Indication: Bone fracture/structure

Source: Arch Intern Med, April 24, 2006;166:869-875.

Research: Researchers investigated whether or not increased calcium intake, which has been proposed as a population-based public health intervention, could prevent osteoporotic fractures. Nearly 1500 women over the age of 70 participated in this study. They were randomized to receive calcium carbonate (600 mg twice daily) or an identical placebo. The primary endpoints included clinical incident osteoporotic fractures, vertebral deformity and adverse events ascertained in five years. Bone structure was also measured using dual x-ray absorptiometry of the hip and whole body, quantitative ultrasonography of the heel, and peripheral quantitative computed tomography of the distal radius.

Results: Among the patients, just over 16% sustained one or more clinical osteoporotic fractures. In the intention-to-treat analysis, calcium supplementation did not significantly reduce fracture risk. However, 830 patients (57%) who took 80% or more of their tablets (calcium or placebo) per year had reduced fracture incidence in the calcium compared with the placebo groups. Calcium-treated patients had improved quantitative ultrasonography findings of the heel, femoral neck and whole-body dual x-ray absorptiometry data, and bone strength compared with placebo-treated patients. Researchers believe that supplementation with calcium carbonate tablets supplying 1200 mg/d is ineffective as a public health intervention in preventing clinical fractures in the ambulatory elderly population owing to poor long-term compliance, but it is effective in those patients who are compliant.