Wednesday, August 8, 2012


A recent meta-analysis published in Environmental Health Perspectives has led to a wave of headlines announcing, "Harvard Study Finds Fluoride Lowers IQ." This is the result of a press release published by the NYS Coalition Opposed to Fluoridation, Inc. and picked up by a number of news outlets including Reuters. The press release is filled with scary sounding quotations from the meta-analysis and paints a very damning picture of water fluoridation. For example:
Harvard University researchers' review of fluoride/brain studies concludes "our results support the possibility of adverse effects of fluoride exposures on children's neurodevelopment." It was published online July 20 in Environmental Health Perspectives, a US National Institute of Environmental Health Sciences' journal (1), reports the NYS Coalition Opposed to Fluoridation, Inc. (NYSCOF)
"The children in high fluoride areas had significantly lower IQ than those who lived in low fluoride areas," write Choi et al.
Further, the EPA says fluoride is a chemical "with substantial evidence of developmental neurotoxicity."
All of which suggests that this new meta-analysis provides the smoking-gun evidence against fluoridation and clearly demonstrates the harms fluoridation poses to children. However, a closer look at the actual text of the meta-analysis reveals none of this to be true, and clearly demonstrates that the authors of the press-release are guilty of Eduction and Accent. Basically, they misrepresent how the study was conducted and what control groups were used. The best summary of what the meta-analysis actually said comes from Dr. Steven Novella, an academic neurologist at Yale University School of Medicine. He writes:
In other words – fluoridated water in the US has the same level of fluoride as the control or low fluoride groups in the China studies reviewed in the recent article, and the negative association with IQ was only found where fluoride levels were much higher – generally above EPA limits.
So, the meta-analysis actually showed that the levels of fluoridation in the US are generally safe, and are not associated with neurological damage to children, but that very high doses (higher than legally allowed in the US) could be damaging to children. Thus, in order for the authors of the press release about this meta-analysis to make their case, they needed to selectively misrepresent the original article and only emphasize the points that supported their anti-fluoridation position while ignoring the full scope of the report as it did not support their preconceived conclusions. And this is exactly what eduction and accent allowed them to accomplish. The problem is then further compounded by folks in the media mindlessly distributing the press release without first checking to see if the press release was accurate.

h/t to The Skeptic's Guide to the Universe

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