For hip fracture , at a 15 % relative risk , the effect estimate lay between the futility boundary and the inferior boundary , meaning there is reliable evidence that vitamin D supplementation does not reduce hip fractures by this amount , but uncertainty remains as to whether it might increase hip fractures .
The effect estimate lay within the futility boundary at thresholds of 0·5 % for total hip , forearm , and total body bone mineral density , and 1·0 % for lumbar spine and femoral neck , providing reliable evidence that vitamin D does not alter these outcomes by these amounts .
INTERPRETATION Our findings suggest that vitamin D supplementation does not prevent fractures or falls , or have clinical ly meaningful effects on bone mineral density .
There were no differences between the effects of higher and lower doses of vitamin D. There is little justification to use vitamin D supplements to maintain or improve musculoskeletal health .
BACKGROUND The effects of vitamin D on fractures , falls , and bone mineral density are uncertain , particularly for high vitamin D doses .
We aim ed to determine the effect of vitamin D supplementation on fractures , falls , and bone density .
Randomized controlled trial of the effects of calcium with or without vitamin D on bone structure and bone-related chemistry in elderly women with vitamin D insufficiency.
There are few data on the relative effects of calcium supplementation with or without extra vitamin D on BMD in patients selected for low vitamin D status . The aim of this study is to evaluate the relative importance of vitamin D and calcium treatment on BMD and bone-related chemistry in elderly women with vitamin D insufficiency . Three hundred two elderly women ( age , 77.2 + /- 4.6 yr ) with serum 25(OH)D concentrations < 60 nM participated in a 1-yr r and omized , double-blind , placebo-controlled trial . All subjects received 1000 mg calcium citrate per day with either 1000 IU ergocalciferol ( vitamin D(2 ) ) or identical placebo ( control ) . The effects of time and time treatment interactions were evaluated by repeated- measures ANOVA . At baseline , calcium intake was 1100 mg/d , and 25(OH)D was 44.3 + /- 12.9 nM ; this increased in the vitamin D group by 34 % but not the control group after 1 year ( 59.8 + /- 13.8 versus 45.0 + /- 13.3 nM , p < 0.001 ) . Total hip and total body BMD increased significantly , and procollagen type I intact N-terminal propeptide ( PINP ) decreased during the study with no difference between the treatment groups ( hip BMD change :  vitamin D , + 0.5 % ; control , + 0.2 % ; total body BMD change : vitamin D , + 0.4 % ; control , + 0.4 % ; PINP change : vitamin D , -3.9 % ; placebo , -2.8 % ) . Although the fasting plasma and urine calcium increased in both groups equally , there was no detectable change in serum PTH . The increase in 25(OH)D achieved with vitamin D supplementation had no extra effect on active fractional intestinal calcium absorption , which fell equally in both groups ( vitamin D , -17.4 % ; control , -14.8 % ) . In patients with a baseline calcium intake of 1100 mg/d and vitamin D insufficiency , vitamin D(2 ) 1000 IU for 1 year has no extra beneficial effect on bone structure , bone formation markers , or intestinal calcium absorption over an additional 1000 mg of calcium . Vitamin D supplementation adds no extra short-term skeletal benefit to calcium citrate supplementation even in women with vitamin D insufficiency
For hip fracture , at a 15 % relative risk , the effect estimate lay between the futility boundary and the inferior boundary , meaning there is reliable evidence that vitamin D supplementation does not reduce hip fractures by this amount , but uncertainty remains as to whether it might increase hip fractures .
The effect estimate lay within the futility boundary at thresholds of 0·5 % for total hip , forearm , and total body bone mineral density , and 1·0 % for lumbar spine and femoral neck , providing reliable evidence that vitamin D does not alter these outcomes by these amounts .
INTERPRETATION Our findings suggest that vitamin D supplementation does not prevent fractures or falls , or have clinical ly meaningful effects on bone mineral density .
There were no differences between the effects of higher and lower doses of vitamin D. There is little justification to use vitamin D supplements to maintain or improve musculoskeletal health .
BACKGROUND The effects of vitamin D on fractures , falls , and bone mineral density are uncertain , particularly for high vitamin D doses .
We aim ed to determine the effect of vitamin D supplementation on fractures , falls , and bone density .