There is currently no firm evidence that vitamin D supplementation decreases or increases cancer occurrence in predominantly elderly community-dwelling women .
Vitamin D₃ supplementation  decreased cancer mortality  and vitamin D supplementation  decreased all-cause mortality , but these estimates are at risk of type I errors due to the fact that too few participants were examined , and to risks of attrition bias originating from substantial dropout of participants .
Combined vitamin D₃ and calcium supplements  increased nephrolithiasis , whereas it remains unclear from the included trials whether vitamin D₃ , calcium , or both were responsible for this effect .
BACKGROUND The evidence on whether vitamin D supplementation is effective in decreasing cancers is contradictory .
OBJECTIVES To assess the beneficial and harmful effects of vitamin D supplementation for prevention of cancer in adults .
Calcium/vitamin D supplementation and coronary artery calcification in the Women's Health Initiative
Objective : Coronary artery calcified plaque is a marker for atheromatous plaque burden and predicts future risk of cardiovascular events . The relationship between calcium plus vitamin D ( calcium/D ) supplementation and coronary artery calcium ( CAC ) has not been previously assessed in a r and omized trial setting . We compared CAC scores after trial completion between women r and omized to calcium/vitamin D supplementation and women r and omized to placebo . Methods : In an ancillary sub study of women r and omized to calcium carbonate ( 1,000 mg of elemental calcium daily ) plus vitamin D3 ( 400 IU daily ) or placebo , nested within the Women 's Health Initiative trial of estrogen among women who underwent hysterectomy , we measured CAC with cardiac CT in 754 women aged 50 to 59 years at r and omization . Imaging for CAC was performed at 28 of 40 centers after a mean of 7 years of treatment , and scans were read central ly . CAC scores were measured by a central reading center with masking to r and omization assignments . Results : Posttrial CAC measurements were similar in women r and omized to calcium/D supplementation and those receiving placebo . The mean CAC score was 91.6 for women receiving calcium/D and 100.5 for women receiving placebo ( rank test P value = 0.74 ) . After adjustment for coronary risk factors , multivariate odds ratios for increasing CAC score cutpoints ( CAC > 0 , ≥10 , and ≥100 ) for calcium/D versus placebo were 0.92 ( 95 % CI , 0.64 - 1.34 ) , 1.29 ( 0.88 - 1.87 ) , and 0.90 ( 0.56 - 1.44 ) , respectively . Corresponding odds ratios among women with a 50 % or higher adherence to study pills and for higher levels of CAC ( > 300 ) were similar . Conclusions : Treatment with moderate doses of calcium plus vitamin D3 did not seem to alter coronary artery calcified plaque burden among postmenopausal women . Whether higher or lower doses would affect this outcome remains uncertain
There is currently no firm evidence that vitamin D supplementation decreases or increases cancer occurrence in predominantly elderly community-dwelling women .
Vitamin D₃ supplementation  decreased cancer mortality  and vitamin D supplementation  decreased all-cause mortality , but these estimates are at risk of type I errors due to the fact that too few participants were examined , and to risks of attrition bias originating from substantial dropout of participants .
Combined vitamin D₃ and calcium supplements  increased nephrolithiasis , whereas it remains unclear from the included trials whether vitamin D₃ , calcium , or both were responsible for this effect .
BACKGROUND The evidence on whether vitamin D supplementation is effective in decreasing cancers is contradictory .
OBJECTIVES To assess the beneficial and harmful effects of vitamin D supplementation for prevention of cancer in adults .