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 .
Serum 25-hydroxyvitamin D status and cardiovascular outcomes in chronic peritoneal dialysis patients: a 3-y prospective cohort study.
BACKGROUND Patients with kidney disease are at high risk of developing 25-hydroxyvitamin D [ 25(OH)D ] deficiency . OBJECTIVE We studied the association between serum 25(OH)D status and clinical outcomes of chronic peritoneal dialysis patients . DESIGN We measured serum 25(OH)D concentrations in 230 prevalent peritoneal dialysis patients and then followed these patients prospect ively for 3 y or until death . RESULTS Serum 25(OH)D was deficient or insufficient ( ie , < 75 nmol/L ) in 87 % of the patients . Adjusting for clinical and demographic factors , every 1-unit increase in log-transformed serum 25(OH)D was associated with a 44 % reduction in the hazard of fatal or nonfatal cardiovascular events ( 95 % CI : 0.35 , 0.91 ; P = 0.018 ) . However , the association was gradually lost when additional adjustment was made in a stepwise fashion for residual glomerular filtration rate ( P = 0.078 ) and echocardiographic measures ( P = 0.39 ) . Kaplan-Meier estimates showed a significantly greater fatal or nonfatal cardiovascular event-free survival probability among patients with serum 25(OH)D > 45.7 nmol/L ( median ) than among patients with concentrations < or= 45.7 nmol/L ( P = 0.004 ) . In addition , patients with 25(OH)D > 45.7 nmol/L had a significantly higher cardiovascular event-free survival probability than did patients with 25(OH)D < or= 45.7 nmol/L in the stratified analysis for patients with left ventricular mass index less than the median ( P = 0.013 ) or normal systolic function ( P = 0.005 ) . CONCLUSIONS A lower serum 25(OH)D concentration was associated with an increased risk of cardiovascular events in chronic peritoneal dialysis patients . Furthermore , serum 25(OH)D status appeared to show a differential influence on the cardiovascular outcomes of peritoneal dialysis patients depending on the degree of left ventricular hypertrophy and systolic dysfunction
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 .