Community water fluoridation is not associated with an increased risk of osteosarcoma, according to a multi-institution team of researchers.
More than 60% of the United States population has access to community water fluoridation, which the Centers for Disease Control and Prevention called one of the 10 great public health achievements of the twentieth century because of its reduction of tooth decay at the population level.
However, fluoride ingestion has been suggested as a possible risk factor for osteosarcoma based on a 1990 animal study, the researchers said. Six of the seven subsequent case-control studies in humans reported that fluoride in drinking water was not associated with osteosarcoma.
The current study assessed whether living in a fluoridated community was a risk factor for osteosarcoma by performing a secondary data analysis using data collected from two separate but linked studies.
Patients for both phase 1 and phase 2 were selected from United States hospitals using a hospital-based matched case-control study design. For both phases, cases were patients diagnosed with osteosarcoma, and controls were patients diagnosed with other bone tumors or non-neoplastic conditions.
In phase 1, 209 cases and 440 controls were patients of record in participating orthopedic departments from 1989 to 1993. In phase 2, 108 cases and 296 controls were incident patients who were identified and treated by orthopedic physicians from 1994 to 2000.
The analysis included all patients who met eligibility criteria on whom the researchers had complete data on covariates, exposures, and outcome. Conditional logistic was used to estimate odds ratios and 95% confidence intervals for the association of community water fluoridation with osteosarcoma.
The adjusted odds ratios for osteosarcoma and ever-having in a fluoridated area for non-bottled water drinkers was 0.51 (0.31 to 0.84), p = 0.008. The same comparison adjusted odds ratios for bottled water drinkers was 1.86 (0.54 to 6.41), p = 0.326.
“These results indicate that residence in a fluoridated community is not related to an increase in risk for osteosarcoma after adjusting for race, ethnicity, income, distance from the hospital, urban/rural living status, and drinking bottled water,” said coauthor Chester Douglass, DMD, PhD, of the Harvard School of Dental Medicine Department of Oral Health Policy and Epidemiology.
“This should not be surprising, given that ingestion of fluoridated water is a common exposure, and osteosarcoma remains a rare disease,” Douglass said.
The study, “A Case-Control Study of Fluoridation and Osteosarcoma,” was published by the Journal of Dental Research.