Tag Archives: Riddell

Author confirms anti-fluoridation activist misrepresentation of her work

Anti-fluoride activists like Paul Connett often distort scientific findings and misrepresent studies. Authors should not give him a free pass and should expose such misinformation about their findings. Image credit: World Congress for freedom of scientific research

Paul Connett, director of the Fluoride Action Network (FAN),  claims “You only have to read four studies…” to come to the conclusion that community water fluoridation (CWF) is bad for your health. One of the studies he refers to is that of Riddell et al (2019) and Connett claimed that this study found “a staggering 284% increase in the prevalence of ADHD among children in fluoridated communities in Canada compared to non-fluoridated ones.”

I commented on this claim in my article Anti-fluoridation propaganda now relies on only four studies. 3: Riddell et al (2019) saying:

“This is just so wrong – Connett has misinterpreted the findings in this paper and completely covered up the fact that the results were dependent on age. He may well be “staggered” but he has made a bad mistake.”

Now, the senior author of this paper has confirmed that Connett was mistaken. She has confirmed that Connett is misrepresenting her work.

I emailed Julia Riddell to check if the Table 4 in her paper was mislabeled because some of the results were from linear regression analyses rather than logical regression analyses (see Anti-fluoridation propaganda now relies on only four studies. 3: Riddell et al (2019)). I also took the opportunity to ask her about Connett’s claim.

In her response she writes:

“I agree with you that the statement “a staggering 284% increase in the prevalence of ADHD among children in fluoridated communities in Canada” is a misinterpretation of our results, . . “

Riddell gives two reasons for saying this:

“First, a percentage should only be used to calculate values that are part of a whole, and thus a percentage is not an appropriate descriptive statistic to discuss these results. Further, and more importantly, I believe this interpretation of the odds ratio is incorrect. Odds is not probability nor is it likelihood of a ADHD diagnosis. Instead, odds = probability(ADHD dx) / probability(no ADHD dx).

In order to calculate a percent increase in the prevalence of ADHD, we would need to know the base rate probability of an ADHD diagnosis in the absence of water fluoridation (that is, what is the prevalence of ADHD ONLY in non-fluoridated communities).”

She writes: “To my knowledge, there has never been a national prevalence rate of ADHD calculated only for non-fluoridated regions, which is why we didn’t interpret the results in this way in our paper.” However, she provides an estimate using a postulated ADHD base rate of 0.08 (8% prevalence). According to her the Odds Ratios she reported in her paper would mean fluoridation would increase ADHD prevalence from 8% to 10%.

This is very different from Paul Connett’s claim. He should withdraw his claim and apologise for his mistake.

Two questions

Paul Connett’s little fiasco raises two questions for me:

1: Will Paul Connett now withdraw his claim and apologise for his mistake/misrepresentation?

I guess the answer is “when Hell freezes over.” He is not known for such apologies – neither is the anti-fluoride movement he leads. It continually misrepresents scientific findings and has never, in my experience, apologised for that misrepresentation when it has been exposed.

In fact, the anti-fluoride movement’s main propaganda thrust relies on citing any scientific work it can present, or misrepresent, as harmful to the case for community water fluoridation. This way it pretends to have the backing of science while relying on the unwillingness or inability of policymakers they bombard with the propaganda to factually check out these claims.

2: Why are researchers not more proactive in countering misrepresentation of their findings like this?

Yes, I know, researchers and especially their institutions do not like to enter into public debates with activists. There is some logic in this – after all, there is the old adage that it is not worth wrestling a pig because the pig enjoys it and both sides end up covered in dirt.

But this particular case is an example of misrepresentation which is being promoted to health policymakers who mainly do not have the scientific skills to check out the claims. It’s not a matter of entering into an unsavoury fight – but of correctly informing these policymakers when such misrepresentation occurs.

The other concern I have is that some anti-fluoride activists, including some well-known members (sometimes paid members) of Paul Connett’s FAN, have developed links with researchers and appear to be influencing publications through the journal peer-review process. In my article Anti-fluoridation propaganda now relies on only four studies. 6: Incestuous relationship of these studies I show how incestuous the publication and peer review process is for some of the scientific papers currently being promoted by anti-fluoride activists. Perhaps this is not too uncommon in science publication (many scientists complain about this sort of thing happening). But the participation of FAN members in the journal peer-review process is worrying as it suggests a relationship which FAN can use to get information about upcoming papers and prepared their propaganda and misinformation claims accordingly.

