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Government Asked to Evaluate the Cancer-Causing Potential Of Fluoride in Tap Water

EWG Cites Compelling Body of Science Linking Fluoride to Rare Bone Cancer in Boys

WASHINGTON — Citing a strong body of peer-reviewed evidence, Environmental Working Group (EWG) today asked the National Toxicology Program (NTP) of the National Institutes of Health (NIH) to list fluoride in tap water in its authoritative Report on carcinogens, based on its ability to cause a rare form of childhood bone cancer, osteosarcoma, in boys. The Report on Carcinogens lists only substances that are known or reasonably anticipated to cause cancer in humans.

In recent years, concerns have grown about the safety of fluoride in tap water. In 2002, the Environmental Protection Agency (EPA) commissioned a study by the National Research Council (NRC) on the overall safety of fluoride in tap water. The final report is expected by February 2006. The NRC, however, does not have the expertise or the mandate to determine the carcinogenicity of fluoride.

EWG recognizes the value of fluoride to dentistry, yet a substantial and growing body of peer-reviewed science strongly suggests that adding fluoride to tap water is not the safest way to achieve the dental health benefits of fluoridation.

Nationwide about 170 million people live in communities with fluoridated water. Adding fluoride to tap water can be a contentious issue. There are ongoing fights over fluoridation in Colorado, New Jersey, Oregon, Vermont, Washington, California, Massachusetts and Nebraska. States with recent battles over fluoridation include New Hampshire, Virginia, Florida, Arkansas and Tennessee.

Research dating back decades, much of it government funded, has long suggested that fluoride added to drinking water presents a unique cancer risk to the growing bones of young boys. New epidemiology provides strong evidence of a link between exposure to fluoride in tap water during the mid-childhood growth spurt between ages 6 and 10, and bone cancer in adolescence. Additional science strongly suggests that fluoride can cause genetic mutations in bone cells directly related to childhood bone cancer.

"We recognize the potential benefits of fluoride to dental health, but there is very compelling evidence that fluoride in tap water can cause bone cancer in boys," said EWG Senior Vice President Richard Wiles. "The government needs to assess the overall strength of the evidence and make a determination of fluoride's cancer-causing potential," Wiles added.

EWG's letter to the NTP and related materials can be found at www.ewg.org/issues/fluoride/20050606/index.php

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Environmental Working Group is a nonprofit research organization based in Washington, D.C., that uses the power of information to protect human health and the environment.

New Harvard Doctoral Thesis Supports Fluoride-bone Cancer Link

Environmental Working Group (EWG) has attached to this petition, key portions of a doctoral dissertation from the Harvard School of Dental Medicine that found a strong, statistically significant relationship between fluoride in tap water at levels commonly found in American water supplies, and the rare but often fatal form of bone cancer, osteosarcoma, in boys. The association is particularly strong when exposure occurs during periods of rapid bone growth that take place between ages five and ten. The findings confirm the results of earlier studies by the U.S. Public Health Service and the New Jersey Department of Health that found an association between fluoride in tap water and bone cancer in males under age 20.

The dissertation by Elise Bassin is titled "Association between fluoride in drinking water during growth and development and the incidence of osteosarcoma for children and adolescents." Bassin was awarded a doctorate by the Harvard School of Dental Medicine in 2001. The research findings from her doctoral dissertation, however, have not yet been published.

The study came to the attention of EWG as a result of a failed attempt to obtain the full doctoral thesis by the staff of the National Research Council committee on fluoride safety. After being repeatedly denied a copy of the thesis, the NRC committee instead sent a committee member to the Harvard Countway Library of Medicine to read the entire document and report back to the committee. Environmental Working Group obtained a copy of the results section of the document from the Fluoride Action Network, who sent two researchers to the library, each of whom were allowed to copy 10 percent of the document.

Dr. Bassin's study measured the risk of osteosarcoma before age 20 based on exposures to fluoride in drinking water during each year of age in childhood. The methodology employed is rigorous and fluoride levels in tap water for each study participant were confirmed for each year of exposure during childhood. The analysis shows significantly elevated risks of bone cancer in boys exposed to fluoridated water during a window of vulnerability, from ages five through ten, with a peak risk associated with exposures at seven years of age.

Elevated bone cancer risks were identified by Bassin at fluoride levels that are commonly found in American water supplies. For drinking water systems with fluoride levels from 30 to 99 percent of the amount recommended by the Centers for Disease Control and Prevention (CDC), Bassin reports elevated risks for exposure from ages five through ten, with a five-fold risk of osteosarcoma for those exposed at age seven (4.94 (1.23-19.8) at 95% CI)). At 100 percent or more of the recommended level (and still far below legal maximum levels), the risk for exposure at seven years old rises to 7.2-fold (1.73-30.0) at the 95% CI (Bassin 2001, pg 95 — see results section attached).

The CDC's recommended fluoride levels are well below what is legally allowed in tap water. The EPA's maximum contaminant limit, or MCL, for fluoride in tap water is 4 parts per million. The CDC recommends optimal fluoride levels ranging from 0.7-1.2 parts per million based on average annual air temperatures and corresponding water consumption rates.

Notably, Bassin's doctoral dissertation was based on a reanalysis of data from another study that found no association between drinking water fluoride levels and bone cancer, co-authored by Harvard Department Chair Dr. Chester Douglass (McGuire 1995). In her reanalysis, Bassin examined the same cases and controls used by Douglass in 1995. Dr. Bassin, however, refined the analysis by limiting cases to individuals exposed at less than 20 years old and conducted a more detailed analysis of fluoride exposure and age-specific effects. The result was a very strong correlation between fluoride exposure and bone cancer, particularly for boys exposed at ages 6 through 8.

Provided by NY State Coalition Opposed to Fluoridation
www.orgsites.com/ny/nyscof