For earlier articles in this series see:
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 fourth study Connett recommends. It’s citation is:
Till, C., Green, R., Flora, D., Hornung, R., Martinez-mier, E. A., Blazer, M., … Lanphear, B. (2020). Fluoride exposure from infant formula and child IQ in a Canadian birth cohort. Environment International, 134(September 2019), 105315.
Till et al (2020)
Finally, according to Connett:
“The fourth* came in 2020, when it was reported that children who were bottle-fed in fluoridated communities in Canada lost up to 9 IQ points compared to those in non-fluoridated communities.”
This claim is just not true as Table 5 below shows. There is no significant difference in IQ (FSIQ) of children, who had been bottle-fed as babies, between fluoridated (mean IQ 106.1) and unfluoridated (mean IQ 106.8) areas. The only difference Till et al (2020) saw between fluoridated and unfluoridated areas was a significant increase of verbal IQ (VIQ – a subset of FSIQ) for breastfed children in fluoridated areas compared with non-fluoridated areas, and a significant decrease in performance IQ (PIQ a subset of FSIQ) for formula-fed babies in fluoridated areas compared with non-fluoridated areas.
Connett appears to have not read the Till et al (2020) paper, or misunderstood it. Perhaps his misunderstanding is derived from the relationships of cognitive measurements with drinking water F – although the relationships are not statistically significant for IQ (FSIQ) (see Table 6 below).
Then perhaps he is grasping at the straws offered by separating the IQ measurements into subsets – VIQ and PIQ. There were no significant relationships for VIQ but there are for the relationships of PIQ to drinking water F for both breastfed and formula-fed children. In fact a decrease of almost 8 PIQ points per 0.5 mg/L water fluoride concentration increase (which the authors argue is the increase seen with fluoridation).
This study has all the hallmarks of a desperate search for significant relations by using other measures of cognitive ability and fluoride exposure when the main relationship (that of FSIQ and CWF) proves not to be statistically significant. This approach, which statisticans are critical of, is common with most of the studies Connett relies on for his current claims.
There is also the problem that the authors in their abstract, and of course the anti-fluoride activists promoting the paper, basically ignore most of the relationships because they are not statistically significant and report only the significant ones – and even then often incorrectly (as does Connett who uses the term IQ inappropriately).
Connett is wrong. His claim that “bottle-fed in fluoridated communities in Canada lost up to 9 IQ points compared to those in non-fluoridated communities” is just plain wrong. In fact, the mean IQ values for bottle-fed children in fluoridated areas of Canada was 106.1 and in non-fluoridated areas was 106.8 according to this study.
Tomorrow I will discuss other studies Connett purposely ignores and attempts to cover up because he cannot construe them as supporting his anti-fluoride narrative – see Anti-fluoridation propaganda now relies on only four studies. 5: Don’t censor yourself.
- Beware of scientific paper abstracts – read the full text to avoid being fooled
- Anti-fluoride propagandists appear not to read the articles they promote
- Bottle fed infants: fluoridated water not a problem
- What are the recent fluoride-IQ studies really saying about community water fluoridation?
- Anti-fluoridationists put faith in new “strong” studies to provide evidence missing in draft NTP review