The Scientist

The Harvard School of Dental Medicine announced last week that it is investigating a faculty member after the watchdog Environmental Working Group (EWG) accused him of misrepresenting a study by a former student that reported that fluoride in drinking water increases the risk of bone cancer in young boys.

According to the EWG, Chester Douglass, Harvard's chair of the Department of Oral Health Policy and Epidemiology, said in a report to the National Institute of Environmental Health Sciences (NIEHS) that the still-unpublished study, by former student Elise Bassin, showed that there was no relationship between fluoride and bone cancer.

However, EWG's Mike Casey told The Scientist that a summary of Bassin's work, now available on the EWG Web site, showed exactly the opposite, suggesting that Douglass is "misrepresenting, quite badly, research that he signed off on." As to the researcher's motives for doing so, Casey noted that Douglass is the editor of a newsletter called the Colgate Oral Care Report, funded by Colgate-Palmolive, which makes fluoride-containing toothpaste.

Casey said that EWG has filed a complaint with the NIEHS and called Harvard to apprise the school of their actions. Both Douglass and Bassin declined to comment for this article.

A Harvard spokesperson told The Scientist that the school is assembling an inquiry committee to investigate the charges, and plans to work with the NIEHS. "The Harvard School of Dental Medicine takes all allegations of misconduct seriously and has a standard system for reviewing allegations of research impropriety," the spokesperson said.

Although Bassin's paper is not yet published, a summary on the EWG Web site says that the report showed a nearly 5-fold higher risk of osteosarcoma in boys who, at age 7, drank water containing 30% to 99% of the amount of fluoride recommended by the U.S. Centers for Disease Control and Prevention (CDC). When boys drank water containing at least 100% of the recommended amount of fluoride, their risk jumped to more than seven times that of unexposed boys.

Casey said that the EWG learned about Bassin's report when they heard that members of a National Academy of Sciences panel discussing osteosarcoma and fluoride were having difficulty getting access to Bassin's research. The EWG looked into the matter further and found "stark contradictions" between Bassin's alleged results and Douglass' presentation of them, Casey noted.

For example, in a report to NIEHS, which gave Douglass money from 1992 to 1999 as part of the "Fluoride Exposure and Osteosarcoma" project, he writes that an "analysis carried out for an Orthopedic Surgery Research meeting reported an odds ratio of 1.2 to 1.4 between fluoride and osteosarcoma that was not significantly different from 1." One of the two references Douglass includes in the report is Bassin's 2001 thesis, which he approved, although it is not clear where any of the data points he cites are taken from.

According to Douglass' report, he and his colleagues found no significant link between fluoride and bone cancer when they examined patient records from orthopedic surgery departments across the United States, and matched cases to controls with different tumors and nontumor controls. To investigate exposure to fluoride, Douglass and his team used CDC fluoridation census data and direct information from regions where cases and controls lived.

Casey noted that the EWG recently released a review of scientific research, including Bassin's, on fluoride in drinking water that showed a "pretty clear link" between fluoride and osteosarcoma. Still, the EWG isn't "organizationally opposed" to fluoride, Casey said. "We're saying this is what the science says. People can draw their own conclusions."

Martin Mahoney of the Roswell Park Cancer Institute and State University of New York, Buffalo, has studied the effects of fluoride in drinking water and found no link between bone cancer and fluoridation. He reviewed the EWG site for The Scientist and said there is not enough information to make any conclusions about Bassin's research, nor Douglass' conduct. He questioned why Bassin's work had not yet been published, given that she completed it in 2001.

G.G. Steiner, of Steiner Laboratories in Kapolei, Hawaii, told The Scientist that he has reviewed every published paper to date on fluoride and cancer and has found no sign that fluoride increases the risk of bone cancer. "It's really a dead issue about fluoride and cancer in science," he said. Steiner, who sells fluoride for use during bone graft surgery, said he has even published research showing that cancer rates appear to decrease as fluoride levels in water increase, suggesting fluoride might actually protect against cancer.

Steiner added that many people are against adding fluoride to water because they don't like having something forced on them, and simply having a connection to Colgate doesn't make Douglass guilty of wrongdoing. "Just because of that, you can't make a leap that he's covering something up," he said.