Dental Groups Defend Fluoride After Study Implicates It in Lower IQs

Richard Gawel


A recent study published by JAMA Pediatrics suggests that there is a link between maternal exposure to fluoride during pregnancy and lower IQ scores measured in children ages 3 to 4. Now, the ADA, the American Academy of Pediatrics (AAP), and the Academy of General Dentistry (AGD) have responded to the study with full support for the use of fluoride in preserving oral health.

Conducted by a multi-institution team of researchers, the study used data on maternal urinary fluoride concentrations and children’s IQ for 512 mother-child pairs, with self-reported data on consumption of tap water and other water-based drinks such as tea and coffee as well as IQ scores for another 400 pregnant women.

The researchers found that a 1-mg/L increase in maternal urinary fluoride was associated with a 4.5-point lower IQ score in boys without a statistically significant association with IQ score in girls. Also, a 1-mg higher intake of fluoride was associated with a 3.7-point lower IQ score among boys and girls. 

While the researchers noted that their study was limited by its observational design which couldn’t account for unmeasured factors that could explain its results, and that it didn’t assess children’s fluoride exposure during infancy, they did conclude that their findings indicated a possible need to reduce fluoride intake during pregnancy.

Noting the attention this study has received, the ADA said it remains committed to fluoridation of public water supplies as the single most effective public health measure to help prevent tooth decay. It also welcomes this study as well as further studies to see if its findings could be replicated with methods that demonstrate more conclusive evidence. 

The ADA further cited more than 70 years of research and practical experience producing an overwhelming weight of scientific evidence indicating that fluoridation of community water supplies is safe. Since its introduction in 1945, the ADA added, community water fluoridation continues to be effective in reducing tooth decay by more than 25% in children and adults.

Meanwhile, the American Academy of Pediatrics also continues to recommend children drink fluoridated tap water and use age-appropriate amounts of fluoride toothpaste despite the study’s findings. 

“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, MD, MPH, chair of the AAP Section on Oral Health Executive Committee.

The AAP said that the results of the study are difficult to interpret given that the IQ difference was small and, in one group, it only appeared in boys. In the group where the association was seen for boys and girls, the fluoride intake was self-reported, which is less reliable. Plus, the study did not look at children’s fluoride intake, only that of pregnant women.

“The burden of dental caries is enormous in our patients. It’s also a big burden in pregnant women,” said Aparna Bole, MD, chair of the AAP Council on Environmental Health Executive Committee, “and we have plenty of evidence about the efficacy of community water fluoridation in reducing that burden of caries.”

Parents concerned about their child’s IQ may consider that dental disease causes children across the United States to miss more than 50 million hours of school each year, said Braun.

“We absolutely want kids to be in school and able to concentrate without pain,” Braun said, “so they can optimize their learning.”

The AGD agrees that, according to generally accepted scientific research, fluoride remains safe at the concentrations found in optimally fluoridated water and is a community health measure that benefits children and adults. The group also believes further research should be conducted before the public changes its water consumption habits, especially during pregnancy.

There are too many variables in the study to come to any definitive conclusion, the AGD said, including a lack of funding and a sample size too small to capture true demographics and other environmental or genetic influences. When used appropriately, the AGD asserts, fluoride is safe and effective in preventing and controlling tooth decay.  

“Fluoride helps prevent tooth decay while minimizing the occurrence of dental fluorosis. Fluoride helps prevent tooth decay by making teeth more resistant to acids that attack enamel and are derived from bacteria in the mouth and certain foods and drinks,” said Neil J. Gajjar, DDS, president of the AGD. 

“By drinking optimally fluoridated water, all members of society regardless of income, education, or ethnicity can benefit from better oral health, not just those who have access to dental care,” said Gajjar, adding that a significant number of pregnant women in particular do not visit a dentist during their pregnancy. 

“Dental care during pregnancy is not only safe and effective, but also essential for combatting the adverse effects of oral disease. During pregnancy, women should continue brushing their teeth twice a day and flossing once a day,” said Gajjar. “Simply put, regular fluoride use throughout life will help protect teeth.”

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