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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Results and conclusions of the National Toxicology Program's rodent carcinogenicity studies with sodium fluoride.
The US National Toxicology Program (NTP) has conducted toxicity and carcinogenicity studies with sodium fluoride administered in the drinking water to F344/N rats and B6C3F1 mice. The drinking water concentrations used in the 2-year studies were 0, 25, 100, or 175 ppm sodium fluoride (equivalent to 0, 11, 45 or
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Revisiting the fluoride-osteosarcoma connection in the context of Elise Bassin's findings: part 2
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A brief report on the association of drinking water fluoridation and the incidence of osteosarcoma among young males
Executive Summary It is well known that fluoride provides important public health benefits by effectively preventing dental caries in children. The Public Health Service (1991) endorses artificial fluoridation of drinking water at a concentration of 0.7-1.2 milligrams of fluoride per liter of water (or parts per million) as the optimally beneficial
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Is fluoride a risk factor for bone cancer? Small area analysis of osteosarcoma and Ewing sarcoma diagnosed among 0-49-year-olds in Great Britain, 1980-2005.
BACKGROUND: Artificial fluoridation of drinking water to improve dental health has long been a topic of controversy. Opponents of this public health measure have cited the possibility of bone cancer induction. The study objective was to examine whether increased risk of primary bone cancer was associated with living in areas
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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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A Critique of Gelberg's Study on Fluoride/Osteosarcoma in New York
The case-control study by Gelberg, published first as a PhD dissertation and then later in two peer-reviewed journals, may represent the most substantive study on fluoride/osteosarcoma previous to Bassin’s 2001 analysis. In assessing Gelberg’s data, we were at first struck by the existence of several notable errors in both the thesis and papers. While these errors do raise questions about the study, our primary concern with Gelberg’s work relates to the methods she used to analyze her data.
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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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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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