Effect of calcitonin on vertebral and other fractures.

We examined the incidence of vertebral and non-vertebral fractures in published randomised clinical trials using calcitonin by parenteral injection or intranasal spray. Trials were reviewed that compared calcitonin with placebo, no therapy, or calcium with or without vitamin D, and that mentioned fracture as an outcome. Studies that compared the effect of calcitonin with other active treatments were excluded. Fourteen trials with 1309 men and women were identified. In the calcitonin and the control groups, vertebral and non-vertebral fractures were summed and divided by the number of individuals originally allocated to the treatment groups. The relative risk of any fracture for individuals taking calcitonin versus those not taking calcitonin was 0.43 (95% CI 0.38-0.50). The effect was apparent for both vertebral fracture (RR 0.45; 95% CI 0.39-0.53) and non-vertebral fractures (RR 0.34; 95% CI 0.17-0.68). When studies identifying patients with fracture, rather than numbers of fractures were pooled, the magnitude of effect was less (RR 0.74; 95% CI 0.60-0.93), and the separate effects on vertebral and non-vertebral fractures was of borderline significance. We conclude that, within the limitations of this study, treatment with calcitonin is associated with a significant decrease in the number of vertebral and non-vertebral fractures.