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 .
Effect of monthly high-dose vitamin D supplementation on falls and non-vertebral fractures: secondary and post-hoc outcomes from the randomised, double-blind, placebo-controlled ViDA trial.
BACKGROUND Adults with low concentrations of 25-hydroxyvitamin D ( 25[OH]D ) in blood have an increased risk of falls and fractures , but r and omised trials of vitamin D supplementation have had inconsistent results . We aim ed to assess the effect of high-dose vitamin D supplementation on fractures and falls . METHODS The Vitamin D Assessment ( ViDA ) Study was a r and omised , double-blind , placebo-controlled trial of healthy volunteers aged 50 - 84 years conducted at one centre in Auckl and , New Zeal and . Participants were r and omly assigned to receive either an initial oral dose of 200 000 IU ( 5·0 mg ) colecalciferol ( vitamin D3 ) followed by monthly 100 000 IU ( 2·5 mg ) colecalciferol or equivalent placebo dosing . The prespecified primary outcome was cardiovascular disease and secondary outcomes were respiratory illness and fractures . Here , we report secondary outcome data for fractures and post-hoc outcome data for falls . Cox proportional hazards models were used to estimate hazard ratios ( HRs ) for time to first fracture or time to first fall in individuals allocated vitamin D compared with placebo . The analysis of fractures included all participants who gave consent and was by intention-to-treat ; the analysis of falls included all individuals who returned one or more question naires . This trial is registered with the Australian New Zeal and Clinical Trials Registry , number ACTRN12611000402943 . FINDINGS Between April 5 , 2011 , and Nov 6 , 2012 , 5110 participants were recruited and r and omly assigned either colecalciferol ( n=2558 ) or placebo ( n=2552 ) . Two participants allocated placebo withdrew consent after r and omisation ; thus , a total of 5108 individuals were included in the analysis of fractures . The mean age of participants was 65·9 years ( SD 8·3 ) and 2971 ( 58 % ) were men . The mean concentration of 25(OH)D in blood was 63 nmol/L ( SD 24 ) at baseline , with 1534 ( 30 % ) having 25(OH)D concentrations lower than 50 nmol/L. Follow-up was until July 31 , 2015 , with a mean treatment duration of 3·4 years ( SD 0·4 , range 2·5 - 4·2 ) . During follow-up , 2638 participants reported having a fall , 1312 ( 52 % ) of 2539 in the vitamin D group compared with 1326 ( 53 % ) of 2517 in the placebo group . The HR for falls-adjusted for age , sex , ethnic origin , history of recent fall , physical activity , and baseline 25(OH)D-was 0·99 ( 95 % CI 0·92 - 1·07 ; p=0·82 ) for vitamin D compared with placebo . Non-vertebral fractures were reported in 292 individuals , 156 ( 6 % ) of 2558 in the vitamin D group and 136 ( 5 % ) of 2550 in the placebo group . The adjusted HR for fractures was 1·19 ( 95 % CI 0·94 - 1·50 ; p=0·15 ) for vitamin D compared with placebo . 123 ( 2 % ) people died  during the trial , 65 assigned vitamin D and 58 allocated placebo ; the difference between treatment groups was not significant . INTERPRETATION High-dose bolus vitamin D supplementation of 100 000 IU colecalciferol monthly over 2·5 - 4·2 years did not prevent falls or fractures in this healthy , ambulatory , adult population . Further research is needed to ascertain the effects of daily vitamin D dosing , with or without calcium . FUNDING Health Research Council of New Zeal and and Accident Compensation Corporation of New Zeal and
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 .