Opponents of fluoride in water are fast to quote a 2019 Canadian examine (Inexperienced et al.) to say that fluoride impacts the IQ of three and 4 yr outdated kids. A brand new peer-reviewed evaluation refutes the validity of this examine, exhibiting that the Canadian researchers relied on invalid measures of each fluoride publicity and IQ. For years, opponents have promoted this and different Canadian research which have misused the identical knowledge set.
The new evaluation, by Guichon, Cooper, Rugg-Gunn, and Dickinson, particulars the intense weaknesses in these research. It cautions that claims about fluoride and IQ based mostly upon them “must be thought-about unacceptable for authorized and coverage functions.”
Vital Flaws
After analyzing knowledge from the Maternal-Toddler Analysis on Environmental Chemical compounds (MIREC) examine, Inexperienced et al stated they discovered an affiliation between fluoride publicity and IQ. The first consequence of this examine was supposed to point out whether or not there are variations in IQ ensuing from fluoride publicity. The authors in contrast the common IQ rating between fluoridated and non-fluoridated Canadian cities. They discovered that the scores have been almost equivalent however didn’t spotlight this. As an alternative, they carried out a subsequent evaluation that the MIREC examine was not designed to assist. MIREC gathered “spot urine samples,” which the Inexperienced et al. authors claimed may measure fluoride publicity of particular person pregnant ladies.
The Guichon paper level to the conclusions of specialists saying spot samples of urinary fluoride are usually not a sound measure of a person’s publicity to fluoride. As well as, the measurement of the youngsters’s IQs was considered as unreliable. The paper questions the reliability of the IQ scores reported for the three and 4 yr olds within the examine. Greatest practices name for assessments to be administered by the identical individual, generally known as an examiner. On this occasion, the IQ assessments in every metropolis have been administered by totally different examiners. That’s the reason Inexperienced et al. ought to have additionally supplied an evaluation of the impression of utilizing totally different take a look at examiners. They didn’t. For these causes, the Guichon paper concluded that MIREC knowledge “can’t be used to make claims that fluoride publicity impacts IQ.”
Reliability
Along with Guichon, the authors of this paper embrace Andrew Rugg-Gunn and Colin Cooper. Rugg-Gunn is a British scientist and worldwide knowledgeable within the measurement of fluoride consumption. Cooper is a British psychologist who has authored greater than a dozen books and scientific articles about human intelligence and associated matters. The fourth co-author, James Dickinson, is an epidemiologist and professor of Household Medication on the College of Calgary, in Canada.
The reliability of fluoride-related research is an important challenge. Fluoride is widely known as a vital option to forestall tooth decay, the most typical persistent illness for each kids and adults. Water fluoridation is supported by the American Academy of Pediatrics, American Dental Affiliation, American Public Well being Affiliation, and different main well being, medical and dental organizations.
Analysis flaws usually don’t come to gentle till lengthy after publication. Journals should maintain authors to excessive requirements, for instance, by following the lead of BMC Public Well being which retracted a fluoride-IQ examine after analyzing severe considerations in regards to the strategies used on this examine.
The Weight of the Proof
Past the brand new evaluation, the security of fluoridation was additional demonstrated by a 2023 meta-analysis of eight. It reported that “fluoride publicity related to group water fluoridation is just not related to decrease IQ scores in kids.”
There was just one fluoride-IQ examine that adopted individuals over a 30-year interval, testing their IQs at a number of ages to find out if a hyperlink existed. That New Zealand examine discovered no hyperlink between fluoride and IQ scores. Analyses of knowledge from Australia, Denmark, Spain, and Sweden even have revealed no affiliation between fluoride and cognitive deficits.
Right here within the U.S., the Facilities for Illness Management and Prevention continues to report that fluoride in water is protected and efficient, decreasing tooth decay by 25% for kids and adults. Tens of millions of individuals all around the globe obtain vital dental well being advantages as a result of their faucet water incorporates fluoride on the really helpful degree to stop tooth decay.
Whereas new analysis on fluoride and fluoridation is essential, to be thought-about a sound contribution the examine design of that analysis should embrace legitimate measures of exposures and well being outcomes.
