions (FAQs) people can check out. Have a look at NZ Blog Rankings FAQ. This is particularly helpful to those wondering how to set up sitemeters. Please note, the system is automatic and relies on blogs having sitemeters which allow public access to the stats.

Here are the rankings of New Zealand blogs with publicly available statistics for May 2016. Ranking is by visit numbers. I have listed the blogs in the table below, together with monthly visits and page view numbers. Meanwhile, I am still keen to hear of any other blogs with publicly available sitemeter or visitor stats that I have missed. Contact me if you know of any or wish help adding publicly available stats to your bog.

You can see data for previous months at Blog Ranks

Subscribe to NZ Blog Rankings Subscribe to NZ blog rankings by Email Find out how to get Subscription & email updates Continue reading

New review shows clear economic benefits from community water fluoridation

Sapere

The NZ Ministry of Health has released a new review of the benefits and costs of water fluoridation in New Zealand.* Unlike most reviews I have discussed here dealing with the scientific aspects, the authors of this review say:

“we take an economist’s perspective; we look at the national cost-effectiveness and cost-benefit of fluoridation, and comment briefly on disparities.”

This perspective is, of course, important to the Ministry of Health which must invest its resources efficiently. These considerations were the prime reason the Ministry commissioned the review from the Sapere Research Group.

Readers who want to read the full report (78 pages) can download it from the link – Review of the Benefits and Costs of Water Fluoridation in New Zealand (pdf, 818 KB).

Strong evidence for benefits

The review points out that oral health is still a major issue for New Zealand. Despite considerable improvement over the last 20 to 30 years, “New Zealand remains a relatively high-caries population:”

“The ‘burden’ of the disease from dental decay is equivalent to three-quarters that of prostate cancer, and two-fifths that of breast cancer in New Zealand.”

It finds strong evidence for the benefits of community water fluoridation (CWF):

“A large body of epidemiological evidence over 60 years, including thorough systematic reviews, confirms water fluoridation prevents and reduces dental decay across the lifespan. The evidence for this benefit is found in numerous New Zealand and international studies and reports.”

Its estimates of the benefits of CWF include:

  • “In children and adolescents, a 40 percent lower lifetime incidence of dental decay (on average) for those living in areas with water fluoridation.”
  • “For adults, a 21 percent reduction in dental decay for those aged 18 to 44 years and a 30 percent reduction for those aged 45+ (as measured by tooth surfaces affected).”
  • “48 percent reduction in hospital admissions for treatment of tooth decay, for children up the age of four years.”

The review expresses this cost-saving in material terms:

“We estimate the 20-year discounted net saving of water fluoridation to be $334 per person, made up of $42 for the cost of fluoridation and $376 savings in reduced dental care. In short, there is a 9 times payoff; adjusting the discount rate from 3.5 percent to 8 percent results in a 7 times payoff.”

This estimate is “robust to significant changes in assumptions.” In fact, their “assumptions around dental costs avoided are likely to be at the lower end of what patients face.”

Quality of life benefits

Not surprisingly the review finds significant benefits of CWF to the quality of life estimates.  Interestingly, it makes the point that while most other health interventions require net health spending, the CWF benefits to quality of life arise from net cost-saving because the savings from reduced need for dental treatments are far greater than the costs of fluoridation.

I can understand the need for economists to quantify the quality of life returns on investment but can not, for the life of me, understand how they can take into account the pain and misery of children who suffer from poor dental health. The review does mention an Oral Health Impact profile which attempts to measure “patient discontent from pain, dry mouth and chewing problems.” But I suspect this goes only a short way to quantifying the personal and subjective problems arising from poor dental health.

In particular, I am thinking of the psychological and physical medium and long-term effects. Poor dental health negatively impacts the child’s schooling and must contribute to learning difficulties. This, in turn, will mean childhood poor dental health reduces a person’s future prospects in employment, adult education, social and personal relationships and general happiness.

Conclusion

The benefits of CWF are clear when considered in financial and economic terms and this new review presents these in a clear and convincing way. It will have an important  influence on the decision makers in the Ministry of Health, parliament and the government – especially as they discuss the new legislation required for the transfer of decision-making on fluoridation from councils to district health boards. But there are also personal and subjective benefits which are much harder to quantify to the satisfaction of economists and other bean counters. In the end, those personal and subjective benefits must bring a positive economic return to society as a whole, as well as the individual. If anything, decision makers and politicians should see that the case for CWF is even stronger than that made by the economic considerations in the review.

