Category Archives: New Zealand

Severe dental fluorosis the real cause of IQ deficits?

A new study finds cognitive function defects, like IQ, in children are not significantly related to fluoride in drinking water. But they are associated with medium and severe dental fluorosis.

This interests me for two reasons:

  1. The report is by Choi and Grandjean who had also authored the 2012 meta-review often used by anti-fluoride activists to claim that community water fluoridation causes a lowering of IQ (the authors subsequently pointed out the high fluoride concentrations in the papers they reviewed meant that conclusion is not valid)
  2. The data reported is consistent with my suggestion in Confirmation blindness on the fluoride-IQ issue that reported relationships between IQ and drinking water fluoride concentration could really indicate a relationship with severe dental fluorosis, and not drinking water fluoride itself.

The new report is:

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.

Firstly – this is only a pilot study and has several acknowledged weaknesses – the small number of children studied (51) being the most obvious. However, this is what was found:

“Sixty percent of the subjects examined had moderate or severe fluorosis. These children were exposed to elevated fluoride concentrations in drinking water. Children with normal or questionable Dean Index were all from households with a water fluoride concentration of 1 mg/L and had urinary fluoride excretion levels below 1 mg/L.”

The children were placed in 3 groups according to their degree of dental fluorosis:

  1. Normal/questionable (N=8)
  2. Very mild/mild (N=9)
  3. Moderate/severe (N=26)

The high proportion of children with moderate/sever dental fluorosis indicates the study involved an area of endemic fluorosis.

And the results of neuropsychological tests:

“Results of multiple regression models show that moderate and severe fluorosis was significantly associated with lower total and backward digit span scores when compared to the reference combined categories of normal and questionable fluorosis (Table 4). Although the associations between fluoride in urine and in drinking water with digit span were not significant, they were in the anticipated direction. Motor coordination and dexterity were not significantly associated with fluoride in drinking water and fluorosis although higher levels were associated with poorer scores as well. Other outcomes did not reveal any association with the fluoride exposure.”

The authors used a number of neuropsychological tests. The digit span test results suggest a “deficit in working memory” for the children with moderate and severe dental fluorosis. None of the other tests used show any signficant relationship with indices for fluoride exposure.

So, this pilot study did not show any association of neuropsychological tests with fluoride concentration in drinking water but it did find an association with medium and severe dental fluorosis. This is consistent with my speculation in Confirmation blindness on the fluoride-IQ issue that “a physical defect like dental and skeletal fluorosis could lead to decreasing IQ.”

I argued that:

“minor physical anomalies are known to be associated with learning difficulties and emotional illness in children (seeHilsheimer & Kurko 1979). It seems entirely reasonable that a physical anomaly like severe dental fluorosis could lead to learning difficulties in children which could be seen as lower IQ values.”

There are many problems with the studies anti-fluoride activists promote relating IQ to fluoride in drinking water. But it could be that any real effect seen with the higher fluoride concentrations could simply be explained by effects of the physical anomaly of medium and severe dental fluorosis common at these higher concentrations.

Unfortunately the authors of this study still do not consider this possibility. I guess it could be that someone with a hammer only sees nails, and chemical toxicologists are only capable of considering brain damage caused by toxic chemicals. The effects of physical anomalies on learning difficulties are probably quite outside their training and experience.

Their confirmation bias and mental blockage on this meant they were considering dental fluorosis as just another indicator of dietary fluoride intake. However, even that assumption has its problems because genetic differences are also known to be involved in dental fluorosis.

I think this must be why they ended with a conclusion that could well be quite unfounded:

“This pilot study in a community with stable lifetime fluoride exposures supports the notion that fluoride in drinking water may produce developmental neurotoxicity”

Dental fluorosis and community water fluoridation

Fluorosis is endemic in many parts of China and the high prevalence of medium/severe dental fluorosis (60%) among the children in the Choi et al (2014) pilot study shows their situation is not at all similar to that in areas of New Zealand and USA using community water fluoridation (CWF).

The figures below give some context.

Here are examples of the different degrees of dental fluorosis.

The graph below shows the situation reported for New Zealand in the 2009 New Zealand Oral health Survey (see Our Oral Health). No severe and only 2% moderate dental fluorosis reported.

This figure (taken from Fluorosis Facts: A Guide for Health Professionals) shows the amount  of moderate and severe dental fluorosis in the US is also very small.

Perhaps we can now contrast the situation here, in areas where CWF is common, with the situation in China in areas with endemic fluorosis where these studies were undertaken. The figure below is a slide from a presentation by Xiang (2014) to Paul Connett’s recent anti-fluoride “get-together” (Xiang 2014). This is not the very mild dental fluorosis attributed to CWF.

(Anti-fluoride people also often single out the study of Xiang, et al (2003). Effect of fluoride in drinking water on children’s intelligence. Fluoride, 36(2), 84–94, because unlike the others it is more detailed.  Xiang’s team has studied areas where fluorosis is endemic.)

Conclusion

Anti-fluoride activists often promote the meta-review of Choi et al (2012) in their arguments against CWF. However, there are many problems with these studies including the fact reported IQ effects were associated with much higher drinking water fluoride concentrations than occurs with CWF.

The new study of Choi et al (2014) did not confirm any association of neuropsychiatric measurements with drinking water fluoride concentration. However, it did show association of negative neuropsychological effects with medium/severe dental fluorosis.

This is consistent with the physical anomaly of severe dental fluorosis being the real cause of IQ effects and not any direct chemical toxic effect.

