Effect of calcitonin on vertebral and other fractures

We examined the incidence of vertebral and non-vertebral fractures in publi shed randomised clinical trials using calcitonin by parenteral injection or intranasal spray. Trials were reviewed that compared calcitonin with place bo, no therapy, or calcium with or without vitamin D, and that mentioned fr acture as an outcome. Studies that compared the effect of calcitonin with o ther active treatments were excluded. Fourteen trials with 1309 men and wom en were identified. In the calcitonin and the control groups, vertebral and non-vertebral fractures were summed and divided by the number of individua ls originally allocated to the treatment groups. The relative risk of any f racture for individuals taking calcitonin versus those not taking calcitoni n was 0.43 (95% CI 0.38-0.50). The effect was apparent for both vertebral f racture (RR 0.45; 95% CI 0.39-0.53) and non-vertebral fractures (RR 0.34; 9 5% CI 0.17-0.68). When studies identifying patients with fracture, rather t han 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-vert ebral fractures was of borderline significance. We conclude that, within th e limitations of this study, treatment with calcitonin is associated with a significant decrease in the number of vertebral and non-vertebral fracture s.