EFFECT OF SALCATONIN GIVEN INTRANASALLY ON BONE MASS AND FRACTURE RATES IN ESTABLISHED OSTEOPOROSIS - A DOSE-RESPONSE STUDY

Objective-To study the dose related response of salmon calcitonin (salcatonin) given intranasally on bone mass and bone turnover and the effect of salcatonin on rates of fracture in elderly women with moderate oteoporosis. Design-Double blind, placebo controlled, randomised group comparison. Setting-Outpatient clinic for research into osteoporosis. Subjects-208 healthy women aged 68-72 years who had a bone mineral content of the distal forearm on average 30% below the mean value for healthy premenopausal women. Interventions-The 208 women were allocated randomly in blocks of four to two years of treatment with either salcatonin 50 IU, 100 IU, or 200 IU given intranasally or placebo. All groups received a calcium supplement of 500 mg. 32 of the women left the study before its end and 164 women complied with the study criteria throughout. Main outcome measures-Bone mineral content of the distal forearm and lumbar spine and rates of vertebral and peripheral fractures after two years of treatment. Results-The average changes in bone mineral content of the spine showed positive outcomes of 1% (95% confidence interval -0.1% to 1.5%) in the group treated with calcium (placebo) and 3% (1.8% to 4.2%) in the group treated with salcatonin 200 IU. There was a significant dose related response to salcatonin, manifested by an increase of 1.0%/100 IU (0.2% to 1.7%, p=0.008). The rate of patients with new fractures was reduced significantly in the women treated with salcatonin to about one third of that in the non-salcatonin treated women (relative risk 0.23 (0.07 to 0.77)). Conclusion-The results suggest that, compared with calcium alone, salcatonin given intranasally reduces the rates of fracture by two thirds in elderly women with moderate osteoporosis. Furthermore, it increases spinal bone mass in a dose dependent manner.