Dr Paul Connett is currently visiting NZ and Australia to promote the views of the anti-fluoridation organisation FAN and its antipodean sub-groups. While he has reportedly spent 17 years ‘researching’ issues associated with community water fluoridation (CWF), he has published neither original research papers on this particular topic nor a systematic review of the existing scientific literature, in leading science journals. He has, however, published a book on the subject, the contents of which formed the basis of an extensive discussion on the Open Parachute science blog (also syndicated to the Science Media Centre’s sciblogs.co.nz). This output doesn’t really justify the ‘expert’ description so adroitly promoted by the FANNZ spokesperson who provided the yahoo item.

Repeated calls for a ‘debate’ are rather misleading as they suggest that there is in fact something to debate. In the case of the science behind CWF, as Sir Peter Gluckman has said, it is effectively settled. To call for a debate is simply an attempt to sow doubt and fear in people’s minds, and any such event would be ‘won’ by the better demagogue and not necessarily on the basis of the actual science presented. Thus it makes perfect sense for TV3 to seek comment from Dr Jonathan Broadbent, who has a solid research record around oral health, rather than to opt for the flawed ‘debate’ format & so give some feeling of false equivalency to an issue where none exists.

The FANNZ claim that our health officials are “

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The claim is based on a published PhD study by Bassin (Bassin et al. 2006), who looked at a sample of 103 children with osteosarcoma and 215 matched controls, and concluded that there was a link between exposure to fluoride and the development of osteosarcoma in boys, but not in girls. They also noted that the findings were preliminary and needed further study, preferably involving biomarkers eg fluoride levels in bone. (Thus it’s interesting, to say the least, that this study is promoted so definitively by those opposed to CWF.) And in fact there have been a number of further studies – none of which support the Bassin group’s findings.

For example, in 2011 Kim et al published the results of a case-control study of 137 osteosarcoma patients and 51 controls. They measured the amount of fluoride present in the bones of patients and control individuals (in this case, patients with other forms of cancer), made allowances for age (& thus duration of exposure to fluoride in drinking water) and gender. The team used the bone assay because, since “fluoride has an affinity for calcified tissues” (ibid.), levels in the bone are a more reliable, objective measure of fluoride exposure than measurements based on residential history or – in the case of the paper by Bassin et al – interviews with patients about their use of fluoridated mouthwashes & supplements, in addition to information on where they’d lived.

The team found there was “no significant difference in bone fluoride levels between cases and controls”, and concluded that

“

[n]o significant association between bone fluoride levels and osteosarcoma risk was detected in our case-control study, based on controls with other tumor diagnoses.”

They also characterised Bassin’s study as ‘exploratory’ and noted that a large number of earlier animal studies, and descriptive and case-control studies in humans, had not found any association between osteosarcoma & fluoride exposure.

Again, in 2012 Levy and Leclerc used information covering the period 1999-2006 from the Centres for Disease Control database to probe the supposed link between CWF and this form of cancer. This was a weaker study than that of Kim’s team, because it used the proportion of a state’s population exposed to CWF as the proxy for fluoride exposure, but it concluded that

“the water fluoridation status in the continental U.S. has no influence on osteosarcoma incidence rates during childhood and adolescence.”

Most recently, Blakey and colleagues (2014) studied more than 4,000 patients with either osteosarcoma (N = 2566) or Ewings sarcoma (N = 1650), with the aim of their study being

“to examine whether increased risk of primary bone cancer was associated with living in areas with higher concentrations of fluoride in drinking water.”

Their conclusions?

“The findings from this study provide no evidence that higher levels of fluoride (whether natural or artificial) in drinking water in [Great Britain] lead to greater risk of either osteosarcoma or Ewing sarcoma.”

In other words, to date the further research Bassin’s team called for has not replicated their findings, and means that claims of a causal link are questionable at best.

“The results of this study do not support the hypothesis that osteosarcoma incidence in the island of Ireland is significantly related to public water fluoridation.” 

“this conclusion must be qualified, in view of the relative rarity of the cancer and the correspondingly wide confidence intervals of the risk estimates.”

Sources:

E.B.Bassin, D.Wypij, R.B.Davis, M.A.Mittleman (2006) Age-specific fluoride exposure in drinking water and osteosarcoma (United States). Cancer Causes Control 2006(17): 421-428

K.Blakey, R.B.Feltbower, R.C.Parslow, P.W.James, B.G.Pozo, C.Stiller, T.J.Vincent, P.Normal, P.A.McKinney, M.F.Murphy, A.W.Craft, & R.J.Q.McNally (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. Int.J.Epidemiol, doi: 10.1093/ije/dyt259. First published online: January 14, 2014.

