A case-control study of topical and supplemental fluoride use and osteosarcoma risk

BACKGROUND

A relationship between fluoride and osteosarcoma has been hypothesized but not validated. To the authors' knowledge, there are no published studies examining topical fluoride or dietary fluoride supplements and osteosarcoma risk. The purpose of this study was to examine the association between ever or never use of topical and dietary fluoride supplements and osteosarcoma.

METHODS

The authors performed a secondary data analysis on data from 2 separate but linked studies. Patients for Phase 1 and Phase 2 were selected from US hospitals using a hospital-based matched case-control study design. Case patients were those who had received diagnoses of osteosarcoma, and control patients were those who had received diagnoses of other bone tumors or nonneoplastic conditions. In Phase 1, case patients (N = 209) and control patients (N = 440) were those seeking treatment at orthopedic departments from 1989 through 1993. In Phase 2, incident case patients (N = 108) and control patients (N = 296) were identified and treated by physicians from 1994 through 2000. This analysis included all patients who met eligibility criteria and on whom the authors had complete data on exposure, outcome, and covariates. The authors used conditional logistic regression to estimate odds ratios and 95% confidence intervals (CIs) for the association of topical fluoride use and supplemental fluoride use with osteosarcoma.

RESULTS

The adjusted odds ratios were 0.94 (95% CI, 0.60 to 1.46) and 0.78 (95% CI, 0.46 to 1.33) for topical fluoride and supplemental fluoride, respectively.

CONCLUSIONS

Neither topical nor dietary fluoride supplements are associated with an increased risk of developing osteosarcoma.

PRACTICAL IMPLICATIONS

Supplemental and topical fluorides used in the dental office and in over-the-counter products are not related to an increased risk of developing osteosarcoma.

A Case-Control Study of Fluoridation and Osteosarcoma

Public health policy decisions in the United States have resulted in 62.4% of the population having access to fluoridated water. The purpose of this study was to examine the association between community water fluoridation and osteosarcoma. A secondary data analysis was performed with data collected from 2 separate but linked studies. Patients for phase 1 and phase 2 were selected from US hospitals via a matched case-control study design. For both phases, cases included patients diagnosed with osteosarcoma, and controls were patients diagnosed with other bone tumors or nonneoplastic conditions. In phase 1, cases (n = 209) and controls (n = 440) were patients of record in the participating orthopedic departments from 1989 to 1993. In phase 2, cases (n = 108) and controls (n = 296) were incident patients who were identified and treated by orthopedic physicians from 1994 to 2000. This analysis included all patients who met eligibility criteria on whom we had complete data on covariates, exposures, and outcome. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% CIs for the association of community water fluoridation with osteosarcoma. A modestly significant interaction existed between fluoridation living status and bottled water use (P = 0.047). The adjusted OR for osteosarcoma and ever having lived in a fluoridated area for nonbottled water drinkers was 0.51 (95% CI, 0.31 to 0.84; P = 0.008). In the same comparison, the adjusted OR for bottled water drinkers was 1.86 (95% CI, 0.54 to 6.41; P = 0.326). Findings from this study demonstrated that community water fluoridation is not associated with an increased risk for osteosarcoma.