A major review of existing research into the health effects of community water fluoridation has found no negative effects associated with the practice.

Community water fluoridation is a public health practice that was introduced to improve dental health by reducing the incidence of tooth decay. Ireland fluoridates its water to 0.7 parts per million (ppm), well within the World Health Organization (WHO) guideline level of 1.5ppm.

The Health Research Board (HRB) is responsible for providing an overview of scientific evidence on potential benefits and risks of fluoridation at regular intervals to the Department of Health.

It has recently published an in-depth review of existing research in relation to the health effects of community fluoridation and according to its CEO, Dr Mairead O’Driscoll, this research “continues to find no definitive evidence that fluoridation is associated with negative health effects”.

The review examined the findings from 30 studies in nine countries, including Ireland. It focused on systemic health.

“We found no evidence for a link between fluoride and most conditions we examined, including bone health, cancer, kidney stones, birth and infant abnormalities and death rates.

“The findings on bone health and cancer are of interest. These conditions were flagged as areas for further monitoring in our review in 2015. This updated review has found no definitive evidence that fluoridation of water was linked to bone health and cancer,” explained HRB research officer and lead author of the report, Dr Kathryn Lambe.

The HRB said that two areas that require further monitoring are thyroid conditions and neuropsychological outcomes. However, the existing research in these areas is limited. Findings have been generally mixed and inconsistent and as a result, they have been unable to provide conclusive evidence of a link between fluoridated water and these outcomes.

New high-quality longitudinal studies, which track the same individuals over time, are needed. Going forward, the HRB will continue to monitor research in this area.

“With new studies emerging all the time, these reviews conducted by the HRB at regular intervals can help equip policy makers with the most up-to-date evidence base to inform decisions in relation to water fluoridation,” Dr O’Driscoll added.

A HRB review focusing on dental health is due to be published next year.