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Standing up to junk science in New Zealand

Last week we saw several local victories for science over pseudoscience. And the US mid-term elections also gave electoral victories supporting community water fluoridation in 5 out of 6 communities where it was voted on.*

Peter Griffin from New Zealand’s Science Media Centre reported on the New Zealand victories in his post Experts shine in fight against junk science.

“It was a week when climate change denial, a “miracle” ebola cure and homeopathy grabbed headlines.

But by and large it was also a week where the media laid out the evidence and featured expert commentary putting the science behind the claims in perspective.”

So, the media seemed to be “on-side” this time and scientific experts were fronting up to counter the pseudoscience.

“The pending arrival in New Zealand of Genesis II Church of Health and Healing leader James Humble to push his Miracle Mineral Solution (MMS) was front page news. Medsafe warned that the treatment acts like an industrial bleach and could cause serious harm to those who took it. Australia’s Nine News reported that four Victorians had been hospitalised after taking the MMS treatment.

Shaun Holt

Dr Shaun Holt

Natural remedies expert Dr Shaun Holt and University of Auckland microbiologist Dr. Siouxsie Wiles made numerous media appearances to explain the pseudoscience Humble has been spreading about MMS, including that it can cure Ebola, HIV and malaria.The Herald reported today that an Auckland man who attempted to attend one of the “non-religious” Church’s seminars in the Hauraki Plains, was removed when it emerged he had not paid the US$500 registration fee, a hint perhaps at the real reason behind Humble’s Australasian tour.”

ebola

NZ Herald’s front page piece on MMS

The latest report from the Intergovernmental Panel on Climate Change renewed the media interest in climate change.

“False balance in climate coverage

Professor Tim Naish and Dr James Renwick, who have both contributed to IPCC reports put the latest update in context for New Zealand on One News and 3 News.

However TVNZ undermined its own climate change coverage by featuring noted climate sceptic and energy sector consultant Bryan Leyland on the Breakfast show, including presenting a graph featuring data supplied by Leyland himself.

By the end of the day the item had been pulled from TVNZ’s website after the broadcaster received numerous complaints from the public, scientists, as well as journalists.”

Then there was the response to the Green Party’s natural products spokesman Steffan Browning’s folly in signing a petition calling for homeopathic treatments to be used in the fight against Ebola. This lead to his demotion within the party and removal of his spokesman role.

“The embarrassing endorsement attracted attention in the UK and the condemnation of Browning’s own caucus.

Writing on Sciblogs, Dr Grant Jacobs applauded Browning’s demotion, but pointed out that he retained other science-related shadow portfolios.

“I’m aware of a number of people who have said they didn’t vote for the Greens because of Steffan Browning’s stance on genetic engineering and others who have said that while they voted for the Greens they don’t approve of Browning’s approach to GMOs and GE.”

Peter Griffin finishes by thanking “all the scientists who stepped up to make sense of the dubious claims journalists and the public were faced with this week.”

I think this also shows what can be achieved when good science journalism is actively promoted by groups like the Science Media Centre, and when scientists and other experts  participate in the social communication media and make themselves available to journalists.


*Support for community water fluoridation in these 5 communities was pretty overwhelming:

Boyne City, Michigan – 68% support for fluoridation: http://goo.gl/BUQVev
Bronson, Michigan – 63% support for fluoridation: http://goo.gl/KogVkP
Kalama, Washington – 73% support for fluoridation: http://goo.gl/wP6xAY
Saline County, Kansas – 67% support for fluoridation: http://goo.gl/Q2IGWL
Healdsburg, California – 68% support for fluoridation: http://goo.gl/KsOCgn

These victories were probably because fluoridation supporters, families and dentists organised public campaigns. See Group wants fluoride vote to keep its teeth.

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October ’14 – NZ blogs sitemeter ranking

grumpy-cat-blog

Image Credit: A Pretty Healthy Life


PLEASE NOTE: Sitemeter is still playing up but far fewer blogs are effected. I have done a manual work around but 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:

Works in progress
Social Media and the 2014 General Election
Sportsfreak
Science Behind the Curtain
Looking in the square
Save our schools NZ

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

Fluoridation – a racist conspiracy?

Political activists campaigning on health issues often resort to scaremongering. This can be dangerous – especially when their stories have no real basis but rely on selective and distorted information.

Paul Connett’s Fluoride Action Network (FAN) often resorts to this sort of scaremongering. Now they are launching a series of stories dressed up as “exposès.”  The first is aimed at African-Americans and claims the US  “federal government has known for five decades that blacks were even more susceptible than whites to serious damage from fluoride added to water supplies, but it urged local governments to fluoridate the population anyway.”

Typically, Connett’s Crowd is promoting this campaign through FAN press releases which get picked up by “natural” health magazines and web pages. The articles are then heavily promoted throughout social media by activists – sometimes even making their way into the mass media (see Gov’t Failed to Warn about Fluoride’s Disproportionate Harm to Black Community and Feds: Blacks Suffer Most From Fluoride, Fluoridate Anyway).

The press release is summed up in the first paragraph:

“Government health authorities knew over 50 years ago that black Americans suffered greater harm from fluoridation, yet failed to warn the black community about their disproportionate risk, according to documents obtained by the Fluoride Action Network (FAN).”

