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 .
High-Impact Exercise and Bones of Growing Girls: A 9-Month Controlled Trial

Abstract : The maximum amount of bone a person can obtain during the first two decades of life is an important determinant of bone mass in later life , and an increase in peak bone mass has been associated with decreased risk for osteoporotic fractures . It is known that growth of bone and thus development of peak bone mass are strongly controlled by genetic factors , but information on the role of environmental factors , such as exercise and nutrition , ( e.g. , exercise ) on growing bone is limited . We tested a hypothesis that in growing girls the benefit of mechanical loading on bone mineral mass and bone strength is better before rather than after the menarche . Sixty-four girls ( 25 premenarcheal , 39 postmenarcheal ) carried out a supervised 9-month step-aerobic program ( two sessions per week ) , each session complemented with additional jumps .  Sixty-two girls ( 33 premenarcheal , 29 postmenarcheal ) served as controls . Bone mineral content ( BMC ) at the lumbar spine and proximal femur was measured by dual-energy X-ray absorptiometry ( DXA ) . In addition , the cortical density ( CoD , mg/cm3 ) and cortical cross-sectional area ( CoA , mm2 ) and the density-weighted polar section modulus ( BSI , mm3 ) of the tibial midshaft were determined by peripheral quantitative tomography ( pQCT ) . In the premenarcheal girls , BMC increased statistically significantly more in the trainees than controls at the lumbar spine ( p= 0.012 ) ( 8.6 % vs 5.3 % ) and femoral neck ( p= 0.014 ) ( 9.3 % vs 5.3 % ) . In the tibial midshaft , the intergroup differences ( CoD , CoA and BSI ) were not significant . The postmenarcheal girls showed no significant post-training intergroup differences in any of the bone parameters ( BMC increased in the lumbar spine 6.0 % vs 4.9 % ; femoral neck 3.4 % vs 3.2 % ; and trochanter 2.6 % vs 3.5 % ) . Although a large proportion of bone mineral increase in the growing girls of this study was attributable to growth itself , this 9-month exercise intervention showed that a clear and large additional bone gain could be obtained in exercising premenarcheal girls , but not in exercising postmenarcheal girls . In other words , exercise seemed more beneficial for additional bone mineral acquisition before menarche ( i.e. , during the growth spurt ) rather than after it
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 .