Posts Tagged SciBlogs

Hypocrisy Ken Perrott Jan 27

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tin foilCredit: The Skeptics’ Guide to the Universe

This cartoon reminded me of some of the local campaigners against fluoridation. They almost all are either strongly connected to the “natural” health movement and its businesses, or, because of their beliefs, are customers of that industry. Yet they often argue that genuine scientific and health experts are in the pay of “big pharma” or similar businesses and are acting as “shills” for industry! That is plain hypocrisy. Similar articles

Sunday reading – Richard Dawkins reads some of his “fan mail” Ken Perrott Jan 25

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This is a more recent version of Richard Dawkins reading some of his “fan mail.”

Don’t remember much of the first batch he read – but get the impression the language skills of fundamentalists has become even poorer in the intervening period.

Warning – explicit language.

via Love Letters to Richard Dawkins – YouTube.

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Is debating with anti-science activists worth the effort? Ken Perrott Jan 22

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I often wonder if the effort put into challenging and debunking misinformation and distortion of science on the internet is worth the effort. After all, it often means debating with dyed-in-the-wool people who have an ideological conviction who are immune to facts. And it is rare for me to actually win over a discussion partner – although, on the positive side – I often feel that I have learned something myself from the exercise.

So this Facebook article from The Credible Hulk pressed a few buttons for me. The bold highlights are mine and serve to identify key questions or concepts.

When undertaking the challenge of refuting various forms of scientifically unsupportable claims, a question that often arises is “are we legitimizing and/or drawing additional attention to people and ideas that might otherwise have had lesser reach and impact?” The idea is that we aren’t going to change the minds of dyed in the wool cranks, and by trying to, we give them free publicity.

This is an important and valid question. I think that there are certain cases in which illuminating and addressing certain quackpot claims can bring such claims and their proponents undeserved recognition and attention from people who otherwise might have never even heard of them. It is possible that it may in some instances be complicit in permitting the development of an unwarranted public perception of legitimacy with respect to the claims.

However, it’s a subtle business we’re in with a lot of catch-22s, because sometimes the opposite can occur.

For instance, by not addressing certain contrarian claims, that can be construed by (how shall I say) “alternative theorists” as a conspiracy of silence on the part of the greater scientific community.

In some such cases, the popularity of a set of unsupported claims can rise to dangerous levels due to being ignored (rather than due to being disputed), in which case we then have no choice but to struggle to put out a fire that was downplayed for too long on the grounds that it might not spread if we downplay it.

Also, much of the fight against pseudoscience involves targeting the reasonable bystanders, many if whom may be amenable to evidence and reasoned discourse, but had simply not previously been exposed to the best information on a subject. Maybe they’d seen headlines and claims that compelled them to think a controversy was afoot when only a manufacturversy existed. They see these interactions and can often tell which side is making the more logical and evidence-based arguments. This furthers people’s science education and increases the number of people who are sufficiently aware to watch out for crackpot claims.

This is desirable, because keeping silent doesn’t improve the average scientific literacy of the population, and thus relegates the knowledge to elite academics alone, in which case people who lack the scientific educational foundation to evaluate the veracity of their claims are forced to choose to either believe or disbelieve their claims on the basis of their personal subjective perception of the ethics and competence of the scientists (instead of following the logic of the science itself and understanding why a particular conclusion is reasonable on the basis of the best available evidence at a given time).

I’m not sure that there exists a perfect solution, but I don’t think that ignoring the anti-science voices is the best option (though we do collectively need to be selective and tactful with which ones we spend time and energy refuting).

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Severe dental fluorosis and cognitive deficits – now peer reviewed Ken Perrott Jan 18

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Last May I raised the possibility that the much touted relationship of small IQ declines for children living in areas with naturally high fluoride in drinking water could be associated with severe dental fluorosis and not a chemical neurotoxicant (see Confirmation blindness on the fluoride-IQ issue). In November I repeated this argument because the recently published work by Choi et al (2015) provided evidence of a statistically significant relationship of cognitive deficits to severe dental fluorosis for Chinese children living in high fluoride areas  (see Severe dental fluorosis the real cause of IQ deficits?).
I am pleased to report the journal Neurotoxicology and Teratology (which published the Choi et al., 2015 paper) have now accepted a peer-reviewed letter to the Editor from me on the subject:

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

Don’t limit possible hypotheses

My letter warns:

“cognitive deficits could have many causes or influences – genetic, environmental and/or social. Researchers need to be careful not to limit their possible hypotheses or research approaches. Unfortunately Choi et al. (2015) appear to be doing just this with their plans for a larger scale study targeted only at “fluoride’s developmental neurotoxicity.””

It points out:

Choi et al. (2012) did highlight the need for further research. Broadbent et al. (2014) showed no effect of fluoride on IQ at the optimum drinking water concentrations used in CWF [community water fluoridation]. However, most of the reports reviewed by Choi et al. (2012) considered data from areas of endemic fluorosis where drinking water fluoride concentrations are higher.”

“Choi et al. (2015) did not find a statistically significant association of drinking water fluoride concentration with any of the neuropsychological measurements. But they did find one for moderate and severe dental fluorosis with the WISC-R digit span subtest.”

This suggests a possible hypothesis involving the effects of negative physical appearance and not a chemical neurotxocant:

“Emotional problems in children have been related to physical anomalies, including obvious oral health problems like severe tooth decay (Hilsheimer and Kurko, 1979). Cognitive deficits can sometimes be related to emotional problems and subsequent learning and behavior problems. Quality of life- particularly oral health related quality of life is negatively related to tooth decay and severe dental fluorosis. It is possible that negative oral health quality of life feelings in children could induce learning and behavior difficulties which are reflected in neuropsychological measurements.”

