New and controversial research published Monday suggests fluoride consumption by pregnant women may lower the IQ of their children.
The JAMA Pediatrics study by Canadian researchers found that pregnant women who drank more fluoridated water had children with lower intelligence scores at ages 3 and 4. Just 1 milligram more per day (about five cups of water) was linked to a loss of 3.7 IQ points for both boys and girls. But boys fared worse when researchers analyzed the amount of fluoride in pregnant women's urine rather than their water intake.
The research examined fluoride levels in the urine of 512 pregnant women in Canada during each trimester and included self-reported daily data on fluoride intake from water and other beverages for 400 pregnant women.
Fluoride as a potential neurotoxin "must now be given serious consideration," Boston Children's Hospital and Harvard Medical School neurologist David C. Bellinger wrote in an accompanying editorial. "If the hypothesis is true, the implications are worrisome."
Study authors wrote the new findings suggest a possible need to reduce fluoride intake during pregnancy.
According to the Atlanta-based Centers for Disease Control and Prevention, fluoride is defined as a naturally occurring mineral released from rocks into water, soil and air. But while all water contains some of the mineral, it's not usually enough to prevent tooth decay, the most common chronic disease in American children—one that disproportionately affects poor, young and minority populations. The American Academy of Pediatrics has long recommended fluoridated toothpaste and tap water for children and issued a statement following the new study's publication.
"There are thousands of articles pointing to the safety of community water fluoridation and we need to continue to look at the impacts, but this study doesn't change the benefits of optimally fluoridated water and exposure to fluoride," said Patricia A. Braun, professor of pediatrics at the University of Colorado and chair of the AAP Section on Oral Health Executive Committee.
The American Dental Association echoed those statements, saying it "remains committed to fluoridation of public water supplies as the single most effective public health measure to help prevent tooth decay." The American College of Obstetricians and Gynecologists also recommends pregnant women continue using fluoridated toothpaste but will consider new evidence in upcoming reviews.
"In the meantime," AAP officials noted in its official statement, "parents concerned about a child's IQ may consider that dental disease causes children across the country to miss over 50 million hours of school each year, according to Dr. Braun."
"This decision to publish this article was not easy," JAMA Pediatrics editor Dimitri A. Christakis wrote in an editorial accompanying the new study, highlighting the study's rigorous methods and sound hypotheses. But "scientific inquiry is an iterative process," he continued. "It is rare that a single study provides definitive evidence. This study is neither the first, nor will it be the last, to test the association between prenatal fluoride exposure and cognitive development."
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