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Effects of calcium supplementation on bone density in healthy children: meta-analysis of randomised controlled trials

BMJ 2006; 333 doi: (Published 12 October 2006) Cite this as: BMJ 2006;333:775
  1. Tania Winzenberg (tania.winzenberg{at}, musculoskeletal epidemiologist1,
  2. Kelly Shaw, specialist medical advisor2,
  3. Jayne Fryer, statistics fellow1,
  4. Graeme Jones, head, musculoskeletal unit1
  1. 1 Menzies Research Institute, Private Bag 23, Hobart, Tas 7001, Australia,
  2. 2Department of Health and Human Services, Hobart, Tas 7000, Australia
  1. Correspondence to: T Winzenberg
  • Accepted 2 August 2006


Objectives To assess the effectiveness of calcium supplementation for improving bone mineral density in healthy children and to determine if any effect is modified by other factors and persists after supplementation stops.

Design Meta-analysis.

Data sources Electronic bibliographic databases, hand searching of conference proceedings, and contacting authors for unpublished data.

Review methods We included randomised placebo controlled trials of calcium supplementation in healthy children that lasted at least three months and had bone outcomes measured after at least six months of follow-up. Two reviewers independently extracted data and assessed quality. Meta-analyses predominantly used fixed effects models with outcomes given as standardised mean differences.

Results We included 19 studies involving 2859 children. Calcium supplementation had no effect on bone mineral density at the femoral neck or lumbar spine. There was a small effect on total body bone mineral content (standardised mean difference 0.14, 95% confidence interval 0.01 to 0.27) and upper limb bone mineral density (0.14, 0.04 to 0.24). This effect persisted after the end of supplementation only at the upper limb (0.14, 0.01 to 0.28). There was no evidence that sex, baseline calcium intake, pubertal stage, ethnicity, or level of physical activity modified the effect.

Conclusions The small effect of calcium supplementation on bone mineral density in the upper limb is unlikely to reduce the risk of fracture, either in childhood or later life, to a degree of major public health importance.


  • Embedded ImageA list of references for the included studies (w1-w35) and the search strategy can be found on

    This review has been published as a Cochrane Review (Winzenberg TM, Shaw K, Fryer J, Jones G. Calcium supplementation for improving bone mineral density in children. Cochrane Database Syst Rev 2006;(2): CD005119). We thank Louise Falzon for her assistance with the design and implementation of the search strategy for this protocol, Lara Maxwell for coordinating assistance with several parts of this review, George Wells for statistical advice, and Guangju Zhai for assistance with translations.

  • Contributors TW, GJ, and KS designed the review protocol. TW and KS undertook screening of articles, data extraction, and quality assessment. TW and JF performed the statistical analyses, with input from GJ. All authors contributed to drafting the manuscript and approved the final version. TW is guarantor.

  • Funding TW received support from the Government of Tasmania through the Dick Buttfield Memorial Fellowship. GJ receives support through a National Health and Medical Research Council practitioner fellowship.

  • Competing interests None declared.

  • Ethical approval Not required.

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