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 .
Urinary tract stone occurrence in the Women's Health Initiative (WHI) randomized clinical trial of calcium and vitamin D supplements.
BACKGROUND The Women 's Health Initiative ( WHI ) r and omized clinical trial ( RCT ) of calcium plus vitamin D ( CaD ) supplements found a 17 % excess in urinary tract stone incidence in the supplemented group . This study evaluated whether this risk is modified by participant characteristics . OBJECTIVE We examined the correlates of urinary tract stone occurrence in the CaD arm of the WHI trial . DESIGN We analyzed an RCT involving 36,282 postmenopausal women aged 50 - 79 y from 40 WHI centers : 18,176 women received 500 mg calcium carbonate plus 200 IU vitamin D(3 ) twice daily ( 1000 mg and 400 IU daily , respectively ) , and 18,106 women received a matching placebo for an average of 7.0 y. The incidence of urinary tract stones was determined . RESULTS The incidence of self-reported clinical ly diagnosed urinary tract stones was more common in the active CaD medication group than in the placebo group ( hazard ratio : 1.17 ; 95 % CI : 1.02 , 1.34 ) : 449 women in the CaD group and 381 women in the placebo group reported a stone during the trial . The rates of self-reported stones did not differ between various demographic , anthropomorphic , dietary , and other hypothesized risk factors according to r and omization assignment . Neither the total calcium intake nor the use of calcium supplements at baseline was associated with the risk of stones . In sensitivity analyses that censored participants who were below 80 % adherence , the findings were similar . CONCLUSIONS Daily supplementation with CaD for 7 y was associated with an increase in the number of self-reported urinary tract stones . These findings have implication s for CaD supplement use . This trial was registered with the WHI at clinical trials.gov as NCT00000611
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 .