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?
Various studies of fluoride-exposed workers, primarily from the aluminium smelting industry, showed an increased incidence of lung and bladder cancer and increased mortality due to cancer. However, no consistent pattern has been observed and in certain cases the greater frequency of cancers can be attributed to substances other than fluoride.
The numerous studies carried out in many countries on populations consuming fluoridated drinking water did not show any consistent evidence of an association between the consumption of controlled fluoridated drinking water and increased frequency of cancer. More...
5.2 What are the effects on teeth and bones?
Fluoride can have both a positive and a negative impact on tooth enamel. Generally, the higher the concentrations of fluoride in drinking water the smaller the likelihood to develop dental caries. However, the prevalence and severity of dental fluorosis within the population increases with the concentration of fluoride in drinking water.
Bones can be negatively affected by fluoride. Cases of skeletal fluorosis are associated with high levels of fluoride in drinking water or in ambient air at work or at home, for instance in areas of China in which coal rich in fluoride is used indoors on open fires for heating and cooking. Although fluoride is the cause of skeletal fluorosis in these cases, many other factors, including nutritional factors, can play a significant role in the severity of the health condition. Evidence for an association between the consumption of fluoridated water and hip fractures is mixed; some studies support the association, others do not, some even report protective effects of fluoride on bones. Two comparative studies carried out on groups of people drinking water with different levels of fluoride showed greater risks of fracture at higher fluoride levels. More...
5.3 Has fluoride caused other health problems?
Studies on human populations did not show any association between the consumption of fluoridated drinking water by mothers and increased risk of spontaneous abortion or congenital malformation. Studies on workers exposed to airborne fluorides have provided no reasonable evidence of effects upon lungs, blood system, liver or kidneys attributable to fluoride exposure alone. More...