Recent meta-analyses reinforce the finding that 10 - 20 μg per day of vitamin D can reduce all-cause mortality and cancer mortality in middle-aged and older people .
Although vitamin D doses were greater than those assessed in the past , we found no new evidence that supplementation could have an effect on most non-skeletal conditions , including cardiovascular disease , adiposity , glucose metabolism , mood disorders , muscular function , tuberculosis , and colorectal adenomas , or on maternal and perinatal conditions .
The compilation of results from 83 trials showed that vitamin D supplementation had no significant effect on biomarkers of systemic inflammation .
The main new finding highlighted by this systematic review is that vitamin D supplementation might help to prevent common upper respiratory tract infections and asthma exacerbations .
There remains little evidence to suggest that vitamin D supplementation has an effect on most conditions , including chronic inflammation , despite use of increased doses of vitamin D , strengthening the hypothesis that low vitamin D status is a consequence of ill health , rather than its cause .
We further hypothesise that vitamin D supplementation could exert immunomodulatory effects that strengthen resistance to acute infections , which would reduce the risk of death in debilitated individuals .
Effect of high-dose vitamin D3 on hospital length of stay in critically ill patients with vitamin D deficiency: the VITdAL-ICU randomized clinical trial.
IMPORTANCE Low vitamin D status is linked to increased mortality and morbidity in patients who are critically ill . It is unknown if this association is causal . OBJECTIVE To investigate whether a vitamin D3 treatment regimen intended to restore and maintain normal vitamin D status over 6 months is of health benefit for patients in ICUs . DESIGN , SETTING , AND PARTICIPANTS A r and omized double-blind , placebo-controlled , single-center trial , conducted from May 2010 through September 2012 at 5 ICUs that included a medical and surgical population of 492 critically ill adult white patients with vitamin D deficiency ( ≤20 ng/mL ) assigned to receive either vitamin D3 ( n = 249 ) or a placebo ( n = 243 ) . INTERVENTIONS Vitamin D3 or placebo was given orally or via nasogastric tube once at a dose of 540,000 IU followed by monthly maintenance doses of 90,000 IU for 5 months . MAIN OUTCOMES AND MEASURES The primary outcome was hospital length of stay . Secondary outcomes included , among others , length of ICU stay , the percentage of patients with 25-hydroxyvitamin D levels higher than 30 ng/mL at day 7 , hospital mortality , and 6-month mortality . A predefined severe vitamin D deficiency ( ≤12 ng/mL ) subgroup analysis was specified before data unblinding and analysis . RESULTS A total of 475 patients were included in the final analysis ( 237 in the vitamin D3 group and 238 in the placebo  group ) . The median ( IQR ) length of hospital stay was not significantly different between groups ( 20.1 days [ IQR , 11.1 - 33.3 ] for vitamin D3 vs 19.3 days [ IQR , 11.1 - 34.9 ] for placebo ; P = .98 ) . Hospital mortality and 6-month mortality were also not significantly different ( hospital mortality : 28.3 % [ 95 % CI , 22.6%-34.5 % ] for vitamin D3 vs 35.3 % [ 95 % CI , 29.2%-41.7 % ] for placebo ; hazard ratio [ HR ] , 0.81 [ 95 % CI , 0.58 - 1.11 ] ; P = .18 ; 6-month mortality : 35.0 % [ 95 % CI , 29.0%-41.5 % ] for vitamin D3 vs 42.9 % [ 95 % CI , 36.5%-49.4 % ] for placebo ; HR , 0.78 [ 95 % CI , 0.58 - 1.04 ] ; P = .09 ) . For the severe vitamin D deficiency subgroup analysis ( n = 200 ) , length of hospital stay was not significantly different between the 2 study groups : 20.1 days ( IQR , 12.9 - 39.1 ) for vitamin D3 vs 19.0 days ( IQR , 11.6 - 33.8 ) for placebo . Hospital mortality was significantly lower with 28 deaths among 98 patients ( 28.6 % [ 95 % CI , 19.9%-38.6 % ] ) for vitamin D3 compared with 47 deaths among 102 patients ( 46.1 % [ 95 % CI , 36.2%-56.2 % ] ) for placebo ( HR , 0.56 [ 95 % CI , 0.35 - 0.90 ] , P for interaction = .04 ) , but not 6-month mortality ( 34.7 % [ 95 % CI , 25.4%-45.0 % ] for vitamin D3 vs 50.0 % [ 95 % CI , 39.9%-60.1 % ] for placebo ; HR , 0.60 [ 95 % CI , 0.39 - 0.93 ] , P for interaction = .12 ) . CONCLUSIONS AND RELEVANCE Among critically ill patients with vitamin D deficiency , administration of high-dose vitamin D3 compared with placebo did not reduce hospital length of stay , hospital mortality , or 6-month mortality . Lower hospital mortality was observed in the severe vitamin D deficiency subgroup , but this finding should be considered hypothesis generating and requires further study . TRIAL REGISTRATION clinical trials.gov Identifier : NCT01130181
Recent meta-analyses reinforce the finding that 10 - 20 μg per day of vitamin D can reduce all-cause mortality and cancer mortality in middle-aged and older people .
Although vitamin D doses were greater than those assessed in the past , we found no new evidence that supplementation could have an effect on most non-skeletal conditions , including cardiovascular disease , adiposity , glucose metabolism , mood disorders , muscular function , tuberculosis , and colorectal adenomas , or on maternal and perinatal conditions .
The compilation of results from 83 trials showed that vitamin D supplementation had no significant effect on biomarkers of systemic inflammation .
The main new finding highlighted by this systematic review is that vitamin D supplementation might help to prevent common upper respiratory tract infections and asthma exacerbations .
There remains little evidence to suggest that vitamin D supplementation has an effect on most conditions , including chronic inflammation , despite use of increased doses of vitamin D , strengthening the hypothesis that low vitamin D status is a consequence of ill health , rather than its cause .
We further hypothesise that vitamin D supplementation could exert immunomodulatory effects that strengthen resistance to acute infections , which would reduce the risk of death in debilitated individuals .