Connett & Hirzy do a shonky risk assesment for fluoride

Paul Connett, executive director of the Fluoridation Action Network (FAN), told me, during our fluoride debate, that he was writing a scientific paper defining a lower safety limit for fluoride than currently accepted. Nothing has been published yet – although a recent FAN newsletter did refer to a risk assessment paper by him and Bill Hirzy currently under review. I look forward to reading this paper, but I am not holding my breath as neither author has an impressive publication record.

Connett described his risk assessment for fluoride in the debate (see Fluoride debate: Paul Connett’s Closing statement) and he and Hirzy have also made comments on this lately. They are rejecting the current risk assessment, based on the incidence of severe dental fluorosis, and using the incidence of IQ deficits instead. To this end, they are heavily promoting the work of Choi et al., (2012) and Xiang et al., (2003) (which reported IQ deficits in areas where fluorosis is endemic). They are also attempting to rubbish published research (such as Broadbent et al., 2014) which show no significant IQ deficits at fluoride concentrations used in community water fluoridation.

Connett and Hirzy have also organised campaigns to congressional representatives in their effort to force a downward revision of the Environmental Protection Agency’s (EPA) standards for fluoridation.

Connett’s approach is a desk study – these guys are not going  to dirty their hands by doing their own research to get useful data. They are taking a value which they claim represent the lowest concentration of fluoride in drinking water below which no IQ deficit was found. They then apply “safety factors” to effectively conclude the only safe concentration is zero (see Scientist says EPA safe water fluoride levels must be zero)!

I will be a bit surprised if they manage to squeeze their paper though a decent review process because their approach is shonky. Look at the way they use the data from Xiang et al., (2003). (I have used the presentations by Connett and Hirzy at last February’s Sydney anti-fluoride conference as sources here). As I pointed out in Connett fiddles the data on fluoride, this data actually does not show a strong relationship between IQ and fluoride. The figure (from Xiang et al., 2003) shows the relationship between IQ and urinary fluoride and, in this case, the fluoride explains only about 3% of the variance in IQ.

Despite being statistically significant (p=0.003) this is certainly not evidence for a causative relationship. Clearly other, unconsidered, factors contribute to the variance and if these were considered the relationship with fluoride may be non-significant.

(Readers may notice the figure uses data for urinary not drinking water fluoride. Unfortunately, Xiang did not give a similar figure for fluoride concentration in drinking water. I have contacted him requesting the similar data for drinking water but so far have not had a meaningful response. Xiang did report drinking water fluoride is well correlated with urine fluoride so the above figure probably gives a good idea of the variability in drinking water fluoride as well).

Connett and Hirzy effectively ignore the high variability in the data and rely on a trick to get this  second graph. By splitting the concentration range into groups and taking the mean IQ for each group they make the situation look a lot more respectable. Who would guess from this trick that fluoride only explained about 3% of the IQ variance?

Connett illustrates his next step with this slide.

Sydney-Feb-21-key-step

He then claims that IQ deficits occur at a fluoride concentration of 1.26 ppm – he appears to have simply subtracted the value of one standard deviation from the mean of the lowest concentration group associated with a significantly different mean IQ to that of Xiang’s “control” group – Xinhaui village. That is strange because surely the first figure indicates  that low IQ values occur even for children with very low urinary fluoride, and most probably drinking water fluoride.

Connett then uses a safety factor of 10 (“to account for the wide range of sensitivity expected for any toxic substance in a large population”). Of course, this produces a maximum “safe” concentration of 0.13 ppm – which rules out all fluoridated water – and most natural water sources!

Sydney Feb 21 B Australia,  2015Connett goes on to promise his offsider, Bill Hirzy, will elaborate on the method they issued. Hirzy’s presentation did mention fluoride intake from other sources besides water. He then presents his conclusion on what the “safe daily dose” is fluoride – but no explanation of why! All the preceding slides in his presentation where self-justifying descriptions of his qualifications, employment history and how great his organisation, FAN, is.

