In subgroup analyses , all cause mortality was significantly lower in trials with vitamin D3 supplementation than in trials with vitamin D2 supplementation ( P for interaction=0.04 ) ; neither vitamin D3 nor vitamin D2 was associated with a statistically significant reduction in all cause mortality .
CONCLUSIONS Vitamin D supplementation alone was not associated with  all cause mortality in adults compared with placebo or no treatment .
Vitamin D supplementation reduced the risk of cancer death by 16 % .
Additional large clinical studies are needed to determine whether vitamin D3 supplementation is associated with lower all cause mortality .
OBJECTIVE To investigate whether vitamin D supplementation is associated with lower mortality in adults .
Vitamin D Supplementation and Survival of Patients with Non–small Cell Lung Cancer: A Randomized, Double-Blind, Placebo-Controlled Trial
Purpose : Higher serum 25-hydroxyvitamin D ( 25(OH)D ) levels are reportedly associated with better survival in early-stage non – small cell lung cancer ( NSCLC ) . Therefore , whether vitamin D supplementation can improve the prognosis of patients with NSCLC was examined ( UMIN000001869 ) . Patients and Methods : A r and omized , double-blind trial comparing vitamin D supplements ( 1,200 IU/day ) with placebo for 1 year after operation was conducted . The primary and secondary outcomes were relapse-free survival ( RFS ) and overall survival ( OS ) , respectively . Prespecified subgroup analyses were performed with stratification by stage ( early vs. advanced ) , pathology ( adenocarcinoma vs. others ) , and 25(OH)D levels ( low , < 20 ng/mL vs. high , ≥20 ng/mL ) . Polymorphisms of vitamin D receptor ( VDR ) and vitamin D – binding protein ( DBP ) and survival were also examined . Results : Patients with NSCLC ( n = 155 ) were r and omly assigned to receive vitamin D ( n = 77 ) or placebo ( n = 78 ) and followed for a median of 3.3 years . Relapse and death occurred in 40 ( 28 % ) and 24 ( 17 % ) patients , respectively . In the total study population , no significant difference in either RFS or OS was seen with vitamin D compared with the placebo group . However , by restricting the analysis to the subgroup with early-stage adenocarcinoma with low 25(OH)D , the vitamin D group showed significantly better 5-year RFS ( 86 % vs. 50 % , P = 0.04 ) and OS ( 91 % vs. 48 % , P = 0.02 ) than the placebo group . Among the examined polymorphisms , DBP1 ( rs7041 ) TT and CDX2 ( rs11568820 ) AA/AG genotypes were markers of better prognosis , even with multivariate adjustment . Conclusions : In patients with NSCLC  , vitamin D supplementation may improve survival of patients with early-stage lung adenocarcinoma with lower 25(OH)D levels . Clin Cancer Res ; 24(17 ) ; 4089–97 . © 2018 AACR
In subgroup analyses , all cause mortality was significantly lower in trials with vitamin D3 supplementation than in trials with vitamin D2 supplementation ( P for interaction=0.04 ) ; neither vitamin D3 nor vitamin D2 was associated with a statistically significant reduction in all cause mortality .
CONCLUSIONS Vitamin D supplementation alone was not associated with  all cause mortality in adults compared with placebo or no treatment .
Vitamin D supplementation reduced the risk of cancer death by 16 % .
Additional large clinical studies are needed to determine whether vitamin D3 supplementation is associated with lower all cause mortality .
OBJECTIVE To investigate whether vitamin D supplementation is associated with lower mortality in adults .