[Bone complications during the treatment of osteoporosis with fluor]

Fourteen osteoporotic women who had been under treatment with fluoride (23 mg/day of fluorine ions) for 12 months on average developed periarticular pain in the lower limbs or pelvis, corresponding to 21 fractures due to bone insufficiency. Six of these fractures were revealed only by radionuclide uptake in the painful areas, whereas the remaining 15 fractures, including 2 of the sacrum, were visible at radiography. Four patients had a past history of hyperthyroidism or were in a state of active hyperthyroidism detected by hormonal assays and iliac bone biopsy when the fractures were diagnosed. The decalcification associated with hyperthyroidism facilitates the occurrence of bone insufficiency fractures, as do treatments with high doses of fluoride, inadequate calcium supplement intake (observed in 5 cases) or the presence before treatment of renal impairment or disorders of bone mineralization, sometimes detected only by iliac bone biopsy. Repeated measurements of blood and urinary fluoride levels during treatment make it possible to adjust fluoride dosage, and lower doses (14 mg/day of fluorine ions) might reduce the incidence of the adverse effects of fluoride on bone.