On the one hand, this may mean authors are hesitant to criticism FAN members and their claims because this could rebound on them during the publication process. On the other hand, it surely means that these people should be treated as valid science commentators and therefore open to challenge by researcher without the stigma of entering into an activist debate.

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Anti-fluoridation propaganda now relies on only four studies. 3: Riddell et al (2019)

Connett promotes Riddell et al (2019) as one of the only four studies one needs to read about fluoridation. But he misunderstands and misrepresents the findings of this study. Image credit: Fluoride Action Network – with my addition.

For earlier articles in this series see:

Part 1: Anti-fluoridation propaganda now relies on only four studies. 1: Bashash et al (2018).

Part 2: Anti-fluoridation propaganda now relies on only four studies. 2: Green et al (2019).

Paul Connett, director of the Fluoride Action Network (FAN), now claims “You only have to read four studies…” to come to the conclusion that community water fluoridation (CWF) is bad for your health. As I said in the first article in this series that is simply bad science. One should not ignore all the other relevant studies – and anyway, these four studies do not say what Connett claims.

In this article, I discuss the third study Connett recommends. It’s citation is:

Riddell, J. K., Malin, A., Flora, D., McCague, H., & Till, C. (2019). Association of water fluoride and urinary fluoride concentrations with Attention Deficit Hyperactivity Disorder in Canadian Youth. Submitted to Environment International, 133(May), 105190.

Riddell et al (2019)

Connett switches his attention from IQ to ADHD saying:

 “The third came in 2019 and found a staggering 284% increase in the prevalence of ADHD among children in fluoridated communities in Canada compared to non-fluoridated ones.”

This is just so wrong – Connett has misinterpreted the findings in this paper and completely covered up the fact that the results were dependent on age. He may well be “staggered” but he has made a bad mistake.

The results reported in Riddell et al (2019) are a mixed bag and somewhat confused – see Table 4. They could not find any significant effect of urinary F (UF) on the diagnosis of ADHD – a result that disappointed them as they understood UF to be the most reliable measure of fluoride exposure. They did find a significant effect of CWF status on ADHD diagnosis (increase odds of diagnosis) but only for older children. There was also a significant effect for water-F.

Table 4: Results of logical regression of ADHD diagnosis against measures of fluoride exposure obtained by Riddell et al (2019). Red tringel indicates significant effect.

But Connett confused himself when attempting to interpret Riddell’s results for the effect of CWF – probably because he did not understand the difference between linear and logical regressions. Riddell et al (2019) did not use data for ADHD prevalence (as Connett implied) so could not produce a relationship of prevalence to CWF. Their data was binary – ADHD diagnosis vs no ADHD diagnosis – and they determined the chance of an ADHD diagnosis in fluoridated compared with unfluoridated areas. Here is how they describe that result:

“Specifically, at the 75th percentile of age (14 years old), the predicted odds of an ADHD diagnosis was 2.8 times greater among youth in a fluoridated region compared with youth in a non-fluoridated region (aOR=2.84, 95% CI: 1.40, 5.76, p < .01), whereas among youth at the 25th percentile of age (9 years old), the predicted odds of an ADHD diagnosis was similar across CWF status (aOR=0.91, 95% CI: 0.41, 1.99, p=.81; Table 4).”

So there was no “staggering 284% increase in the prevalence of ADHD among children in fluoridated communities .  .” Just that the chance, or predicted odds, of an ADHD diagnosis was 2.84 times greater for 14-year-old youth in fluoridated areas (but the same for 9-year-olds). The odds ratio of 2.84 is still relatively small (see Rules of thumb on magnitudes of effect sizes). And Connett ignored the fact this result was age-specific.

They also report results for the hyperactivity/inattention subscale score from the Strengths and Difficulties Questionnaire (SDQ h/i). Again, no significant effect of UF but significant effects of CWF and water-F for older children. I won’t comment on this further because the data reported in the paper is confused – probably because of a mistake in the paper’s Table 4. I have emailed Julia Riddell about this problem but not yet had a reply.

Connett’s claim of a “284% increase in the prevalence of ADHD” due to fluoridation is simply wrong and demonstrated he did not understand the statistical analysis used in this paper. 

Tomorrow I will discuss the fourth study Connett now relies on – Till et al (2020) – see Anti-fluoridation propaganda now relies on only four studies. 4: Till et al (2020).

See also:

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