BOSTON — Harvard University said it is investigating whether a dentistry professor who edits a newsletter funded by a toothpaste maker played down research showing an increased cancer risk from drinking fluoridated tap water.
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The school will work with the National Institute of Environmental Health Sciences to review Chester Douglass’ research into fluoride exposure and osteosarcoma, a rare form of bone cancer, Harvard Medical School spokesman John Lacey said.
The institute awarded a $1.3 million study grant in 1992 to Douglass, who found that the odds of having osteosarcoma after drinking fluoridated water were “not statistically different” from the odds for those who drank non-fluoridated water.
Elise Bassin, a doctoral student supervised by Douglass who studied some of the same people, reported in her 2001 thesis that boys who drink fluoridated water appear to have an increased risk of developing the bone cancer.
The Environmental Working Group, an advocacy group based in Washington, D.C., filed an ethics complaint against Douglass last month after discovering that he cited Bassin’s research in his final grant report. In it, he said her work supported his claim that there was no significant risk from fluoridated water, even though Bassin had found a strong link between fluoride levels in tap water and an increased osteosarcoma risk for boys.
Richard Wiles, senior vice president of the environmental group, also said there is a conflict of interest between Douglass’ research and his position as editor in chief of the Colgate Oral Health Report, a quarterly newsletter funded by Colgate-Palmolive Co., which makes fluoridated toothpaste.
“It’s safe to say that he appears to be one of the leading members of the fluoride apologists group of scientists,” Wiles said. “Clearly, the fluoride-using industry, the dental industry, has an interest in the image of fluoride as being a healthy, good thing.”
A woman who answered the phone on Wednesday at Douglass’ office said he was on vacation and unavailable for comment.
Committee to review allegations
In a statement Wednesday, the Harvard School of Dental Medicine said it was following standard practice in allegations of research impropriety and will assemble a committee to review them.
Christine Bruske, a spokeswoman for NIEHS, said the institute is reviewing the letter it received from the Environmental Working Group alleging “scientific misconduct” by Douglass, who heads Harvard’s Department of Oral Health Policy and Epidemiology.
Bassin declined to comment. Her thesis has not yet been published and is not available to the public, but the environmental group obtained it and cited excerpts in a letter sent to Douglass last month.
“Among males, exposure to fluoride at or above the target level was associated with an increased risk of developing osteosarcoma,” Bassin wrote. “The association was most apparent between ages 5-10 with a peak at 6 to 8 years of age.”
Douglass’ study looked at men and women of all different ages who drank fluoridated tap water. Bassin looked at the boys and girls used in Douglass’ study and verified fluoride levels in tap water for each year of the child’s life.
“She found the strongest association ever between fluoridated tap water and bone cancer among boys,” Wiles said.
Safety of fluoridated water questioned
Fluoridation of tap water in the United States began in the 1950s and was seen as an effective way to fight tooth decay.
Controversy over the practice began to grow in the 1970s after a study found a high incident in bone structure defects in Newburgh, N.Y., one of the first communities in the country to fluoridate its water, when compared with the rate in the non-fluoridated town of Kingston, N.Y.
A study completed in 1991 by the U.S. Public Health Service found that rates of osteosarcoma were significantly higher among males under 20 who lived in communities with fluoridated water than in those without it.
Other major studies have reached the opposite conclusion, including a 1995 study by the New York State Health Department that found fluoride exposure does not increase the risk for childhood osteosarcoma.
Wiles said the Environmental Working Group does not oppose fluoridated toothpaste because most fluoride in toothpaste is not ingested. He said when fluoride is ingested through tap water, it can stimulate growth at the end of bones, where osteosarcoma occurs.
“I think the industry realizes that the public may not make the distinction,” Wiles said. If fluoride gets a big black eye in tap water then the public is going to wonder about this fluoride in my toothpaste.”
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