Anti-fluoride activists simply can’t help it. They will post on social media citations to anything they think shows that fluoride is harmful – even if the studies are completely irrelevant to community water fluoridation (CWF). This despite Paul Connett, director of the Fluoride Action Network (FAN), claiming “You only have to read four studies…” to come to the conclusion that CWF is bad for your health.
Connett claims that he has it all sewed up with these four studies from areas where CWF is used or fluoride exposure values are similar to that for CWF. So I thought this would mean activists would give up citing studies from areas of endemic fluorosis where fluoride exposure is much larger. But no – here we go again with FAN returning to the reliance on endemic fluorosis studies with the claim:
“NEW STUDY: Each 1.0 mg/L increment in [urinary fluoride] concentration corresponded with an increase in the prevalence of psychosomatic problems.”
The local fluoride Free NZ activist group (FFNZ) simply repeats the claim. Anti-fluoride activists have a consistent habit of simply repeating these sort of claims, together with citation, without bothering to actually check what the cited papers say or how relevant the study really is to their cause. These activists seem to make a hobby of this – one can see their work every day on Twitter and Facebook. If nothing else one has to admire their dedication to the cause, if not there understanding of what they cite.
In this case, the study is not at all relevant to CWF. Here is its citation.
Wang, A., Duan, L., Huang, H., Ma, J., Zhang, Y., & Ma, Q. (2020). Association between fluoride exposure and behavioural outcomes of school-age children: a pilot study in China. International Journal of Environmental Health Research, 00(00), 1–10.
Briefly, it reports results for a comparison of six behavioural scores for 325 resident school-age children (7–13 years old) living in Tongxu County of Henan Province in China with a measure of fluoride exposure (urinary fluoride using a single morning collected sample). There was no statistically significant relationship with of five of these behavioural scores (conduct problems, learning problems, Impulsive-hyperactive, anxiety or ADHD index) with urinary fluoride but there was with one – Psychosomatic problems.
It’s a very weak relationship – one has only to look at how the data is scattered in the figures in the paper to see this:
Notice that the urinary fluoride concentration (Fluoride in the graphs) cover a range much higher than is typical for areas where CWF is used – usually much less than 2 mg/L. Not surprising, as it is from an area of endemic fluorosis. Also noticeable is that some of the high fluoride value data points are outliers which of course will influence the statistical analysis.
Not all the data is available but extraction of the data from the figure for Psychosomatic Problems enabled me to check the effect of outliers at high urinary fluoride concentrations. When only the data for urinary fluoride concentrations below 3 mg/L are considered there is no statistically significant relationship. This is even more true when only the data for urinary fluoride concentrations below 2.5 mg/L is considered. And these concentrations are still higher than found for children living in areas where CWF is used.
This study is completely irrelevant to CWF. In fact, if only the low urinary fluoride concentrations more relevant to CWF are considered the study shows absolutely no negative effect of fluoride on child behaviour. If anything, the study actually could be used to support CWF.
But this does not stop anti-fluoride campaigners from promoting the study on social media as if it supported their arguments. I guess the promotion of irrelevant work like this is simply a result of the way they mine citations – promoting anything that could appear to indicate problems with fluoride -even when the studies are completely irrelevant. It’s also a result of the thoughtless way citations are used and studies are promoted by people who don’t understand or even bother to read the studies they cite and promote.