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 .
Double-blinded randomized study of high-dose calcitriol plus docetaxel compared with placebo plus docetaxel in androgen-independent prostate cancer: a report from the ASCENT Investigators.
PURPOSE To compare the safety and activity of DN-101 , a new high-dose oral formulation of calcitriol design ed for cancer therapy , and docetaxel with placebo and docetaxel . PATIENTS AND METHODS Patients with progressive metastatic and rogen-independent prostate cancer and adequate organ function received weekly docetaxel 36 mg/m2 intravenously for 3 weeks of a 4-week cycle combined with either 45 microg DN-101 or placebo taken orally 1 day before docetaxel . The primary end point was prostate-specific antigen ( PSA ) response within 6 months of enrollment , defined as a 50 % reduction confirmed at least 4 weeks later . RESULTS Two hundred fifty patients were r and omly assigned . Baseline characteristics were similar in both arms . Within 6 months , PSA responses were seen in 58 % in DN-101 patients and 49 % in placebo patients ( P = .16 ) . Overall , PSA response rates were 63 % ( DN-101 ) and 52 % ( placebo ) , P = .07 . Patients in the DN-101 group had a hazard ratio for death of 0.67 ( P = .04 ) in a multivariate analysis that included baseline hemoglobin and performance status . Median survival has not been reached for the DN-101 arm and is estimated to be 24.5 months using the hazard ratio , compared with 16.4 months for placebo . Grade 3/4 adverse events occurred in 58 % of DN-101 patients and in 70 % of placebo-treated patients ( P = .07 ) . Most common grade 3/4 toxicities for DN-101 versus placebo were neutropenia ( 10 % v 8 % ) , fatigue ( 8 % v 16 % ) , infection ( 8 % v 13 % ) , and hyperglycemia ( 6 % v 12 % ) . CONCLUSION This study suggests that DN-101 treatment was associated with improved survival , but this will require confirmation because survival was not a primary end point . The addition of weekly DN-101 did not increase the toxicity of weekly docetaxel
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 .