A Cochrane review included 24 studies with a total of 1 299 subjects. No individual intervention (bisphosphonates, vitamin D sterol or calcitonin) was associated with a reduction in fracture risk compared with placebo. Combining results for all active interventions against placebo demonstrated any treatment of bone disease was associated with a reduction in the RR of fracture (RR 0.51, 95% CI 0.27 to 0.99). Bisphosphonates (any route), vitamin D sterol, and calcitonin all had a beneficial effect on the bone mineral density at the lumbar spine. Bisphosphonates and vitamin D sterol also had a beneficial effect on the bone mineral density at the femoral neck. Bisphosphonates had greater efficacy for preventing bone mineral density loss when compared head-to-head with vitamin D sterols.
Comment: The quality of evidence is downgraded by limitations in study quality (e.g. unclear allocation concealment, inadequate intention-to-treat adherence, small sample sizes) and by inconsistency (heterogeneity in study populations, interventions and outcomes).