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 .
Vitamin D affects survival independently of vascular calcification in chronic kidney disease.
BACKGROUND AND OBJECTIVES Cardiovascular disease is the main cause of mortality in chronic kidney disease ( CKD ) patients .  Vitamin D might have beneficial effects on vascular health . The aim of this study was to determine the prevalence of vitamin D deficiency ( 25-hydroxyvitamin D [ 25D ] < or= 15 ng/ml ) and insufficiency ( 25D levels between 16 and 30 ng/ml ) in a cohort of patients at different CKD stages and the relationships between vitamin D serum levels , vascular calcification and stiffness , and the mortality risk . DESIGN , SETTING , PARTICIPANTS & MEASUREMENTS One hundred forty CKD patients ( 85 men , mean age 67 + /- 12 yr ; CKD stages 2 [ 8 % ] , 3 [ 26 % ] , 4 [ 26 % ] , 5 [ 7 % ] , and 5D [ ( 33 % ] ) were allocated for a prospect i ve study . Serum levels of 25D and 1,25-dihydroxyvitamin D , aortic calcification score , and pulse wave velocity ( PWV ) were evaluated . RESULTS There was a high prevalence of vitamin D deficiency ( 42 % ) and insufficiency ( 34 % ) . Patients with 25D < or= 16.7 ng/ml ( median ) had a significantly lower survival rate than patients with 25D > 16.7 ng/ml ( mean follow-up , 605 + /- 217 d ; range , 10 to 889 ; P = 0.05 ) . Multivariate adjustments ( included age , gender , diabetes , arterial pressure , CKD stage , phosphate , albumin , hemoglobin , aortic calcification score and PWV ) confirmed 25D level as an independent predictor of all-cause mortality . CONCLUSIONS Vitamin D deficiency and insufficiency were highly prevalent in this CKD cohort . Low 25D levels affected mortality independently of vascular calcification and stiffness , suggesting that 25D may influence survival in CKD patients via additional pathways that need to be further explored
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 .