Difference between areas of endemic fluorosis and CWF

This hypothesis is applicable to children in areas of endemic fluorosis but is not relevant to areas where CWF is used:

“Sixty percent of the children in the Choi et al. (2015) pilot study had dental fluorosis graded as moderate or severe. This likely reflects the endemic fluorosis of the study area. Only a few percent of individuals in areas exposed to the optimum levels of drinking water fluoride used in CWF have dental fluorosis that severe. For example, a recent oral health survey in New Zealand found 2% of individual had moderate dental fluorosis and 0% had severe dental fluorosis (Ministry of Health, 2010). Similarly a US survey found only 2% of individuals exhibited moderate dental fluorosis and less the 1% severe dental fluorosis (Beltrán-Aguilar et al., 2010).”

“Tooth decay and other oral defects negatively impact a child’s quality of life as assessed by children and parents (Barbosa and Gavião, 2008; Nurelhuda et al., 2010; de Castro et al., 2011; Aguilar-Díaz et al., 2011; Biazevic et al., 2008; Abanto et al., 2012Krisdapong et al., 2012; Bönecker et al., 2012; Locker, 2007). Quality of life impacts have also been found for dental fluorosis, but there is a marked difference in physical appearance and quality of life assessments for children with moderate/severe dental fluorosis compared with those having none/questionable or very mild/mild forms.

The physical appearance of moderate and severe forms of dental fluorosis is generally considered undesirable so we could expect these forms to be associated with poor quality of life and this appears to be the case (Chankanka et al., 2010; Do and Spencer, 2007; Chikte et al., 2001). In contrast, most studies report no effect or a positive effect of questionable, very mild and mild forms of dental fluorosis on quality of life (Do and Spencer, 2007; Chankanka et al., 2010; Peres et al., 2009; Biazevic et al., 2008; Büchel et al., 2011; Michel-Crosato et al., 2005).

Given the different patterns of dental fluorosis severity in areas of endemic fluorosis and areas where CWF is practiced and fluoride intakes are likely to be optimal it seems reasonable to expect a difference in ways fluoride intake influences health-related quality of life and possibly cognitive factors.”

My purpose in this letter was to argue that other mechanisms besides chemical neurotoxicity should be considered in these studies. I hope researchers take this on board and look forward to the response of Choi and her co-workers to this suggestion.

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Those evil chemicals Ken Perrott Jan 15

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Looks like community water fluoridation has become an issue in the upcoming by-election for the New Plymouth City Council. All the usual arguments are being promoted but the one I find most grating is the rejection of fluoride because “it is a chemical.”

So I loved this comment:

“I vote that anyone who doesn’t want the chemicals added to their water has all the chemicals removed from their bodies… they can keep what’s left.”


body elements

“Internet and social media misinform thousands daily” Ken Perrott Jan 14

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A recent analysis of the internet and social media illustrates the up-hill battle science and health professionals, and pro-science lay people, often face with misinformation and outright distortion of science. The authors show the problem for the case of community water fluoridation and concluded:

“The Internet and social media are misinforming thousands of people daily about the safety, health, and economic benefits of community water fluoridation. The leading anti-fluoridation website had 5 to 60 times more traffic than the two leading profluoridation health organizations. All Groups and Pages analyzed on Facebook were against fluoridation, while 99 percent of the videos searched on YouTube and the majority (70 percent) of fluoridation tweets on Twitter were anti-CWF fluoridation.”

This study drew important lessons for science and health professions:

Pro-fluoridation organizations need to have a better presence on the Internet and utilize social media to educate the American people about the facts on fluoridation. Individual dental and health practitioners need to educate their patients about fluoridation, so their patients will not be easily misguided by misinformation on the Internet and social media.

And, of course, these lessons are just as applicable to New Zealand.

The study is reported in the paper:

Mertz & Allukian (2014). Community Water Fluoridation on the Internet and Social Media. Journal of the Massachusetts Dental Society, 63(2), 32–36. (You can download a pdf here.)

They monitored website traffic for major fluoridation websites from June 2011 – May 2012 and fluoridation information on Facebook on April 3, 2012. In addition they collected search data for the term “fluoridation” on Twitter for 2 periods (March 1 – 14 and April 1 – 14, 2012) and on YouTube for April 3, 2012.

The data

I illustrate some examples of the data presented in the figures and tables below.

This figure shows that the most important anti-fluoridation website, Paul Connett’s Fluoride Action Network, had far more traffic than the Wikipedia fluoridation section and the institutional web sites (which are pro-fluoridation) on fluoridation.


The situation for Facebook groups and pages was even more dire with 193 search results being “anti” while none were “pro.”


The Twitter search also showed far more anti- than pro-fluoridation tweets, although the data shows  the numbers are influenced by important articles.


Some observations

Of course this is a limited study and much more could be said about this situation, the business interests driving it and possible solutions. I list a few observations below:

1: This study is a snapshot in time. For example, Table 1 would look a little different at this time (January 2015) than it did in April 2012. There are now a number of specifically pro-fluoridation, or at least uncommitted Facebook pages and groups.

My brief search for Facebook “pages” and “groups” using the words fluoride or fluoridation showed about 8 pro-fluoridation, or neutral, pages in the first 50 results for “fluoride” and 2 for “fluoridation.” There were about 4 “pro” Facebook groups in the first 50 for either of these two search terms.

Things are improving. In New Zealand we have seen an increased activity of pro-science groups since the undemocratic decision (now reversed) of the Hamilton City Council to stop fluoridation. This was under pressure from anti-fluoride activists (nationally and internationally) and against the expressed wishes of the citizens. Similar fight-backs are happening overseas – in USA, Canada, Ireland and the UK. The progress is welcome  but more is required. Although I should note there is a tendency for anti-fluoridation activists to set up Facebook pages for many locations where there may have been suggestions of campaigns but the pages become inactive in a short while.

2: Who is financing these anti-fluoridation websites and social media activity? There is a clear connection between the “natural” health industry and anti-fluoridation organisations and activity. Paul Connett’s Fluoride Action Network is organisationally connected with Mercola’s “natural” health business (and anti-vaccination groups) through the “Health Liberty” organisation  and financial flows from Mercolla to FAN are well known. Similarly in  New Zealand the “natural” health industry, through the NZ Health trust, has financed legal action of anti-fluoridation groups (see Who is funding anti-fluoridation High Court action? and Corporate backers of anti-fluoride movement lose in NZ High Court).