So the evidence, the “document,” on which they hang this story, is a memo.

memo

Now, that is very pathetic to hang a campaign on, isn’t it. And the campaigners are also relying on the false idea that anything obtained via freedom of information inquiry must have been “secret” or “hidden” from the public eyes. (Incidentally they do the same with the Certificates of Analysis for fluoridation chemicals used by water treatment plants – even appearing to think that listing an analytical result for contaminants, however small, is somehow “proof” that the contamination is a problem – see Fluoridation: emotionally misrepresenting contamination and Natural News comes out with a load of heavy metal rubbish on fluoride).

Differences in dental fluorosis prevalence not hidden

But the scientific information comparing prevalence of dental fluorosis among US whites and African-Americans is neither new or hidden. In fact, FAN’s press release does refer to a little of this published data, but again typically they distort it.

In particular it uses data from studies where fluoride in drinking water were often higher than the optimum levels for community water fluoridation (CWF). Consequently the studies include some people exhibiting the medium and severe forms of dental fluorosis never observed with CWF.

One of the papers cited is Martinez-Mier, E. A., & Soto-Rojas, A. E. (2010). Differences in exposure and biological markers of fluoride among White and African American children. Journal of Public Health Dentistry, 70(3), 234–40. It did report higher amounts of dental fluorosis in the African-American children they studied. But it also found that the African-American children in the study reported using larger amounts of toothpaste and had higher urine fluoride concentrations than white children. It concluded:

“Differences in fluoride exposure between two racial groups were observed. These differences are complex and need to be better defined.”

This does not warrant claims of  African-Americans being more susceptible than whites. Nor is the information “explosive” as the FAN press release claims.

Another study cited was Williams, J. E., & Zwemer, J. D. (1990). Community Water Fluoride Levels, Preschool Dietary Patterns, and the Occurrence of Fluoride Enamel Opacities. Journal of Public Health Dentistry, 50(4), 276–281. But the study actually doesn’t back up the FAN claims as these authors found:

“higher TSIF scores [an index of dental fluorosis prevalence] were associated with city children significantly more than with county children. There was no association of TSIF scores either in the city children or the county children with respect to gender, race, preschool dietary patterns, or dentifrice ingestion.”

Another cited paper is Butler, W. J., Segreto, V., & Collins, E. (1985). Prevalence of dental mottling in school-aged lifetime residents of 16 Texas communities.  American Journal of Public Health, 75(12), 1408–1412. These authors found “children who were White or had a Spanish surname had about the same prevalence of mottling while Blacks had a higher prevalence.” This appears to support the FAN claim but air conditioning in the children’s home and total dissolved solids and zinc in the drinking water also influenced prevalence of mottling. Significant mottling only occurred where  drinking water fluoride concentrations were over 2 ppm making the conclusions irrelevant to CWF where concentrations are usually in the range 0.7 to 1 ppm

Finally, they cite Beltrán-Aguilar, E. D. ., & Gooch, B. F. ; (n.d.). Surveillance for Dental Caries, Dental Sealants, Tooth Retention, Edentulism, and Enamel Fluorosis — United States, 1988–1994 and 1999–2002. Yes, this study did show African American had a slightly higher prevalence of very mild and mild dental fluorosis, as the figure below shows.

s403a1f19

They did not advance an explanation for this but note that “different hypotheses have been proposed, including biologic susceptibility or greater fluoride intake.” One could also suggest differences in residential location – especially as some of the people in the study had moderate or severe dental fluorosis indicating they were likely consuming drinking water with a fluoride content above the level recommended for CWF.

But we could make the same comparisons with tooth decay data from this study (see figure below):

s403a1f1

Perhaps we should be jumping up and down about the increased racial sensitivity of African-Americans and Mexican Americans to the disease of tooth decay and claim that this information has been suppressed or nothing done about the problem.

Or perhaps, as is most likely happening, authorities are just getting on with the job of working out how to deal with health inequalities in different ethnic groups.

 Conclusion

This campaign is just another of the scaremongering attempts of Connett’s crowd. Appealing to conspiracy theorists it uses a memo obtained as part of a freedom of information inquiry to imply a cover-up. The campaing cites studies which do show real differences but do not show they result from differences in sensitivity. And they are not large enough to justify the extreme language of the press release and reports.

Of course there may be similarities in the dental health conditions of disadvantaged ethnic groups in the US, and in New Zealand and Australia, but the way some anti-fluoride propagandists have used these press releases to “prove” that NZ Maori and Australian Aborigine are adversely effected by CWF borders on naive racism.

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September ’14 – NZ blogs sitemeter ranking

education-bloggers


PLEASE NOTE: Sitemeter is playing up again making it impossible to automatically get the stats for some blogs – those I list below. Maybe more bloggers will shift to StatCounter or other counter.

No stats could be found for these blogs:

Works in progress Sportsfreak
Weakly Whirled News Infectious thoughts
Two Minutes Sport Science Behind the Curtain
Wysiwygpurple’s Blog Grumpollie
Stats Chat Louis’ Outlook
Webweaver’s world West City Darts
Social Media and the 2014 General Election A conservative perspective
Love your work Save our schools NZ
Today is my birthday The Meaning of Trees
This Mum Rocks

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 September 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

Subscribe to NZ Blog Rankings

Subscribe to NZ blog rankings by Email

Find out how to get Subscription & email updates

Continue reading

Peer review of an anti-fluoride “peer review”

In  Anti-fluoride activists define kangaroo court as “independent” I promised to review the anti-fluoridationist International Peer Review.” This is Anti-fluoride  critique of 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).

So here is my peer review, of a review, of a review.