F.M.Kim, C.Hayes, P.L.Williams, G.M.Whitford, K.J.Joshipura, R.N.Hoover, C.W.Douglass, & the National Osteosarcoma Etiology Group (2011) An assessment of bone fluoride and osteosarcoma. J.Dent.Res. 90(10): 1171-1176. doi: 10.1177/0022034511418828, PMCID: PMC3173011

M.Levy & B.S.Leclerc (2012) Fluoride in drinking water and osteosarcoma incidence rates in the continental United States among children and adolescents. Cancer Epidemiol. 36(2): e83-88. doi: 10.1016/j.canep.2011.11.008. Epub 2011 Dec 19.

H.Comber, S.Deady, E.Montgomery & A.Gavin (2011) Drinking water fluoridation and osteosarcoma incidence on the island of Ireland. Cancer Causes Control 22(6): 919-924. doi: 10.1007/s10552-011-9765-0

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“Since 1960, there have been 177 Nobel Prize winners in chemistry and medicine. Therefore, only 8% of these prize winners opposed or had reservations about fluoridation. Dr Connett does not differentiate between the number of the 14 who had reservations and those who were opposed. The only correct inference from the data from the Nobel Prize winners is that many of them supported fluoridation or had no firm viewpoint.”
(from http://www.health.govt.nz/system/files/documents/pages/response-50-reasons-oppose-fluoridation_1.pdf)

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“The data on Fluoride exposure and IQ presented at the Tehran Conference helps to explain Ireland’s ranking of 26th of 34 participating OECD countries for students skills and knowledge in Mathematics in the Programme on International Student Assessment.”

Waugh links to a press release from the Irish Parliament, which clearly refers to the 2009 data, (the 2012 results will not be available until 3 December this year), and then attempts to link Ireland’s results to water fluoridation in that country.
Water’s been fluoridated in Ireland (in urban centres anyway) since the 1970s. For the 2009 PISA results Ireland was significantly below OECD average in Maths, significantly above for science & the ‘reflect & evaluate’ component of literacy, & not significantly different from the average for all other aspects of literacy. In 2006 Irish students’ results for science were significantly above the OECD average, while maths was on the average, and overall literacy was average or above average. It would appear that there was little change between 2000 & 2003 (possible improvement in some areas), & 2003 data appear comparable to 2006.

 
So how likely is it that Waugh’s claim that the decline, particularly in maths, noted in 2009 data is due to fluoridation? Can this really underpin a sudden & recent decline in students’ cognitive abilities? (And why wouldn’t that have been noted earlier, given the duration of fluoridation in that country?) I suspect changes in the Irish economy may have had a greater impact on student performance & the education system in general, considering that they’ve been running austerity budgets since 2008 – budgets which cumulatively have taken 28 billion Euros out of the economy.

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References are separated into two Appendices and the ‘Endnotes’, which together add up to around 80 pages. At least some sources of those in the appendices don’t appear to be cited in the main body of the work, which surprised me a bit: if the material in them is relevant to the book’s core thesis, then personally I’d expect to see them cited therein.

On to the endnotes: the first thing I noticed is that a fair number of sources appeared to have been listed multiple times, even within a single chapter. This does have the effect of pumping up the size of the references section. How much? I sat down & did a quick count (& yes, I may have missed some).

Looking only at duplicate references within chapters (not between, although there was some duplication there), I found 389 examples where the same source is given multiple citation numbers: 31% of the total 1244 numbered references in the Endnotes are duplicates. That leaves 855 ‘single’ citations, of which 32 are for newspaper stories, magazines, and newsletters; 25 letters, 20 testimonials/personal communications; and 17 videos. The remainder was for books (45) and various journal articles and reports.
Now, I’d actually expect a number of ‘non-traditional’ sources in a popular science book, one that’s hoping to get people to read more widely on the subject. But it’s the first time I’ve seen TV programs/videos, letters, and newspaper articles described as ‘scientific literature’. (This is not to say anything about the content of the book because I’ve only started looking through it. But it does show the commenters’ claims to be somewhat hyperbolic.)

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“I attended the free public lecture by Dr Graham Saunders, senior lecturer in inorganic chemistry at Waikato University, last night, titled “Fluoride, Friend or Foe?” which was sponsored by the Waikato branch of The Royal Society of NZ. Despite constantly assuring his audience that his area of expertise was restricted to the chemistry of fluoride (which cannot be disputed), he regularly strayed dangerously off that path onto the “pro-fluoride” bandwagon and showed himself to be obviously well out of his depth when questioned further on dental and medical issues by some of the more qualified members of the audience.”