3: Is there an underlying purposeful strategy behind then internet and social media anti-fluoridation activity? Definitely. I gave an example illustrating this in Anti-fluoridationist astro-turfing and media manipulation. Activist groups will create press releases pretending to be scientifically authoritative. These are picked up by the “natural” health web sites and magazines (and sometimes, if they are lucky) by the main media. They get coverage on Facebook pages and are tweeted – often automatically by internet bots and the web sites themselves. They can easily create “Twitter storms” this way and widely spread their misinformation.

Here are some typical examples that get repeated ad nauseum:

And, the misinformation cycle gets repeated. Information on Twitter gets reproduced in blog comments and included in web sites and press releases.

4: Institutional web sites are not really suitable for this sort of debate on the internet and in social media. This is partly the problem of a serious, rational or logical web presence challenging an often emotional web presence. A calm explanation of the science challenging claims appealing to preconceived prejudices and emotional needs.

Also, institutions traditionally have felt such debates are somewhat “below” them, preferring not to get into what they see as “street-fighting.” Recently I heard of a case where an anti-pseudoscience group had asked permission to use material from a professional dental site for use in a booklet. They were turned down because the association could not see why this was necessary!

This suggests that pro-science activists should consider taking the initiative, launching their own web sites, etc., and participating in these sorts of struggles, rather than relying on existing institutions. Similarly such activists should see they can play a far more active role on Facebook and Twitter than institutions can, or a willing to.


This study shows that people are in general being misinformed by social media and the internet about community water fluoridation. I suggest this is not accidental – political and business interests are actively encouraging this misinformation. In particular, the “natural” health industry plays a key role in promoting misinformation on fluoridation.

Recently things are improving a little with a fight back from pro-science groups and individuals. I suggest their activity is essential as institutional groups and media outlets are not suited for  internet and social media debates.

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“I just know” Ken Perrott Jan 12

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This is from a satirical site – but the trouble is many people seems to think this way. They are continually commenting on blogs and other social media and think their arguments trump science!

From The Spudd.


“I just know” replaces systematic reviews at top of evidence pyramid

The Society for Healthcare Epidemiology of America (SHEA) announced today that “I just know” will replace systematic reviews as the top level of evidence available in medical research. For years scientists and doctors have dismissed anecdotes from the likes of anti-vaxxers and pseudoscience pushers, but it appears they are finally ready to listen.

“After much research and deliberation, we feel we cannot ignore what a parent or conspiracy theorist feels “in their gut”. There are just too many anecdotes and too many people buying untested alternative health products to ignore this any longer,” explained SHEA spokesman Dr. Harold Rami.

Homeopaths, Naturopaths, Chiropractors and anti-vaxxers the world over are celebrating this as a huge victory.

“Even though my son was showing signs of autism before he got vaccinated, I know in my gut and in my heart that it was still the vaccines that caused it,” said mother and anti-vaccine advocate Cheryl Jones.

“This is a big win for us,” said Naturopath and homeopathy dispenser, Paul Theroult. “I have seen it many times. I sell my patients a homeopathic remedy – for say the common cold – and then bam, they are cured within one to two weeks. There is no science backing up my claim that the homepathic pill cured their cold, but in my gut I just know it did.”


Fluoride Free NZ report disingenuous – conclusion Ken Perrott Jan 06

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This is the third and last article in a series critiquing contributions to the Fluoride Free NZ report Scientific and Critical Analysis of the 2014 New Zealand Fluoridation Report which is aimed at discrediting the recent review Health Effects of Water Fluoridation: a Review of the Scientific Evidence produced by the Royal Society of NZ together with the Office of the Prime Minister’s Chief Science Advisor (hereafter refered to as the Royal Society Review).

My first article, Peer review of an anti-fluoride “peer review” discussed Kathleen Theissen’s contribution. (It also discussed a draft contribution by Chris Neurath which does not appear in the final version). The second article, Cherry-picking and misinformation in Stan Litras’s anti-fluoride articlecritiques Stan Litras’s contribution. This one discusses H. S. Micklem’s contribution.

See The farce of a “sciency” anti-fluoride report for an analysis of the close relationships between the authors and peer reviewers of the Fluoride Free NZ report and anti-fluoride activist groups.

There are a few smaller articles by Paul Connett and Mark Atkins. They do not deal with the contents of the Royal Society Review so I will not comment on them here.

This article below completes my critique of the Fluoride free NZ report.

H. S. Micklen, who wrote the second article in the Fluoride Free NZ report, is one of the coauthors, together with Paul Connett, of the book  The Case against Fluoride which anti-fluoride activists treat as gospel. His article was “peer-reviewed” by James Beck, the other co-author of the book.

In my comments I use the section headings used by H. S. Micklem.

Dental fluorosis

I think Micklen’s comments on dental fluorsis are quite muddled. He confuses the relevance of the different grades of dental fluorosis and unfairly attributes the more severe forms to community water fluoridation (CWF). Consequently he calculates a cost of dental treatment which is wrong.

Recently I put dental fluorosis, its different grades and its contribution to oral health satisfaction into context with the image below (see Water fluoridation and dental fluorosis – debunking some myths):

Dental fluorosis of grades none, questionable, very mild and mild are common in countries suitable for CWF – in both fluoridated and unfluoridated areas. Fluoridation may cause a small increase in mild grades. But these first 4 grades (none – mild) are judged purely “cosmetic. In fact children and parents often judge the grades “questionable – mild” more highly than “none.” Research finds these milder forms of dental fluorosis often improve dental health related quality of life (Do and Spencer, 2007; Chankanka et al., 2010; Peres et al., 2009; Biazevic et al., 2008; Büchel et al., 2011; Michel-Crosato et al., 2005).

