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Fluoride

5. What effects have actually been seen in humans?

  • 5.1 Has fluoride exposure caused cancer?
  • 5.2 What are the effects on teeth and bones?
  • 5.3 Has fluoride caused other health problems?

5.1 Has fluoride exposure caused cancer?

The source document for this Digest states:

Epidemiological investigations on the effects of fluoride on human health have examined occupationally exposed workers employed primarily in the aluminium smelting industry and populations consuming fluoridated drinking-water. In a number of analytical epidemiological studies of workers occupationally exposed to fluoride, an increased incidence of lung and bladder cancer and increased mortality due to cancer of these and other sites have been observed. In general, however, there has been no consistent pattern; in some of these epidemiological studies, the increased morbidity or mortality due to cancer can be attributed to the workers’ exposure to substances other than fluoride.

The relationship between the consumption of fluoridated drinking-water and morbidity or mortality due to cancer has been examined in a large number of epidemiological studies, performed in many countries. There is no consistent evidence of an association between the consumption of controlled fluoridated drinking-water and increased morbidity or mortality due to cancer.

Source & ©: IPCS "Environmental Health Criteria for Fluorides", (EHC 227), 
Summary of the Report, Chapter 1.7: Effects on humans 

For more information, see the full IPCS document,
Chapter 8.1.3.1: Cancer 

5.2 What are the effects on teeth and bones?

The source document for this Digest states:

Fluoride has both beneficial and detrimental effects on tooth enamel. The prevalence of dental caries is inversely related to the concentration of fluoride in drinking-water. The prevalence of dental fluorosis is highly associated with the concentration of fluoride, with a positive dose–r esponse relationship.

Cases of skeletal fluorosis associated with the consumption of drinking-water containing elevated levels of fluoride continue to be reported. A number of factors, such as nutritional status and diet, climate (related to fluid intake), concomitant exposure to other substances and the intake of fluoride from sources other than drinking-water, are believed to play a significant role in the development of this disease. Skeletal fluorosis may develop in workers occupationally exposed to elevated levels of airborne fluoride; however, only limited new information was identified.

Evidence from several ecological studies has suggested that there may be an association between the consumption of fluoridated water and hip fractures. Other studies, however, including analytical epidemiological investigations, have not supported this finding. In some cases, a protective effect of fluoride on fracture has been reported.

Two studies permit an evaluation of fracture risk across a range of fluoride intakes. In one study, the relative risks of all fractures and of hip fracture were elevated in groups drinking water with >1.45 mg fluoride/litre (total intake >6.5 mg/day); this difference reached statistical significance for the group drinking water containing >4.32 mg fluoride/litre (total intake 14 mg/day). In the other study, an increased incidence of fractures was observed in one age group of women exposed to fluoride in drinking-water in a non-dose-dependent manner.

Source & ©: IPCS "Environmental Health Criteria for Fluorides", (EHC 227), 
Summary of the Report, Chapter 1.7: Effects on humans 

For more information, see the full IPCS document,
Chapter 8.1.3.2: Skeletal fluorosis 
Chapter 8.1.3.3: Skeletal fracture 
Chapter 8.1.3.8: Dental effects 

5.3 Has fluoride caused other health problems?

The source document for this Digest states:

Epidemiological studies show no evidence of an association between the consumption of fluoridated drinking-water by mothers and increased risk of spontaneous abortion or congenital malformation. Other epidemiological investigations of occupationally exposed workers have provided no reasonable evidence of genotoxic effects or systemic effects upon the respiratory, haematopoietic, hepatic or renal systems that may be directly attributable to fluoride exposure per se

Source & ©: IPCS "Environmental Health Criteria for Fluorides", (EHC 227), 
Summary of the Report, Chapter 1.7: Effects on humans 

For more information, see the full IPCS document,
Chapter 8.1.3.4: Reproductive effects 
Chapter 8.1.3.5: Repiratory effects 
Chapter 8.1.3.6: Neurobehavioural effects 
Chapter 8.1.3.7: Genotoxic effects 
Chapter 8.2: Occupationally exposed workers 


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