Monitoring fluoride therapy in osteoporosis by dual photon absorptiometry.

Dual photon absorptiometry (DPA) was used to evaluate changes in bone mineral mass in 108 osteopenic patients. Ninety were treated with fluoride and 18 served as controls. All osteopenic patients and 9 of the controls took calcium and vitamin D supplements. In 16 women estrogens were combined with the fluoride therapy. Seven patients received prednisone. Significant positive changes in bone mineral mass in the lumbar spine could be demonstrated over a mean observation time of 14-15 months in all groups treated with fluoride but not in the control group. The average increase in bone mineral mass in the lumbar spine (L2, L3 and L4 combined) ranged from 3.57% +/- 1.42% (sem, p less than 0.05) in women on fluoride to 10.36% +/- 3.17% (p less than 0.01) in men and 10.18% +/- 2.39% (p less than 0.001) in women on estrogen and fluoride. Changes in bone mineral mass in femoral necks (left and right combined) and femoral diaphysis were not significant. In the control group no significant changes were observed (lumbar spine: -1.68% +/- 1.75%, femoral necks -0.09% +/- 3.3% and femoral diaphysis -2.32% +/- 2.40%). It is concluded that a positive effect of fluoride on trabecular bone in the spine can be demonstrated with DPA on a group basis when data processing is done in a uniform way by a single observer. Its longitudinal use in individual patients necessitates a series of measurements to overcome the analytical error.