The case for fluoride

Skeletal fluorosis occurs in countries where the natural concentration of fluoride in water is more than 8 ppm and exposure is for 20 years or more. This is not a public health issue in Australia. Fluoride is indeed deposited in the bones, and gradually accumulates with time, but epidemiological studies do not indicate any causal association between fluoride and bone disorders. Studies of the effect of exposure to fluoridation on fracture incidence have shown fracture incidence to decrease, increase or remain unaffected. These results are inconsistent because the studies were poorly designed, using small numbers of people, different methods and differing fluoride levels. They did not always consider confounding factors such as age, diet, weight, physical activity, hormone therapy, alcohol use and smoking, all of which are well recognised influences on the risk of fractures.

The better designed studies suggest water fluoridated at optimal levels has a protective effect against hip fracture. Several well-designed studies after 1998 have similarly found either no increase in the risk of hip fracture or a reduced risk with optimally fluoridated drinking water. Dental fluorosis is a defect in the development of tooth enamel. The link between natural levels of fluoride in drinking water and dental fluorosis has been known for over 100 years. Fluorosis occurs at exposures to fluoride above the optimal level. Mildly fluorosed enamel is fully functional and resists acid attack better than enamel from low or optimally fluoridated areas. Dental fluorosis occurs in both fluoridated and non-fluoridated areas. Some overseas studies show the biggest increases in its incidence are in areas of non-fluoridated water supply.

Dental fluorosis is a result of total fluoride absorption from all sources - natural sources, fluoridated water, or inappropriate use of fluoride toothpaste and or supplements at a young age. It is acknowledged that children should not receive excessive amounts of fluoride, so much so that manufacturers formulate specific toothpaste for children and recommend its use in small amounts, to reduce the risk of mottled enamel. The crucial age for fluoride intake as a risk for dental fluorosis is from 22 to 26 months, the time of development of the permanent front teeth. Adults do not develop dental fluorosis. Dental fluorosis is undesirable but not a threat to health. It is not as disfiguring or disabling as severe tooth decay or missing teeth.

Claims that fluoride is allergenic are not supported. Evidence shows that fluoride is unlikely to produce effects on the immune system. There is strong evidence against suggestions linking Down syndrome to fluoridation. Claims that optimally fluoridated water causes repetitive strain injury (RSI), sudden infant death syndrome (SIDS), diminished intelligence or Alzheimer’s disease are unsubstantiated. The Alzheimer’s Association itself supports fluoridation to help maintain the dental health of those with dementia.

The assertion that fluoride has “been largely ignored in Australia as a toxic chemical” is incorrect. Fluoride has been subject to considerable and continuing investigations regarding all aspects of human health. It is trite to suggest that fluoride is “the protected pollutant”, since it has undergone intensive scientific scrutiny over many years, and is still considered a benign and efficacious means of preventing tooth decay.

In many countries, particularly in Europe, where for technical or other reasons it is not feasible to fluoridate the water supply, table salt or milk are fluoridated. Indeed, the health effects of fluoride have been reviewed by “socially responsible chemists and biochemists”, and their deliberations and conclusions conveyed to both the Commonwealth Government, through the NHMRC, and the Victorian Government, in an independent enquiry, and through the Department of Human Services.

In Australia in the 1950s, dental decay in children and adults was uniformly and uncontrollably high across social and demographic boundaries. In 1953, the Tasmanian town of Beaconsfield was the first in Australia to add fluoride to a public water supply. During the 1960s and 1970s, water fluoridation was introduced in most Australian capital cities. Dental decay has since declined in most Australian children to about 10 per cent of what it was in the 1950s. About three quarters of Australians receive the health benefit of living in fluoridated water areas. Dental health in fluoridated areas is significantly better than in nonfluoridated areas.

The best available evidence from studies after cessation of water fluoridation demonstrates a subsequent increase in the incidence of dental decay. Australia has established, centralised and regulated supplies of reticulated water. The fluoridation process and levels in domestic water are monitored regularly to ensure a reliable source in compliance with the Australian Drinking Water Guidelines. The government’s peak medical advisory body, the National Health and Medical Research Council, reaffirmed in 1993, and again in 1999, that fluoride concentrations in public water supplies ranging from 0.6 to 1.1 ppm, depending on the climate, are a safe and effective dose of fluoride for dental health.

Water fluoridation has been endorsed by more than 150 public health and scientific organisations, including the Fédération Dentaire Internationale; Irish Forum on Fluoridation; International Association for Dental Research; Ontario Ministry of Health, Canada; UK National Health Service Centre for Reviews and Dissemination, University of York; and WHO. The British Medical Association, the British Dental Association and the British Fluoridation Society remain convinced that there is no definitive evidence of any adverse risk to human health from water fluoridation, and that introduction of fluoridation in areas of high need would significantly reduce tooth decay and bring the additional benefit of a reduction in the number of general anaesthetics administered to children.

The American Dental Association estimates that “… every dollar spent on putting fluoride in water saves about $80 in dental health costs …” In April 1999, the Centers for Disease Control and Prevention stated, “Community water fluoridation ranks with eradication of smallpox and polio as one of the 10 great public health achievements of the 20th century”. In conclusion, on the basis of the current evidence, it would be remiss of government to deny the community the public health benefits from water fluoridated at the optimal levels.