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 Monthly High-Dose Vitamin D Supplementation on Cardiovascular Disease in the Vitamin D Assessment Study: A Randomized Clinical Trial
Importance Cohort studies have reported increased incidence of cardiovascular disease ( CVD ) among individuals with low vitamin D status . To date , r and omized clinical trials of vitamin D supplementation have not found an effect , possibly because of using too low a dose of vitamin D. Objective To examine whether monthly high-dose vitamin D supplementation prevents CVD in the general population . Design , Setting , and Participants The Vitamin D Assessment Study is a r and omized , double-blind , placebo-controlled trial that recruited participants mostly from family practice s in Auckl and , New Zeal and , from April 5 , 2011 , through November 6 , 2012 , with follow-up until July 2015 . Participants were community-resident adults aged 50 to 84 years . Of 47 905 adults invited from family practice s and 163 from community groups , 5110 participants were r and omized to receive vitamin D3 ( n = 2558 ) or placebo ( n = 2552 ) . Two participants retracted consent , and all others ( n = 5108 ) were included in the primary analysis . Interventions Oral vitamin D3 in an initial dose of 200 000 IU , followed a month later by monthly doses of 100 000 IU , or placebo for a median of 3.3 years ( range , 2.5 - 4.2 years ) . Main Outcomes and Measures The primary outcome was the number of participants with incident CVD and death , including a prespecified subgroup analysis in participants with vitamin D deficiency ( baseline deseasonalized 25-hydroxyvitamin D [ 25(OH)D ] levels < 20 ng/mL ) . Secondary outcomes were myocardial infa rct ion , angina , heart failure , hypertension , arrhythmias , arteriosclerosis , stroke , and venous thrombosis . Results Of the 5108 participants included in the analysis , the mean ( SD ) age was 65.9 ( 8.3 ) years , 2969 ( 58.1 % ) were male , and 4253 ( 83.3 % ) were of European or other ethnicity , with the remainder being Polynesian or South Asian .  Mean ( SD ) baseline deseasonalized 25(OH)D concentration was 26.5 ( 9.0 ) ng/mL , with 1270 participants ( 24.9 % ) being vitamin D deficient . In a r and om sample of 438 participants , the mean follow-up 25(OH)D level was greater than 20 ng/mL higher in the vitamin D group than in the placebo group . The primary outcome of CVD occurred in 303 participants ( 11.8 % ) in the vitamin D group and 293 participants ( 11.5 % ) in the placebo group , yielding an adjusted hazard ratio of 1.02 ( 95 % CI , 0.87 - 1.20 ) . Similar results were seen for participants with baseline vitamin D deficiency and for secondary outcomes . Conclusions and Relevance Monthly high-dose vitamin D supplementation does not prevent CVD . This result does not support the use of monthly vitamin D supplementation for this purpose . The effects of daily or weekly dosing require further study . Trial Registration clinical trials.gov Identifier :
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 .