Tag Archives: Canada

Local anti-fluoride activists tell porkies yet again

FFNZ confuses lack of low fluoride studies on rats with human studies

Well, I suppose that’s not news. A bit surprising, though, because they are claiming the absence of research on fluoridation and IQ – which sort of conflicts with the previous attempts to actually condemn and misrepresent the actual research on fluoridation and IQ.

Fluoride Free NZ’s (FFNZ) face book page is claiming:

Would you be interested to know that no studies have been conducted on fluoridated water at 0.7ppm to determine whether there is IQ reduction? The National Toxicology Program are currently completing research to fill this gap. You would have thought that they would have done this in the 1950s before starting the fluoridation program wouldn’t you?

There have actually been three recent studies from three different countries which have specifically investigated the claim of an effect of fluoridation on IQ – and, unsurprisingly, all threes studies showed there was no effect.

Here are those studies:

New Zealand

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.

In fact, anti-fluoride activists in the US, as well as New Zealand, have campaigned against this study. Their major criticism is that the study also included the effect of fluoride tablet use. They argue that this makes the unfluoridated control group useless because many participants will have consumed fluoride tablets. However, they ignore the fact that the statistical analysis corrected for this but still found no statistically significant difference in IQ of children and adults from fluoridated and unfluoridated areas.

Sweden

Other critics of the Broadbent et al. (2014) study have raised the issue of experimental power because of the numbers of people in the study. This could be a valid issue as it would determine the minimum effect size capable of being detected. Aggeborn & Öhman (2016) made that criticism of Broadbent et al., (2016) and all other fluoride-IQ studies. Their study is reported at:

Aggeborn L, Öhman M. (2016) The Effects of Fluoride in the Drinking Water. 2016.

Aggeborn & Öhman (2016) used much larger sample size than any of the other studies – over 81,000 observations compared with around 1000 or less for the commonly cited studies. It was also made on continually varying fluoride concentrations using the natural fluoride levels in Swedish drinking waters (the concentrations are similar to those in fluoridated communities), rather than the less effective approach of simply comparing two villages or fluoridated and unfluoridated regions. The confidence intervals were much smaller than those of other cited fluoride-IQ studies. This makes their conclusion that there was no effect of fluoride on cognitive measurements much more definitive. Incidentally, their study also indicated no effect of fluoride on the diagnosis of ADHD or muscular and skeleton diseases.

Canada

Another recent fluoridation-IQ study is that of Barbario (2016) made in Canada:

Barberio, AM. (2016). A Canadian Population-based Study of the Relationship between Fluoride Exposure and Indicators of Cognitive and Thyroid Functioning; Implications for Community Water Fluoridation. M. Sc. Thesis; Community Health Sciences, University of Calgary.

This study also had a large sample size – over 2,500 observations. This reported no statistically significant relationship of cognitive deficits to water fluoride.

Incidentally, Barberio (2016) also found there was no evidence of any relationship between fluoride exposure and thyroid functioning. That puts another pet claim of anti-fluoride campaigners to rest.

Animal studies

So much for NZFF’s claim that “no studies have been conducted on fluoridated water at 0.7ppm to determine whether there is IQ reduction.” But, just a minute, they are quoting the National Toxicology Program (NTP):

“No studies evaluated developmental exposure to fluoride at levels as low as 0.7 parts per million, the recommended level for community water fluoridation in the United States. Additional research is needed.”

But they omit the next sentence from the quote:

“NTP is conducting laboratory studies in rodents to fill data gaps identified in the systematic review of the animal studies.”

The NTP is discussing the research with animals, mainly rats, where effects of fluoride on the cognitive behaviour of the test animals have been reported but the fluoride concentrations are very high. And NTP’s assessment base on the review of the literature found only “a low to moderate level of evidence that the studies support adverse effects on learning and memory in animals exposed to fluoride in the diet or drinking water.” Hence the need for more research.

As part of the NTP’s research, which is currently underway, there are plans to extend studies to low fluoride concentrations more typical of that used in community water fluoridation.

