Common Questions
Does calcitonin reduce the risk of fractures?
There has only been one randomized, placebo-controlled trial of calcitonin with sufficient power to detect a change in fracture rates. The PROOF (Prevent Recurrence of Osteoporotic Fractures) trial, a prospective 5 year dose response study of nasal calcitonin (100 IU, 200 IU or 400 IU), included 1255 postmenopausal osteoporotic women (1). The relative risk of developing new fractures was decreased by 33% in the group taking 200 IU/ day as compared to placebo. The overall RR was 21% when all treatment groups were included. There was no significant effect on hip BMD or fracture rate at any dose.
Some experts feel that the evidence from this study is weak and unreliable because there was no statistically significant reduction of fractures in either of the 100 IU or 400 IU treatment groups and 59% of the patients had dropped out before the end of the study (2). Also, the study was only partially blinded as physicians and patients were aware of the BMD results during the study.
A meta-analysis of 30 randomized controlled trials (duration of > one year) using calcitonin (nasal, rectal, parenteral) showed a pooled RR of 0.46 in the incidence of vertebral fractures but no effect on nonvertebral fractures (3).
- Chesnutt III CH, Silverman S, Andriano K, et al. A randomized trial of nasal spray salmon calcitonin in postmenopausal women with established osteoporosis: The Prevent Recurrence of Osteoporotic Fractures Study. Am J Med 2000; 109: 267-76.
- Cummings SR, Chapurlat RD. What PROOF proves about calcitonin and clinical trials. Am J Med 2000; 109: 330-1.
- Cranney A, Tugwell P, Zytaruk N, et al. The Osteoporosis Methodology Group and The Osteoporosis Research Advisory Group. Meta-analyses of therapies for postmenopausal osteoporosis: VI. Meta-analysis of calcitonin for the treatment of postmenopausal osteoporosis. Endocr Rev 2002; 23(4): 540-51.