Background: Injectable calcitonin is effective in reducing spinal bone loss in steroid-dependent asthma but side effects are frequent. In contrast, a nasal spray presentation has been shown to be effective and well tolerated in involutional osteoporosis. To test the efficacy of nasal calcitonin a two year prospective trial was conducted in 44 steroid-dependent asthmatic patients.
Methods: All patients received a calcium supplement of 1000 mg and were allocated randomly into two groups treated with either salmon calcitonin nasal spray (200 IU every other day, n = 22) or calcium alone (n = 22) for two years. All patients completed the first year of the study. Five patients in each group dropped out during the second year. In the calcitonin group one patient developed generalised pruritus and four lost steroid dependence, and in the calcium alone group five were no longer dependent on steroids. The efficacy of treatment was evaluated as follows: bone turnover assessed by biochemical markers, bone loss assessed by serial measurement of lumbar spine density, and rates of bone fractures.
Results: The bone mass in the calcitonin group increased by 2.7% in the first year while in the group receiving calcium alone it decreased by 2.8%; this difference was significant. Calcitonin prevented more bone loss during the second year while the calcium alone group continued losing bone mass (-7.8%). The difference between means was 0.1077 (95% CI 0.0381 to 0.1773). Three new fractures occurred in both groups. No changes in biochemical parameters were detected in either group.
Conclusions: Calcitonin given intranasally increased spinal bone mass during the first year of treatment and maintained bone mass in a steady state during the second year. These results suggest that calcitonin may be a useful agent to prevent steroid-induced osteoporosis. However, the lack of effect of calcitonin on the rate of vertebral fractures does not permit its recommendation for routine use in preventing steroid-induced osteoporosis.