IQ-Risk-Assessment-02.26.15

Conclusions

Connett and Hirzy are claiming IQ deficits are more important than dental fluorosis for setting of maximum fluoridation levels in drinking water. They are campaigning to get this accepted by legislators and the EPA.

Connett has been promising publication in a scientific journal for several years and recently implied that a paper is under review. If their publication efforts are successful a more critical assessment of their approach will be possible.

Available information indicates Connett and Hirzy have no original data but are relying on data from a study of children in an area of endemic fluorosis in China. They are refusing to accept published information from areas where community water fluoridation exists.

Their analysis also appears to rely on a tricky processing of the data to obscure the fact that fluoride probably only explains about 3% of the variance in IQ measured by the Chinese researchers! Legislators and policy makers would be foolish indeed to make changes to fluoridation standards on the basis of such data and poor analysis.

I could, of course, be wrong so eagerly await the Connett & Hirzy (2016?) paper.

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Making mountains out of scientific mole hills

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Richard Horton, Editor of the Lancet speaking at the Global Health Metrics & Evaluation conference 2011. (Photo credit: Vimeo.)

The controversial Lancet editor, Richard Horton, has produced an opinion piece which some are interpreting as an attack on medical science, if not science in general. His article, What is medicine’s 5 sigma?, is being touted by websites like Collective Evolution as authoritative “evidence,” or justification, for their attempts to manufacture doubt on scientific issues (see Editor In Chief Of World’s Best Known Medical Journal: Half Of All The Literature Is False). And, of course, these messages are spread far and wide in social media like Facebook and Twitter by activists for various anti-science causes.

Horton, of course, exaggerates. He calls a spade a shovel – or even a giant earth moving machine. That is music to the ears of propagandists and manufacturers of doubt in the anti-vaccination, anti-fluoridation or even climate change denial movements. But, putting aside the damage such exaggeration causes for a moment, I do sympathise with some of Horton’s claims.

Provisional nature fo scientific knowledge

Horton begins with the statement “A lot of what is published is incorrect.”

While he appears to think this claim has shock value it is hardly news to scientific researchers. By its very nature, scientific knowledge is both provisional and incomplete. In the real world, no scientific idea or theory can accord completely with the true objective reality. We are always dealing with just a part of that reality. And our theories are always being replaced by new, updated and more complete theories which give better explanations of reality.  Let’s be clear, though, in most cases this is not a simple mechanical replacement but usually a modification to, or improvement of, existing theories.

So, yes, published science is “incorrect” in that it is always incomplete and provisional. It is always open to sceptical consideration and improvement – or even rejection.

However, Horton has really brought in the earth-moving machinery when he advances “the idea that something has gone fundamentally wrong with one of our greatest human creations.” 

Modern science is indeed “one of our greatest human creations” – despite the fact that it is by its very nature incomplete and imperfect.  Despite all the human problems influencing science it has still enabled us to solve many problems, to provide a more comfortable and safer existence for much of the world’s population and provided us with amazing technology (which critics of science enthusiastically use without being aware of the irony involved).

Sure, we still have many pressing problems to solve but no-one can seriously believe that science cannot contribute to the solution of these problems. In the end, despite all the human frailties inherent in such human endeavours, no other approach to obtaining knowledge and solving problems can seriously compete with science.

Some real problems

Horton gets specific:

“The case against science is straightforward: much of the scientific literature, perhaps half, may simply be untrue. Afflicted by studies with small sample sizes, tiny effects, invalid exploratory analyses, and flagrant conflicts of interest, together with an obsession for pursuing fashionable trends of dubious importance, science has taken a turn towards darkness.”

He also refers to those papers relying on correlations without showing causation, saying:

“Our love of “significance” pollutes the literature with many a statistical fairy-tale.”