Micklem is straw-clutching to take one reference used by the Royal Society Review out of context to imply that these studies are wrong because “subjects liked the appearance of a complete set of artificially white teeth.” He says “they did not like the whiteness associated with fluorosis.”  But the authors actually say:

“The ranking of images of teeth with a fluorosis score of TF 1 may lead to the inference this sample of 11 to 13 year olds do not consider milder presentations of fluorosis to be aesthetically objectionable. The very white teeth represented an unnatural presentation that could only be achieved by cosmetic procedures. . . . This is consistent with previous work related to dental aesthetics [18,19] whereby teeth with mild forms of fluorosis (TF 1, TF2) were rated similarly.”

Micklem raises the bogey of the cost of veneers (up to $1750 per tooth) but this is just scaremongering as veneers would not be used for teeth with these mild grades of fluorosis.

Moderate and severe grades of dental fluorosis are common in areas where fluorosis is endemic, but relatively rare where CWF is used. Occurences in the later case, despite the low concentrations of fluoride in treated drinking water, will have other causes – high natural levels in well water, industrial pollution, excessive consumption of toothpaste, etc.

Treatment of moderate and severe cases of dental fluorosis using veneers may well be appropriate for a very few young people in countries like New Zealand and the US but it is misleading to attribute this to CWF. Interestingly, Micklem’s misattribution mirrors that of Ko and Thiessen (2014). They also assumed all moderate and  severe dental fluorosis was caused by CWF thereby enabling them to declare no cost benefit to CWF because of the required dental treatments.

Micklem has simply continued the anti-fluoride propagandist tradition of confusing data for the relative amounts of different grades of dental fluorosis and attributing problems with the rare moderate and severe forms to the more common questionable and mild forms.

Neurotoxicity and IQ

In this section Micklem attempts to contrast the Choi et al (2012) metareview with the Broadbent et al (2014) study. He erroneously refers to both as being relevant to CWF and “the case that water fluoridation poses a development risk to human intelligence.”

Let’s make this clear. The Choi et al (2012) review did not include studies of CWF. The authors made clear that their results should not be seen as relevant to CWF. Most of the brief reports they reviewed studied areas of endemic fluorosis and Xiang (2014) (one of the authors of an included study) gives some idea of how this is manifested in a title slide to a recent talk.

The only study Micklem comments on that involved CWF was that of Broadbent at al (2014).  Micklem describes this as “inconclusive” but does not say why. Do I detect some bias there?

Given the available studies I think the Royal Society review was justified in concluding “that on the available evidence there is no appreciable effect on cognition arising from CWF.”

Passing on to the question of the Choi et al (2012) metareview, which is not relevant to CWF. Micklen concedes that included studies were individually  “not strong” but argues “the existence of so many studies almost all saying the same (important) thing” should be treated with attention and respect. I agree – but lets not allow that attention and respect to be blind. Let’s be aware of the limitations and attempt to understand what the results might mean.

The authors of that metareview have extended their work to making their own measurements in a pilot study (Choi et al., 2014). In this new paper they did not find a significant relationship between cognitive deficit measurements and drinking water fluoride. We need to accommodate this finding in our assessment of the metareview.

Choi et al (2014) did find a significant association of cognitive deficits with severe dental fluorosis.  Perhaps we need to respect that finding and give it some attention. Rather than the assuming the mechanism of such cognitive deficits is the speculated but unproven neurotoxic activity of fluoride we should be open to other possible mechanisms (Perrott 2015)..

I have done so with my article  and would welcome any feedback Micklem could give on this. I feel that the effects of a physical deformity like severe dental fluorosis on learning is a more realistic mechanism (for which there is a lot of published evidence) than some sort of vague chemical toxicity which has never been noted at these low concentrations.

Incidentally, Micklem attempts to discredit the Royal Society’s understanding of the Choi et al (2012) saying it suggested that the measured IQ reduction was “arguably negligible.” The Royal Society review actually said:

“Setting aside the methodological failings of these studies, Choi et al. determined that the standardised weighted mean difference in IQ scores between “exposed” and reference populations was only -0.45. The authors themselves note that this
difference is so small that it “may be within the measurement error of IQ testing”.[172]”

Choi et al., (2012) said:

“The estimated decrease in average IQ associated with fluoride exposure based on our analysis may seem small and may be within the measurement error of IQ testing.”

And their abstract reported the “standardized weighted mean difference in IQ score between exposed and reference populations was –0.45 (95% confidence interval: –0.56, –0.35).”

There has been some confusion because Choi et al., (2012) used a standardised weighted mean difference to accommodate the different IQ scales used in the studies they reviewed. But their warning about the small size of the calculated difference and its relationship to measurement errors in IQ testing is relevant.

The Royal Society Review did indeed make a mistake in the executive summary where it referred to a claimed IQ shift of “less than one IQ point” when it should have said “less than one standard deviation.” I discussed this in Did the Royal Society get it wrong about fluoridation? and noted that even Harvard University made the same mistake in its inital press release of the Choi et al (2012) work.

I think the Authors of the Royal Society Review should correct that mistake, as Harvard University did – but it does not change the fact there is no mistake in the review’s evaluation of the Choi et al (2012) paper.


In this section Micklem attempts to cast doubt on the Royal Society Review’s comments on the form of fluoride in drinking water and a possible role of fluoride in releasing lead from pipe fittings.

The hydrolysis of fluorosilicic acid when diluted during water treatment may not be completely understood (nothing ever is) but recent high quality research (Urbansky & Schock 2000; Urbansky 2002; Finney et al., 2006) has confirmed the review’s statement it is “effectively 100% dissociated to form fluoride ion under water treatment conditions.” Despite acknowledging the need for more and better research Urbansky (2002) concluded “all the rate data suggest that equilibrium should have been achieved by the time the water reaches the consumer’s tap if not by the time it leaves the waterworks plant.”

This debate only exists among anti-fluoride propagandists because of selective and motivated reliance on old and poor quality research, together with confirmation bias. For example, the report by Crosby (1969) that “evidence from specific-ion electrode and conductivity measurements at 25° confirms that sodium fluorosilicate, at the concentration normally present in public water supplies, is dissociated to at least 95%” is interpreted by Coplan et al., (2007) as “proof” the fluorosilicate is 5% unhydrolysed!

