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 .
HRT and Vit D in prevention of non-vertebral fractures in postmenopausal women; a 5 year randomized trial.
OBJECTIVES We investigated the incidence of new non-vertebral fractures  during HRT or low-dose vitamin ( Vit ) D3 supplementation in a 5-year prospect i ve trial . METHODS A total of 464 early postmenopausal women , ( a subgroup of the Kuopio Osteoporosis Study , n = 13,100 ) were r and omized to four groups : ( 1 ) HRT , a sequential combination of 2 mg estradiol valerate and 1 mg cyproterone acetate ; ( 2 ) Vit D ( 300 IU/day and 100 IU/day during the fifth years ) ; ( 3 ) HRT + Vit D ; and ( 4 ) placebo .  Lumbar ( L2 - 4 ) and femoral neck bone mineral densities ( BMD ) were determined by dual X-ray absorptiometry ( DXA ) at baseline , after 2.5 and 5 years of treatment . All new symptomatic non-vertebral , radiographically defined fractures were recorded . RESULTS Altogether , 368 women ( 79 % ) completed the 5 year treatment . In all , 32 women had 39 non-vertebral fractures during a mean of 4.3 year follow-up ( HRT 4 , Vit D 10 , HRT + Vit D 8 and placebo 17 ) . The reduction in the incidence of new non-vertebral fractures was significant in women with HRT alone ( P = 0.032 ) when adjusted by baseline BMD and previous fractures ; observed also with the intention-to-treat principle ( P = 0.048 ) . When the HRT groups were pooled , HRT showed a significantly lower incidence of new non-vertebral fractures ( P = 0.042 ) than women receiving placebo and also after adjusting as above ( P = 0.016 ) ; both in valid-case and in the intention-to-treat analysis . In the Vit D group , the fracture incidence was non-significantly decreased ( P = 0.229 ) in comparison with the placebo group . The estimated risk of new non-vertebral fractures among women treated with HRT alone was 0.29 ( 95 % CI , 0.10 - 0.90 ) and with Vit D 0.47 ( 95 % CI , 0.20 - 1.14 ) and with HRT + Vit D 0.44 ( 95 % CI , 0.17 - 1.15 ) , in comparison with the placebo group ( adjusted by femoral BMD and previous fractures ) . CONCLUSIONS This study is the first prospect i ve trial confirming the beneficial effect of HRT on prevention of peripheral fractures in non-osteoporotic postmenopausal women . The effect of low-dose Vit D remains to be proved
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 .