WALL STREET JOURNAL
JULY 22, 2005.

Fluoridation, Cancer: Did Researchers Ask The Right Questions?
By Sharon Begley

WHEN HEALTH OFFICIALS decided to add fluoride to the water supply of Grand Rapids, Mich., in 1945, they plunged ahead despite the lack of a rigorous, large-scale study of the risks and benefits. And for most of the next 60 years, fluoridation research has gone pretty much like that. It has not been science's finest hour.

Questions about fluoridation have returned with renewed vigor because of allegations of scientific misconduct against a prominent researcher at the Harvard School of Dental Medicine. The Environmental Working Group, an advocacy organization in Washington, charged last month that Chester Douglass misrepresented an unpublished study about bone cancer and fluoridated tap water. In written testimony to the National Research Council last year, Dr. Douglass said he had found no evidence that fluoridation increased risk of osteosarcoma, a rare bone cancer. But a 2001 study he cited, and oversaw, found that boys who drink fluoridated water have a greater risk of developing the disease. (Dr. Douglass did not respond to requests for comment.)

More interesting than what Dr. Douglass said or didn't say, however, is the study he swept under the rug. It was conducted by one of his doctoral students, Elise Bassin. She started with the same raw data as her mentor -- 139 people with osteosarcoma and 280 healthy "controls" -- but saw a way to improve on it. Since most of the 400 people diagnosed in the U.S. each year with osteosarcoma are kids, and since any ill effect of fluoride would likely come when bones are growing most quickly, she focused on the 91 patients who were under 20.

HER RESULT: Among boys drinking water with 30% to 99% of the fluoride levels recommended by the U.S. Centers for Disease Control and Prevention, the risk of osteosarcoma was estimated to be five times as great as among boys drinking nonfluoridated water. At 100% or more, the risk was an estimated seven times as high. The association was greatest for boys six to eight.

To be sure, one study proves nothing. Moreover, Dr. Bassin hasn't published her core findings (though in 2004 she and colleagues published a description of their methodologies). As Boston University epidemiologist Richard Clapp says, "Peer review picks up things that even doctoral students at Harvard might miss."

So I asked scientists to read the study. BU's Kenneth Rothman, founding editor of the journal Epidemiology, called it of "publishable quality." Zeroing in on young patients, he said, was good science: "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.

Besides focusing on kids, Dr. Bassin and her colleagues found out where each cancer patient ever lived, and what kind of water they drank when. Other studies have just noted what water a patient was drinking at the time of diagnosis. The problem with that is, you risk classifying someone as drinking nonfluoridated water who in fact drank fluoridated water when it mattered -- in childhood. The result is that the osteosarcoma rates of people drinking fluoridated water might look no different from those of people drinking nonfluoridated. "She did great shoe-leather epidemiology," says William Maas, head of oral health at the CDC and a supporter of fluoridation.

PREVIOUS STUDIES have been contradictory. A 1991 animal study by the National Toxicology Program concluded that fluoride might raise the risk of osteosarcoma, but only in male rats, not female. Also in 1991, a scientist at the National Cancer Institute found "an unexplained increase" in osteosarcoma in men under 20 in fluoridated communities. Most human studies, though, provide "no credible evidence for an association between fluoride in drinking water and the risk of cancer," said a 1993 NRC report.

But when you look carefully at the negative studies, you have to wonder. Some investigated a link to all cancers; because osteosarcoma is rare, an increase would be unlikely to show up in that vast sea. Other studies were tiny, or included adults as old as 84, which would wash out effects that target kids. Most categorized osteosarcoma patients as drinking fluoridated or nonfluoridated water based on where they lived at diagnosis, not as kids. Concerned about such lapses, the NRC report called the studies "of limited sensitivity."

Even if fluoridation causes just a few hundred cases of osteosarcoma every year, does the public health benefit justify that risk? "When we started fluoridating water, we thought to get the benefits it would have to get incorporated into the enamel before the tooth erupted," which happens only if you swallow it, says the CDC's Dr. Maas. But that turns out not to be so. Topical fluoride, as in gels and toothpaste, works at least as well.

Most proponents now say fluoridation cuts the rate of tooth decay 18% to 25%. How much is that? Less than one tooth surface. "The absolute impact of 18% or even 25% is low," says Stephen Levy of the University of Iowa, who supports fluoridation.

The next authoritative report on fluoridation will be the NRC's. One scientist close to the committee thinks it may be released this fall, months later than expected. "We thought this was going to be routine," he says. "It wasn't." With fluoridation, it seldom is.

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Fluoride in tap water linked to bone cancer

By: Staff
Biotech Business Week
July 25, 2005

Newly available research, out of Harvard University, links fluoride in tap water, at levels most Americans drink, to osteosarcoma, a rare form of bone cancer.

The Environmental Working Group (EWG), a Washington DC-based organization, urges that fluoride in tap water be declared a known or probable cancer cause, based on this and previous animal and human studies, reports the New York State Coalition Opposed to Fluoridation.

Elise Bassin, PhD writes, in her Harvard doctoral thesis, " ... for males less than twenty years old, fluoride level in drinking water [about1partpermillion] during growth is associated with an increased risk of osteosarcoma."

According to EWG, "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."

Citing a strong body of peer-reviewed evidence, including the Bassin study, EWG urges an expedited review of fluoride for inclusion in a U.S. government report of substances known or feared to be cancer-causing in humans.

Richard Wiles, EWG's senior vice president, told the British newspaper The Observer, "I've spent 20 years in public health trying to protect kids from toxic exposure. Even with DDT, you don't have the consistently strong data that the compound can cause cancer as you now have with fluoride."

High-quality epidemiological studies show a strong association between fluoride in tap water and osteosarcoma in boys, reports EWG.

EWG's Wiles writes, "The safety of fluoride in America's tap water is a pressing health concern ... the weight of the evidence strongly supports the conclusion that millions of boys in these [fluoridated] communities are at significantly increased risk of developing bone cancer as a result."

Fluoride is added to water supplies in a questionable attempt to reduce tooth decay. Pro-fluoridation studies are outdated and flawed as revealed in British and U.S. reviews of the literature.

This article was prepared by Biotech Business Week editors from staff and other reports. Copyright 2005, Biotech Business Week via NewsRx.com.