Opponents of water fluoridation are fast to quote a 2019 Canadian research (Inexperienced et al.) to say that fluoride impacts the IQ of three and 4 yr previous kids. A brand new peer-reviewed evaluation refutes the validity of this research, displaying 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 information set.
The brand new evaluation, authored 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 “needs to be thought-about unacceptable for authorized and coverage functions.”
Vital Flaws
After analyzing information from the Maternal-Toddler Analysis on Environmental Chemical compounds (MIREC) research, Inexperienced et al stated they discovered an affiliation between fluoride publicity and IQ. The first end result of this research was supposed to indicate whether or not there are variations in IQ ensuing from fluoride publicity. The authors in contrast the typical IQ rating between fluoridated and non-fluoridated Canadian cities, discovered that the scores have been practically equivalent, however didn’t spotlight this. As a substitute, they carried out a subsequent evaluation that the MIREC research was not designed to help. MIREC gathered “spot urine samples,” which the Inexperienced et al. authors claimed might measure fluoride publicity of particular person pregnant ladies.
The Guichon paper cites the conclusions of consultants that spot samples of urinary fluoride will not be a legitimate measure of a person’s publicity to fluoride. As well as, the measurement of the kids’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 research as a result of finest observe requires the assessments to be administered by the identical particular person, generally known as an examiner. On this occasion, the IQ assessments in every metropolis have been administered by totally different examiners. In that case, Inexperienced et al. ought to have offered an evaluation of the affect of utilizing totally different take a look at examiners. They didn’t. For these causes, the Guichon paper concluded that MIREC information “can’t be used to make claims that fluoride publicity impacts IQ.”
Reliability
Along with Guichon, the authors of this paper embody Andrew Rugg-Gunn and Colin Cooper. Rugg-Gunn is a British scientist and worldwide professional within the measurement of fluoride consumption. Cooper is a British psychologist who has authored greater than a dozen books, chapters or scientific articles about human intelligence and associated subjects. 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 a crucial concern as a result of fluoride is widely known as a vital solution to forestall tooth decay, the most typical continual illness for each kids and adults. Water fluoridation is really helpful by the American Academy of Pediatrics, American Dental Affiliation, American Public Well being Affiliation, and different main well being, medical and dental organizations.
The failings of a analysis paper usually don’t come to mild till lengthy after publication. Journals ought to maintain authors to excessive requirements, for instance, by following the lead of BMC Public Well being, which retracted a fluoride-IQ research after analyzing critical considerations concerning the strategies used on this research.
The Weight of the Proof
Past the brand new evaluation, the security of fluoridation was additional demonstrated by a 2023 meta-analysis of eight research that reported “fluoride publicity related to neighborhood water fluoridation shouldn’t be related to decrease IQ scores in kids.”
There was just one fluoride-IQ research to comply with people over a 30-year interval, testing their IQs at a number of ages to find out if a hyperlink existed. That New Zealand research discovered no hyperlink between fluoride and IQ scores. Analyses of information 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 fluoridated water is protected and efficient, decreasing tooth decay by 25% for kids and adults. Thousands and thousands of individuals all world wide obtain vital dental well being advantages as a result of their faucet water incorporates fluoride on the really helpful stage to forestall tooth decay.
Whereas new analysis on fluoride and fluoridation is vital, to be thought-about a sound contribution the research design of that analysis should embody legitimate measures of exposures and well being outcomes.