Micklem relies on then papers of Master et al., (2000), Copelan et al 2007 and Mass et al., (2007) to argue that fluoride treatment chemical enhances lead release from pipes. However, I think an objective assessment of these paper would conclude the authors argue determinedly for a preconceived hypothesis and that many of their arguments are irrelevant and faulty. This is not to dismiss their finding on lead levels in drinking water – but as Masters et al., (2000) themselves point out – “statistical association should not be confused with causation.” 

Similarly, I suggest that Micklen’s reliance on Sawan et al., (2010) to support Copelan’s hypothesis amounts to special pleading as those workers used drinking water concentration of 100 mg/L of fluoride and 30 mg/L of lead.


Micklem uses the old anti-fluoride activist trick of fixating on a cherry-picked paper which fits his agenda and downplaying or attempting to discredit papers which don’t. He concentrates on Bassin et al (2006), despite its description by its authors as “an explanatory study” requiring “further research” to “confirm or refute” its conclusions. That paper fits Micklem’s agenda because it found a statistically increased risk of osteosarcomas in male boys exposed to water fluoridated at 1.2 mg/L F.

In such a complex area, for a cancer with such a low incidence, a balanced overall consideration of research reports is necessary. All papers have their advantages and drawbacks so conclusions should be derived from proper consideration of the total research findings – as the Royal Society review appears to have done.

The Bassin (2006) findings have not been confirmed by any later work – despite a range of such studies (Kim et al., 2011; Comber et al., 2011; Levy and Leclerc 2012; Blakey et al., 2014). The Royal Society Review pointed out previous reviews had all concluded that “based on the best available evidence, fluoride could not be classified as carcinogenic in humans.” And that “more recent studies have not changed this conclusion.”

Micklem hasproduced nothing to counter that conclusion.

Cardiovascular and renal effects

Micklen attempts to use the paper, Martín-Pardillos et al., (2014), cited by the Royal Society Review, against the reviews conclusions. The review presents the paper this way:

“A number of studies indicate that fluoride may reduce aortic calcification in experimental animals and humans.[199] This preventive effect was recently confirmed by in vitro experiments, but in vivo findings from the same studies showed the opposite result – that phosphate-induced aortic calcification was accelerated following exposure of uremic rats to fluoride in water at around 1.5 mg/L.[200] The authors suggested that chronic kidney disease could be aggravated by relatively low concentrations of fluoride, which (in turn) accelerates vascular calcification. However, further studies are required to test this hypothesis.”

Martín-Pardillos et al., (2014) proceeded from the hypothesis that fluoride did not initiate calcification but because it is attracted to calcified deposits it may influence subsequent crystallisation of the calcified material.

Their in vitro results indicated a protective effect against calcification. While the opposite was observed with the 5/6 nephrectomised rats with induced calcification they still concluded:

“The direct inhibition of ectopic calcification could still occur in vivo when the renal function is correct, such as during aging or even the initial stages of diabetes, and this possibility deserves further research.”

This is relevant to healthy humans without chronic kidney disease (CKD).

The acceleration of induced vascular calcification with the 5/6 nephrectomised rats does raise the need for further studies, and monitoring the situation with humans suffering CKD. But let’s not forget the rat model was extreme. Rats had all of one kidney and 2/3 of the other kidney removed. They were also fed a phosphate enriched diet and the induced CKD was clearly indicated by urea and creatine blood concentration.

Of course these findings are relevant when considering ongoing research and monitory the situation of CKD human patients. As the authors say “the effects of fluoride on renal function and vascular health are more complicated than expected.”

However, the current advice of the National Kidney Foundation is that:

“Dietary advice for patients with Chronic Kidney Disease (CKD) should primarily focus on established recommendations for sodium, calcium, phosphorus, energy/calorie, protein, fat, and carbohydrate intake. Fluoride intake is a secondary concern.”

Given that such patients are already monitory their diet and more advanced cases also probably regularly monitory blood indicators  any possible effect of fluoride for individuals should be detected. It is likely that by the time any problem with fluoride in drinking water is indicated other problems will also have occurred and patients will be taking steps such as water filtering and careful dietary management to handle their situation.

In fact individually directed management of food and drinking water appears to be a sensible way of handling problems if they do occur with a few people.

Micklem’s “call for CKD sufferers to be warned to avoid tap water” is too extreme and alarmist. Already the advice is that persons with CKD should be notified of the potential risk of fluoride exposure and be kept up to date with new research. Any patients who are particularly worried can then take steps like using filtered water for their own peace of mind. This seems more appropriate than denying the rest of the population access to a simple, effective and safe (for them at least) social policy like CWF.


This completes my critique of the Fluoride Free NZ report.

The original Royal Society review, Health Effects of Water Fluoridation: a Review of the Scientific Evidence, was prepared in response to a request from councils for a summary of the current science on CWF. This is because over the last few years activists political groups, like Fluoride Free NZ (and its international associate Fluoride Action Network) have bombarded New Zealand councils with misinformation and distortion of the science in campaigns to prevent CWF or get it removed

Councils do not have the expertise to critical consider claims made by such activist groups and have adopted a policy of requesting central government take over their responsibilities on the issue. Until that happens, however, councils will continue to have such decisions forced upon them.

The Royal Society review provides a timely and authoritative source of information for councils. Understandably Fluoride Free NZ feels somewhat trumpted by the review. So it is understandable this activist groups, and the international associate will use their media influence to try to discredit it.

This report is an attempt to fool councils by pretending to be objective and international. Yet, as my articles in this series show, it is simply a put-up job. It is not objective – all the authors and “peer reviewers” are working for or associated with the Fluoride Action Network or its associates. The articles follow the typical cherry-picking and confirmation bias of such activist organisations.

