Abstract
In an effort to examine the effect of exposure to sodium fluoride on the incidence of bone tumors induced by ionizing radiation, the femoral-tibial joint of the left hind limb of 100 male F344 rats was irradiated with 3000 R from a 137Cs source and the animals divided into two groups of 50. One group was then administered drinking water containing 250 ppm sodium fluoride for two years while the other group received plain deionized water. Two additional groups of 50 male F344 rats (not exposed to radiation) received drinking water containing 250 ppm sodium fluoride (113 ppm fluoride ion), or plain deionized water for two years. Survival, mean body weights, food and water consumption of all groups was comparable throughout the two year study duration. Bone fluoride analysis conducted at the end of the study revealed significant accumulation of fluoride in the bones of groups of rats exposed to sodium fluoride. Exposure to irradiation, sodium fluoride, or both irradiation and sodium fluoride was not associated with an increase in bone tumors or other neoplastic lesions. Non-neoplastic lesions of incisor teeth including ameloblast and odontoblast degeneration and malformation of enamel and dentine, were increased in groups exposed to sodium fluoride.
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Fluoridation and cancer: The biology and epidemiology of bone and oral cancer related to fluoridation
Recent studies showing substantial increases in the incidence of bone cancer and osteosarcoma in,males (but not females) exposed to fluoride gave us the unique opportunity of using females as a control group to determine whether there is a link: between fluoridation and bone cancer in males. Using three different data
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Clastogenic activity of sodium fluoride to rat vertebral body-derived cells in culture
The US National Toxicology Program has shown equivocal evidence of carcinogenic activity of sodium fluoride (NaF) in male F344/N rats based on the occurrence of five osteosarcomas in treated animals. In the study the osteosarcomas developed mainly in the rat vertebrae. To provide a possible mechanistic basis for the observed
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Fluoride in drinking water and osteosarcoma incidence rates in the continental United States among children and adolescents
INTRODUCTION: It has been suggested that fluoride in drinking water may increase the risk of osteosarcoma in children and adolescents, although the evidence is inconclusive. We investigated the association between community water fluoridation (CWF) and osteosarcoma in childhood and adolescence in the continental U.S. METHODS: We used the cumulative osteosarcoma
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Time trends for bone and joint cancers and osteosarcomas in the Surveillance, Epidemiology and End Results (SEER) Program
At the request of the Committee, we have enclosed a brief description of the time trends for bone and joint cancers and for osteosarcomas in the Surveillance, Epidemiology and End Results (SEER) Program of the National Cancer Institute (NCI), and the relationship of these trends to fluoridation of drinking water
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Revisiting the fluoride-osteosarcoma connection in the context of Elise Bassin's findings: part I
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Fluoride & Osteosarcoma: A Timeline
Several human epidemiological studies have found an association between fluoride in drinking water and the occurrence of osteosarcoma (bone cancer) in young males. These studies are consistent with the National Toxicology Program's (NTP) cancer bioassay which found that fluoride-treated male rats had an dose-dependent increase in osteosarcoma. Although a number of studies have failed to detect an association between fluoride and osteosarcoma, none of these studies have measured the risk of fluoride at specific windows in time, which based on recent results, is the critical question with respect to fluoride and osteosarcoma.
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NTP Bioassay on Fluoride/Cancer (1990)
In 1977, the U.S. Congress requested that animal studies be conducted to determine if fluoride can cause cancer. The result of the Congressional request was an extensive animal study conducted in the 1980s by the National Toxicology Program (NTP) and published in 1990. The main finding of NTP's study was a dose-dependent increase in osteosarcoma (bone cancer) among the fluoride-treated male rats.
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Fluoride's Mutagenicity: In vitro Studies
According to the National Toxicology Program, "the preponderance of evidence" from laboratory "in vitro" studies indicate that fluoride is a mutagenic compound. Many substances which are mutagens, are also carcinogens (i.e. they can cause cancer). As is typical for in vitro studies, the concentrations of fluoride that have generally been tested
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Fluoride's Mutagenicity: In vivo Studies
Consistent with dozens of in vitro studies, a number of in vivo studies, in both humans and animals, have found evidence of fluoride-induced genetic damage. In particular, research on humans exposed to high levels of fluoride have found increased levels of "sister chromatid exchange" (SCE). As noted in one study: "In
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Fluoride/Osteosarcoma Link Is Biologically Plausible
The "biological plausiblility" of a fluoride-osteosarcoma link is widely acknowledged in the scientific literature. The biological plausibility centers around three facts: 1) Bone is the principal site of fluoride accumulation, particularly during the growth spurts of childhood; 2) Fluoride is a mutagen when present at sufficient concentrations, and 3) Fluoride can stimulate the proliferation of osteoblasts (bone-forming cells).
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