Elsevier

Bone

Volume 21, Issue 6, December 1997, Pages 527-533
Bone

Original article
First- and second-year effects in trials of calcium supplementation on the loss of bone density in postmenopausal women

https://doi.org/10.1016/S8756-3282(97)00181-6Get rights and content

Abstract

The analysis of clinical trials investigating the effect of calcium on the loss of bone mass or density has been based on the assumption that the effects are the same for all years of follow-up. Hence the average annual rate of loss is calculated and compared in the calcium and control groups. In this metaanalysis, we investigated this assumption and found that it is not tenable in the groups randomized to calcium for most sites that have been measured. The rate of bone loss was significantly less in the first year after randomization than in the second year. By contrast, the rate of loss in the control groups was less in the second year than the first, although this was not significant. At the spine, femoral neck, trochanter, intertrochanter, midtibia, and ultratibia, the effect of calcium in reducing bone loss was statistically significant compared with control only in the first year after randomization; there was no difference in rates between the groups in the second year. The effect of calcium compared to control in two arm sites and Ward's triangle was of a similar magnitude but was not statistically significant. We recommend that analysis and metaanalysis of trials should always consider the effects on a year-by-year basis.

References (34)

  • T. Chevalley et al.

    Effects of calcium supplements on femoral bone mineral density and vertebral fracture rate in vitamin-D-replete elderly patients

    Osteopor Int

    (1994)
  • R.G. Cumming

    Calcium intake and bone mass: A quantitative review of the evidence

    Calcif Tissue Int

    (1990)
  • B. Dawson-Hughes et al.

    A controlled trial of the effect of calcium supplementation on bone density in postmenopausal women

    New Engl J Med

    (1990)
  • P.J.M. Elders et al.

    Calcium supplementation reduces vertebral bone loss in perimenopausal women: A controlled trial in 248 women between 46–55 years of age

    J Clin Endocrinol Metab

    (1991)
  • T. Fujita et al.

    Calcium supplementation in osteoporosis

    Osteopor Int

    (1993)
  • T. Hansson et al.

    The effect of fluoride and calcium on spinal mineral content: A controlled, prospective (3 years) study

    Calcif Tissue Int

    (1995)
  • R.P. Heaney

    The bone-remodeling transient: Implications for the interpretation of clinical studies of bone mass change

    J Bone Miner Res

    (1994)
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