But these problems are, in essence, not new and do not justify his purple prose about “a turn towards darkness.” That prose is rather hypocritical considering his own role in the publication of, and resistance to the retraction of, Andrew Wakefield’s article claiming a causal link between standard childhood vaccinations (measles, mumps and rubella) and autism (see  Why Is Richard Horton Still The Editor Of The Lancet?).

The fact is that poor quality research does get published – even by reputable journals like The Lancet (see for example Repeating bad science on fluoride). Poor quality research is not always knocked back, or improved, by the peer review processes journals use. These peer review processes themselves can be very flawed and even suffer from cronyism (see Poor peer review – and its consequences) and Poor peer-review – a case study) .

Many studies are poorly designed, report tiny effects and use small sample sizes. Many rely on statistically significant correlations which may be meaningless without any evidence for causation. Peer reviewers and journal editors, if they are actually conscientiously doing their jobs, are forced to make judgment calls. There is an argument for sometimes getting such studies into the literature where they can be critically examined and discussed. (Horton himself justified his decision to publish Andrew Wakefield’s article, which he acknowledged was an inferior study by claiming it would generate debate on the autism/vaccine issue).

But this backfires when uncritical journalists report the studies as scientifically credible, even gospel truth, when they are far from it. This is compounded by propagandists for activist groups who, confirmation bias in full flight, latch on to such studies to give “scientific authenticity” to their unscientific claims. And then promote them far and wide.

Recently we saw this with published papers claiming a link between fluoridation and thyroid problems (Peckham et al., 2015 – see Paper claiming water fluoridation linked to hypothyroidism slammed by experts) and ADHD (Malin and Till, 2015 – see ADHD linked to elevation not fluoridation). These papers were prime examples of Horton’s “statistical fairy tales.”

Reader beware

So, I am repeating a theme I often promote here. When it comes to the scientific literature it really is a matter of “reader beware.”

The reader must approach this literature carefully – intelligently and critically. The reader has the task of identifying “statistical fairy tales,” poor study designs and problems of tiny effects or small sample sizes. If the reader does not have the ability to do so they need to seek the opinions of qualified experts – and I don’t mean the self-appointed “world experts” leading activists groups or the google-informed commenters who seem to dominate social media and the internet.

After all, it is the real expert, many of whom are active researchers, who critically assess the scientific literature on a daily basis. And if they are participants in an active scientific community problems of confirmation bias are reduced.

The “reader beware” approach is even more necessary with the “scientific” claims often bandied about in the popular news media – mainstream media and especially the ideologically motivated “alternative” media.

I am an avid reader of the NZ Listener – which I consider a reputable mainstream journal. But every week I am annoyed by the small snippets reporting some new scientific claim (usually related to popular health issues) relying on individual scientific papers which I would place in Horton’s group of “statistical fairy tales.” I hope most readers are intelligent enough to seek further advice before taking such reports seriously.

But this annoyance is minor compared with what I feel about the rubbish I see daily on the internet daily. Ideologically motivated activists dominate social media here. They opportunistically link to such media reports, and even the original scientific papers, to give “scientific justification,” and confirmation bias for their unscientific messages.

When it comes to the internet one cannot repeat often enough – reader beware.

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Don’t expect to see chemical safety data sheets in restaurants

I keep coming across this very naive form of chemophobic scare-mongering – the use of safety data sheets to frighten consumers about trace chemicals in their environment, food and drink.

Here is an example anti-fluoridation propagandists continually use – safety data sheets for fluoridation chemicals like fluorosilicic acid. Often these people simply reproduce the image without comment – thinking this somehow proves their argument!

data sheets

I have discussed this issue for water treatment chemicals before (see Water treatment chemicals – why pick on fluoride?).

