Published: 10 November 2022

Impact of community water fluoridation on systemic health excluding oral health. An evidence review

Community water fluoridation was introduced in Ireland in 1964 as a public health measure to prevent tooth decay. It is important for policymakers to keep up to date with the international research on the effects of community water fluoridation, so that the benefits and possible harms are known.

In 2015, the Health Research Board’s Evidence Centre published an evidence review that found that there was no definitive evidence that water fluoridation at optimal levels (0.4–1.5 ppm) had a negative impact on general or systemic health. However, it is essential, and required by legislation, to continuously monitor and evaluate the evidence to ensure that no new safety issues are identified.

This 2022 review updates the 2015 review and collates English-language research published between 1990 and 2021, based on a comprehensive search. A total of 30 studies reported across 37 papers from nine countries were identified and included in the review.

We found that there continues to be no definitive evidence that community water fluoridation has negative health effects. We found no conclusive evidence for a link between water fluoridation and bone health, cancer, kidney stones, birth and infant abnormalities, and death rates. The evidence is generally of low quality and most of the studies included, due to their designs, cannot provide evidence for causal relationships. Neuropsychological and thyroid outcomes emerged as areas requiring further monitoring, as the existing research is inconclusive and limited in scope. Overall, further high-quality research examining community water fluoridation and neuropsychological and thyroid outcomes is needed.



  • Kathryn Lambe
  • Ailish Farragher
  • Tonya Moloney
  • Salome Sunday
  • Jean Long

Publication (PDF, 3 MB)

Publication (PDF, 3 MB)

Health Research Board
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