Here About That Fluoridation Study

You may have heard of a meta-study that showed that fluoride in drinking water lowered IQs..

Rather unsurprisingly, the study is complete pants. 

It failed peer review multiple times, and they finally assembled a hand picked review committee, and then SELFpublished this as a monograph:

Federal toxicology researchers on Monday finally published a long-controversial analysis that claims to find a link between high levels of fluoride exposure and slightly lower IQs in children living in areas outside the US, mostly in China and India. As expected, it immediately drew yet more controversy.

The study, published in JAMA Pediatrics, is a meta-analysis, a type of study that combines data from many different studies—in this case, mostly low-quality studies—to come up with new results. None of the data included in the analysis is from the US, and the fluoride levels examined are at least double the level recommended for municipal water in the US. In some places in the world, fluoride is naturally present in water, such as parts of China, and can reach concentrations several-fold higher than fluoridated water in the US.

The authors of the analysis are researchers at the National Toxicology Program at the National Institute of Environmental Health Sciences. For context, this is the same federal research program that published a dubious analysis in 2016 suggesting that cell phones cause cancer in rats. The study underwent a suspicious peer-review process and contained questionable methods and statistics.

The new fluoride analysis shares similarities. NTP researchers have been working on the fluoride study since 2015 and submitted two drafts for peer review to an independent panel of experts at the National Academies of Sciences, Engineering, and Medicine in 2020 and 2021. The study failed its review both times. The National Academies' reviews found fault with the methods and statistical rigor of the analysis. Specifically, the reviews noted potential bias in the selection of the studies included in the analysis, inconsistent application of risk-of-bias criteria, lack of data transparency, insufficient evaluations of potential confounding, and flawed measures of neurodevelopmental outcomes, among other problems.

After the failing reviews, the NTP selected its own reviewers and self-published the study as a monograph in August.

And here is the money quote:

………

The study's primary meta-analysis only included 59 of the studies: 47 with a high risk of bias and 12 with a low risk. This analysis looked at standardized mean differences in children's IQ between higher and lower fluoride exposure groups. Of the 59 studies, 41 were from China.

Among the 47 studies with a high risk of bias, the pooled difference in mean IQ scores between the higher-exposure groups and lower-exposure groups was -0.52, suggesting that higher fluoride exposure lowered IQs. But, among the 12 studies at low risk for bias, the difference was slight overall, only -0.19. And of those 12 studies, eight found no link between fluoride exposure and IQ at all.

This study is General Jack Ripper raving about Russians attacking our purity of essence.