First, we need to be clear – Safety Data Sheets (or Material Safety Data Sheets) are not relevant to the chemicals we come across in our food drink – at the concentration they exist in these foods or drink. The safety data sheets are there for the use of those workers who must handle, transport  and dispose of concentrated chemicals. As Wikipedia explains:

“A SDS [Safety Data Sheet] for a substance is not primarily intended for use by the general consumer, focusing instead on the hazards of working with the material in an occupational setting.”

In the article I link to above I give information, including that from safety data sheets, for the range of chemicals used in water treatment. Chemicals like Aluminium sulphate or alum, used as a flocculation and coagulation agent and chlorine which is used as a disinfection agent (here is the safety data sheet for chlorine).

The safety data sheets for these chemicals can be just as scary as for fluorosilicic acid. Even scarier for chlorine, which was used as a chemical weapon in the first world war. And the information is important for the people handling the concentrated chemicals, manufacturing them, transporting them and disposing of them to waste where necessary.

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Safety data sheets are important for people transporting concentrated chemicals.

But these sheets are completely irrelevant to people interested in the safety and nutritional value of their food which do not contain such concentrated chemicals (except for water, of course).

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Safety data sheets are irrelevant to consumers of food and drink –  don’t expect your waiting staff to provide them in a restaurant.

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Being open-minded

This meme is for those commenters here who accuse me of having a closed mind.

open minded

I am always happy to change my opinion or view of things – if there is evidence to suggest I should.

And no, claims that “science once thought the world was flat,” or “science once supported smoking,” is not a credible argument that we should ignore current scientific consensus. It’s especially not an argument we should suddenly adopted unsupported claims as “gospel truth.”

Along these same lines, it’s worth considering this quote from Carl Sagan – if you want me to consider a really extraordinary claim your evidence had better be exceptional.

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RSNZ Science Book Prize winner – Tangata Whenua

Tangata Whenua: an Illustrated History won the Royal Society of NZ Science 2015 book prize. It is written by Atholl Anderson, the late Dame Judith Binney and Aroha Harris and published by Bridget Williams Books. The book charts the sweep of Māori history from ancient origins through to the twenty-first century.

In announcing this result on Friday Dr Andrew Cleland, Chief Executive of the Royal Society of New Zealand, noted that Tangata Whenua incorporates research from a range of disciplines from the sciences, including social science, and the humanities, which mirrors the breadth of scholarship supported by the Society.

In addition to being a history, the book is based on research on genetics and climate science as well as:

  • archaeology (the study of past human activity through material left behind by human populations)
  • anthropology (study of human society)
  • ethnography (study of culture)
  • paleoecology (study of past ecosystems or environments, reconstructed from fossils).

The other books shortlisted for the 2015 Royal Society of New Zealand Book Prize were:

  • The Wandering Mind by Michael Corballis (Auckland University Press)
  • Gathering Evidence by Caoilinn Hughes (Victoria University Press)
  • Dolphins of Aotearoa: Living with New Zealand Dolphins by Raewyn Peart (Craig Potton Publishing)
  • Manuka: the Biography of an Extraordinary Honey by Cliff Van Eaton (Exisle Publishing)

You can buy your own copy from Whitcoulls for $99.99.

See also:

New Zealand science book prize – 2015 Short list
The Long Journey to Aotearoa – Veronika Meduna, Radio NZ, talks to Atholl Anderson

Don’t put all the blame on the Germans – a lesson from World War II

800px-Khatyn_Memorial,_Belarus

Sculpture of the “Unbowed man” at the Khatyn Memorial site. The sculpture depicts Yuzif Kaminsky, the only adult to survive the massacre, holding his dead son Adam. Credit: John Oldale.Click to enlarge

The recent commemorations of Victory Day in Europe – the 70th anniversary of the end of the second world war in Europe – got me thinking about how we refer to Germany as the perpetrator of the horrors in that war. Often we more correctly use the term “Nazi Germany” – but still it must place a burden of guilt on many Germans who were, and are innocent.

On the other hand, it seems to me, it almost ignores the very real responsibility of people from other nations for these atrocities. (Although, granted some speakers will also refer to involvement of collaborators).