General comments

Anti-fluoride activists have  busily mentioned all the apparent contributors to this critique but I will only deal with Kathleen Theissen’s and Chris Neurath’s comments as only these have any substance.  James Beck declined comment saying only “On the current New Zealand case I don’t think I can do any better than Chris has done.” Similarly Speeding Micklem says only that “Chris’s analysis is excellent.”

Hardy Limeback does not engage at all with the science in the Royal Society Review, but does express his emotional attitude towards it. He says:

“I can’t be bothered to show step by step where this review does not meet the standards of critical scientific analysis. . . . Chris is right on the ball in critiquing this review. I’m not sure many people will appreciate just how detailed he is.
I’m disgusted by how sloppy the NZ reviewers were. They were obviously politically motivated.”

However, Limeback’s comment on the use they will make of their critique is interesting:

“The effort to critiquing every paragraph of the NZ review is taxing but once it is done and posted on the website, it would be most useful for those people who want to take on the promoters of fluoridation who will undoubtedly use this review to support the profluoridation agenda and point to how unscientific, one-sided, politically motivated this review really is.
I would be happy to lend my name to the list of scientific reviewers of this critique.”

So, you can get an idea of what their purpose is in their “peer review.”

Now, the specific issues raised in Theissen and Neurath’s comments.

Margin of safety

The Royal Society Review found some population groups may exceed the prescribed “safe” levels of F intake. So Theissen concludes that “the fluoride concentration in drinking water is too high and should be lowered.” However, she ignores completely the review’s comments on this issue.

“Infants 0-6 months of age who are exclusively fed formula reconstituted with fluoridated water will have intakes at or exceeding the upper end of the recommended range (UL; 0.7 mg/day). The higher intakes may help strengthen the developing teeth against future decay, but are also associated with a slightly increased risk of very mild or mild dental fluorosis. This risk is considered to be very low, and recommendations from several authoritative groups support the safety of reconstituting infant formula with fluoridated water.”

The review also noted that children from 1 – 4 yrs old do not exceed recommended levels on F intake but intake from ingested toothpaste my increase intake above recommended levels. It goes on to conclude:

“Consumption of fluoridated water is highly recommended for young children, as is the use of fluoride toothpaste (regular strength – at least 1000ppm), but only a smear of toothpaste should be used, and children should be supervised during toothbrushing to ensure that toothpaste is not swallowed/eaten.”

I also discussed the issue of risk for formula-fed infants in my article When politicians and bureaucrats decide the science  and in my exchange with Paul Connett. Here I note how “peace of mind” advice to those parents who may be concerned about increased risk of dental fluorosis gets presented by anti-fluoride people as safety warnings.

Adequacy of standards for fluoride intake

Theissen discusses the adequacy of a stands for F intake at length but her only beef with the Royal Society Review on this appears to be that it doesn’t challenge existing standards. She herself considers that these standards should be revised to “obtained values much lower than those currently considers desirable by the New Zealand government.” But here she is promoting a personal agenda and not objectively critiquing the Royal Society Review.

Effects of community water fluoridation (CWF) in NZ

Theissen considers that the NZ review offered “little documentation for the beneficial effects of fluoride.” Strange – has she read the review? Table A2 lists 21 major reviews it considered and 7 New Zealand sources were included – the 2009 NZ Oral Health Survey and regional studies in Otago, Southland, Canterbury, Wellington, Auckland and Northland.

If that was insufficient for Theissen then why is her only counter to mention John Coulquhoun’s reminiscences in his article of 1997? It is not enough for Theissen to use his assertions “that there are virtually no differences in tooth decay rates related to fluoridation” and “25 percent of children had dental fluorosis.” But has she bothered to check out his data at all critically? Why no more citations supporting her  claim?

Coulquoun was a committed anti-fluoridationist  and a critical check of his claims show them to be unreliable. Here is a sentence from the abstract of his paper Colquhon 1985:

“In the unfluoridated areas all the children, and in the fluoridated areas only selected children, had received regular topical fluoride treatments.” And he concluded “When the socioeconomic variable is allowed for, child dental health appears to be better in the unfluoridated areas.”

Apart from the wishful thinking displayed in his interpretation of a statistically non-significant difference he has glossed over the fact that both fluoridated and unfluoridated groups were receiving fluoride treatments of one sort or another!

Similarly, Theissen puts more trust in Colquhoun’s brief comment on dental fluorsis than the several  pages on this subject in the review. Anti-fluoride propagandists are continually misrepresenting dental fluorosis data to imply any extremely mild forms attributable to fluoridation should be treated like the severe forms which are not caused by fluoridation. The Royal Society review’s comment on the aesthetic effects help bring some context back on this issue:

“It is important to note that the seemingly high prevalence of fluorosis reported in some studies and systematic reviews includes mainly mild and very mild (and sometimes questionable) degrees of fluorosis, with only a small proportion that would be considered to be of aesthetic concern.

Surveys have shown that very mild to mild dental fluorosis is not associated with negative impact on perception of oral health,[142] and that adolescents actually preferred the whiteness associated with mild fluorosis.[143] In a recent study, adolescents answered a questionnaire regarding the impact of enamel fluorosis on dental aesthetics, older adolescents rated photographs of mild fluorosis more favorably than younger ones. A fluorosis score indicative of moderate fluorosis was the level considered to have aesthetic significance. Carious teeth were rated significantly lower than fluorosed teeth.[144]

Carcinogenicity and genotoxicity

Theissen, like almost all anti-fluoride propagandists, relies completely on the  the Bassin et al (2006) study for evidence here and ignores later studies which did not confirm Bassin’s work. In my exchange with Connett I criticised him for the same tactic (see Fluoride debate: Final article – Ken Perrott):

“the importance Paul gives to a single study on fluoride and osteosarcoma illustrates his mechanical and selective approach to “weight of evidence.” He has not bothered including either the study by Comber et al (2011) of this issue in Ireland or the study by Levy & Leclerc (2012) for the US. Possibly because both of these concluded that water fluoridation has no influence on osteosarcoma incidence rates.”

