Water fluoridation, osteoporosis, fractures - recent developments

Background: Optimal (1ppm) water fluoridation is seen as the most socially equitable way to prevent dental caries, however concerns about the safety o f fluoridation are periodically raised. Methods: Research on effects on bone published since the 1991 National Heal th and Medical Research Council report on water fluoridation was reviewed. Results: Thirty-three studies were identified. Adverse effects in animal fe eding studies were only seen at doses much greater than those currently use d in artificial water fluoridation. The majority of animal studies showed n o effect or a beneficial effect of low fluoride doses. The results of ecolo gical studies were conflicting. One of the two cohort studies showed an inc rease in fracture incidence at fluoride levels four times greater than opti mal water fluoridation and the other showed no effect after 20 years' optim al fluoridation. The cross-sectional studies showed a favourable effect on bone mineral density. The clinical trials predominantly showed increased bo ne density in several sites associated with fluoride treatment of 9-22.6mg fluoride per day for one-four years. Conclusion: These studies provide a substantial body of evidence that fluor ide at up to 1ppm does not have an adverse effect on bone strength, bone mi neral density or fracture incidence.