The Khatyn Massacre

Many years ago I visited the war memorial at Khatyn, in Belarus. This was a very moving experience because it symbolised how that nation had lost a quarter of its population during the war. All the residents of this village had been herded into barns which were then set alight – anyone attempting to escape was shot. The photo above shows part of the memorial depicting the man who was thought to be the sole survivor.

Very moving.

I certainly got the impression that this horror was perpetrated by German soldiers. But my reading in recent days convinces me I was wrong, and had been wrongly informed. The perpetrators were a nazi battalion – but one established in Kiev and made up mainly of Ukrainian nationalists. Here are some details from the Wikipedia entry on the Khatyn massacre:

Khatyn or Chatyń (Belarusian and Russian: Хаты́нь, pronounced [xɐˈtɨnʲ]) was a village of 26 houses and 156 inhabitants in Belarus, in Lahoysk Raion, Minsk Region, 50 km away from Minsk. On 22 March 1943, the entire population of the village was massacred by the 118th Schutzmannschaft Nazi battalion. The battalion was formed in July 1942 in Kiev and was made up mostly of Ukrainian nationalist collaborators from Western Ukraine, Hiwis[1][2][3] and the DirlewangerWaffen-SS special battalion.

The massacre was not an unusual incident in Belarus during World War II. At least 5,295 Belarusian settlements were burned and destroyed by the Nazis, and often all their inhabitants were killed (some amounting up to 1,500 victims) as a punishment for collaboration with partisans. Khatyn became a symbol of all those villages. In the Vitebsk region, 243 villages were burned down twice, 83 villages three times, and 22 villages were burned down four or more times. In the Minsk region, 92 villages were burned down twice, 40 villages three times, nine villages four times, and six villages five or more times.[4] Altogether, over 2,000,000 people were killed in Belarus during the three years of Nazi occupation, almost a quarter of the country’s population.[5][6]

It’s worth following up some of the links for more details.

The Ukrainian Auxiliary Police, which included the Schutzmannschaft Nazis involved in this and many other massacres, carried out anti-Jewish and anti-partisan operations in most areas of Ukraine. While these units were formed directly after the German invasion of the USSR in 1941 Ukrainian nationalist organisations existed before that invasion. These extremist organisations were not just “nationalist,” but were racist – expressing hatred for Poles, Jews and above all, Russians. And these three groups became their victims during the war.

Misinforming tourists

I had happily accepted the story that the Khatyn Massacre was perpetrated by “Nazis” – assuming they were German Nazis. So this information came as a bit of a shock to me. Worse – the role of such nationalist forces was not talked about much during Soviet times in fear of encouraging antagonism between the different republics. So innocent tourists were left in the dark about the true origins of the perpetrators – despite the fact that the leaders of the battalion involved had been brought to justice. As Wikipedia says:

“The commander of one of the platoons of 118th Schutzmannschaft Battalion, Ukrainian Vasyl Meleshko, was tried in a Soviet court and executed in 1975. The Chief of Staff of 118th Schutzmannschaft Battalion, Ukrainian Grigory Vassiura, was tried in Minsk in 1986 and found guilty of all his crimes. He was sentenced to death by the verdict of the military tribunal of the Belorussian military district.

The case and the trial of the main executioner of Khatyn was not given much publicity in the media; the leaders of the Soviet republics worried about the inviolability of unity between the Belarusian and Ukrainian peoples.”

