Communities throughout Canada and the US add fluoride to their drinking water supplies to prevent dental cavities. As we’ve written about before, some opponents claim that the risk of adverse health effects outweighs the public health benefits of fluoridation. A recent report by the U.S. Public Health Service (US PHS) recommends an optimum fluoride concentration at the low end of the previously recommended range in order to reduce dental fluorosis. They did not find a link between fluoridation and any other adverse health impacts.
The US PHS recommended that the concentration of fluoride should be decreased to 0.7 mg/L. Health Canada’s Fluoride Expert Panel also recommended a 0.7 mg/L fluoride concentration in its 2008 report. Both found that at this concentration the risk of fluorosis – mottling of the tooth enamel – would be limited while still providing protection from cavities. The previous 1962 US PHS guidelines recommended a range between 0.7 mg/L and 1.2 mg/L, depending on the outdoor air temperature.
The change is based on new data showing:
- an increased prevalence of dental fluorosis in the US;
- there is no connection between children’s water intake and outdoor air temperature; and
- the contribution of fluoride in drinking water to total fluoride exposure.
The US PHS reviewed public comments raising concerns about the impact of fluoridation on bone fractures and skeletal fluorosis, carcinogenity, IQ and other neurological effects, endocrine disruption and other issues. For most concerns, it found that there was no evidence of a connection. For other concerns, such as the risk of skeletal fluorosis, it found that 0.7 mg/L was well below the concentration that could cause an adverse effect.
Although the US PHA has recommended a reduction, opponents of fluoridation are unlikely to find much support for their cause in this report.