So while Theissen is upset the Review “dismisses” Bassin’s work, this is not the “out of hand” rejection she implies. The Review says:

“The few studies that have suggested a cancer link with CWF suffer from poor methodology and/or errors in analysis. Multiple thorough systematic reviews conducted between 2000 and 2011 all concluded that based on the best available evidence, fluoride (at any level) could not be classified as carcinogenic in humans. More recent studies, including a large and detailed study in the UK in 2014, have not changed this conclusion. “

Neurotoxicity

I partially agree with Neurath’s charge on the inadequacy of the Royal Society’s comment on the standardised weighted mean difference in IQ scores discussed by Choi at al (2012). Some people have made a lot of the confusion around this issue. I would like someone with good statistical skills to comment on the risks involved in making such an analysis in a meta study where there is no conformity of experimental design or treatment in the individual studies.  Wikipedia lists a number of pitfalls in statistical meta analysis, two of which seem particularly relevant here – publication bias and agenda-driven bias. In my article Quality and selection counts in fluoride research I described how the studies used had been selected and it is hard not to see an agenda behind this. So, I do think Choi et al’s statistical analysis is questionable.

However,  this issue is irrelevant to CWF because of the generally high drinking water fluoride concentrations used in these studies. Theissen and Neurath resort to the special pleading in their efforts to avoid that problem.

Theissen stressed that in the Choi et al review “One study had “high” at 0.88 mg/L, quite relevant to CWF.” Neurath says “In fact, one of the Chinese IQ studies had an average water concentration of 0.88 mgL in the high exposure group.”

At first sight this seems relevant to CWF and Paul Connett, like many anti-fluoride activists, stress this study in defending the relevance of Choi et al (2012). Strange then that none of them actually discuss the study details. Perhaps we should.

The study is a one and a half pages newsletter report:

Lin et al (1991). The relationship of of low-iodine and high-fluoride environment to subclinical cretinism in Xinjiang. Iodine Deficiency Disorder Newsletter, 24–25.

It has few of the details we normally expect in scientific papers. For example, I would like to know what the range of fluoride concentrations was in the drinking water, what other dietary intake occurred, how was the “dental fluorosis” observed defined, etc.

Children from low iodine areas were compared with a group from another area that had received iodine supplementation. About 15% of the children suffered mental retardation, 69% of these exhibited subclinical endemic cretinism. The effect of iodine supplementation was clear, the effect of fluoride not so clear. But anyway, hardly a report to hang any conclusion on about CWF in New Zealand.

They also resorted to special pleading to downplay other problems with these studies:

Theissen:

“the one study . .  that did not show lower IQ still showed a tendency in that direction (just not statistically significant) and it certianly did not show clear absence of any effect”

“While some of the neurotixicity studies did not address confounders, some did handle them responsibly” [Most of them didn’t]

Neurath:

“most of the studies did consider other sources of exposure such as from food dried over coal fires . . . This in almost all studies, major alternative sources of fluoride exposure were ruled out or controlled for” ”  – [In fact they weren’t as most didn’t consider other inputs]

“several of the studies did consider each of these potentially confounding factors, and at least one group of researchers (lead by Xiang) considered all of them and more.” [yes, one – “all and more” – but why not consider Xiang in detail then? Why try to spread his thoroughness throughout all these meagre studies?

“simply failing to assess these factors in a study does not mean the study was confounded and produced invalid results.” [well no, but isn’t it best to check known confounders?]

fan-conf-2014-sturmer-300x200

“Connett’s get-together” – 5th FAN Conference, Sept 6-8, 2014. Credit: Photo by Corey Sturmer,

Anti-fluoride people also often single out the study of Xiang, et al (2003). Effect of fluoride in drinking water on children’s intelligence. Fluoride, 36(2), 84–94, because unlike the others it is more detailed.  Xiang’s team has studied areas where fluorosis is endemic. Here is a slide from his presentation  to Paul Connett’s recent anti-fluoride “get-together” (Xiang 2014). This is not the very mild dental fluorosis attributed to CWF.

xiang-Endemic fluorosis

Now I think severe dental fluorosis like this would create learning difficulties for children in the same way dental decay does (Seirawan et al 2012). I suggested this in Confirmation blindness on the fluoride-IQ issuePresumably Xiang could have analysed his data to check if the apparent IQ drop was correlated with the prevalence of dental fluorosis. I would think that could be an obvious first step.

Theissen  berates the Royal Society review for suggesting there is no plausible mechanism for the effect of F on IQ. Instead she resorts to special pleading again – admitting “no mechanism has been established,” attributing that to lack of research, not the absence of a mechanism. And then speculating on possible mechanism related to thyroid function, etc. The trouble is that this sort of special pleading can soon convert logical possibilities into established proof in the minds of the faithful. And meanwhile an obvious possible cause of the IQ data may be staring her in the face but she is oblivious because it does not involve “brain damage.”

