Study Examines Link Between Fluoridated Water And IQ


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A new study published recently in JAMA Pediatrics appears to show that drinking fluoridated tap water while pregnant could lower the IQ of the child. Study author Christine Till, a neuropsychologist at Toronto’s York University, and her colleagues reported that their data suggested that Canadian women who drank fluoridated tap water while pregnant had children with slightly lower IQ scores than children whose mothers lived in cities that didn’t fluoridate their water.

The researchers obtained their data set from the Maternal-Infant Research on Environmental Chemicals study, or MIREC. That study, conducted by Canada’s public health department, tracked various measures for thousands of mothers who gave birth between 2008 and 2012. The study also measured the toddlers’ IQ after the children’s third birthday.

The authors of the new study estimated the fluoride intake of 400 women based on their reported consumption of tap water and black tea, which is high in fluoride, as well as the levels of fluoride in municipal water linked to the women’s postal codes. Some of the women lived in fluoridated cities and some did not. After controlling for factors such as household income and education, the researchers found that a 1 milligram daily increase in fluoride intake was associated with a 3.7-point drop in children’s IQ.

The Centers for Disease Control and Prevention (CDC) considers water fluoridation one of the 10 top health achievements of the past century, reducing the prevalence of cavities by about one-fourth. Amesheia Buckner, an agency spokeswoman, said, “Community water fluoridation is one of the most practical, cost-effective, equitable and safe measures communities can take to prevent tooth decay.” The American Academy of Pediatrics also recommends fluoride in toothpastes and tooth varnishes for children to prevent tooth decay.

According to the CDC, about 66 percent of people in the United States had fluoride in their drinking water as of 2014. There are still dozens of cities in the United States, like Portland, Oregon, that do not add fluoride to city water. Health experts in America are warning that public policy and drinking water consumption should not be changed on the basis of this study.