Fluoride and heart disease – another myth

Here is another anti-fluoride rubber duck which keeps surfacing – the myth that cardiovascular disease is “linked to” fluoride. This myth relies on misrepresentation of a study reported in Nuclear Medicine Communications 2 years ago.

The paper is Li et al (2012) Association of vascular fluoride uptake with vascular calcification and coronary artery disease. (download pdf). It shows that an injected fluoride isotope (¹⁸F) concentrates in existing calcified material in coronary arteries. The authors suggest detection of the injected ¹⁸F could provide a clinical method of identifying cardiovascular risk.

This is very clear from the conclusion reproduced in their abstract:

“CONCLUSION: sodium [¹⁸F]fluoride PET/CT might be useful in the evaluation of the atherosclerotic process in major arteries, including coronary arteries. An increased fluoride uptake in coronary arteries may be associated with an increased cardiovascular risk.”

The “fluoride uptake” refers to uptake of the radioactive isotope in the coronary arteries, 40 minutes after its injection – not dietary uptake of fluoride. The correlation observed is between arterial calcification and ¹⁸F uptake – not dietary fluoride.

Yet anti-fluoride activists are referring to the paper to claim that heart disease is linked to dietary fluoride intake, especially from fluoridated water. For example, Declan Waugh claimed:

“Current research has also identified the link between fluoride and atherosclerosis.³⁷⁰“

And yes his reference 370 is Li etal (2012) (see When politicians and bureaucrats decide the science).

The local anti-fluoride activist organisation Fluoride Action Network of New Zealand (FANNZ) today repeated this misinformation on their Facebook page (see Los Angeles Healthcare System Study Links Fluoride With #1 Cause Of Death – Cardiovascular Disease):

“The results of this study therefore have vast implications for our collectively becoming aware of one main contributing factor to the ongoing scourge heart disease, namely municipal water fluoridation. “

They also make similar claims on their webpage – see Fluoridation and Heart Disease):

“Research published in January 2012⁽¹⁾ concluded that there was a direct correlation between the fluoride level in arteries, including coronary arteries, and artherosclerosis . . . . . this unquestionably proves that fluoride does accumulate in soft tissue – something fluoridation promoters deny emphatically, claiming it all goes to the bones or teeth, and never the soft tissues.”

I repeat – the correlation reported is between atherosclerosis and the injected ¹⁸F. Nothing to do with dietary F intake at all. This correlation results from the fact the injected fluoride has an affinity with calcium and is therefore attracted to clacifying material . As the authors say:

“Currently, sodium [¹⁸F]fluoride positron emission tomography (PET)/CT is the most sensitive imaging modality to detect active bone formation”

And:

“Calcification in atherosclerosis occurs through an active process that resembles bone formation”

Misrepresentation by motivated confirmation bias

So a clear misrepresentation of a scientific paper. Is this a mistake or is it intentional?

Clearly there is motivated confirmation bias going on. Understandably these activists will select anything to fit their case, even to the extent of making such whopping mistakes. Perhaps one can understand an individuial making such a mistake if they are simply glancing through titles, or abstracts, looking for “ammunition.”

But this is a mistake that keeps repeating. And it get’s included in their “authoritative” statements. For example Declan Waugh’s report is often used in submissions to councils and the Hamilton City Council admitted to being impressed by it. They describe it as one of the key pieces of information that lead them to their mistaken decision to stop fluoridation (see When politicians and bureaucrats decide the science). You can down load their own assessment of the information they considered important  –Scientific research supporting the stopping of fluoridation. 

On the one hand activist organisations like this should take more care with the material they prepare. When mistakes like this are pointed out they lose their credibility.

On the other had bodies like city councils should take more care in accepting information from submitters. They should be aware of the ever-present problem of confirmation bias which is inevitable with activist groups. They should not be impressed by something that looks “sciency” with large numbers of references.

Above all, they should always seek expert advice, rely on information from people who have the skills to undertstand the scientific literature and be aware of these sorts of mistakes.

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