Fluoride has long been added to most of the tap water in the United States to help prevent tooth decay. But a new study shows that fluoridated water may hamper the brain development of unborn babies.
The study collected data from 220 mother-child pairs, examining fluoride levels during pregnancy and child behavior at age 3. A 0.68 milligram increase per liter in fluoride exposure was linked to nearly double the chance of a child showing clinically-significant neurobehavioral problems at age 3. The neurobehavioral issues included emotional reactivity, somatic complaints (such as headaches and stomachaches), anxiety and symptoms linked to autism.
MORE: New measles case reported in Philadelphia region
The results of this study – the first in the U.S. – adds to the "... weight of the scientific literature" that "... supports an association of prenatal fluoride exposure with adverse child cognitive and neurobehavioral development in North America," the authors wrote.
The National Institute of Dental Research began fluoridating most of the U.S. water supply in 1948 after research showed that adding fluoride to water at safe levels helped fight cavities. Philadelphia's drinking water is fluoridated at 0.6 to 0.8 mG/L, according to the water department.
"Our findings are noteworthy, given that the women in this study were exposed to pretty low levels of fluoride — levels that are typical of those living in fluoridated regions within North America," Ashley Malin, lead author of the study and an assistant professor of epidemiology at the University of Florida said in a statement. Malin conducted the research as a postdoctoral scholar at the university's Keck School of Medicine.
In recent years, hundreds of U.S. communities have stopped adding fluoride to their water supplies or voted to prevent its addition. The supporters of this movement say that people should be given the choice whether they want to add fluoride to their drinking water, noting the availability of dental products that contain fluoride. The Centers for Disease Control and Prevention has deems fluoride safe and effective at preventing tooth decay.
The latest study, published Monday in the medical journal JAMA, was conducted by researchers at the University of California with partial funding from the National Institutes of Health.
Data for the study came from the Maternal and Developmental Risks from Environmental and Social Stressors Center for Environmental Health Disparities at the Keck School of Medicine, which follows predominantly Hispanic families in Los Angeles from pregnancy throughout childhood.