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

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

International trends in the incidence of bone cancer are not related to drinking water fluoridation

BACKGROUND:  Because osteosarcomas may develop in rats exposed to fluoridated water, water fluoridation might pose a cancer risk to humans. METHODS:  A time trend analysis of the cumulative risk (CR) of bone cancer for the period 1958-1987 for 40 cancer registry areas showed an increased risk for young males in

Revisiting the fluoride-osteosarcoma connection in the context of Elise Bassin's findings: part I

Integrative analyses of key genes and regulatory elements in fluoride-affected osteosarcoma.

Osteosarcoma is one of the most malignant tumors in adolescents with severe outcomes while fluoride is one of the most abundant elements in the environment. Epidemiological evidence has elucidated the relationship between fluoride and osteosarcoma, but the molecular mechanisms are extremely complicated. Microarray profiles were downloaded from the Gene Expression

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

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.

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.

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. 

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).