A lesson for today

So the message is – when your hear about Nazi atrocities the perpetrators were not necessarily German. We should not forget the role played by collaborators and non-German nationalists in the Holocaust and other atrocities.

epa04318197 New soldiers of Ukrainian army battalion 'Azov' attend their oath of allegiance ceremony before departing to eastern Ukraine in Kiev, Ukraine, 16 July 2014. The government in Kiev does not recognize the declared independence of the Donetsk and Luhansk regions, and pro-Russian militants refuse to cooperate with the pro-European leadership in Kiev. Ukraine insisted that there would be no ceasefire or negotiations before the pro-Russian separatists in the country's east give up their arms.  EPA/ROMAN PILIPEY

New soldiers of Ukrainian army battalion ‘Azov’ attend their oath of allegiance ceremony before departing to eastern Ukraine in Kiev, Ukraine, 16 July 2014.Image Credit: EPA/ROMAN PILIPEY

And this is not an abstract appeal. Today the inheritors of the Ukrainian nationalist organisations which committed these atrocities are alive and very active in Ukraine. They even have military battalions fighting in the current civil war. Worse, the US has now sent their own troops into Ukraine to train National Guard battalions which include units like the Azov Batallion which is based on extreme National Socialist ideology.

Talk about a slippery slope.

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The problem of “Fact-Resistant Humans”

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OK, this is satire so don’t take it literally. But this article in The New Yorker makes a good point – Scientists: Earth Endangered by New Strain of Fact-Resistant Humans.


MINNEAPOLIS (The Borowitz Report) – Scientists have discovered a powerful new strain of fact-resistant humans who are threatening the ability of Earth to sustain life, a sobering new study reports.

The research, conducted by the University of Minnesota, identifies a virulent strain of humans who are virtually immune to any form of verifiable knowledge, leaving scientists at a loss as to how to combat them.

“These humans appear to have all the faculties necessary to receive and process information,” Davis Logsdon, one of the scientists who contributed to the study, said. “And yet, somehow, they have developed defenses that, for all intents and purposes, have rendered those faculties totally inactive.”

More worryingly, Logsdon said, “As facts have multiplied, their defenses against those facts have only grown more powerful.”

While scientists have no clear understanding of the mechanisms that prevent the fact-resistant humans from absorbing data, they theorize that the strain may have developed the ability to intercept and discard information en route from the auditory nerve to the brain. “The normal functions of human consciousness have been completely nullified,” Logsdon said.

While reaffirming the gloomy assessments of the study, Logsdon held out hope that the threat of fact-resistant humans could be mitigated in the future. “Our research is very preliminary, but it’s possible that they will become more receptive to facts once they are in an environment without food, water, or oxygen,” he said.

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What a nice idea

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Click to enlarge – Moscow Celebration of Victory day.
Image Credit:
 NBC News

The recent commemorations of ANZAC Day (in New Zealand), Victory day (Internationally) and Mothers’ day got me thinking about how we mark these events. Thinking spurred on by a family discussion precipitated by a difference of opinion about the Victory day Celebrations (or the reporting of them) in Moscow.

Firstly – Mothers’ day. I was struck by Facebook entries some of my relatives made dedicated to their mothers. The sincere expression of love and respect for, and thanks to, their Mothers. Quite moving but really lovely to see the expressions of gratitude to parents.

ANZAC Day is a notable day in New Zealand. In my youth, many people felt bad about it because of its glorification of war and support of a bad war in Indo-China. Being of “call-up” age at the time my pacifist tendencies (and support for the Vietnamese) meant I rejected what ANZAC Day seemed to stand for then.

But more recently ANZAC Day celebrations in New Zealand have come to recognise the horrors of war, to oppose militarism and to be a time when we remember the sacrifices of our relatives who died in wars. It has come to be more concentrated on the losses at Gallipoli in the First World war (the event which initially launched ANZAC day).

There was very little here marking the Victory Day Celebrations commemorating the end of the war in Europe on 8/9 May, 1945. And local reporting of overseas commemoration events was no better. A pity, as many New Zealanders did fight and die in Europe – and for a much better reason than some other wars we have fought in.

Personalising the commemorations

The media sometimes makes a big thing of the Military Parade in Moscow’s celebration of Victory Day – and I must admit military parades don’t appeal to me. But, unfortunately, our media often ignores the mass participation in Victory Day Celebrations. The photograph at the head of this post is a shot from this year’s mass commemoration in Moscow (click to enlarge – it is worth it).

