Is it true that young males living in fluoridated communities have an increased risk of bone cancer?
BFS suggested answer
No. The evidence on fluoridation and cancer – including bone cancer – has been reviewed by expert committees – including the Knox committee here in the UK, and the National Cancer Institute in the USA. There is no evidence whatsoever to support the claim that fluoridated water is associated with an increase in cancer anywhere in the body.
BFS suggested answer refuted
The mutagenicity of fluoride supports the conclusion that fluoride is a probable human carcinogen. An important toxicologic consideration is that a toxic substance stores at the same place it exerts its toxic activity.
Dr William Marcus, Environmental Protection Agency scientist
Fluoride and genetic damage
Many studies have noted a link between fluoride and genetic toxicity. Dr W. Klein and colleagues at Austria’s Siebersdorf Research Centre found in 1977 that 1 ppm fluoride inhibited DNA repair enzyme activity by 50 per cent and caused genetic and chromosome damage.1 This was confirmed in 1982 at the University of Missouri.2 Sperm cells were damaged by fluoride in a test carried out at Holland’s Leiden University, leading to a ‘highly significant increase in mutation’.3
Scientists at the West German Central Laboratory for Mutagenicity Testing4 and at Columbia University5 came up with similar findings showing that fluoride also caused genetic damage to eggs in both insects and mammals. And a committee of the National Research Council of Canada, which reviewed the research in 1977, concluded that ‘fluoride has displayed mutagenic activity in studies of vegetation, insects, and mammalian oocytes. There is a high correlation between carcinogenicity and mutagenicity of pollutants, and fluoride has been one of the major pollutants in several situations where a high incidence of respiratory cancer has been observed.’
In 1993 the US National Institutes of Environmental Health Sciences stated: ‘In cultured human and rodent cells, the weight of evidence leads to the conclusion that fluoride exposure results in increased chromosome aberrations.’6
In Poland, scientists at the Pomeranian Medical Academy reported that as little as 0.6 ppm fluoride produced chromosomal damage to human white blood cells.7
Even Procter & Gamble, which makes Crest (fluoridated) toothpaste, produced a study showing that 1 ppm fluoride causes genetic damage8 – so it’s no secret.
Fluoride and cancer
A mutagen is a substance that can induce genetic mutations in an organism: changes that may affect the structure, development and physical characteristics of any subsequent offspring. Similarly, a carcinogen is a substance that can cause cancer. The two may be very similar, and many substances that cause mutations also cause cancer. Scientists in several countries have demonstrated that this is the case with fluoride.
Dr R.A. Holman of the Royal Institute of Pathology stated in 1961:
Fluoride is a well-known inhibitor of several enzyme systems, and can form spectroscopically recognizable compounds with the enzyme catalase, resulting in its inhibition. Catalase poisoning has been linked with the development of viruses and the causation of several diseases, including cancer. Many observers have suggested that the agents (fluorides and other toxic environmental substances) which decrease the catalase in the cells may predispose those cells to tumour formation.9
In the USA, a comparison between the ten largest fluoridated cities and the ten largest unfluoridated cities showed that, whereas cancer rates had been similar initially, after twenty years the fluoridated cities had 10 per cent more cancer deaths than the unfluoridated ones.10 These figures were checked and confirmed in 1976 by the US National Cancer Institute.
