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 status and clinical outcomes in incident dialysis patients: results from the NECOSAD study.
BACKGROUND The majority of dialysis patients suffer from vitamin D deficiency , which might contribute to an adverse health outcome . We aim ed to eluci date whether European dialysis patients with low 25-hydroxyvitamin D ( 25(OH)D ) levels are at increased risk of mortality and specific fatal events . METHODS This was a prospect i ve cohort study of incident dialysis patients in the Netherl and s ( the NECOSAD ) . We selected all patients with measured 25(OH)D at 12 months after the start of dialysis , the baseline for our study . By Cox regression analyses , we assessed the impact of 25(OH)D levels on short-term ( 6 months of follow-up ) as well as longer-term mortality ( 3 years of follow-up ) . Associations of 25(OH)D levels with cardiovascular and non-cardiovascular mortality were also determined . RESULTS The data from 762 patients ( 39 % females , age 59 ± 15 years , 25(OH)D = 18 ± 11 ng/mL ) were available . Fifty-one and 213 patients  died during a follow-up of 6 months and 3 years , respectively . After adjustments for possible confounders , the hazard ratio ( HR ) ( with 95 % CI ) for mortality was 2.0 ( 1.0 - 3.8 ) for short-term and 1.5 ( 1.0 - 2.1 ) for longer-term mortality when comparing patients with 25(OH)D levels ≤ 10 ng/mL with those presenting with 25(OH)D levels > 10 ng/mL. Adjusted HRs for cardiovascular mortality were 2.7 ( 1.1 - 6.5 ) and 1.7 ( 1.1 - 2.7 ) for short- and longer-term mortality , respectively . For non-cardiovascular mortality , we observed no relevant association overall . The impact of 25(OH)D levels on clinical events was modified by parathyroid hormone ( PTH ) status , with low 25(OH)D levels meaningfully affecting outcomes only in patients with PTH levels above the median of 123 pmol/L. CONCLUSIONS Vitamin D deficiency in dialysis patients is associated with an adverse health outcome , in particular with short-term cardiovascular mortality . Intervention studies are urgently needed to evaluate whether vitamin D supplementation improves health outcomes of dialysis patients
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 .