Subgroup analyses in the observational studies indicated that risk of mortality was significantly higher in studies with lower baseline use of vitamin D supplements .
The effects observed for vitamin D3 supplementation remained unchanged when grouped by various characteristics .
However , for vitamin D2 supplementation , increased risks of mortality were observed in studies with lower intervention doses and shorter average intervention periods .
Conclusions Evidence from observational studies indicates inverse associations of circulating 25-hydroxyvitamin D with risks of death due to cardiovascular disease , cancer , and other causes .
Objective To evaluate the extent to which circulating biomarker and supplements of vitamin D are associated with  mortality from cardiovascular , cancer , or other conditions  , under various circumstances .
A randomized, controlled trial of quadriceps resistance exercise and vitamin D in frail older people: the Frailty Interventions Trial in Elderly Subjects (FITNESS).
OBJECTIVES To determine the effectiveness of vitamin D and home-based quadriceps resistance exercise on reducing falls and improving the physical health of frail older people after hospital discharge . DESIGN Multicenter , r and omized , controlled trial with a factorial design . SETTING Five hospitals in Auckl and , New Zeal and , and Sydney , Australia . PARTICIPANTS Two hundred forty-three frail older people . INTERVENTIONS Patients were r and omized to receive a single dose of vitamin D ( calciferol , 300,000 IU ) or placebo tablets and 10 weeks of high-intensity home-based quadriceps resistance exercise or frequency-matched visits . MEASUREMENTS The primary endpoints were physical health according to the short-form health survey at 3 months and falls over 6 months . Physical performance and self-rated function were secondary endpoints . Assessment s took place in the participants ' homes at 3 and 6 months after r and omization and were performed by blinded assessors . RESULTS There was no effect of either intervention on physical health or falls , but patients in the exercise group were at increased risk of musculoskeletal injury ( risk ratio = 3.6 , 95 % confidence interval = 1.5 - 8.0 ) . Vitamin D supplementation did not improve physical performance , even in those who were vitamin D deficient ( < 12 ng/mL ) at baseline . CONCLUSION Neither vitamin D supplementation nor a home-based program of high-intensity quadriceps resistance exercise improved rehabilitation outcomes in frail older people after hospitalization . There was no effect of vitamin D on physical performance , and the exercises increased the risk of musculoskeletal injury . These findings do not support the routine use of these interventions at these dosages in the rehabilitation of frail older people
Subgroup analyses in the observational studies indicated that risk of mortality was significantly higher in studies with lower baseline use of vitamin D supplements .
The effects observed for vitamin D3 supplementation remained unchanged when grouped by various characteristics .
However , for vitamin D2 supplementation , increased risks of mortality were observed in studies with lower intervention doses and shorter average intervention periods .
Conclusions Evidence from observational studies indicates inverse associations of circulating 25-hydroxyvitamin D with risks of death due to cardiovascular disease , cancer , and other causes .
Objective To evaluate the extent to which circulating biomarker and supplements of vitamin D are associated with  mortality from cardiovascular , cancer , or other conditions  , under various circumstances .