Animal studies

Theissen rejects the Royal Society’s dismissal of results from animal studies because of the high concentrations used in them. She says baldly “animals require much higher exposures (5-20 times higher, or more; see NRC 2006; 2009). But what does NRC 2006 actually say (The NRC 2009 simply references NRC 2006)? It discussed the contradictory data used for attempting to show a ratio between humans and rats for blood plasma levels and concluded:

“Dunipace et al. (1995) concluded that rats require about five times greater water concentrations than humans to reach the same plasma concentration. That factor appears uncertain, in part because the ratio can change with age or length of exposure. In addition, this approach compares water concentrations, not dose. Plasma levels can also vary considerably both between people and in the same person over time (Ekstrand 1978).”

Again Theissen resorts to special pleading converting a vague possibility into an established “fact” in an effort to justify the unquestioned use of animal studies using high concentrations.

Mullinex et al (1995) also attempted to justify use of similar animal studies by comparison of blood plasma F levels. However, there is a huge range and variability in these levels so extremely easy to make subjective justification. I am suspicious of such speculation.

While I am happy to  acknowledge that it may be too simple to equate the effects for humans and animals at the same intakes, I think Theissen’s assertion “animals require much higher exposures” is straw-clutching. Millunex et al (1995) exhibited the same straw-clutching when she asserted plasma levels in her rats were similar to those in “humans exposed to high levels of fluoride.” Anti-fluoride activists love to quote Mullinex while ignore or downplaying the word “high.” She was quoting plasma F concentrations for children receiving 5 – 10, and 16 mg/L F, 10 or 20 times higher than used in CWF! But the huge effect of treatment time on plasma F concentration in rats must surely warn any objective reader to be very careful about these sort of claims. (Rats receiving 125 ppm F had plasma concentrations of about 0.1 mg/L after 6 weeks exposure but 0.64 ± 0.31  mg/L after 20 weeks).

Endrocrine effects

Theissen appears not to have properly read this section of the Royal Society Review.

Contrary to her assertion it does refer to the NRC discussion of these effects and comments:

“Most of the reviewed animal studies were designed to ascertain whether certain effects occurred, and not to determine the lowest exposures at which they occurred. The report concluded that fluoride (at unspecified levels) can affect normal endocrine function or response, and that better characterisation of fluoride exposure in humans in epidemiological studies is needed to investigate the potential endocrine effects of fluoride.”

It acknowledges potential effects (at unspecified levels) despite Theissen’s claim it “failed to mention” them. However, at this time no such effects have been observed in humans at the concentrations used in CWF. So the Review summarises its findings this way:

“A number of other alleged effects of CWF on health outcomes have been reviewed, including effects on reproduction, endocrine function, cardiovascular and renal effects, and effects on the immune system. The most reliable and valid evidence to date for all of these effects indicates that fluoride in levels used for CWF does not pose appreciable risks of harm to human health.”

Conclusion

The Royal Society Review evaluated current scientific knowledge on health effects of fluoridation. It was requested by the Auckland Council on behalf of several local Councils. They wanted a review of the scientific evidence for and against the efficacy and safety of fluoridation of public water supplies. This requirement arose from the recent campaigns by anti-fluoridation activists who targeted individual councils with a barrage of misinformation.

We should understand that the size and accessibility of the Review is aimed at informing public decision-making on the issue.  For this reason it also deals with New Zealand aspects. It is not meant to be as extensive and detailed as the 530 page US National Research Council report.

Hopefully any future consideration of community water fluoridation by local body councils will be better informed because of the Royal Society review. In particular it should help counter the sort of misinformation that has confused some councils in the past.


References

Colquhoun, J. (1985). Influence of social class and fluoridation on child dental health. Community Dentistry and Oral Epidemiology, 13(1), 37–41.

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.

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.

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. doi:10.1007/s10552-011-9765-0

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

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.

Lin Fa-Fu, Aihaiti, Zhao Hong-Xin, Lin Jin, Jiang Ji-Yong, Maimaiti, and A. (1991). The relationship of of low-iodine and high-fluoride environment to subclinical cretinism in Xinjiang. Iodine Deficiency Disorder Newsletter, 24–25.

Ministry of Health. (2010). Our Oral Health: Key findings of the 2009 New Zealand Oral Health Survey. Wellington: Ministry of Health.

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

National Research Council. (2006) Fluoride in Drinking Water: A Scientific Review of EPA’s Standards. Washington, DC: The National Academies Press.

Seirawan, H., Faust, S., & Mulligan, R. (2012). The impact of oral health on the academic performance of disadvantaged children. American Journal of Public Health, 102(9), 1729–34.

Thiessen, KM., & Neurath, C. (2014). International Peer Review of the Royal Society/PM Science Advisor Office Fluoridation Review. Internet document.

Xiang, Q; Liang, Y; Chen, L; Wang, C; Chen, B; Chen, X; Zhouc, M. (2003). Effect of fluoride in drinking water on children’s intelligence. Fluoride, 36(2), 84–94.

Xiang, Q. (2014) Fluoride and IQ research in ChinaKeynote Address at FAN’s 5th Citizens’ Conference on Fluoride.

 

 

The information war – The NZ Listener takes up arms

First – have a look at this satirical programme from Germany. It has English captions but is worth watching a few times for the subtleties.

I have commented before about the information war going on around the Ukrainian conflict. It might seem like a distant issue here (and it usually doesn’t get much coverage). But I believe the biassed propaganda we are exposed to is dangerous because of its jingoism.

