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 .
Vitamin D3 supplementation and upper respiratory tract infections in a randomized, controlled trial.
BACKGROUND R and omized controlled trials testing the association between vitamin D status and upper respiratory tract infection ( URTI ) have given mixed results . During a multicenter , r and omized controlled trial of colorectal adenoma chemoprevention , we tested whether 1000 IU/day vitamin D(3 ) supplementation reduced winter episodes and duration of URTI and its composite syndromes , influenza-like illness ( ILI ; fever and ≥2 of sore throat , cough , muscle ache , or headache ) and colds ( no fever , and ≥2 of runny nose , nasal congestion , sneezing , sore throat , cough , swollen or tender neck gl and s ) . METHODS The 2259 trial participants were aged 45 - 75 , in good health , had a history of colorectal adenoma , and had a serum 25-hydroxyvitamin D level ≥12 ng/mL. They were r and omized to vitamin D(3 ) ( 1000 IU/day ) , calcium ( 1200 mg/day ) , both , or placebo . Of these , 759 participants completed daily symptom diaries . Secondary data included semiannual surveys of all participants . RESULTS Among those who completed symptom diaries , supplementation did not significantly reduce winter episodes of URTI ( rate ratio [ RR ] , 0.93 ; 95 % confidence interval [ CI ] , .79 - 1.09 ) including colds ( RR , 0.93 ; 95 % CI , .78 - 1.10 ) or ILI ( RR , 0.95 ; 95 % CI , .62 - 1.46 ) , nor did it reduce winter days of illness ( RR , 1.13 ; 95 % CI , .90 - 1.43 ) . There was no significant benefit according to adherence , influenza vaccination , body mass index , or baseline vitamin D status . Semiannual surveys of all participants ( N = 2228 ) identified no benefit of supplementation on ILI ( odds ratio [ OR ] , 1.14 ; 95 % CI , .84 - 1.54 ) or colds ( OR , 1.03 ; 95 % CI , .87 - 1.23 ) . CONCLUSIONS Supplementation with 1000 IU/day vitamin D(3 ) did not significantly reduce the incidence or duration of URTI in adults with a baseline serum 25-hydroxyvitamin D level ≥12
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 .