See The farce of a “sciency” anti-fluoride report for an analysis of the close relationships between the authors and peer reviewers of the Fluoride Free NZ report and anti-fluoride activist groups.

The Fluoride Free report is simply disingenuous – a sham aimed at fooling councils.


Bassin, E. B., Wypij, D., Davis, R. B., & Mittleman, M. a. (2006). Age-specific fluoride exposure in drinking water and osteosarcoma (United States). Cancer Causes & Control : CCC, 17(4), 421–8.

Biazevic, M. G. H., Rissotto, R. R., Michel-Crosato, E., Mendes, L. A., & Mendes, M. O. A. (2008). Relationship between oral health and its impact on quality of life among adolescents. Brazilian Oral Research, 22(1), 36–42.

Blakey, K., Feltbower, R. G., Parslow, R. C., James, P. W., Gómez Pozo, B., Stiller, C., … McNally, R. J. (2014). Is fluoride a risk factor for bone cancer? Small area analysis of osteosarcoma and Ewing sarcoma diagnosed among 0-49-year-olds in Great Britain, 1980-2005. International Journal of Epidemiology, 43(1), 224–34.

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.

Büchel, K., Gerwig, P., Weber, C., Minnig, P., Wiehl, P., Schild, S., & Meyer, J. (2011). Prevalence of Enamel Fluorosis in 12-year-Olds in two Swiss Cantons. Schwiz Monatsschr Zahnmed, 121(7/8), 652–656.

Chankanka, O., Levy, S. M., Warren, J. J., & Chalmers, J. M. (2010). A literature review of aesthetic perceptions of dental fluorosis and relationships with psychosocial aspects/oral health-related quality of life. Community Dentistry and Oral Epidemiology, 38(2), 97–109. x

Choi, A. L., Sun, G., Zhang, Y., & Grandjean, P. (2012). Developmental fluoride neurotoxicity: A systematic review and meta-analysis. Environmental Health Perspectives, 120(10), 1362–1368.

Choi, A. L., Grandjean, P., Sun, G., & Zhang, Y. (2013). Developmental fluoride neurotoxicity: Choi et al. Respond. Environmental Health Perspectives, 121(3), A70.

Choi, A. L., Zhang, Y., Sun, G., Bellinger, D., Wang, K., Yang, X. J., … Grandjean, P. (2014). Association of lifetime exposure to fluoride and cognitive functions in Chinese children: A pilot study. Neurotoxicology and Teratology, 47, 96–101.

Comber, H., Deady, S., Montgomery, E., & Gavin, A. (2011). Drinking water fluoridation and osteosarcoma incidence on the island of Ireland. Cancer Causes & Control : CCC, 22(6), 919–24.

Coplan, M. J., Patch, S. C., Masters, R. D., & Bachman, M. S. (2007). Confirmation of and explanations for elevated blood lead and other disorders in children exposed to water disinfection and fluoridation chemicals. Neurotoxicology, 28(5), 1032–42.

Crosby, N. T. (1969). Equilibria of fluorosilicate solutions with special reference to the fluoridation of public water supplies. Journal of Applied Chemistry, 19(4), 100–102.

Do, L. G., & Spencer, A. (2007). Oral Health-Related Quality of Life of Children by Dental Caries and Fluorosis Experience. Journal of Public Health Dentistry, 67(3), 132–139.

Eason, C., & Elwood, JM. Seymour, Thomson, WM. Wilson, N. Prendergast, K. (2014). Health effects of water fluoridation : A review of the scientific evidence. Royal Society of New Zealand and Office of the Prime Minister’s Chief Science Advisor, Wellington.(p. 74).

Finney, W. F., Wilson, E., Callender, A., Morris, M. D., & Beck, L. W. (2006). Reexamination of hexafluorosilicate hydrolysis by 19F NMR and pH measurement. Environmental Science & Technology, 40(8), 2572–7.

Kim, F. M., Hayes, C., Williams, P. L., Whitford, G. M., Joshipura, K. J., Hoover, R. N., & Douglass, C. W. (2011). An assessment of bone fluoride and osteosarcoma. Journal of Dental Research, 90(10), 1171–6.

Ko, L., & Thiessen, K. M. (2014). A critique of recent economic evaluations of community water fluoridation. International Journal of Occupational and Environmental Health

Levy, M., & Leclerc, B.-S. (2012). Fluoride in drinking water and osteosarcoma incidence rates in the continental United States among children and adolescents. Cancer Epidemiology, 36(2), e83–e88.

Maas, R. P., Patch, S. C., Christian, A.-M., & Coplan, M. J. (2007). Effects of fluoridation and disinfection agent combinations on lead leaching from leaded-brass parts. Neurotoxicology, 28(5), 1023–31.

Martín-Pardillos, A., Sosa, C., Millán, A., & Sorribas, V. (2014). Effect of water fluoridation on the development of medial vascular calcification in uremic rats. Toxicology, 318C, 40–50.

Masters, RD; Coplan, MJ; Hone, BT; Dykes, J. (2000). Association of silicofluoride treated water witrh elevated blood lead. NeuroToxicology, 21(6), 1091–1100.

Michel-Crosato, E., Biazevic, M. G. H., & Crosato, E. (2005). Relationship between dental fluorosis and quality of life: a population based study. Brazilian Oral Research, 19(2), 150–155.

Peres, K. G., Peres, M. a, Araujo, C. L. P., Menezes, A. M. B., & Hallal, P. C. (2009). Social and dental status along the life course and oral health impacts in adolescents: a population-based birth cohort. Health and Quality of Life Outcomes, 7, 95.

Perrott, K. W. (2015). Severe dental fluorosis and cognitive deficits. Neurotoxicology and Teratology. In press.

Sawan, R. M. M., Leite, G. A. S., Saraiva, M. C. P., Barbosa, F., Tanus-Santos, J. E., & Gerlach, R. F. (2010). Fluoride increases lead concentrations in whole blood and in calcified tissues from lead-exposed rats. Toxicology, 271(1-2), 21–6.

