Public health impacts of water fluorides: Current evidence from a rapid systematic review

Fluoride is a naturally occurring mineral present in soil, food, and water supplies, with concentrations varying geographically. At low concentrations, fluoride is beneficial for dental health, particularly in preventing dental caries. However, higher concentrations of fluoride exposure are associated with adverse effects, such as dental fluorosis. To optimise oral health outcomes while mitigating risks, the World Health Organisation (WHO) recommends a maximum fluoride concentration of 1.5 mg/L in drinking water (WHO, 2017). Water fluoridation is the most globally practiced public health intervention to reduce the prevalence and severity of dental caries and reduce dental health inequalities. Approximately 400 million people across 25 countries are currently have access to artificially fluoridated water at a levels of 0.7-1 mg/L, while an additional 50 million people, worldwide, consume water with naturally occurring fluoride at comparable concentrations. A substantial body of evidence supports the benefits of water fluoridation for both children and adults, including the prevention of dental caries, reduction of oral health inequalities, and overall improvement in health outcomes (Young, 2015). A recently updated Cochrane systematic review of non-randomised studies (Iheozor-Ejiofor, 2024) reported that community water fluoridation, particularly for children, is associated with a reduction in decayed, missing (due to caries), and filled teeth over time (mean difference: 0.24, 95% confidence interval: -0.03 to 0.52, p = 0.09; based on two studies including 2,908 children). Despite its proven benefits, there is ongoing debate regarding the potential harmful effects of fluoride on human health. While extensive research highlights fluoride's benefits and the risks of both insufficient and excessive fluoride intake, understanding the broader human health implications of water fluoridation remains limited. This rapid review aims to systematically explore the existing literature on the human health impacts of water fluoridation. Unlike previous studies, which predominantly rely on narrative literature review methods, this review adopts systematic review methodology to synthesise evidence on the effects of water fluoridation on human health. Existing research in this area have mainly used a narrative literature review approach (Solanki, 2022). References: World Health Organization (2017) WHO Guidelines for drinking-water quality, fourth edition and WHO 2006 Young N, Newton J, Morris J, Morris J, Langford J, Iloya J, Edwards D, Makhani S, Verne J. Community water fluoridation and health outcomes in England: a cross-sectional study. Community Dent Oral Epidemiol. 2015 Dec;43(6):550-9. doi: 10.1111/cdoe.12180. Epub 2015 Jul 8. PMID: 26153549. Iheozor-Ejiofor Z, Walsh T, Lewis SR, Riley P, Boyers D, Clarkson JE, Worthington HV, Glenny A-M, O'Malley L. Water fluoridation for the prevention of dental caries. Cochrane Database of Systematic Reviews 2024, Yogendra Singh Solanki, Madhu Agarwal, A.B. Gupta, Sanjeev Gupta, Pushkar Shukla Fluoride occurrences, health problems, detection, and remediation methods for drinking water: A comprehensive review, Science of The Total Environment, Volume 807, Part 1, 2022.