The 1987 figures for the incidence of registered cancers in communities in the USA and the 1985 fluoridation census by the US Department of Health and Human Services enabled scientists to conduct an epidemiological analysis of the correlation between the two in the United States. They found significant correlations in both sexes between water fluoridation and numbers of cancers of the digestive system (tongue, mouth, pharynx, oesophagus, stomach, colon, rectum and pancreas), the respiratory system (larynx, bronchi and lungs), and the renal system. In the sexual organs, contradictions were seen. In women, cancers of the breast, cervix and ovary were increased in fluoridated areas, whereas in males those of the prostate, testis and penis were apparently inhibited. The authors considered that the different effects suggest that fluoride may act as an environmental hormone. The dose–response relationship between the numbers of bone cancers in male teenagers and the amount of fluoridation was statistically significant. These significant relationships indicated that fluoride may be, not an initiator, but a promoter of cancer.11
The world’s leading authority on the biological effects of fluoride, Dr John Yiamouyiannis, estimates that 30,000–50,000 deaths each year in the United States are directly attributable to fluoride.12 Dr Dean Burk, the chief chemist emeritus of the US National Cancer Institute, agreed. ‘In point of fact, fluoride causes more human cancer death, and causes it faster, than any other chemical’, he said.
The cancer link is covered up
Osteosarcoma is a rare form of bone cancer, but it is the most common form of bone cancer in children and one of the principal cancers of childhood.
Because of concerns that fluoride might cause cancer, in 1977 the US Congress ordered the US Department of Health and Human Services to conduct the National Toxicology Program animal study. The results were published in 1990.13 The study showed that sodium fluoride caused osteosclerosis (abnormal bone density), oral tumours, a rare bone cancer (osteosarcoma) and a rare liver cancer called hepatocholangiocarcinoma at cumulative dosages comparable to those ingested by humans over a number of years.
Normally, when a drug is being tested, two groups of people or animals are selected to be as nearly alike as possible. One, the intervention group, has the drug, while the other, called the control group, has none. After a period of time, the two groups are compared and any differences detected. But this did not happen in the NTP study: the control group also received fluoride, albeit at a lower rate.14 Thus, the control animals were not controls at all, but low-dosage experimental animals. This raised the level of cancers observed in all animals and hid the effect supposedly being studied, leading to a finding that fluoride did not cause cancer.
Drs Robert Carton and William Marcus noted this and a number of other problems, including the fact that many of the cancers found were downgraded to commoner types, which had the effect of downgrading the results still further, or even eliminating them altogether.15 Despite these manipulations, the occurrence of osteosarcoma, an unusual cancer for rodents, in male rats showed a statistically significant positive linear relationship to fluoride dosage. In other words, the more fluoride the rodents had, the more cancers they developed.
On 26 April 1990, a conference was held to peer-review the NTP draft report. Dr Marcus, senior science advisor, Criteria and Standards Division, wrote a memo to its acting director, Alan B. Hais, reporting that he was disturbed by much of what he read in the NTP report:
The highest dosed level of rats had lower levels of fluoride in their bones (5,470 ppm) compared to people (7,000 ppm) at the MCL [maximum contaminant level] of 4 ppm. This can be interpreted as people who ingest drinking water at the MCL have 1.3 times more fluoride in their bones than male rats who get osteosarcoma. This is the first time in my memory that animals have lower concentrations of the carcinogen at the site of adverse effect than do humans. An important toxicologic consideration is that a toxic substance stores at the same place it exerts its toxic activity. This is true of benzene and now for fluoride. Fluoride, however, is at twice the concentration in human bones compared to benzene, which is 10 to 100 [times] greater in animal marrow. This portends a very serious problem.16
The fluoride dosages in this study were comparatively low: the doses of other substances tested for carcinogenicity ranged from 6 to 500 times the fluoride dosage (see Table 1). This study is highly relevant, as the average cumulative dosage of fluoride ingested by people living in fluoridated communities reaches that of the low-dosage rats after only thirty-eight years; for many people, the average cumulative dosage will equal that of the mid-dosage rats in a lifetime, and for some will even approach that of the high-dosage rats.
 |
||
Substance |
Daily dose (mg/kg) |
MCL (mg/litre) |
|
||
Fluoride |
7.9a |
4 |
Carbon tetrachloride |
47 |
0.005 |
Benzene |
50 |
0.005 |
Chloroform |
160 |
0.1 |
Tetrachloroethylene |
386 |
0.005 |
Red dye #3 |
4000 |
None |
|
||
Source: Professor David R. Hill, Fluoride: Risks and Benefits. Disinformation in the service of big industry. Presented in Calgary’s Operation and Environment Committee, 10 September 1997.
aThis fluoride dosage caused bone cancer in male rats.