The high concentrations used in animal studies is a major flaw in the anti-fluoride activist use of them to oppose community water fluoridation. For example, Mullinex et al (1995) (very commonly cited by anti-fluoride campaigners) fed test animals drinking water with up to 125 mg/L of fluoride (concentrations near 0.8 mg/L of fluoride are used in community water fluoridation).

While it is unlikely that the NTP research will find any significant effects of fluoride on the cognitive behaviour of rats at the low concentrations used in community water fluoridation the anti-fluoride campaigners have their fingers (and probably toes as well) crossed.

NTP will begin publishing the results of their new research next year (see Fluoride and IQ – another study coming up).

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More nails in the coffin of the anti-fluoridation myths around IQ and hypothyroidism

thyroid_fluoride

Large Canadian study finds no effect of fluoridation on thyroid health

A new Canadian study shows no relationship of cognitive deficits or diagnosis of hypothyroidism with fluoride in drinking water. This work is important because it counters the claims made by anti-fluoride campaigners. While the campaigners cite scientific studies to support their claims, those studies are usually very weak, or irrelevant because they involve areas of endemic fluorosis where drinking water fluoride concentrations are much higher than in situations where community water fluoridation (CWF) is used.

The study is reported in:

Barberio, A. M. (2016). A Canadian Population-based Study of the Relationship between Fluoride Exposure and Indicators of Cognitive and Thyroid Functioning; Implications for Community Water Fluoridation. MSc Thesis, University of Calgary

This new study is important as it has the advantages of using a large representative sample of the Canadian population, with extensive data validation and quality control measures. It also uses individual-level estimates of fluoride exposure on the one hand, and thyroid health and cognitive problems on the other.

Fluoride exposure was measured both by concentration in tap water for selected households and concentration in urine samples from individuals.

Thyroid health

The Canadian study found:

“Fluoride exposure (from urine and tap water) was not associated with impaired thyroid functioning, as measured by self-reported diagnosis of a thyroid condition or abnormal TSH level.”

This contradicts the conclusions from the population-level study of Peckham et al., (2015) which reported that fluoridation was correlated with the prevalence of hypothyroidism. That study is quoted extensively by anti-fluoridation activists but has been roundly criticised because it did not include the influence of confounders – particularly iodine which is known to influence thyroid health.

Barberio (2016) also suggests that the different recommended fluoride concentrations used for CWF in Canada and the UK, and the fact that the Peckham et al (2015) study did not involve individual measures, could also be factors in the different findings.

Cognitive functioning

The Canadian study reported:

“Fluoride exposure (from urine and tap water) was not associated with self-reported diagnosis of a learning disability.”

Barberio (2016) did also investigate a more detailed diagnosis for cognitive problems and found:

“Higher urinary fluoride was associated with having ‘some’ compared to ‘no’ cognitive problems . . . . however, this association:

  • Was weak;

  • Was not dose-response in nature; and

  • Disappeared when the sample was constrained to those for whom we could discern fluoride exposure from drinking water.”

I guess anti-fluoride activists might latch on to this last point regarding urinary fluoride but, at least as far as tap water fluoride is concerned, there was no relationship with learning difficulties.

Conclusion

So – yet another large-scale study contradicts anti-fluoridationist claims. It shows that CWF has no influence on cognitive problems or thyroid health.

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Another defeat for anti-fuoridation claims about arsenic

Anti-fluoride campaigners make a song and dance about contaminants, particularly arsenic, in fluoridation chemicals. However, a new study shows there is actually nothing to worry about – and, in fact, these campaigners should be more concerned with natural sources of arsenic, than with fluoridation chemicals.

The study is:

Peterson, E., Shapiro, H., Li, Y., Minnery, J. G., & Copes, R. (2015). Arsenic from community water fluoridation: quantifying the effect. Journal of Water and Health.

Past studies estimated the arsenic contribution to drinking water from fluoridation using the arsenic concentration of the fluoridation additives. This new study went further and compared the actual arsenic concentrations of  1329 paired raw water and treated drinking water samples. The samples were taken from 121 drinking water systems in Ontario, Canada.

The graph below compares the mean values of arsenic concentrations in raw water and treated water for both fluoridated (49%) and unfluoridated systems (51%).

