Fluoride Exposure in Utero Linked to Lower IQ in Kids, New Study Says
Fluoride Exposure in Utero Linked to Lower IQ in Kids, New Study Says
In a new study published on September 19, 2017, in the journal Environmental Health Perspectives, researchers have found a link between fluoride in the urine of pregnant women and lower measures of intelligence in children.
The Study:
M, D, Hu H, et al. 2017. Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6–12 Years of Age in Mexico.
Excerpt from study: In
this study, higher levels of maternal urinary fluoride during pregnancy
(a proxy for prenatal fluoride exposure) that are in the range of
levels of exposure in other general population samples of pregnant women
as well as nonpregnant adults were associated with lower scores on
tests of cognitive function in the offspring at 4 and 6–12 y old.
Comment from FAN:
The new study found a very large effect. An increase in urine fluoride of 1 mg/L was associated with a drop in IQ of 5 to 6 points. To put this into perspective with the fluoride levels ingested by the Mexican mothers and the levels ingested in fluoridated parts of the USA, the average fluoride intake in the Mexican mothers was about the same as that in women in the USA. It was not substantially higher. The range of fluoride levels in Mexico also corresponded closely to the range found in most of the USA. The higher levels were similar to what is found in areas in the USA with fluoridated water, and the lower levels were similar to what is found in most unfluoridated parts of the USA.Most of the Mexican women had urine fluoride between 0.5 and 1.5 mg/L. Studies have found that adults in the USA have between about 0.6 and 1.5 mg/L, almost exactly the same range. From the low end of that range to the high end is a difference of 1 mg/L which is what caused the 5 to 6 IQ point difference in the children of the study mothers.
This new study had fluoride exposures almost the same as what is found in fluoridating countries like the USA.
The paper shows the relationship between urine fluoride and IQ in the graph (Figure 2) reproduced here:
The data in this graph has been adjusted for numerous potential confounding factors like sex, birth weight, gestational age, and whether the mother smoked. Other potential confounders had already been ruled out, including lead, mercury, alcohol consumption during pregnancy, mother’s education, mother’s IQ, and quality of home environment.
FAN has redrawn this graph in simplified form to better illustrate the relationship found between mothers’ urine fluoride and
childrens’ IQ.
This simplified version of the graph highlights the range of urine fluoride levels common in women in the USA with the blue text and bracket. When comparing mothers at the low end to those at the high end of this range, the subsequent loss of IQ in their children was 6 points. The light red shaded zone around the relationship line is the 95% Confidence Interval and demonstrates that the relationship is statistically significant across the entire range of fluoride exposures.
Quotes:
Newsweek, Children’s IQ Could Be Lowered By Mothers Drinking Tap Water While Pregnant, by Dana Dovey, September 19:
… “This is a very well-conducted study,
and it raises serious concerns about fluoride supplementation in water,”
says Dr. Leonardo Trasande, a pediatrician who studies potential links
between environmental exposures and health problems at New York
University Langone Health. (He was not involved in the new study.)
Trasande emphasizes that the levels of
fluoride seen among the mothers in this study are slightly higher than
what would be expected in U.S., based on current fluoride
supplementation levels. However, he also explains that fluoride is known
to disrupt thyroid function, which in turn is crucial for brain
development.
“These new insights raise concerns that
the prenatal period may be highly vulnerable and may require additional
reconsideration,” Trasande says.
… Dr. Howard Hu, the study’s lead
investigator, and a professor of environmental health, epidemiology and
global health at [the University of Toronto’s] Dalla Lana School of
Public Health, says the fact that the fluoride levels in the mothers was
most predictive of the drop in test scores may be due to the fact that
the brains of babies develop so rapidly while they are in utero.
“This is consistent with a growing
appreciation in environmental health that the growing fetal nervous
system is more sensitive to exposures than a developed nervous system,”
he told CTVNews.ca by phone from Sydney.
… [The article quotes the lead investigator of the study, Dr Howard Hu:]
“This is a very rigorous epidemiology study. You just can’t deny it.
It’s directly related to whether fluoride is a risk for the
neurodevelopment of children. So, to say it has no relevance to the
folks in the U.S. seems disingenuous.”
… “Why would anybody rate the equivalency
or supremacy of reducing tooth decay by about one cavity a lifetime
when what’s at stake is the mental development of your children? It’s
utterly preposterous,” said Connett, executive director of the Fluoride
Action Network.
Press Releases:
University of Toronto: Higher levels of fluoride in urine associated with lower intelligence in children. The study’s lead investigator, Dr Howard Hu, is Professor of Environmental Health, Epidemiology and Global Health at the University’s Dalla Lana School of Public Health. September 19.
… “Our study shows that the growing fetal
nervous system may be adversely affected by higher levels of fluoride
exposure,” said Dr. Howard Hu, the study’s principal investigator … “It
also suggests that the pre-natal nervous system may be more sensitive to
fluoride compared to that of school-aged children.”
American Dental Association Response to Study Regarding Fluoride Intake in Mexico. September 19.
The American Dental Association (ADA)
examined a study in Environmental Health Perspectives based on fluoride
intake in Mexico, and concludes the findings are not applicable to the
U.S. The ADA continues to endorse fluoridation of public water as the
most effective public health measure to prevent tooth decay…
Fluoride Free New Zealand issued this press release New US Government Study on Fluoride Damage to Brain on September 21.
[In response to the study] Fluoride Free
New Zealand is calling on the 23 councils (out of the total of 67) that
still fluoridate, to urgently implement a moratorium on fluoridation to
protect the brains of children being born today in their community… This
is particularly relevant to New Zealand where half of the population is
currently subjected to fluoridation…
Articles:
CTV (Canadian TV), Higher levels of fluoride in urine linked to lower IQ scores in children, by Angela Mulholland, September 19.Collective Evolution, Fluoride exposure in utero linked to lower IQ in kids, study says, by Kalee Brown, September 20.
Daily Mail (UK), Pregnant women exposed to flouride are more likely to have kids with low IQ, study shows, by Mia De Graaf, September 20.
Medical Xpress, Higher levels of fluoride in pregnant woman linked to lower intelligence in their children, by Nicole Bodnar, September 20.
Montreal Gazette: Researchers urge caution over study linking fluoride exposure in pregnancy to lower IQs in children, by , September 20.
Newsweek, Children’s IQ Could Be Lowered By Mothers Drinking Tap Water While Pregnant, by Dana Dovey, September 19.
Readers’ Digest, If you drink this type of water during pregnancy, your child’s IQ could suffer, by Sam Benson Smith, September 20.
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