And this week the NZ Listener brought the conflict right into our living rooms with an editorial which uses the same innuendo and unconfirmed claims that feeds this jingoism (see Alarmed World).

Out of the blue in a piece seeming to be about Islamic State and the conflict in the Middle East we get this:

The West faces a similar test of its resolve in Ukraine, where attempts to deter Russian-backed aggression have been largely ineffectual. The world knows that Russia supports the separatist rebellion in eastern Ukraine, that it has troops on Ukrainian soil and that it probably supplied the missiles that brought down a Malaysian airliner. Yet the European Union’s sanctions against Russia have succeeded only in provoking economic counter-measures that have hurt European food producers, for whom Russia was a $19 billion export market, and threats to ban “unfriendly” airlines from Russian airspace.

The assertion the “world knows” has become a substitute for evidence! The world certainly knew when the USSR invaded Hungary and Czechoslovakia, or the US invaded Iraq. We could see the evidence. Tanks surging across borders, planes bombing, troops on the ground. But nothing of that here (except the occasional soldier who claims to have lost his way – or fuzzy satellite photos of combine harvesters*).

[Yes, I know the presence in Ukraine of Russian and other voluntary (or even mercenary) fighters is well established – fighting on both sides. But that is not the same as invasion of a foreign army the media often claims.]

The “world knows” that Russia “probably” supplied missiles used to shoot down Malaysian airline MH17 – when the world knows nothing of the sort! At this stage this issue is wide open (see MH17 – Preliminary report leaves most conspiracy theories intact) – but it seems our media thinks we don’t deserve anything better than unwarranted claims on such a serious matter.

That shows no respect for the victims of this tragedy.

As for the danger of this sort of biased reporting and media manipulation, and the jingoism it promotes, we can read the last paragraph in the Listener editorial.

“What has become painfully apparent, in both the Middle East and Ukraine, is that the democratic West is susceptible to paralysis and self-doubt when confronted with the forces of totalitarianism and autocracy. Perhaps it’s time to consider what the world’s fate might have been without the moral resolve exhibited by Churchill and Roosevelt in World War II.”

Isn’t this the sort of talk used to prepare a population for war?


UPDATE

* Of course I have taken poetic license here about these fuzzy photos. After all,  whether these were photos of artillary or combine harvesters is not evidence for or against an invasion. We know that both sides in Ukraine have plenty of artillery weapons and are using them. But for the pedantic, and those confused by my aside, here are some links to the combine harvester/artillery story:

Dave Lindorff writes about it in his article Satellite Images of Alleged Russian Artillery in Ukraine Come A-Cropper. He produced this photo below:

combines.preview

And commented:

“In the ongoing propaganda campaign mounted by the Obama administration to claim that Russia has “invaded” Ukraine from the east, it offered up some grainy black-and-white satellite images purporting to show heavy Russian military equipment inside Ukraine.

I earlier noted how unlikely it was that heavy mobile artillery pieces would be set up in a perfect line in what appeared to be a field of crops, with, as the government claimed, cannons aimed towards Ukrainian positions in toward the west. As I pointed out, there was no sign of piles of ammunition alongside these “units” as we routinely see in closeups of heavy mobile artillery — for example in photos of IDF pieces positioned outside of Gaza. I also noted the unlikelihood that such equipment would have been set up in an open field, unprotected by trees or other cover, and lined up to make for easy targeting by enemy artillery or air attack.

Now an alert reader from the agricultural state of Texas (Laredo, TX to be precise), has sent a note suggesting out that what the supposedly incriminating images most likely show are combines in a field of grain or some other crop planted in rows. He sent along photos showing harvesters, which of course feature a long, straight “cannon-like” tube which is used to shoot the harvested grain up and into an accompanying truck to be hauled off to market or to a storage silo.”

Here is a higher resolution of the satellite photo which, I understand, came from the US State Department:

artillery_2

(from European Union Court of Justice Imposes Anti-Rasmussen Rule – Sanctions Cannot Be Imposed by Reason of Fabrication, Lies, Dissimulation)

I wouldn’t pretend to draw any definite conclusions from these photos but I think Dave Lindorff  has a point:

“Now maybe the released satellite images do show Russian artillery, but given Washington’s extensive history of abject lying in the interest of promoting its war agenda (think Gulf of Tonkin, Iraq WMDs and mobile poison gas factories, Assad gas attacks in Damascus, etc.), it’s worth taking the claim with a “grain” of…well, in this case actual grain.”

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Activist’s anti-science adverts found misleading – again

The activist Fluoride Free NZ (FFNZ) organisation have had a bad year with the Advertising Standards Authority (ASA). They have had half a dozen complaints against them for misleading advertising upheld.

The latest complaint referred to FFNZ’s adverts for a meeting they organised in Rotorua last July. This advert claimed

“Informed Doctors and Dentists say:
KEEP FLUORIDE OUT
Keep Rotorua’s water safe. It’s our right to choose.
Swallowing Fluoride

Is unsafe for babies
Doesn’t protect teeth
Can cause harm.”

The complaint basically was that these claims were presented as matters of fact, rather than opinion. And the declarations of harm, danger to babies and lack of effectiveness protecting teeth were effectively claims implying scientific  substantiation. It also raised the issue of misrepresentation of the views of New Zealand doctors and dentists – implying that the claims are supported by a majority of these professional when they aren’t. Quite the opposite.

In fact, FFNZ can get only about half a dozen such professionals willing to promote their message. It is dishonest to then use these handful of mavericks to imply the whole profession supports the anti-fluoride claims.