*Note: The Cabinet papers on the assessment of benefits from fluoridation and the upcoming legislative changes required to transfer decisions to District Health Board have also been released. These papers are very interesting and give an idea of the different factors the government has considered and the likely way the new legislation will go. I recommend any readers searching for more details on this to download the papers from this link:

DECISION-MAKING ON THE FLUORIDATION OF DRINKING-WATER SUPPLIES.

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Debating fluoridation and tyranny – Tom O’Connor responds

planA-planB-consentw

Individual consent – what does it mean and how is it obtained?

This article below is a guest contribution from Tom O’Connor responding to my article Attempting a tyranny of the minority on fluoridation. I invited Tom to discuss the issue here, and offered him a right of reply because I think there is value in discussing the points he raised in his Timaru Courier opinion piece and  that I critiqued in my article.

Unfortunately, in this issue, the scientific arguments are very often a proxy for underlying values issues, at least on the part of opponents of fluoridation. It is in the nature of values issues that there is no “correct” answer (in contrast to arguments about facts). Nevertheless, the values issues are important so I hope they can be developed in discussion here around Tom’s original opinion piece and his response here. In the end, such issues are decided by democratic and political means so open discussion of the issues is important.


Firstly I am not opposed to the use of fluoride to combat tooth decay per se. Nor do I have any “anti-fluoride mates” as you put it. If the government wants to make fluoride freely available there are many ways of doing that without imposing it on everyone.

There are three main elements to the fluoride debate. The first is the efficacy or otherwise of fluoride as a preventative for tooth decay.

The second is the use of reticulated potable water as a means of delivering anything other than clean water to the community.

The third is the issue of mass medication, or mass treatment or mass therapy of people without individual consent and practical convenient and affordable alternatives. Legislating to declare a medical treatment is not a medical treatment simply on the ground that the dose rate is measured in parts per million is one of the most stupid and dishonest things I have ever seen any government do. Many medications are measured in such minute quantities.

The Grey Power Federation objection to the proposed addition of fluoride to potable reticulated water is based on the third element only. We do not have a policy in the first element simply because we do not have the expertise or scientific qualifications to develop such a policy. We have not considered the second element.

That policy has been, in my view, adequately explained in the Timaru Courier opinion piece you refer to. The following comments are therefore mine alone and do not necessarily reflect the opinion of Grey Power members or anyone else.

Efficacy

As you rightly point out there is probably nothing to be gained in participating in the endless argument between proponents and opponents of fluoride as an oral health treatment. Both sides have accused the other of engaging in pseudo-science and scare mongering. Both are, to some extent, probably accurate and in agreement on that point alone. However, where doubts exist, it is probably better to err on the side of caution.

Reticulated water

Territorial local authorities have the responsibility to provide potable water to their communities where no other sources are available or suitable. The principle responsibility of local authorities, as outlined in the Drinking Water Standards for New Zealand, administered by the Ministry of Health, is to ensure drinking water is as free from all other substances and organisms as possible. Using reticulated potable water to convey anything else, be it medical or not, is contrary to that principle.

The use of chlorine to remove micro-organisms and other pathogens is designed to remove unwanted and potentially unsafe matter from drinking. At the end of that process there is not supposed to be any detectable chlorine. That there often is demonstrates the difficulty of getting the addition of trace elements correct. That is a very different matter to the deliberate introduction of an additional substance which many people don’t want.

Mass treatment and individual consent

This is not the first time mass medication or treatment has been introduced in New Zealand. Iodine deficiency, as a cause for goitre, was discovered in the early 1900s and to address the problem table salt was iodised at up to 80mg of iodine per kilogram of salt in 1938. This was accompanied by an extensive public education programme and there was always un-iodised salt as a practical, convenient and affordable option on grocer shop shelves for those who did not want it.

Suggesting that those who object to fluoride in the water they pay their local authority to deliver can obtain alternative supplies from a community tap or buy it from the supermarket is unacceptable. These options are not possible, practical, convenient or affordable for many people.You may also recall a recent proposal to add folic acid to all bread products as a means of addressing a reproductive issue for women. The public outcry which saw that proposal dropped was not solely based on doubts about the efficacy of folic acid but the fact they many people simply did not want their bread medicated with anything for any reason.

You may also recall a recent proposal to add folic acid to all bread products as a means of addressing a reproductive issue for women. The public outcry which saw that proposal dropped was not solely based on doubts about the efficacy of folic acid but the fact they many people simply did not want their bread medicated with anything for any reason.

There are practical and cost effective methods of providing fluoride for those who want it. Forcing it on those who don’t want it is simply unacceptable in a free society.

Tom O’Connor


I will post a response to Tom’s arguments in a few days. Meanwhile, readers are welcome to make their own arguments in the comments section.

Ken Perrott

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