Conclusions and Relevance In this systematic review and meta- analysis , neither intermittent nor daily dosing with st and ard doses of vitamin D alone was associated with reduced risk of fracture , but daily supplementation with both vitamin D and calcium was a more promising strategy
Importance Vitamin D and calcium supplements are recommended for the prevention of fracture , but previous r and omized clinical trials ( RCTs ) have reported conflicting results , with uncertainty about optimal doses and regimens for supplementation and their overall effectiveness .
Objective To assess the risks of fracture associated with differences in concentrations of 25-hydroxyvitamin D ( 25[OH]D ) in observational studies and the risks of fracture associated with supplementation with vitamin D alone or in combination with calcium in RCTs .
Vitamin D3 and calcium to prevent hip fractures in elderly women.
BACKGROUND Hypovitaminosis D and a low calcium intake contribute to increased parathyroid function in elderly persons .  Calcium and vitamin D supplements reduce this secondary hyperparathyroidism , but whether such supplements reduce the risk of hip fractures among elderly people is not known . METHODS We studied the effects of supplementation with vitamin D3 ( cholecalciferol ) and calcium on the frequency of hip fractures and other nonvertebral fractures , identified radiologically , in 3270 healthy ambulatory women ( mean [ + /- SD ] age , 84 + /- 6 years ) . Each day for 18 months , 1634 women received tricalcium phosphate ( containing 1.2 g of elemental calcium ) and 20 micrograms ( 800 IU ) of vitamin D3 , and 1636 women received a double placebo . We measured serial serum parathyroid hormone and 25-hydroxyvitamin D ( 25(OH)D ) concentrations in 142 women and determined the femoral bone mineral density at base line and after 18 months in 56 women . RESULTS Among the women who completed the 18-month study , the number of hip fractures was 43 percent lower ( P = 0.043 ) and the total number of nonvertebral fractures was 32 percent lower ( P = 0.015 ) among the women treated with vitamin D3 and calcium than among those who received placebo . The results of analyses according to active treatment and according to intention to treat were similar . In the vitamin D3-calcium group , the mean serum parathyroid hormone concentration had decreased by 44 percent from the base-line value at 18 months ( P < 0.001 ) and the serum 25(OH)D concentration had increased by 162 percent over the base-line value ( P < 0.001 ) . The bone density of the proximal femur increased 2.7 percent in the vitamin D3-calcium group and decreased 4.6 percent in the placebo group ( P < 0.001 ) . CONCLUSIONS Supplementation with vitamin D3 and calcium reduces the risk of hip fractures and other nonvertebral fractures among elderly women
Conclusions and Relevance In this systematic review and meta- analysis , neither intermittent nor daily dosing with st and ard doses of vitamin D alone was associated with reduced risk of fracture , but daily supplementation with both vitamin D and calcium was a more promising strategy
Importance Vitamin D and calcium supplements are recommended for the prevention of fracture , but previous r and omized clinical trials ( RCTs ) have reported conflicting results , with uncertainty about optimal doses and regimens for supplementation and their overall effectiveness .
Objective To assess the risks of fracture associated with differences in concentrations of 25-hydroxyvitamin D ( 25[OH]D ) in observational studies and the risks of fracture associated with supplementation with vitamin D alone or in combination with calcium in RCTs .