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Reposting a more skeptical comment to provide some balanced responses: https://old.reddit.com/r/slatestarcodex/comments/cslscx/is_f...

>Sci-Hub Link: https://sci-hub.se/10.1001/jamapediatrics.2019.1728

>Study itself: https://sci-hub.se/10.1001/jamapediatrics.2019.1729

>A decent amount of this is focused on Black Tea consumption during pregnancy which is apparently a problem: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4808922/

>Collected skeptical commentary at the Science Media Centre: https://www.sciencemediacentre.org/expert-reaction-to-study-...

>First, the claim that maternal fluoride exposure is associated with a decrease in IQ of children is false. This finding was non-significant (but not reported in the abstract). They did observe a decrease for male children and a slight increase in IQ (but non-significant) for girls. This is an example of subgroup analysis – which is frowned upon in these kinds of studies because it is nearly always possible to identify some subgroup which shows an effect if the data are noisy. Here the data are very noisy. A further issue is that the estimate of the decrease in IQ for male offspring is unfeasibility large – at 4-5 IQ points. This level of average deficit would be readily detectable in previous studies and is likely a reflection of bias or very noisy data (the interval estimate here is very wide). As high fluoride areas are not randomly assigned there are also countless uncontrolled confounders. While they did correct for a limited set of covariates, the overall effect was non-significant with and without covariates. In summary it is not correct to imply that the data here show evidence of a link between maternal fluoride exposure and IQ. The average change in IQ is not statistically significant.

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