A study associating drinking fluoridated water with osteosarcoma, a rare malignant bone tumor, was published last Wednesday on “Cancer Causes and Control”, an online peer-review journal of Harvard University.

Elise B. Bassin, a clinical instructor in Oral Health Policy and Epidemiology, who led the study, wrote in an e-mail that she found a significant relationship between fluoride and cancer—contradicting the findings of her dissertation adviser Chester Douglass, the chair of the Oral Health Policy and Epidemiology Department at the Harvard School of Dental Medicine.

“We found an association between fluoride levels in drinking water during childhood and osteosarcoma for males diagnosed before age 20 years,” she wrote.

Douglass’ $1.3 million dollar, 15 year study did not find a link between drinking fluoridated water and developing osteosarcoma. He said Bassin’s study is a subset of his study and that he had not been able to replicate her results.

The Environmental Working Group, a Washington D.C. based advocacy group, recently filed an ethics complaint against Douglass because he allegedly cited Bassin’s study in his report, despite the opposite conclusions reached by the two studies. Douglass said he just listed Bassin’s study as a related publication and not a reference.

Douglass has received widespread criticism for defending the use of fluoride while being editor of a publication funded by a fluoride toothpaste maker.

Douglass wrote a letter in “Cancer Causes and Control,” where Bassin’s work was published, warning readers to take the results of Bassin’s study with discretion.

“Readers are cautioned not to generalize and over-interpret results... before making conclusions, and before influencing any related policy decisions,” he wrote.

—Staff writer Doris A. Hernandez can be reached at dahernan@fas.harvard.edu.