According to the National Toxicology Program (NTP), “the preponderance of evidence” from laboratory studies indicates that fluoride is a mutagen (a compound that can cause genetic damage). A chemical that can cause genetic damage is one that can likely cause, or contribute to, the development of cancer.
While the concentrations of fluoride causing genetic damage in laboratory studies are generally far higher than the concentrations found in human blood, there are certain “microenvironments” in the body (e.g., the bones, bladder, kidneys, oral cavity, pineal gland) where cells can be exposed to fluoride levels that are comparable to those causing genetic damage in the laboratory. Moreover, some research has found that cells of primates (including great apes and humans) are more susceptible to fluoride’s mutagenic effects than cells of rodents. These factors may help explain why seven studies since the 1990s have found evidence of genetic damage in humans with high fluoride exposures. (Some studies have not found this association.)
Fluoride & Osteosarcoma (Bone Cancer)
The concern that fluoride can cause cancer has been fueled by evidence linking it to a serious form of bone cancer known as osteosarcoma. This evidence includes a government animal study as well as several studies of human populations living in the United States.
Osteosarcoma is a rare, but deadly, form of cancer that strikes primarily during the teenage years. A national case control study published in 2006 by Harvard scientists found that boys exposed to fluoridated water during their 6th, 7th, and 8th years of life (the mid-childhood growth spurt) had a significantly elevated risk of developing osteosarcoma during adolescence. (Bassin 2006). The sex-specific link between fluoride and osteosarcoma in young males is consistent with the government’s animal study, (NTP 1990), which found osteosarcomas in the fluoride-treated male rats, but not the female ones. It is also consistent with previous studies by the National Cancer Institute and New Jersey Department of Health, which both found associations between fluoridation and osteosarcoma in young males, but not females. (Cohn 1992; NCI 1990)
Although a number of studies have found no association between fluoride and osteosarcoma, the Harvard study by Bassin is the only study to ever carefully considered the “age-specific” risk of fluoride exposure. As the renowned epidemiologist Kenneth Rothman explained to the Wall Street Journal:
“‘If there were an adverse effect of fluoride, it’s possible an effect of early exposure would be manifest in the first 20 years of life – but not after.’ Looking at all ages, in other words, could conceal any link between fluoridation and cancer.”
Fluoride/Osteosarcoma Link Is “Biologically Plausible”
It is widely acknowledged that the fluoride/osteosarcoma connection is a biologically plausible one. When the connection between a chemical and a cancer is biologically plausible, studies that detect an association between the two are taken more seriously, as the association is less likely to be a random fluke.
The plausibility of a fluoride/osteosarcoma connection is grounded in the three considerations:
- Bone is the principal site of fluoride accumulation, particularly during the growth spurts of childhood;
- Fluoride is a mutagen when present at sufficient concentrations; and
- Fluoride stimulates the proliferation of bone-forming cells (osteoblasts), which may ”increase the risk for some of the dividing cells to become malignant.” (NRC 2006).
Fluoride & Bladder/Lung Cancer
In addition to osteosarcoma, a number of studies of fluoride-exposed workers have found associations between airborne fluoride exposure and both bladder and lung cancer. Although fluoride’s association with these cancers has generally been attributed to poly aromatic hydrocarbons (PAH) — a non-fluoride airborne contaminant — a twenty-year study of a workplace with no PAH exposure found a similarly elevated rate of both bladder and lung cancer in the fluoride-exposed workers. (Grandjean 2004). Based on these findings, the authors concluded that “fluoride should be considered a possible cause of bladder cancer and a contributory cause of primary lung cancer.”
Fluoride & Bone Cancer: Is Harvard Professor Hiding a Link?
Fluoride Linked to Bone Cancer in Fed Study
Fluoride appears to have caused bone cancer in rodents in a recently completed National Toxicology Progran (NTP) study, and the chemical is now at risk of being classified a carcinogen, according to internal documents and statements obtained from the Environmental Protection Agency (EPA).
Don't Drink the Water? Brush your teeth, but the fluoride from your tap may not do much good -- and may cause cancer
Government researchers have new evidence that casts doubt on the benefits of fluoridation and suggests that it is not without risk. The most incendiary results come from the National Toxicology Program (NTP), which in 1977 was ordered by Congress to determine whether fluoride causes cancer. This week NTP plans to release data showing that lab rats given fluoridated water had a higher rate of a rare bone cancer called osteosarcoma.
Caries Preventative Already Has One Rap Against It
The NTP's findings will make it difficult for the Environmental Protection Agency (EPA) not to classify fluoride a carcinogen, thereby terminating 40 years of public-water fluoridation in the United States.
Micronucleus and Sister Chromatid Exchange Frequency in Endemic Fluorosis
The rise of sister chromatid exchange (SCE) and micronucleus (MN) in the peripheral blood lymphocytes of the fluorine-intoxicated patients indicates that fluorine is a mutagenic agent which can cause DNA and chromosomal damage.
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
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
Harvard's Statement on Chester Douglass/Scientific Misconduct
Statement Concerning the Outcome of the Review into Allegations of Research Misconduct Involving Fluoride Research BOSTON-August 15, 2006-The Harvard Medical School and School of Dental Medicine (HSDM) review of Chester Douglass, DMD, PhD, professor of oral health policy and epidemiology at HSDM, has concluded that Douglass did not intentionally omit, misrepresent,
Interview with EPA's Dr. William Hirzy About Fluoride & Cancer
The following is an excerpt of Michael Connett's interview with Dr. J. William Hirzy, Senior Vice President of EPA's Headquarters Union in Washington DC. The interview took place on July 3, 2000, a couple days after Hirzy testified before the US Senate calling for an independent review of the tumor slides from
Interview with EPA's Dr. William Marcus on NTP's Fluoride/Cancer Study
The following is an interview with Dr. William Marcus, Senior Science Advisor in EPA's Office of Drinking Water, concerning the National Toxicology Program's animal study on fluoride & cancer.
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