Dietary recommendations and r and omized trials on vitamin D supplementation should evaluate whether increases in circulating 25-hydroxyvitamin D levels match expectations -- for instance , the average increases obtained by trials on vitamin D3 without concomitant calcium supplements
CONTEXT Few studies in subjects over 50 yr of age have evaluated the influence of variable doses of vitamin D supplementation on serum 25-hydroxyvitamin D levels .
OBJECTIVE We performed a meta- analysis of changes in circulating 25-hydroxyvitamin D level associated with vitamin D supplementation in Caucasian subjects over 50 yr old .
Calcium plus vitamin D supplementation and the risk of fractures.
BACKGROUND The efficacy of calcium with vitamin D supplementation for preventing hip and other fractures in healthy postmenopausal women remains equivocal . METHODS We recruited 36,282 postmenopausal women , 50 to 79 years of age , who were already enrolled in a Women 's Health Initiative ( WHI ) clinical trial . We r and omly assigned participants to receive 1000 mg of elemental [ corrected ] calcium as calcium carbonate with 400 IU of vitamin D3 daily or placebo .  Fractures were ascertained for an average follow-up period of 7.0 years . Bone density was measured at three WHI centers . RESULTS Hip bone density was 1.06 percent higher in the calcium plus vitamin D group than in the placebo group ( P<0.01 ) . Intention-to-treat analysis indicated that participants receiving calcium plus vitamin D supplementation had a hazard ratio of 0.88 for hip fracture ( 95 percent confidence interval , 0.72 to 1.08 ) , 0.90 for clinical spine fracture ( 0.74 to 1.10 ) , and 0.96 for total fractures ( 0.91 to 1.02 ) . The risk of renal calculi increased with calcium plus vitamin D ( hazard ratio , 1.17 ; 95 percent confidence interval , 1.02 to 1.34 ) . Censoring data from women when they ceased to adhere to the study medication reduced the hazard ratio for hip fracture to 0.71 ( 95 percent confidence interval , 0.52 to 0.97 ) . Effects did not vary significantly according to prer and omization serum vitamin D levels . CONCLUSIONS Among healthy postmenopausal women , calcium with vitamin D supplementation result ed in a small but significant improvement in hip bone density , did not significantly reduce hip fracture , and increased the risk of kidney stones . ( Clinical Trials.gov number , NCT00000611 . )
Dietary recommendations and r and omized trials on vitamin D supplementation should evaluate whether increases in circulating 25-hydroxyvitamin D levels match expectations -- for instance , the average increases obtained by trials on vitamin D3 without concomitant calcium supplements
CONTEXT Few studies in subjects over 50 yr of age have evaluated the influence of variable doses of vitamin D supplementation on serum 25-hydroxyvitamin D levels .
OBJECTIVE We performed a meta- analysis of changes in circulating 25-hydroxyvitamin D level associated with vitamin D supplementation in Caucasian subjects over 50 yr old .