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 .
Effect of Calcium and Vitamin D Supplementation on Blood Pressure: The Women's Health Initiative Randomized Trial
Experimental and epidemiological studies suggest that calcium and vitamin D supplements may lower  blood pressure . We examined the effect of calcium plus vitamin D supplementation on blood pressure and the incidence of hypertension in postmenopausal women . The Women 's Health Initiative Calcium/Vitamin D Trial r and omly assigned 36 282 postmenopausal women to receive 1000 mg of elemental calcium plus 400 IU of vitamin D3 daily or placebo in a double-blind fashion . Change in blood pressure and the incidence of hypertension were ascertained . Over a median follow-up time of 7 years , there was no significant difference in the mean change over time in systolic blood pressure ( 0.22 mm Hg ; 95 % CI : −0.05 to 0.49 mm Hg ) and diastolic blood pressure ( 0.11 mm Hg ; 95 % CI : −0.04 to 0.27 mm Hg ) between the active and placebo treatment groups . This null result was robust in analyses accounting for nonadherence to study pills and in baseline subgroups of interest , including black subjects and women with hypertension or high levels of blood pressure , with low intakes of calcium and vitamin D or low serum levels of vitamin D. In 17 122 nonhypertensive participants at baseline , the hazard ratio for incident hypertension associated with calcium/vitamin D treatment was 1.01 ( 95 % CI : 0.96 to 1.06 . ) In postmenopausal  women , calcium plus vitamin D3 supplementation did not reduce either blood pressure or the risk of developing hypertension over 7 years of follow-up
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 .