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 and postmenopausal breast cancer survival: a prospective patient cohort study
Introduction Vitamin D has been postulated to be involved in cancer prognosis . Thus far , only two studies reported on its association with recurrence and survival after breast cancer diagnosis yielding inconsistent results . Therefore , the aim of our study was to assess the effect of post-diagnostic serum 25-hydroxyvitamin D [ 25(OH)D ] concentrations on overall survival and distant disease-free survival . Methods We conducted a prospect i ve cohort study in Germany including 1,295 incident postmenopausal breast cancer patients aged 50 - 74 years . Patients were diagnosed between 2002 and 2005 and median follow-up was 5.8 years . Cox proportional hazards models were stratified by age at diagnosis and season of blood collection and adjusted for other prognostic factors . Fractional polynomials were used to assess the true dose-response relation for 25(OH)D. Results Lower concentrations of 25(OH)D were linearly associated with higher risk of death ( hazard ratio ( HR ) = 1.08 per 10 nmol/L decrement ; 95 % confidence interval ( CI ) , 1.00 to 1.17 ) and significantly higher risk of distant recurrence ( HR = 1.14 per 10 nmol/L decrement ; 95%CI , 1.05 to 1.24 ) . Compared with the highest tertile ( ≥ 55 nmol/L ) , patients within the lowest tertile ( < 35 nmol/L ) of 25(OH)D had a HR for overall survival of 1.55 ( 95%CI , 1.00 to 2.39 ) and a HR for distant disease-free survival of 2.09 ( 95%CI , 1.29 to 3.41 ) . In addition , the association with overall survival was found to be statistically significant only for 25(OH)D levels of blood sample s collected before start of chemotherapy but not for those of sample s taken after start of chemotherapy ( P for interaction = 0.06 ) . Conclusions In conclusion , lower serum 25(OH)D concentrations may be associated with poorer overall survival and distant disease-free survival in postmenopausal breast cancer 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 .