Calcium was more effective than placebo in reducing rates of bone loss after two or more years of treatment .
REVIEW ER 'S CONCLUSIONS Calcium supplementation alone has a small positive effect on bone density .
The data show a trend toward reduction in vertebral fractures , but it is unclear if calcium reduces the incidence of non vertebral fractures
BACKGROUND Although calcium is one the simplest and least expensive strategies for preventing osteoporotic fractures calcium supplementation is nevertheless not without controversy ( Kanis 1989 ; Nordin 1990 ) .
The Food and Drug Administration in the US has permitted a bone health cl aim for calcium-rich foods , and the NIH in its Consensus Development Process approved a statement that high calcium intake reduces the risk of osteoporosis .
OBJECTIVES To assess the effects of calcium on bone density and fractures in postmenopausal women .
Calcium supplementation reduces vertebral bone loss in perimenopausal women: a controlled trial in 248 women between 46 and 55 years of age.
To study the effect of calcium supplementation on  perimenopausal bone loss , 295 women were r and omized into a control group and 2 supplementation groups receiving , respectively , 1000 and 2000 mg elemental calcium/day for a period of 2 yr . We observed a significant decrease in lumbar bone loss in relation to the calcium supplementation ( mean loss after 2 yr of 3.5 % in the control group vs. 1.3 % and 0.7 % in the 1000 and 2000 mg groups , respectively ) , a significant increase in urinary calcium excretion , and a significant decrease in the urinary hydroxyproline/creatine ratio , serum alkaline phosphatase , osteocalcin , and 1,25-dihydroxyvitamin D. The effect of calcium supplementation on lumbar bone loss was significant in the first year of supplementation , but not in the second . However , the urinary hydroxyproline/creatinine ratio and the serum alkaline phosphatase level remained significantly decreased in the treatment groups at the end of the study ; this was not the case for serum osteocalcin . Calcium supplementation did not have a significant effect on metacarpal cortical bone loss . The difference in biochemical parameters between the 2 supplementation groups was small . No significant interaction was observed between the menopausal status of the subjects and the effect of calcium supplementation . We conclude that calcium supplementation retards lumbar bone loss in the first year of calcium supplementation by reducing bone turnover . However , the effect on lumbar bone loss over a longer time span is still uncertain
Calcium was more effective than placebo in reducing rates of bone loss after two or more years of treatment .
REVIEW ER 'S CONCLUSIONS Calcium supplementation alone has a small positive effect on bone density .
The data show a trend toward reduction in vertebral fractures , but it is unclear if calcium reduces the incidence of non vertebral fractures
BACKGROUND Although calcium is one the simplest and least expensive strategies for preventing osteoporotic fractures calcium supplementation is nevertheless not without controversy ( Kanis 1989 ; Nordin 1990 ) .
The Food and Drug Administration in the US has permitted a bone health cl aim for calcium-rich foods , and the NIH in its Consensus Development Process approved a statement that high calcium intake reduces the risk of osteoporosis .
OBJECTIVES To assess the effects of calcium on bone density and fractures in postmenopausal women .