The AAP is continuing to recommend fluoride for caries prevention while expressing concerns about the validity of a new report linking high fluoride levels to lower IQ in children.
“While additional research to better understand the association and potential biologic mechanisms would be important, there’s nothing about the research that makes me concerned (about) … low levels of fluoride through use of toothpaste and drinking fluoridated water,” said Charlotte W. Lewis, M.D., M.P.H., FAAP, a member of the AAP Section on Oral Health.
The National Toxicology Program released a 324-page systematic review of published literature showing that 18 of 19 studies it deemed “high-quality” found higher levels of fluoride linked to lower IQ in children. Authors said they have “moderate confidence” in the association.
The report has important limitations. High fluoride exposure was defined as at least 1.5 milligrams per liter of water, which is double the concentration U.S. officials recommend in community water. Also, the studies included for analysis were geographically heterogeneous, with different study populations. Socioeconomic, physical, familial, cultural, genetic, nutritional, and environmental confounders affect IQ. It is unclear whether data on children’s IQ extracted from a variety of different studies are accurate, comparable, or generalizable, according to AAP experts.
The review was designed to evaluate the literature on exposure to fluoride and possible associations with IQ. It was not intended to determine if it is biologically plausible for fluoride to impact IQ or to demonstrate cause and effect. AAP experts said comparing the results of IQ tests that were not performed or assessed under similarly controlled conditions does not yield reliable conclusions.
Dr. Lewis, professor of pediatrics at the University of Washington School of Medicine and attending physician at Seattle Children’s Hospital, said authors left out large population-based studies that found no link between fluoride and IQ. She also noted the National Academies of Sciences, Engineering and Medicine twice rejected previous drafts of the NTP report.
“I’m concerned there are some questions about the validity of those (NTP) conclusions and that they’re not supported by the entirety of the research,” Dr. Lewis, said. “And they’re not really supported by other groups that have tried to do systematic analyses and meta-analyses looking at these results and have come to very different conclusions.”
Dental caries is one of the most common chronic diseases in children and can have lifelong consequences. It disproportionately impacts children who are racial minorities, come from low-income families or have special needs.
Fluoride is an effective way to prevent caries with decades of research supporting its safety and effectiveness. Communities that have stopped fluoridating water have seen dental caries increase.
The AAP continues to recommend children use age-appropriate amounts of fluoride toothpaste and drink optimally fluoridated water to protect their teeth. Children living in communities without fluoridated water should supplement with dietary fluoride. Fluoride varnish should be applied to children’s teeth as recommended by the U.S. Preventive Services Task Force.
“Like many things, you can’t take unlimited amounts of it,” Dr. Lewis said. “But within a narrow range, it’s … quite beneficial and it’s essentially transformed the oral health of our country by having it in the water supply.”
Resources
- AAP clinical report Fluoride Use in Caries Prevention in the Primary Care Setting
- AAP Campaign for Dental Health
- Information for parents from HealthyChildren.org on fluoride
