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 .
A Trial of Calcium and Vitamin D for the Prevention of Colorectal Adenomas.
BACKGROUND Epidemiologic and pre clinical data suggest that higher intake and serum levels of vitamin D and higher intake of calcium reduce the risk of colorectal neoplasia . To further study the chemopreventive potential of these nutrients , we conducted a r and omized , double-blind , placebo-controlled trial of supplementation with vitamin D , calcium , or both for the prevention of colorectal adenomas . METHODS We recruited patients with recently diagnosed adenomas and no known colorectal polyps remaining after complete colonoscopy . We r and omly assigned 2259 participants to receive daily vitamin D3 ( 1000 IU ) , calcium as carbonate ( 1200 mg ) , both , or neither in a partial 2 × 2 factorial design . Women could elect to receive calcium plus r and om assignment to vitamin D or placebo . Follow-up colonoscopy was anticipated to be performed 3 or 5 years after the baseline examinations , according to the endoscopist 's recommendation . The primary end point was adenomas diagnosed in the interval from r and omization through the anticipated surveillance colonoscopy . RESULTS Participants who were r and omly assigned to receive vitamin D had a mean net increase in serum 25-hydroxyvitamin D levels of 7.83 ng per milliliter , relative to participants given placebo . Overall , 43 % of participants had one or more adenomas diagnosed during follow-up . The adjusted risk ratios for recurrent adenomas were 0.99 ( 95 % confidence interval [ CI ] , 0.89 to 1.09 ) with vitamin D versus no vitamin D , 0.95 ( 95 % CI , 0.85 to 1.06 ) with calcium versus no calcium , and 0.93 ( 95 % CI , 0.80 to 1.08 ) with both agents versus neither agent . The findings for advanced adenomas were similar . There were few serious adverse events . CONCLUSIONS Daily supplementation with vitamin D3 ( 1000 IU ) , calcium ( 1200 mg ) , or both after removal of colorectal adenomas did not significantly reduce the risk of recurrent colorectal adenomas over a period of 3 to 5 years . ( Funded by the National Cancer Institute ; Clinical Trials.gov number , NCT00153816 . )
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 .