Subgroup analyses showed that these results were generally consistent regardless of the calcium or vitamin D dose , sex , fracture history , dietary calcium intake , and baseline serum 25-hydroxyvitamin D concentration .
Conclusions and Relevance In this meta- analysis of r and omized clinical trials , the use of supplements that included calcium , vitamin D , or both compared with placebo or no treatment was not associated with a lower risk of fractures  among community-dwelling older adults .
Importance The increased social and economic burdens for osteoporosis-related fractures worldwide make the prevention of such injuries a major public health goal .
Previous studies have reached mixed conclusions regarding the association between calcium , vitamin D , or combined calcium and vitamin D supplements and fracture incidence in older adults .
Objective To investigate whether calcium , vitamin D , or combined calcium and vitamin D supplements are associated with a lower fracture incidence in community-dwelling older adults .
Randomized controlled trial of calcium in healthy older women.
PURPOSE Calcium has been shown to have positive effects on bone mineral density in postmenopausal women . However , these effects are small , it is unknown whether they are sustained with long-term use , they have not been shown with intention-to-treat analyses , and the evidence for fracture prevention with calcium monotherapy is inconsistent . METHODS A r and omized controlled trial of calcium ( 1 g/day as the citrate ) in 1471 healthy postmenopausal women ( aged 74+/-4 years ) was performed to assess the effects on  bone density and fracture incidence over 5 years . RESULTS Follow-up was complete in 90 % of subjects , and average medication compliance was 55 % to 58 % . Calcium had a significant beneficial effect on bone density ( intention-to-treat analysis ) , with between-groups differences at 5 years of 1.8 % ( spine ) , 1.6 % ( total hip ) , and 1.2 % ( total body ) . Effects were greater in a per- protocol analysis ( 5-year differences of 2.3 % , 2.8 % , and 1.8 % , respectively ) . A total of 425 fractures occurred in 281 women .  Hazard ratios , based on time to first fracture , were 0.90 ( 95 % confidence interval [ CI ] , 0.71 - 1.16 ) for any symptomatic fracture , 0.72 ( 95 % CI , 0.44 - 1.18 ) for vertebral , 3.55 ( 95 % CI , 1.31 - 9.63 ) for hip , and 0.65 ( 95 % CI , 0.41 - 1.04 ) for forearm fracture . Per- protocol analysis found respective hazard ratios of 0.86 ( 95 % CI , 0.64 - 1.17 ) , 0.62 ( 95 % CI , 0.33 - 1.16 ) , 3.24 ( 95 % CI , 0.65 - 16.1 ) , and 0.45 ( 95 % CI , 0.24 - 0.87 ) . Height loss was reduced by calcium in the per- protocol population ( P=.03 ) . Serum alkaline phosphatase and procollagen type-I N-terminal propeptide were lower in the calcium group at 5 years , but constipation was more common . CONCLUSIONS Calcium results in a sustained reduction in bone loss and turnover , but its effect on fracture remains uncertain . Poor long-term compliance limits its effectiveness
Subgroup analyses showed that these results were generally consistent regardless of the calcium or vitamin D dose , sex , fracture history , dietary calcium intake , and baseline serum 25-hydroxyvitamin D concentration .
Conclusions and Relevance In this meta- analysis of r and omized clinical trials , the use of supplements that included calcium , vitamin D , or both compared with placebo or no treatment was not associated with a lower risk of fractures  among community-dwelling older adults .
Importance The increased social and economic burdens for osteoporosis-related fractures worldwide make the prevention of such injuries a major public health goal .
Previous studies have reached mixed conclusions regarding the association between calcium , vitamin D , or combined calcium and vitamin D supplements and fracture incidence in older adults .
Objective To investigate whether calcium , vitamin D , or combined calcium and vitamin D supplements are associated with a lower fracture incidence in community-dwelling older adults .