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Date reviewed: 10/10/2000 Fluoridated WaterVirtually all water contains fluoride. In the 1940s, scientists discovered that the higher the level of natural fluoride in the community water supply, the fewer the dental caries (cavities) among the residents. Currently, more than half of all Americans live in areas where fluoride is added to the water supply to bring it up to the level considered best for dental health. The possible relationship between fluoridated water and cancer has been debated at length. However, a February 1991 Public Health Service (PHS) report on the results of a year-long survey showed no evidence of an association between fluoride and cancer in humans. The survey, which involved a review of more than 50 human epidemiological studies produced over the past 40 years, led the investigators to conclude that optimal fluoridation of drinking water "does not pose a detectable cancer risk to humans as evidenced by extensive human epidemiological data reported to date." In one of the studies reviewed for the PHS report, scientists at the National Cancer Institute evaluated the relationship between the fluoridation of drinking water and the number of deaths due to cancer in the United States during a 36-year period, and the relationship between water fluoridation and number of new cases of cancer during a 15-year period. After examining more than 2.2 million cancer death records and 125,000 cancer case records in counties using fluoridated water, the researchers concluded that there was no indication of increased cancer risk associated with fluoridated drinking water. In 1993, the Subcommittee on Health Effects of Ingested Fluoride of the National Research Council conducted an extensive literature review concerning the association between fluoridated drinking water and increased cancer risk. The review included more than 50 human epidemiological studies and six animal studies. The Subcommittee concluded that none of the data demonstrated an association between fluoridated drinking water and cancer. A recent report by the Centers for Disease Control and Prevention supported these findings. The report concluded that studies to date have produced "no credible evidence" of an association between fluoridated drinking water and an increased risk for cancer. The Environmental Protection Agency (EPA) Web site has more information about drinking water and health. It includes information about drinking water quality and standards. The Web site is located at http://www.epa.gov/safewater/dwhealth.html on the Internet. References Bucher JR, Hejtmancik MR, Toft JD 2d, Persing RL, Eustis SL, Haseman JK. Results and conclusions of the National Toxicology Program's rodent carcinogenicity studies with sodium fluoride. International Journal of Cancer 1991;48(5):733737. Centers for Disease Control and Prevention. Public Health Service report on fluoride benefits and risks. Journal of the American Medical Association 1991;266(8):10611062, 10661067. Centers for Disease Control and Prevention. Achievements in public health, 19001999: fluoridation of drinking water to prevent dental caries. Morbidity and Mortality Weekly Report 1999;48(41):933940. National Research Council, Subcommittee on Health Effects of Ingested Fluoride. Carcinogenicity of Fluoride. In: Health Effects of Ingested Fluoride. Washington, D.C.: National Academy Press, 1993. National Toxicology Program. NTP technical report on the toxicology and carcinogenesis studies of sodium fluoride (CAS No. 7681494) in F344/N rats and B6C3F1 mice (drinking water studies). In: Toxicology and carcinogenesis studies of sodium fluoride. Research Triangle Park, NC: U.S. Department of Health and Human Services, 1990. United States Department of Health and Human Services, Committee to Coordinate Environmental Health and Related Programs, Ad Hoc Subcommittee on Fluoride. Review of fluoride benefits and risks: report of the Ad Hoc Subcommittee on Fluoride of the Committee to Coordinate Environmental Health and Related Programs. Washington, D.C.: Public Health Service, Department of Health and Human Services, 1991. Sources of National Cancer Institute Information
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