Table 1. Comparison of dosages used to test suspected carcinogens, and the maximum contaminant levels (MCL) allowed
Despite all the machinations, the NTP study did not give fluoride a clean bill of health. Fluoride’s particular affinity for bone adds to the significance of the link with the bone cancers that affected males.
Animal trials are confirmed in human studies
In the light of the NTP study on rodents and of epidemiologic evidence of an increase in a bone cancer, osteosarcoma, in boys and young men, especially in fluoridated areas, Dr Perry Cohn of the New Jersey Department of Health in America surveyed the incidence of this cancer in seven counties of New Jersey relative to water fluoridation. He found that, as demonstrated in Table 2, the incidence of osteosarcoma in boys in the fluoridated areas was up to 4.6 times higher than in the unfluoridated areas.17 In a similar study of three New Jersey municipalities, the incidence of osteosarcoma reached levels nearly seven times higher in the fluoridated than in the unfluoridated areas. Cohn also found that the general population in the fluoridated areas was five times as likely to suffer from cancer.
|
||||
Age |
Area fluoridation |
No. of cases |
Population |
Rates of |
|
||||
Seven counties, New Jersey, USA, 1979–87 |
||||
0–9 |
Fluoridated |
2 |
48,129 |
4.6 |
Unfluoridated |
1 |
102,123 |
1.0 |
|
10–19 |
Fluoridated |
10 |
62,990 |
17.6 |
Unfluoridated |
7 |
151,384 |
5.1 |
|
20–49 |
Fluoridated |
5 |
141,429 |
3.9 |
Unfluoridated |
5 |
348,570 |
1.5 |
|
Three municipalities, New Jersey, USA, 1979–87 |
||||
0–9 |
Fluoridated |
2 |
38,654 |
5.7 |
Unfluoridated |
1 |
46,708 |
2.3 |
|
10–19 |
Fluoridated |
10 |
50,297 |
20.0 |
Unfluoridated |
2 |
67,678 |
3.2 |
|
20–49 |
Fluoridated |
4 |
115,367 |
3.8 |
Unfluoridated |
2 |
153,713 |
1.4 |
|
|
||||
Source: Cohn PD. A brief report on the association of drinking water fluoridation and the incidence of osteosarcoma among young males. Trenton, NJ: New Jersey Department of Health, 8 November 1992.
aPer 100,000.
Table 2. Fluoride and osteosarcoma in young males
It is not surprising that any cancer caused by fluoride should be a bone cancer, and it is equally unsurprising that it should occur in the young, as fluoride accumulates primarily in bones, and children, who are actively forming bone, have a higher uptake of fluoride into bone than adults. Further, bone in knees, ankles, shoulders and wrists, where childhood osteosarcoma most often occurs, shows a high response to fluoride.18
Cohn’s study also showed that fluoride affects males differently from females – whereas male cancers tended to be of the bones, females were more susceptible to soft-tissue cancers. This means it is important to consider the sexes separately in trials to avoid watering down, and thus hiding, significant effects. This has not been done.
Given the large number of people in the New Jersey study, and given the results of the NTP study, you might expect alarm bells to have rung loudly for the US public health system, especially as the US Department of Health and Human Services had previously noted a rise in such cancers among young males in fluoridated areas during the first five years of fluoridation.19 Instead, the executive summary of the NTP, which is the only part likely to be read by high-ranking government officials, starts by praising the dental benefits of fluoridation, and then fails to present the results clearly.
Many people in Britain and Ireland ingest more than the ‘optimum’ amount of fluoride, some by six times or more.20 With increasingly widespread fluoride contamination, these amounts will rise, in which case it will take less time to accumulate dosages similar to those of the rats.
