New research examines the link between maternal consumption of fluoridated water and lower IQs in their children.According to recent estimates, 66% of all United States residents receive fluoridated water through their taps. Adding fluoride to drinking water has been a public health practice for decades, with the main purpose of preventing tooth decay and preserving oral health.
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However, recently, there have been concerns about the safety of fluoride. Previous observational studies have found an association between exposure to fluoridated drinking water and lower intelligence scores in children.
Furthermore, fluoride can cross the placenta, and it tends to accumulate in brain areas responsible for learning and memory.
So, researchers — many from York University, in Toronto, Canada — have wondered whether a mother's exposure to fluoridated tap water during pregnancy affects her offspring's intelligence scores.
Rivka Green, from York University's Faculty of Health, is the lead author of the new study, which appears in the journal JAMA Pediatrics.
The possible effects of fluoride in water
Green and colleagues explain the motivation for their research, saying that while previous observational studies have found a link between drinking fluoridated water and reduced child IQ scores, these studies did not assess "exposure during fetal brain development."
So, the current study included 601 pairs of mothers and their children, who resided in six cities across Canada. The children were aged 3–4 years, and 41% of the mother-child pairs lived in communities with fluoridated tap water.
The researchers used two measures of fluoride exposure during pregnancy: They used data on "maternal urinary fluoride (MUF) concentrations" as well as self-reported intake of tap water and other drinks containing water, such as tea and coffee.