You ask, we Answer: Does fluoridated water cause bone cancer? 

Next installment of series on 'Fluoridation Facts'

With the release of the ADA’s new edition of Fluoridation Facts, readers can learn the answers to hundreds of frequently asked questions about community water fluoridation and the latest scientific research. Fluoridation Facts — the Association’s free resource on fluoridation that examines the mineral’s effectiveness, safety, practice and cost-effectiveness — works to assist policymakers and the general public in making informed decisions about fluoridation. The new edition contains more than 400 references and 10 new Q&A’s for a total of 69 covered over 114 pages.

In an ongoing series, the ADA News is delving into many questions explored in the book through conversations with experts about fluoridation information and misinformation — from overall effectiveness to whether ingesting fluoride impacts IQ, health and reproduction.

Catherine Hayes, D.M.D., chair of the department of oral health policy and epidemiology at Harvard School of Dental Medicine, discussed whether fluoridated water causes osteosarcoma — question #33 in "Fluoridation Facts."

The question of whether fluoridated water causes osteosarcoma, a form of bone cancer, gained traction in the 1990’s when researchers, while looking at osteosarcoma, gave rats in a study exceptionally high levels of fluoride. While researchers considered the evidence to be equivocal, Dr. Hayes said, they did find a slightly higher incidence of bone cancer in those particular rats.

An exploratory analysis from 2006 found an increased risk for osteosarcoma in boys aged 7 exposed to fluoridated drinking water, but not consistently for girls, the ADA said. This prompted a case control study co-authored by Dr. Hayes that analyzed fluoride levels in bone samples from 137 human patients with primary osteosarcoma and bone samples from 51 patients with other malignant bone tumors who served as the control group.

“What was found is that there was no difference in bone fluoride concentrations in the people who had the osteosarcoma versus those who did not. And that was pretty significant because no one had really ever done that before,” Dr. Hayes said.

She noted that researchers examined patients’ residential histories and fluoride supplements. They conducted an analysis on individuals who lived in fluoridated communities versus those who did not, and found there was no difference in osteosarcoma risk. Dr. Hayes also added that osteosarcoma is already a very rare form of cancer.  

“There’s no evidence whatsoever to suggest that fluoridated water causes osteosarcoma. If it did, we would see much higher levels of osteosarcoma in the country,” she said.  

For more information on this free resource, visit ADA.org/FluoridationFacts.