Effects of treatment with fluoride on bone mineral density and fracture risk - A meta-analysis

Abstract

Summary: Fluoride has fallen into discredit due to the absence of an anti-fracture effect. However, in this meta-analysis, a fracture reducing potential was seen at low fluoride doses [≤20 mg fluoride equivalents (152 mg monofluorophosphate/44 mg sodium fluoride)]: OR=0.3, 95% CI: 0.1-0.9 for vertebral and OR=0.5, 95% CI: 0.3-0.8 for non-vertebral fractures. Introduction: Fluoride is incorporated into bone mineral and has an anabolic effect. However, the biomechanical competence of the newly formed bone may be reduced. Methods: A systematic search of PubMed, Embase, and ISI web of science yielded 2,028 references. Results: Twenty-five eligible studies were identified. Spine BMD increased 7.9%, 95% CI: 5.4-10.5%, and hip BMD 2.1%, 95% CI: 0.9-3.4%. A meta-regression showed increasing spine BMD with increasing treatment duration (5.04±2.16%/year of treatment). Overall there was no significant effect on the risk of vertebral (OR=0.8, 95% CI: 0.5-1.5) or non-vertebral fracture (OR=0.8, 95% CI: 0.5-1.4). With a daily dose of >20 mg fluoride equivalents (152 mg monofluorophosphate/44 mg sodium fluoride), there was a statistically significant reduction in vertebral (OR=0.3, 95% CI: 0.1-0.9) and non-vertebral (OR=0.5, 95% CI: 0.3-0.8) fracture risk. With a daily dose >20 mg fluoride equivalents, there was no significant reduction in vertebral (OR=1.3, 95% CI: 0.8-2.0) and non-vertebral (OR=1.5, 95% CI: 0.8-2.8) fracture risk. Conclusions: Fluoride treatment increases spine and hip BMD, depending on treatment duration. Overall there was no effect on hip or spine fracture risk. However, in subgroup analyses a low fluoride dose (≤20 mg/day of fluoride equivalents) was associated with a significant reduction in fracture risk. © 2007 International Osteoporosis Foundation and National Osteoporosis Foundation.