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 .
Skeletal and hormonal responses to vitamin D supplementation during sunlight deprivation in Antarctic expeditioners
Summary Sunlight deprivation results in vitamin D deficiency but serum vitamin D levels can be maintained above 50nmol/L when supplemented with 50,000IU at least every alternate month . Introduction Anta rct ic expeditioners are exposed to prolonged sunlight deprivation result ing in vitamin D deficiency . We hypothesised that monthly dosing of 50,000 IU vitamin D ( ~1,600 IU daily ) will increase serum 25-hydroxyvitamin D ( 25(OH)D ) , suppress parathyroid hormone ( PTH ) and improve bone mineral density ( BMD ) , 50,000 IU alternate months ( ~800 IU daily ) will maintain these measures , while a single 50,000 IU dose pre-departure ( ~1,00 IU daily ) will not be protective . Methods This was a r and omised double-blind study involving 110 healthy adults : 91 males , mean age 41 years ( range 24–65 years ) working in Anta rct ica for up to 12 months , who we administered 50,000 IU vitamin D3 monthly , alternate months or a single dose pre-departure  . Serum 25(OH)D , PTH , osteocalcin , CTx and calcium were assessed at baseline , mid- and end of expedition . Proximal femur and lumbar spine BMD were assessed pre- and post-expedition . Results Baseline 25(OH)D was 59 ± 14 nmol/L. By mid-expedition , 25(OH)D increased by 7 nmol/L in those supplemented monthly ( p < 0.05 ) and remained unchanged in those supplemented in alternate months . In those given a single dose pre-departure , 25(OH)D decreased by 8 nmol/L ( p < 0.05 ) and PTH increased by 27 % ( p < 0.09 ) . Serum osteocalcin increased by ~22 % in all groups but BMD remained unchanged . If serum 25(OH)D was > 50 nmol/L at baseline , 25(OH)D was maintained above this level with all regimens . If 25(OH)D was < 50 nmol/L at baseline , monthly or alternate month regimens were needed to achieve levels > 50 nmol/L , the single pre-departure dose was ineffective . Conclusion During sunlight deprivation of up to 12 months , serum 25(OH)D levels can be maintained above 50 nmol/L when expeditioners are provided with 50,000 I U at least every alternate month
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 .