It is the nature of this mass participation which interested me.  It is sometimes called the parade of The immortal regiment. Here is how the US Rusky Mir Foundation, which reported on an immortal regiment march in New York, describes this mass participation:

“The Immortal Regiment (or Besmertny Polk) dates from 2012, when people in the Siberian city of Tomsk were debating how to keep the memory of World War II heroes alive even as the veterans themselves passed on. They asked people to create large posters with photos of their relatives who had served in the war, and carry them in Victory Day parades. This year, more than 800 cities will have a “Besmertny Polk” parade.”

That is the idea that appeals to me – the use of portraits of lost relatives in these commemorations. It personalises the celebration and expression of gratitude – in much the same way that Facebook posts on Mothers’ day do. And it figuratively enables our lost relatives to be seen participating in the events.

Wouldn’t it be nice to see more people bring along and display photos of their relatives in New Zealand’s ANZAC celebrations? That would help improve the personal and family aspects of the celebration and the display would surely be moving.

Here is some video footage of the Moscow parade – but there is a lot more around, much of it from other countries.

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Water fluoridation effective – new study

A recent Australian study shows community water fluoridation (CWF)  has a beneficial effect on oral health, even after taking into account the known effects of socioeconomic status and sugar consumption.

This is important because anti-fluoride propagandists are always pushing the mistaken claim that CWF is based only on “old science” and that “the science establishment” refuses to check these old findings. These propagandists have also latched onto the concern over the effects of excessive sugar consumption on general and oral health to claim that any apparent beneficial effect of CWF would disappear if sugar consumption was reduced.

The study is reported in:

Blinkhorn, A. S., Byun, R., Mehta, P., & Kay, M. (2015). A 4-year assessment of a new water-fluoridation scheme in New South Wales, Australia. International Dental Journal.

It  followed changes in the dental health of children in Gosford City, NSW, after introduction of CWF in 2008. It compared this with the oral health of children living in areas that had been fluoridated for over 40 years, and with those in the Shires of Ballina and Byron which were unfluoridated and had no plans to introduce CWF.

CWF clearly beneficial

The figure below compares the average numbers of decayed, missing and filled teeth (dmft) of 5-7 year-old children in 2008 (just before introduction of CWF to Gosford city – the “newly fluoridated area) with new batches of 5-7 year-old children in 2010 and 2012. In all three periods comparisons were made to similar children in the unfluoridated and long-term fluoridated areas.

dmft-aus1

Of course, anti-fluoridation activists might pick up on the improved oral health of children in unfluoridated areas in 2012 (and they might even try to ignore the rest of the data). But the clear message is that even though there may be a general improvement in oral health over time the children in the fluoridated areas still showed a clear benefit.

Influence of other factors

This study included measurement of other factors known to influence oral health. Statistical analysis of the data showed poorer dental health was significantly related to:

  • lower socioeconomic status;
  • origins (poorer dental health when mothers were born in a non-English speaking country;
  • lower educational level attained by parents, and
  • sugary drink consumption (poorer dental health where children consumed one or more drinks a day).

But, importantly, the statistical analysis showed a significant beneficial influence of CWF after taking these other factors into account. The following graph compares the dmft for newly fluoridated and unfluoridated areas relative to long-term fluoridated areas (defined as 1.0)

dmft-aus2

We can see that by 2012, 4 years after introduction of CWF, there is no significant difference between the oral health of children in the long-term and newly fluoridated areas. However, the oral health of children in the unfluoridated areas was significant poorer at all times.

Conclusion

Origins, socioeconomic status and consumption of sugary drinks have a statistically significant effect on children’s oral health. However, even when these are taken into account this research shows a clear beneficial effect of CWF on children’s dental health.

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Follow the money?

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