The complainant also pointed out the advert was effectively indulging in scaremongering because it claimed there was harm, when there wasn’t any, and it appeared to be promoting the advice of professionals, when professionals weren’t saying what was claimed.

The ASA ruling concludes:

“The Complaints Board said the advertisement was likely to mislead as the claims were presented as facts, but were not substantiated by the Advertiser, in breach of Basic Principle 3 and Rule 2 and was not saved by advocacy, in breach of Rule 11 of the Code of Ethics. It said the advertisement unjustifiably played on fear, in breach of Rule 6 of the Code of Ethics and was socially irresponsible in breach Basic Principle 4 of the Code of Ethics and the Complaints Board ruled the matter was upheld.

It is good to see more people coming forward to make these sort of complaints. The anti-science lobby has been getting away with this sort of misrepresentation for years. Hopefully the experience of the ASA upholding such complaints will embarrass organisation like this to be more careful in their advertising.

In many cases all it takes is a simple sentence to clarify the advert is presenting the viewpoint or belief  of the advertiser, rather than scientifically established facts.

Anti-fluoride activists define kangaroo court as “independent”

A kangaroo court is a mock or illegal court that is set up in violation of established legal procedure

The international anti-fluoride movement seems somewhat pre-occupied with thew situation in New Zealand.  In the last few months they have unleashed their “big guns” to attack two publications from local scientific researchers.  First was their attempt to discredit the paper 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. Now they have produced an International Peer Review of the  review Health Effects of Water Fluoridation: a Review of the Scientific Evidence. This was commissioned by Sir Peter Gluckman, the New Zealand Prime Minister’s Chief Science Advisor and Sir David Skegg, President of the Royal Society of New Zealand at the request of Auckland City on behalf of several local Councils.

Fluoride Free NZ pretends that the Royal Society Review “was sent out for review by five independent international experts” and a press release from their astroturf organisation the NZ Fluoridation Information Service repeats the independent claim (see NZ fluoridation report trashed by international reviewers).

Well let’s have a look. How independent are the authors of the critique?

An “independent” peer review?

I don’t think so. Here are the authors – chosen by the anti-fluoride movement, of course – together with affiliations and a little history


Kathleen Theissen, Environmental Risk Scientists. I don’t know what the affiliation “environment Risk Scientists,” is. Perhaps a consultancy. However, she is still listed as an affiliate on the Oak Ridge Center for Risk Analysis web site. Theissen was one of the minority* anti-fluoride members on the National Research Council Committee on Fluoride in Drinking Water which produced the NRC reviewFluoride in Drinking Water: A Scientific Review of EPA’s Standards.” She frequently writes articles and submissions opposing community water fluoridation

Chris Neurath, Research Director, American Environmental Health Studies Project. Neurath is also the “Research Director,” of Paul Connett’s Fluoride Action Network (FAN). The American Environmental Health Studies Project is really just the Fluoride Action Network in drag with a couple of other similar organisations tied in.

Hardy Limeback, Head of Preventive Dentistry, University of Toronto. Limeback was also an anti-fluoride minority member of the  National Research Council Committee on Fluoride in Drinking Water which produced the NRC review Fluoride in Drinking Water: A Scientific Review of EPA’s Standards.” He is also an anti-fluoride activist who writes often on the issue and a member of the Advisory Board of Paul Connett’s Fluoride Alert Network.

 

James Beck, a co-author together with Paul Connett of the anti-fluoridation book The Case against Fluoride.

Spedding Micklem, also a co-author together with Paul Connett of the anti-fluoridation book The Case against Fluoride.


So, definitely not independent

This is a serious distortion of the truth by Fluoride Free NZ because they have continual described the authors of the Royal Society Review as not independent. They wrote, for example (see Fluoridation review ‘Dirty Science’ – Fluoride Free NZ):

“The NZ “expert panel” included only people who were already known to be ardently in favour of fluoridation and not one single person who is known to be opposed, or even someone neutral. It was therefore already a foregone conclusion.”

So, I can only conclude that these people define “independent” to mean that they agree with them – they have an anti-fluoride political stance. And they define anyone whose scientific work produces an objectively determine conclusion favourable to the consensus understanding of the effectiveness and safety of community water fluoridation as not independent!

I can only repeat, how do these hypocritical people sleep straight in their bed’s at night.

How valid are their criticisms

OK, so these people are not independent – but how valid are there criticisms. That is another issue. I am preparing a detailed analysis of the claims made in this critique and will post it in the next few days. So, watch this space.


*Three of the 12 members of the committee expressed disagreement with some fo the committee’s conclusions.

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August ’14 – NZ blogs sitemeter ranking

 
Hager
Bloggers in the thick of election campaign? Image Credit: Against the Current


PLEASE NOTE: Sitemeter is playing up again making it impossible to automatically get the stats using the normal process. I have done a manual work around but it was still impossible to get the stats for a number of blogs that I list below. Maybe more bloggers will shift to StatCounter or other counter.

No stats could be found for these blogs:

Blog
Works in progress
Weakly Whirled News
Two Minutes Sport
Wysiwygpurple’s Blog
Stats Chat
Social Media and the 2014 General Election
Love your work
Today is my birthday
This Mum Rocks
Sportsfreak
Infectious thoughts
Science Behind the Curtain
Grumpollie
Louis’ Outlook
West City Darts
Woodleigh Nursery
Kyle MacDonald
A conservative perspective
Save our schools NZ

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 August 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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