In fact, Dr Saunders was meticulously careful to acknowledge where his expertise stopped. On at least 2 occasions other audience members gave additional information relating to questions asked by others. He also – as is his right as an expert in the area of fluoride chemistry – pointed out where this had been misrepresented by those opposing fluoridation.

“I was even more astounded to hear Dr Saunders’ reply when he was asked if he had taken part in the Council-run fluoride tribunal in May this year. He replied that no, he had not been consulted, which had really annoyed him and that he had since contacted the council to complain about it. Is Dr Saunders arrogant or just ignorant?”

Dr Saunders is neither arrogant nor ignorant of this issue, & his answer was more complex than it has been represented by Pat. He made it clear that he was concerned that the University’s scientists had not been asked to provide expert opinion to the Council (& in fact a question from the floor asked him specifically – were you asked to provide advice?), but that he had made a personal written submission to the tribunal. He was not able to attend the actual hearings given other prior commitments, and yes, given his inability to attend he had expected that the Council might have contacted him to discuss some of the points that he made in his written submission.

“Surely Dr Saunders is aware that the council had very publicly advertised the tribunal and had asked for written and oral submissions from any person or organisation that had an interest in the issue. All were accepted, read and analysed and the council decision was based on this evidence by a vote of 7/1.”

See above. He was aware and made that written submission.

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Food varies quite a bit in its water content, but they’ve assumed an average of 50% water content and an average daily intake (from the USDA figure for average Americans) of 2.18kg wet weight, so 1.06kg dry weight of food per day.

On that diet our hypothetical someone would then need to take in 21.3mg F- each day to experience chronic fluorosis. Until fluoridation was discontinued, Hamilton’s town supply water had 0.7-1ppm fluoride ie a maximum of 1mg/L. This means our someone would need to take in 21.3 L of water a day, and maintain that intake, for fluorosis to become a reality. (At this level water intoxication would be a real threat.)

The estimated mean highest daily F- intake in New Zealanders – any age group, & from a combination of diet and town supply fluoridated water, is around 2.1mg/day (Cressey et al, 2010, J.Pub.Health.Dent 70: 327-336).

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Source:
http://www.health.govt.nz/publication/drinking-water-standards-new-zealand-2005-revised-2008

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Sources:
Bataineh, H.N., Nusier, M.K. (2006) Impact of NaF on aggression, sexual behaviour and fertility in male rats. Fluoride 39(4): 293-301

http://www.donotlink.com/dem1

The post Another example of a paper not showing what’s claimed for appeared first on Making Sense of Fluoride.

For example: a study by Reddy et al (2011) is said to have found that fluoride accumulated at very high levels in rats’ brains. The researchers used 2 groups of male rats: one experimental group, one control. There were only 6 animals in each group, which is a very small sample size & means that the data could be skewed by a single abnormal result.

The control group supposedly received no fluoride, but then there was no information on fluoride levels in the tap water they drank or the rat chow they ate. This is a significant flaw & I’d have thought it should have been picked up by peer review.
The experimental rats apparently received 20ppm fluoride by nasogastric tube for 2 months. Actually, it’s not actually clear what dose they received: the abstract says 20ppm NaF, but the methods section says “20ppm concentration of fluoride”. These are 2 different things & again, peer review should have picked this up & required clarification. Either way the dose is about an order of magnitude higher than you’d find in fluoridated municipal water in New Zealand, which means that the paper didn’t support the commenter’s assertions of the harm done by fluoridation. Also, after those 2 months the researchers recorded 864 mg/kg F- in the rats’ brains: given that a large proportion of fluoride is normally excreted, and some of the rest fixed in apatites in bone, this figure looks extremely high & should surely have been questioned by the referees.
And in addition, both groups of rats lost a great deal of weight during the course of the study. While the average body weight of the animals was 180g (+/-20g), after 2 months the control animals weighed on average 111g, while the experimental group was down to 93g (both +/- 2g). This strongly suggests they were either ill, or not receiving adequate food; furthermore, starvation can cause inflammatory changes to tissues & so could itself explain the changes the researchers observed in the rats’ nervous systems.

Do people read these papers before they cite them?

Sources:

Reddy, P.Y., Reddy, K.P., Kumar, K.P. (2011) Neurodegenerative changes in different regions of brain, spinal cord and sciatic nerve of rats treated with sodium fluoride. J.Med.Allied Sci 1(1): 30-35

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