Urbansky, E. T. (2002). Fate of fluorosilicate drinking water additives. Chem. Rev., 102, 2837–2854.

Urbansky, E. T., & Schock, M. R. (2000). Can Fluoridation Affect Water Lead Levels and Lead Neurotoxicity ? In American Water Works Association Annual Conference (pp. 1–31).

Xiang, Q. (2014) Keynote Address on IQ studies published in China. Fluoride Action network.

Spotting Bad Science Ken Perrott Jan 04

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Compound Interest has produced another great infographic in their series. This one helps us to spot bad science.

 Click to enlarge.  You can download the current version as a PDF here.

It is worth thinking about each of the suggested 12 criteria.

I particularly liked that it advises one to carefully evaluate scientific papers even when they are published in a reputable journal. A good journal and peer review is not a guarantee that the paper is faultless or that its findings can be accepted without proper consideration.

December ’14 – NZ blogs sitemeter ranking Ken Perrott Jan 01

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2015 Happy New Year Strands Line Glow Dark Background


PLEASE NOTE: Sitemeter is still playing up but far fewer blogs are effected. It was still impossible to get the stats for a the blogs that I list below. Maybe more bloggers will shift to StatCounter or other counter.

No stats could be found for these blogs:

Science Behind the Curtain Grumpollie

There are now over 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 December 2014. 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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Rank Blog Visits/month Page Views/month
1 Whale oil beef hooked 1764050 2999841
2 Kiwiblog 278787 515827
3 The Standard 182211 392090
4 Transport Blog 132767 136571
5 The Daily Blog 126534 203164
6 Liturgy 83527 114819
7 NewZeal 30718 38530
8 The Dim-Post 29689 36470
9 Offsetting Behaviour 20125 22499
10 No Right Turn 19569 25861
11 Throng New Zealand 18867 33306
12 No Minister 16683 21716
13 Fields of Blood 14535 18128
14 Music of sound 14512 18361
15 Homepaddock 12891 17907
16 13th Floor 11688 16643
17 The REAL Steve Gray 11600 14952
18 Liberation 11550 15237
19 Keith Johnson Wellington NZ 11216 11487
20 MandM 10990 11809
21 Hot Topic 10669 15465
22 TVHE 10252 11210
23 Imperator Fish 9547 12904
24 Right Reason 8814 12221
25 Open Parachute 8479 11311
26 Tikorangi: The Jury Garden 7481 9800
27 Aotearoa: A wider perspective 7140 9127
28 On the Left 7058 10652
29 Dark Brightness 6135 6184
30 Talking Auckland 6023 7908
31 Bill Bennett 5908 9223
32 Lindsay Mitchell 5402 7278
33 Matte Shot 5056 8686
34 Cycling in Christchurch 4771 6649
35 In the back of the net 4716 8097
36 Anglican down under 4501 5712
37 New Zealand Conservative 4300 4465
38 Lance Wiggs 4215 4904
39 Autism & Oughtisms 4186 4233
40 Vomkrieg 4124 6131
41 Reading the maps 4047 5520
42 Mousehouse 4032 6762
43 Quote Unquote 3817 4256
44 Chris no-frills 3753 4870
45 Save our Schools NZ 3473 4353
46 AmeriNZ 3290 3899
47 Ultimate Student 2975 3689
48 Kiwi Cakes 2865 3721
49 Scepticon 2658 2974
50 OracleNZ by Francisco Munoz Alvarez 2642 2900
51 Sciblogs 2486 3387
52 Windy Hilltops 2278 3421
53 Super Rugby Tips 2107 2527
54 Rodney’s Aviation Ramblings 2002 2602
55 Home education Foundation 1918 2688
56 1888 2260
57 The Woolshed Wargamer 1830 3510
58 Open Parachute @ SciBlogs 1825 1987
59 Pdubyah – a life just as ordinary 1798 2121
60 Waiology 1768 2147
61 Scotty Donaldson 1697 2548
62 Undeniably Atheist 1638 1845
63 Woodleigh Nursery 1633 3809
64 ROI Marketing 1508 2019
65 Canterbury Atheists 1464 1679
66 Keeping Stock 1461 1770
67 Put ‘em all on an island 1421 1731
68 Otagosh 1398 2241
69 Notes from the bartender 1324 1525
70 Crime Watch 1309 1996
71 Michael Jeans 1236 1554
72 Eye on the ICR 1127 1453
73 Sustain:if:able Kiwi 1124 1683
74 Blessed Economist 1086 1475
75 james lin’s blog 1076 1114
76 Man of Errors 1072 1234
77 PM of NZ 1059 1238
78 A communist at large 986 1322
79 Off the couch 961 1548
80 Episto 957 1300
81 Einstein Music Journal# 951 1116
82 Life Behind the IRon Drape 900 1946
83 One Furious Llama 847 964
84 ICT Teaching and Learning  845 1039
85 misc.ience @ Sciblogs 841 946
86 Socialist Aotearoa 834 923
87 The Beehive Mandate 821 1141
88 Quietly in the backgroud 802 1084
89 Life of Andrew 794 923
90 Social Media & the 2014 Election 789 1023
91 Stratford Aerodrome 783 1056
92 Brennan McDonald 696 750
93 Ideologically impure 667 729
94 My thinks 666 764
95 A Bee of a Certain Age 660 764
96 Derek’s blog 643 918
97 Brad Heap 634 850
98 Tauranga Blog 617 664
99 goNZo Freakpower Brains Trust 610 650
100 Tales from a Caffeinated Weka 599 937
101 Show your workings 575 793
102 Media Sport and Other Rantings 543 625
103 From the Earth’s End 532 708
104 Skeptiocon @ Sciblogs 530 588