Other cancers
Fluoride may have a causal relationship with more than just bone cancer in males:
Respiratory cancer
An environmental committee of Canada’s National Research Council stated in 1977: ‘Fluoride is a persistent bioaccumulator . . . There is a high correlation between carcinogenicity and mutagenicity of pollutants, and fluoride has been one of the major pollutants in several situations where a high incidence of respiratory cancer has been observed.’21 (Emphasis added)
Oral cancer
The NTP rat study also noted an increase in oral cancers in the rat. Combined oral papilloma and carcinoma approached statistical significance in males in the trend test. The NTP did not consider these tumours to be related to fluoride intakes and concluded that the finding pointed to a possible, but not yet probable, relationship. However, oral cancer rates in humans have risen markedly in the last few decades, despite the fact that smoking is on the decrease.
Uterine cancer
The Japanese Ryukyu Islands, including the island of Okinawa, were under US administration from 1945 to 1972. During that time, fluoride was added to the drinking water in most regions. It was a unique opportunity to study the effects of the change. Dr E. Tohyama of the Department of Preventive Medicine, School of Medicine, University of the Ryukyus, Okinawa, studied the relationship between fluoride concentration in drinking water and uterine cancer death rates in twenty Okinawan towns over the period.22 The study results were noteworthy:
•A significant positive correlation existed between fluoride concentration in drinking water and uterine cancer deaths.
•This association remained significant even after adjusting for the potential confounding variables.
•The time trends in the uterine cancer deaths were related to changes in water fluoridation practices.
Tohyama wasn’t the first Japanese to look for links between fluoride and cancer. Researchers there had achieved a degree of understanding of fluoride consumption and human cancer by 1984. Using levels of fluoride that, according to the US National Cancer Institute, would determine whether fluoridation of public drinking water caused cancer, Dr Takeki Tsutsui of the Nippon Dental College showed that ‘fluoride caused not only genetic damage but was also capable of transforming normal human cells into cancer cells’.23
Tsutsui’s work in Japan was confirmed in 1988 by researchers at the Argonne National Laboratory in France.24 They also discovered that fluoride has a synergistic effect with other cancer-causing chemicals in the food and environment. Interestingly, this work confirmed yet more studies sponsored by the US National Cancer Institute. In 1963, low levels of fluoride increased the rate of melanomas in living organisms from 12 to 100 per cent in a study at University of Missouri, Saint Louis.25 These studies were further amplified by work done at the University of Texas by the Taylors, who found that 1 ppm fluoride in drinking water increased tumour growth rate in mice by 25 per cent.26 Fluoride, like mercury and lead, suppressed the immune system.
According to Dr John Yiamouyiannis, studies in the United States and Canada have shown that cancer death rates are from 4 to 40 per cent higher in areas where the water is fluoridated than in areas where it is not.
Conclusion
This is a small taste of the vast amount of literature detailing fluoride’s ability to cause genetic and chromosomal damage to body cells. All cancers are, after all, caused merely by changes to a cell’s DNA.
The American Food and Drug Administration (FDA) does not allow anything that has been shown to be carcinogenic in animal tests to be put in food. Even if fluoride did not cause cancer in humans, the fact that it does so in animals should automatically bar it from entering the food chain.
1.Klein W et al. DNA repair and environmental substances. Z Angew Bader-Klimaheilkunde 1977; 24 (3): 218–23.
2.Mohamed A, Chandler ME. Cytological effects of sodium fluoride on mice. Fluoride 1982; 15 (3): 110–18.
3.Mukerjee RN, Sobels FH. The effect of sodium fluoride and iodoacetamide on mutation induction by Xirradiation in mature spermatozoa of Drosophila. Mutat Res 1968; 6: 217–25.
4.Vogel E. Strong antimutagenic effects of fluoride on mutation induction by trenimon and 1-phenyl-3,3-dimethyltriazine in Drosophila melanogaster. Mutat Res 1973; 20: 339–52.
