There was no effect of calcium supplementation  on femoral neck or lumbar spine BMD .
There was no evidence of effect modification by baseline calcium intake , sex , ethnicity , physical activity or pubertal stage .
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 clinical ly 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 can not be extrapolated to children with medical conditions affecting bone metabolism
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 .
To determine the effectiveness of calcium supplementation for improving BMD  in children .
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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 .
A school-based exercise intervention elicits substantial bone health benefits: a 2-year randomized controlled trial in girls.
OBJECTIVE Childhood weight-bearing physical activity is recognized as an important determinant of peak bone mass , and physical activity intervention may represent a feasible strategy for primary prevention of osteoporosis . Previous school-based exercise interventions have all been of < 10 months in duration . We implemented a high-impact , circuit-based , jumping intervention ( 10 minutes , 3 times a week ) over 2 school years and compared changes in bone mineral content ( BMC ) over 20 months ( 2 school years ) in 9.9 + /- 0.6-year-old intervention girls ( N = 32 ) and controls ( 10.3 + /- 0.4 years , N = 43 ) . METHODS We measured BMC for the total body , lumbar spine , proximal femur ( and femoral neck and trochanteric subregions ) , and lean and fat mass by dual-energy radiograph absorptiometry ( Hologic QDR 4500 ) , and height , sitting height , leg length , and weight at baseline and 20 months . We assessed Tanner stage , general physical activity , and calcium intake by question naire . RESULTS Girls were Tanner breast stage 1 to 3 at baseline . There were no significant differences in baseline or 20-month change in body size or composition , average physical activity , or calcium intake between groups . There were substantially greater gains in lumbar spine ( 41.7 % vs 38.0 % ) and femoral neck ( 24.8 % vs 20.2 % ) BMC in intervention than in control girls ( P < .05 , analysis of covariance ; covariates were baseline BMC and height , change in height , physical activity , and final Tanner stage ) . CONCLUSION Three brief sessions of high-impact exercise per week implemented over 2 consecutive years within the elementary school curriculum elicited a substantial bone mineral accrual advantage in pubertal girls
There was no effect of calcium supplementation  on femoral neck or lumbar spine BMD .
There was no evidence of effect modification by baseline calcium intake , sex , ethnicity , physical activity or pubertal stage .
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 clinical ly 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 can not be extrapolated to children with medical conditions affecting bone metabolism
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 .
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 .