FLUORIDE THERAPY FOR OSTEOPOROSIS

Objective: To present the latest findings on the use of fluoride in th e treatment of osteoporosis. Options: Plain sodium fluoride (NaF), ent eric-coated sodium fluoride (EC-NaF), sodium monofluorophosphate (Na2F PO4), slow-release sodium fluoride (SR-NaF); fluoride with a calcium s upplement. Outcomes: Fracture and loss of bone mineral density in oste oporosis; increased bone mass, prevention of fractures and improved qu ality of life associated with treatment. Evidence: Relevant clinical s tudies and reports were examined, with an emphasis on recent prospecti ve, randomized, controlled trials. Clinical practices in European coun tries were also considered. Values: Reducing fractures, increasing bon e mineral density and minimizing side effects of treatment were given a high value. Benefits, harms and costs: NaF therapy stimulates bone f ormation and may be effective in preventing osteoporotic fractures. It may be an acceptable alternative treatment to estrogen or bisphosphon ate therapy and useful in premenopausal and corticosteroid-induced ost eoporosis and in some patients with mid osteogenesis imperfecta. Toxic effects are dependent on formulation and dosage. They include a range of gastrointestinal and musculoskeletal conditions. EC-NaF is associa ted with less toxicity than plain NaF; its gastrointestinal toxicity i s negligible. Na2FPO4 has no gastrointestinal toxicity, but can give r ise to skeletal toxicity. SR-NaF appears to have no side effects when given intermittently. Carcinogenicity has not been found in vivo with fluoride therapy, despite in vitro results. Recommendations: New data indicate that fluoride therapy should be re-evaluated as a potentially effective treatment of osteoporosis with minimal side effects. More s tudies are needed of slow-release fluoride formulations, intermittent treatment schedules and calcium supplementation of fluoride. Studies s hould be undertaken to see if it is advantageous to initiate treatment with antiresorptive agents before or in combination with fluoride. Co nclusive data have not been presented regarding the benefit of any spe cific type of calcium supplement. Further studies on the basic mechani sm of action of fluoride on the skeleton are necessary to evaluate flu oride's potential to stimulate bone formation therapeutically. Validat ion: These recommendations were developed by the Scientific Advisory B oard of the Osteoporosis Society of Canada at its 1995 Consensus Confe rence. They are in agreement with and supplement the consensus stateme nt of the First International Workshop on Fluoride and Bone, Niagara-o n-the-Lake, Ont., 1988. Sponsors: Sponsors of the 1995 conference incl uded the Dairy Farmers of Canada, Eli Lilly Canada, Inc., Hoffmann-La Roche Canada Limited, Merck Frosst Canada Inc. and Proctor & Gamble Ph armaceuticals Canada Inc.