Community water fluoridation: No evidence of negative effects on newborns

Peer-Reviewed Publication

University of Basel

Fluoride is used worldwide to prevent tooth decay – for example, in dental care products, table salt, and, in some countries, in drinking water. However, health concerns are raised, particularly in places where fluoride is added to drinking water. An international research team involving the University of Basel has evaluated data from over 11 million births and reached a clear conclusion.

Fluoride protects teeth by strengthening enamel, repairing early damage, and thus preventing tooth decay. In addition to toothpaste and mouthwash, fluoride is also used specifically to improve dental health across the entire population – especially among children from low-income families.

In Switzerland, this has been done since the 1980s, primarily by adding fluoride to table salt. In the US, fluoride has been added to drinking water since the late 1940s. The rollout happened gradually at the municipal level and today reaches more than 60% of the population.

Data from 11.5 million births

This practice has repeatedly been the subject of criticism. There are fears of possible adverse effects on infant health, which could manifest as lower birth weight or an increased risk of preterm birth. An international research team has therefore investigated whether the intake of fluoride via drinking water could have such effects. The analysis was based on data from approximately 11.5 million births in the US over 21 years.

The result is clear: “We couldn't find any negative effects,” says Dr. Benjamin Krebs, lead author of the study, which was published in the journal JAMA Network Open. Neither average birth weight, nor the duration of pregnancy, nor the risk of premature birth differed measurably when comparing changes before and after the introduction of community water fluoridation with regions that did not introduce fluoridation.

Criticism from the highest level

Public health measures are currently under critical scrutiny in the US: Secretary of Health and Human Services Robert F. Kennedy Jr. recently praised the state of Utah for banning the addition of fluoride to drinking water. He also called for a re-evaluation of recommendations on community water fluoridation. This is precisely where the study focuses: “It is important to review such population-wide measures in a methodologically sound way,” says Benjamin Krebs.

Studies claiming that fluoride is harmful have repeatedly caused a stir. “However, it is important to understand what studies actually measure and compare. Often, they merely show that certain effects occurred together. This does not necessarily mean that fluoride was the cause—other factors may also play a role,” says the economist.

Birth weight as an established health indicator

For their analysis, the researchers evaluated data from over 670 counties in the US collected between 1968 and 1988. They compared births before and after the introduction of community water fluoridation and related these changes to regions without fluoridation, in order to account for regional differences as well as broader time trends.

“Birth weight is a recognized indicator of newborn health,” explains Krebs. “It is particularly well suited for investigating possible effects during pregnancy, not least because we know exactly how long the unborn children were exposed to fluoride.” With their findings, the researchers support the recommendations made by the authorities to promote caries prevention.