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 and breast cancer recurrence in the Women's Healthy Eating and Living (WHEL) Study.
BACKGROUND There is a paucity of research evaluating the relation between  vitamin D  and recurrence of breast cancer after treatment . OBJECTIVE This study was design ed to evaluate the associations between circulating concentrations of  25-hydroxyvitamin D [ 25(OH)D ]  and dietary , supplemental , and total intake of vitamin D  and recurrent or new breast cancer events within the Women 's Healthy Eating and Living ( WHEL ) Study . DESIGN A prospect i ve cohort study design ( n = 3085 ) was used to evaluate the relation between dietary , supplemental , and total vitamin D intake and recurrent breast cancer , and a nested case-control study with 512 matched pairs was used for analysis of the association between 25(OH)D and breast cancer recurrence . RESULTS No relation between 25(OH)D and breast cancer recurrence was observed . Compared with women with serum concentrations of 25(OH)D ≥ 30 ng/mL , adjusted odds ratios ( 95 % CI ) for breast cancer recurrence were 1.14 ( 0.57 , 2.31 ) for those with concentrations < 10 ng/mL , 1.00 ( 0.68 - 1.48 ) for concentrations ≥ 10 and < 20 ng/mL , and 1.05 ( 0.76 , 1.47 ) for concentrations ≥ 20 and < 30 ng/mL. No significant associations were observed when analyses were stratified by pre- and postmenopausal status or for local , regional , or distant recurrence or death . Vitamin D intake was not related to breast cancer recurrence overall , although for premenopausal women there was a significant inverse association between dietary vitamin D intake and recurrence ( P for trend = 0.02 ) . CONCLUSION These results do not provide support for a relation between concentrations of 25(OH)D after treatment and the recurrence of breast cancer . This trial is registered at clinical trials.gov for the WHEL Study as NCT00003787
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 .