Monofluorophosphate increases lumbar bone density in osteopenic patients: a double-masked randomized study

Abstract

To assess the efficacy of combined sodium monofluorophosphate and calcium therapy (FC) in increasing lumbar bone mineral density (BMD) in patients with low bone mass, we conducted a prospective double-masked randomized study in 94 patients aged 50-70 years. Patients were selected on the basis of a lumbar BMD at least 2 standard deviations (SD) below the young adult mean (T-score) but without evidence of previous vertebral fracture (severe osteopenia). They were randomly assigned to receive for 2 years, twice a day, either FC (13.2 mg F-, i.e. 100 mg sodium monofluorophosphate, and 500 mg Ca2+) or C (500 mg Ca2+). Vertebral BMD was measured by dual photon absorptiometry from L2 to L4. Comparison at final assessment in the 76 eligible patients (Student's t-test) showed a statistically significant difference between the two groups in the mean BMD increase in favour of FC. Furthermore, Student's t-test showed a significantly greater increase in lumbar BMD in FC-treated patients at 1 year, at 18 months and after 2 years (mean increase of 7.1%/year). These results were confirmed by ANOVA at 1 year, at 18 months and after 2 years of treatment. Of the FC-treated patients, 71.4% were considered to have responded (i.e. they showed an increase in lumbar BMD of more than 0.034 g/cm2). The dosage of 26.4 mg fluoride ion/day (i.e. 200 mg monofluorophosphate/day) therefore appears to be safe and to increase the BMD effectively in patients with low bone mass prior to vertebral fracture.