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ADA responds to study suggesting association between lower IQ and fluoridation

September 20, 2017

By Michelle Manchir

The ADA on Sept. 19 issued a response to a study published online the same day that suggested an association between higher prenatal fluoride exposure and lower IQ scores.

For the study, researchers examined 299 mother-child pairs in Mexico, including their general cognitive indexes and IQ analyses, and concluded that “higher prenatal fluoride exposure, in the general range of exposures reported for other general population samples of pregnant women and nonpregnant adults, was associated with lower scores on tests of cognitive function in the offspring at age 4 and 6–12 years.”

The findings, however, are not applicable to the U.S., according to the ADA’s news release, which also noted that the Association “continues to endorse fluoridation of public water as the most effective public health measure to prevent tooth decay.”

In responding to the study’s conclusions, the ADA noted that the intake of fluoride in Mexico “is significantly different from the U.S.,” because fluoride is added to salt and because fluoride naturally exists in varying degrees in community water. In the U.S., fluoride is not added to salt and is only added to water “in cases where the natural occurrence of fluoride is lower than the rec-ommended level to prevent tooth decay,” the ADA said.

Furthermore, it is unknown how the subjects of the study ingested fluoride — whether through salt, water, or both — so “no conclusions can be drawn regarding the effects of community water fluoridation in the U.S.”

The study, Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6–12 Years of Age in Mexico, was published in Environmental Health Perspectives.

The ADA endorses community water fluoridation as safe and effective for preventing tooth decay based on 70 years of scientific research. To see scientific evidence and other information about fluoridation, visit