Calcium supplementation for improving bone mineral density in children.
What this study found
Calcium supplementation had little overall effect on bone mineral density in healthy children. A small, statistically modest benefit was seen at the upper limb, and that effect persisted after supplementation stopped, but it was unlikely to translate into a clinically meaningful reduction in fracture risk. Many other bone sites and outcomes showed no statistically significant difference, and the review concluded that the evidence does not support calcium supplementation as a public health intervention for healthy children. The findings should not be extrapolated to children with medical…
- Study & population
- Systematic review and meta-analysis of 19 randomized trials in healthy children and adolescents under 18 years without medical conditions affecting bone metabolism.
- Intervention
- Calcium supplementation was tested in multiple forms, including calcium carbonate, calcium citrate malate, calcium phosphate, milk extract, and milk minerals, at doses ranging from 300 mg/day to 1200 mg/day, usually given orally for the trial duration versus placebo.
- Key limitation
- The included trials were heterogeneous in calcium form, dose, duration, age, pubertal status, baseline calcium intake, ethnicity, and outcome site, which limits comparability.
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Open PDFOriginal abstract
BACKGROUND Clinical trials have shown that calcium supplementation in children can increase bone mineral density (BMD) although this effect may not be maintained. There has been no quantitative systematic review of this intervention. OBJECTIVES . To determine the effectiveness of calcium supplementation for improving BMD in children. . To determine if any effect varies by sex, pubertal stage, ethnicity or level of physical activity, and if any effect persists after supplementation is ceased. SEARCH STRATEGY We searched CENTRAL, (Cochrane Central Register of Controlled Trials) (Issue 3, 2005), MEDLINE (1966 to 1 April 2005), EMBASE (1980 to 1 April 2005), CINAHL (1982 to 1 April 2005), AMED (1985 to 1 April 2005), MANTIS (1880 to 1 April 2005) ISI Web of Science (1945 to 1 April 2005), Food Science and Technology Abstracts (1969 to 1 April 2005) and Human Nutrition (1982 to 1 April 2005). Conference abstract books (Osteoporosis International, Journal of Bone and Mineral Research) were hand-searched. SELECTION CRITERIA Randomised controlled trials of calcium supplementation (including by food sources) compared with placebo, with a treatment period of at least 3 months in children without co-existent medical conditions affecting bone metabolism. Outcomes had to include areal or volumetric BMD, bone mineral content (BMC), or in the case of studies using quantitative ultrasound, broadband ultrasound attenuation and ultrasonic speed of sound, measured after at least 6 months of follow-up. DATA COLLECTION AND ANALYSIS Two authors independently assessed trial quality and extracted data including adverse events. We contacted study authors for additional information. MAIN RESULTS The 19 trials included 2859 participants, of which 1367 were randomised to supplementation and 1426 to placebo. There was no heterogeneity in the results of the main effects analyses to suggest that the studies were not comparable. There was no effect of calcium supplementation on femoral neck or lumbar spine BMD. There was a small effect on total body BMC (standardised mean difference (SMD) +0.14, 95% CI+0.01, +0.27) and upper limb BMD (SMD +0.14, 95%CI +0.04, +0.24). Only the effect in the upper limb persisted after supplementation ceased (SMD+0.14, 95%CI+0.01, +0.28). This effect is approximately equivalent to a 1.7% greater increase in supplemented groups, which at best would reduce absolute fracture risk in children by 0.1-0.2%per annum. There was no evidence of effect modification by baseline calcium intake, sex, ethnicity, physical activity or pubertal stage. Adverse events were reported infrequently and were minor. AUTHORS' CONCLUSIONS While there is a small effect of calcium supplementation in the upper limb, the increase in BMD which results is unlikely to result in a clinically significant decrease in fracture risk. The results do not support the use of calcium supplementation in healthy children as a public health intervention. These results cannot be extrapolated to children with medical conditions affecting bone metabolism.