No; a new study from Ethiopia does not indicate fluoridation is bad for your bones

Anti-fluoride activists are continually citing scientific studies from areas of endemic fluorosis where dietary F intake is very high in their propaganda against community water fluoridation where F intake is low. Image credit: Science in the age of fake news

Anti-fluoride propagandists on social media have got into a bit of a frenzy about a new study using sonic scans to estimate bone quality. The propagandists are using it as “evidence” against community water fluoridation (CWF). But it simply is not relevant. The Ethiopian study looked at drinking water fluoride and urinary fluoride concentrations up to 15.5 mg/L whereas the fluoride concentration of drinking water in areas where CWF is used is about 0.5 mg/L

The study is:

Godebo, T. R., Jeuland, M., Tekle-Haimanot, R., Shankar, A., Alemayehu, B., Assefa, G., … Wolfe, A. (2020). Bone quality in fluoride-exposed populations: A novel application of the ultrasonic method. Bone Reports, 12(November 2019), 100235. https://doi.org/10.1016/j.bonr.2019.100235

The technique used by these researchers “measures the speed of sound waves (SOS) in bone, as influenced by a combination of bone parameters (e.g., microstructure, collagen composition, cortical thickness, and bone density) that are related to bone quality.” The SOS is reported in m/s.

Drinking water fluoride

Anti-fluoride activists have been citing this paper and telling councils in North America that fluoridation will lead to a decrease in bone quality of 15.8 m/s (measured by the sonic scanning method) for every 1 mg/L increase in drinking water F. This figure is taken from the abstract – “a 1 mg/L increase in F- in drinking water was related to a reduction of 15.8 m/s (95% CI: −21.3 to −10.3)” and is based on a fluoride concentration range of 0 to 15.5 mg/L. The relationship is shown in this figure from the paper:

SOS in all adults and F- concentrations in corresponding community water sources (r = 0.45, p < 0.0001).

But, of course, these drinking water concentrations are very much larger than anyone experiences where there is CWF. So I have extracted the data for the lower concentration levels – up to 4 mg/L. Still far too high for CWF. The resulting data shows no significant effect of drinking water fluoridation on bone quality:

SOS in all adults and F- concentrations in corresponding community water sources for lower drinking water F concentrations more relevant to CWF

The positive relationship (B= 12.326, 95% CI=-15.5, 40.1) is not statistically significant. The data does not show any effect of CWF on bone quality.

Urinary fluoride

The paper reported a similar situation for urine F – 24-hour collection. This is the figure from the paper:

Association between F- concentrations in drinking water and tibia SOS measures (r =0.36; p < 0.0001).

The anti-fluoride propagandist will quote the abstract of the paper:

“A 1 mg/L increase in 24-h urinary F-(range: 0.04–39.5 mg/L) was linked to a reduction of 8.4 m/s (95% CI: −12.7, −4.12) of adult tibial SOS.”

but, of course, those urine-F concentrations are very much higher than observed where CWF is used. Restricting the data to urine F concentrations lower than about 3.5 mg/L produces the following figure:

SOS in all adults and urinary-F concentrations in corresponding community water sources for lower urinary-F F concentrations more relevant to CWF

The negative relationship (B= -4.85, 95% CI=-54.37, 44.67) is not statistically significant. The data does not show any effect of CWF on bone quality. Urinary F data for people in areas where CWF is used is not well defined but values are generally less than 2 mg/L.

But the dedicated anti-fluoride activist doesn’t care about the facts

Health problems are common in areas of endemic fluorosis where dietary fluoride intake is excessive. This is a real problem in areas of the Middle East, Africa, China and India. Even in parts of Europe. So, of course, there are published scientific studies of these problems and it is not hard to find papers relating health problems to dietary fluoride intake.

But none of those studies are relevant to areas where CWF is used because dietary fluoride intake is very much lower.

That doesn’t stop dedicated anti-fluoride activists. They simply wildly exaggerate their claims – for example, they claim there are hundreds of studies showing that fluoride lowers the IQ of children but never mention that the overwhelming majority of those studies were made in areas of endemic fluorosis so are just not relevant to CWF

There is only a very small handful of studies possibly suggesting health problems from CWF. But all these are weak, suffer from poor statistical analysis or have produced conflicting and contradictory results. I mention some of these recent studies in my article What are the recent fluoride-IQ studies really saying about community water fluoridation?

Of course, these studies must be discussed – but they need to be discussed critically and intelligently. Not simply promoted together with the host of studies from areas of endemic fluorosis as an argument for stopping CWF.

It is the nature of social media that these sort of fake claims are easily promoted by anti-fluoride and anti-vaccination activists. The bone quality study discussed here is currently being pushed via Twitter to councillors in North American local governments. There are no attempts to analyse this or other studies – simply to promote them as “evidence” of problems with CWF

Social media is not going to go away and it is the responsibility of people in public office and policymakers to take such ideologically-motivated propaganda with a healthy grain of salt. All such claims need to be critically analysed. If the councillors receiving this information do not feel capable of making this analysis they should call on experts for advice.

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