5.Jagiello G, Lin J-S. Sodium fluoride as potential mutagen in mammalian eggs. Arch Environ Health 1974; 29: 230–5.
6.Zeiger E, Shelby MD, Witt KL. Genetic toxicity of fluoride. Environ Mol Mutagen 1993; 21: 309–18.
7.Jachimczak D, Skotarczak B. The effect of fluorine and lead ions on the chromosomes of human leucocytes in vitro. Genet Pol 1978; 19 (3): 353–7.
8.Aarderna MJ, Gibson DP, Leboeuf RA. Sodium fluoride-induced chromosome aberrations in different stages of the cell cycle: a proposed mechanism. Mutat Res 1989; 223: 191–203.
9.Holman RA. Prevention of dental caries. Br Med J 1961; 1110–11.
10.Yiamouyiannis JA, Burk D. Fluoridation of public water systems and the cancer death rate in humans. Presented at the 67th Annual Meeting of the American Society of Biologists and Chemists and the American Society of Experimental Biologists, June 1976.
11.Takahashi K, Akiniwa K, Narita K. Cancer-promoting power of fluoridation. Presented at the 22nd Conference of the International Society for Fluoride Research, Bellingham, Washington, USA, 24–27 August 1998.
12.Yiamouyiannis JA. Fluoride: The aging factor. Delaware, OH: Health Action Press, 1983.
13.Toxicology and carcinogenesis studies of sodium fluoride (CAS No. 7681-49-4) in F344/N rats and B6C3F1 mice. National Toxicology Program Technical Report TR 393. National Institutes of Health, US Department of Health and Human Services, 1990.
14.US Department of Health and Human Services Subcommittee Review, 1991: 73.
15.Carton RJ, Marcus WL. Internal memorandums from the US Environmental Protection Agency, where Dr Carton was an environmental scientist and Dr Marcus a senior science advisor and toxicologist in the Office of Drinking Water. The memorandums are dated 1 May 1990, 1 June 1990, 24 September 1990 and 18 October 1990.
16.Marcus WL. Fluoride conference to review the NTP draft fluoride report. Memorandum to Alan B. Hais. US Environmental Protection Agency, 1 May 1990.
17.Cohn PD. A brief report on the association of drinking water fluoridation and the incidence of osteosarcoma among young males. Trenton, New Jersey: New Jersey Department of Health, 8 November 1992.
18.Gelberg KH, Fitzgerald EF, Hwang S, Dubrow R. Fluoride exposure and childhood osteosarcoma: A case control study. Am J Public Health 1995; 85: 1678–83.
19.US Department of Health and Human Services Subcommittee Review, 1991: 82.
20.Mansfield P. We underestimate the damage done by fluorides. Mansfield, Louth, Lincs, 1997.
21.Associate Committee On Scientific Criteria For Environmental Quality. Environmental fluoride. NRCC No. 16081. National Research Council of Canada, 1977.
22.Tohyama E. Relationship between fluoride concentration in drinking water and mortality rate from uterine cancer in Okinawa prefecture, Japan. J Epidemiol 1996; 6: 184–91.
23.Tsutsui T, Suzuki N, Ohmori M. Sodium fluoride induced morphological and neoplastic transformation, chromosome aberrations, sister chromatid exchanges and unscheduled DNA synthesis in cultured Syrian hamster embryo cells. Cancer Res 1984; 44: 938–41.
24.Jones CA, Callahan MF, Huberman E. Sodium fluoride promotes morphological transformation of Syrian hamster embryo cells. Carcinogenesis 1988; 9: 2279–84.
25.Herskowitz IH, Norton IL. Increased incidence of melanotic tumors in two strains of Drosophila melanogaster following treatment with sodium fluoride. Genetics 1963; 48: 307–10.
26.Taylor A, Taylor NC. Effect of sodium fluoride on tumor growth. Proc Soc Exp Biol Med 1965; 119: 252–5.