Peterson

The data shows that even after treatment the concentration of arsenic due to natural sources is about 0.44 ppb. Fluoridation added a mere 0.07 ppb to this! (ppb = parts per billion = micrograms/litre = μg/L).

The authors concluded that fluoridation is associated with an extra 0.078 ppb compared with non-fluoridated systems when controlling for other factors (raw water concentrations, treatment processes and water source).

Let’s put these figures in context. The maximum acceptable value (MAV) for arsenic in drinking water is 10 ppb. So even the raw water mean concentration of 0.69 ppb (0.44 ppb after treatment) is safe. And the extra arsenic in fluoridated water is only 0.7% of the MAV!

Surely the sensible person will worry about natural sources of arsenic long before getting their knickers in a twist over the contribution from fluoridation.

I drew a similar conclusion from some New Zealand (Hamilton City) data in my article Fluoridation: putting chemical contamination in context. In that case, the contribution for arsenic from natural sources was much higher (around 30 ppb in the raw water – 3 times the MAV, and about 3 ppb in the treated water – a third of the MAV ).

New paper confirms previous studies

This new study confirms previous work based on the measured concentration of arsenic in fluoridating chemicals. That work produced regulations defining maximum permissible levels of contamination in water treatment chemicals. These are based on a maximum contribution of 1 ppb – 10% of the MAV.

Peterson et al., (2015) indicates the extra arsenic resulting from fluoridation is less that 10% of these standards. This is likely to be much less in Australia and New Zealand as the actual arsenic concentrations in the major fluoridating agent used, fluorosilicic acid, are much lower than those used in North America.

So – my message to anti-fluoridation campaigners is stop worrying about arsenic due to fluoridation. If you must worry then check out the concentration  of arsenic in your drinking water, and the raw water source, due to natural sources.

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Another book for the kids

This looks like another great sciency book for young kids. Ankylosaur Attack (Tales of Prehistoric Life) is aimed at an age level of 4 and up. It should really appeal to the kid already interested in dinosaurs.

The author is Daniel Loxton. He is also  the author and illustrator of Evolution: How We and All Living Things Came to Be which I reviewed in One for the kids. That book is a finalist for Canada’s largest children’s non-fiction prize, the Norma Fleck Award. (Winner to be announced Oct 4, 2011.)

Here is the book description for Ankylosaur Attack:

“This mind-blowing feast for the eye uses photo-realistic, computer-generated images to illustrate what dinosaurs might have looked like in their natural environment. Complementing the extraordinary images is an exciting, scientifically accurate story about a young ankylosaur (a plant-eating, heavy-plated dinosaur) living along the banks of a grassy lake. When he encounters an old ankylosaur, he gently endeavours to make contact, only to be rebuffed. Then a T. rex attacks, and the youngster knows the old dinosaur is in grave danger. Will the T. rex triumph? It looks that way, until the young ankylosaur comes to the rescue, tail club swinging. Ankylosaur Attack is book one in the Tales of Prehistoric Life series. Dramatic stories + eyepopping visuals = a surefire hit with young dinosaur lovers.”

Publication date is September 1, 2011.

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The clash of science and politics

I am awaiting the Employment Court’s decision of Jim Salinger’s case (see Clamping down on science communication). However, related to this is the scandal blowing up in the UK over the sacking of the Professor David Nutt as the governments chief science advisor on drugs. Prof. Nutt was chairman of the Advisory Council on the Misuse of Drugs. Two other members of the Council have resigned in protest (see  Government drug adviser David Nutt sacked, David Nutt’s sacking provokes mass revolt against Alan Johnson and Drug expert quits panel over sacking of David Nutt).

A couple of local science bloggers have posts giving the background to Prof. Nutt’s sacking and the issues involved. Have a look at Peter Griffin’s When science and politics collide – the fallout from the Nutt affair at Griffin’s Gadgets and Grant Jacobs’ When is a scientific paper political campaigning? at Code for Life.

Related to the issue of the conflict between science and politics is this panel discussion Do We Still Believe in Science? It took place a few days ago at the Quantum to Cosmos Festival held at the Perimeter Insitute in Waterloo, Ontario, Canada. There are also some other great videos from this festival listed on the programme.

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See also: Cabinet in drug war over sacking

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