105 Exile in New zealand 528 640
106 Anne Free Spirit 510 1950
107 Code for Life 497 562
108 True Paradigm 484 607
109 sticK 479 578
110 Life is not a race to be finished first 476 690
111 Room One @ Auroa School 450 1020
112 roarprawn 449 589
113 The IT Countrey Justice 437 552
113 Polit Ecol 437 507
115 Goings on at the Madbush Farm 427 530
116 Tararua District Library 418 540
117 Dad4justice 413 439
118 kiwiincanberra 408 463
118 Wokarella 408 463
120 Hitting Metal With A Hammer 407 530
121 The Little Waaagh! That Could 391 472
122 Four seasons in one 389 422
123 Unity Blog 368 374
124 Family integrity 366 391
125 Software development and stuff 359 373
126 Artichoke 358 402
127 Get Out Gertrude! 345 457
128 Glenview 9 344 382
129 Kutarere’s Blog  325 356
130 Kidney Punch  314 347
131 Taradale Blog# 300 540
132 Helen Heath 292 299
133 Perissodactyla 291 330
134 Halfdone 290 358
135 Jo Blogs 289 442
136 288 300
136 SmallTorque 288 325
138 Riddled 277 467
139 Capitalism is bad 271 332
140 Glennis’s Blog Page# 270 360
141 Samuel Dennis 263 275
142 Spatula Forum 262 303
142 White & Black 262 314
142 Teaching the Teacher 262 314
145 Room 5 @ Melville Intermediate School 240 300
146 Cut your hair 235 238
147 eyeCONTACT 231 351
148 ElephaNZa  228 233
149 Creative Voice# 210 240
149 Nelsonian’s life 210 300
151 MartinIsti Blog 203 297
152 The Gentically Insane 192 245
152 The Genetically Insane 192 245
154 kiwi simplexity 185 203
155 Sharlene says 184 207
156 Upstage 183 246
157 Prior Knowledge  173 189
158 Cimba7200’s thoughts 172 209
159 Aphrodite rises 170 198
160 Pointless and adsurb 169 202
161 The Fundy Post 166 237
162 Science in a van 163 193
163 Toni Twiss 158 158
164 Canvassing for opinion 156 187
165 Lost Soul 155 163
166 Mountains of Our Minds# 150 180
167 Dragonsinger 148 161
168 John Macilree’s Blog 143 157
169 High voltage learning during the Christchurch earthquakes 142 251
170 Write to travel 138 168
170 ZNO 138 177
172 Ruggerblogger 137 213
172 0 137 213
172 New Zealand Indian Fine Arts Society 137 144
175 Rest Area 300m 132 154
176 You’re Underthinking 129 135
177 Ellie Great 126 139
178 The Well read Kitty 124 129
179 AnneKcam
120 210
180 $100 Dialysis 115 137
180 Millenium X 115 159
182 At home with Rose 110 133
183 Politicalisation 93 96
184 Pt England Scribes 90 90
184 The Official Ebenezer Teichelmann Blog# 90 90
184 John Macilree’s Weblog# 90 120
187 jo russ photo diary 89 212
188 Looking in the square 83 88
189 Carolyn’s blog 76 89
190 Journey to a mini me 75 93
191 New Zealand female Firefighter calendar 70 73
191 Shelly van Soest Artist 70 71
193 Webweaver’s world 65 283
194 SageNZ 64 73
195 Digital learning 60 60
195 James McKerrow – Surveyor 1834-1919# 60 90
195 Sam Books and Thoughts 60 85
195 Korero Pt England 60 60
195 Sleeping with books 60 60
195 Virtual North 60 60
195 Moving the crowd 60 120
202 Creative Collision 55 56
203 Springston School Library Blog 54 78
203 Whitireia Journalism School 54 66
205 NZ First Youth 50 70
205 Stats Chat 50 70
205 University of Otago, Law Library Blog 50 98
208 Moderation Blog 45 49
209 KJT 40 45
210 Frontlawn 39 48
211 Nathanael Baker 38 44
211 Something Interesting to read 38 59
213 Oracle of Okarito 37 45
214 Discovery Time 35 61
215 Busy Peas 32 38
216 Room 24, 2012 30 30
216 Nine Inch Nails 30 30
216 Chris Jillet – Mountaineer# 30 30
216 ICTPD 30 30
216 Kiwi Chronicles 30 30
216 Football Tragic NZ 30 30
222 UpsideBackwards 29 126
223 ah! New Year’s Resolution 27 27
224 The First Fifteen @ TIS 26 48
224 round design 26 27
226 Works in progress 25 27
226 No Mum is an Island 25 34
226 Social Policy Bonds Blog 25 26
229 Stitchbird 22 28
230 LoveColour Blog 19 33
231 TimG_Oz Blog 18 21
231 Kiwiaventuras 18 19
233 The Secret Life of Russ  17 21
234 Mad Young Thing 16 16
235 Blair for Mayor 13 15
235 global village governance 13 20
235 Robtuckerpix’s Blog  13 13
238 SilverSpikes Photography  12 17
239 Relatively science 11 12
239 A developing Geneticist 11 14
239 In this moment 11 16
242 Augmented Ether 10 11
243 Palmerston North.ifo 9 10
243 Porirua EMO 9 9
243 ZL2UCX’s Blog 9 9
246 DMP Lead Free 8 9
246 A conservative perspective 8 11
248 Two Minutes Sport 7 8
248 Think Beyond 7 7
248 Tangled up in purple 7 8
248 The Meaning of Trees 7 7
252 Scott & Sarah Kennedy 6 6
252 Wysiwygpurple’s Blog 6 7
252 Uncensored 6 6
252 Liminal Spaces 6 6
256 ObservatioNZ 5 5
256 Rambling Reflections 5 5
258 pasture Harmonies 4 4
259 Xenolexicon 3 5
259 TraLIS blog 3 4
259 Fuller’s watch# 3 3
262 This Mum Rocks 2 2
262 amiria [blog] 2 2
262 Bob McKerrow – Wayfarer 2 2
262 Roger Nome’s progressive Politics 2 2
262 Born on State Highway 1 2 2
262 Yea or Nay 2 2
268 Moments of Whimsy 1 1
268 Dark Brightness 1 1
270 Louis’ Outlook 0 1
270 Warrington Taylor# 0 30

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