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 Effects of Vitamin D Supplementation in Postmenopausal Black Women
Black women have lower serum 25-hydroxyvitamin D ( 25[OH]D ) levels and higher parathyroid hormone ( PTH ) levels than white peers but lower bone turnover , suggesting skeletal resistance to PTH . Our objective was to determine if vitamin D supplementation ( 1,000 IU/day ) would prevent bone loss and whether vitamin D receptor ( VDR ) polymorphisms modify the response . We performed a 2-year r and omized , controlled , double-blind study of 1,000 IU vitamin D3 vs. placebo in postmenopausal black women with serum 25(OH)D levels < 20 ng/mL ( n = 103 ) .  Measurements of 25(OH)D , PTH , and bone turnover were evaluated at baseline and 3 , 6 , 12 , 18 , and 24 months . DNA was extracted from peripheral blood leukocytes , and genotyping was conducted using st and ard techniques . Spine and hip bone mineral density ( BMD ) was measured at baseline and every 6 months . Serum 25(OH)D increased 11 ng/mL with vitamin D supplementation ( p < 0.001 ) , with no change in the placebo group . Vitamin D supplementation produced a significant decline in PTH at 3 months only , with no differences in bone turnover between placebo and vitamin D at any time point . Two-year changes in BMD were not significantly different between placebo- and vitamin D-treated black women at any skeletal site . Despite similar elevations in 25(OH)D , femoral neck BMD was only responsive to vitamin D supplementation in FF subjects ( n = 47 ) , not Ff/ff subjects ( n = 31 ) . Vitamin D supplementation does not appear to influence  bone loss in black women . However , in the FF polymorphism of the VDR gene group , vitamin D supplementation may retard the higher rate of bone loss
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 .