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 .
Prenatal Vitamin D Supplementation and Child Respiratory Health: A Randomised Controlled Trial
Background Observational studies suggest high prenatal vitamin D intake may be associated with reduced childhood wheezing .  We examined the effect of prenatal vitamin D on childhood wheezing  in an interventional study . Methods We r and omised 180 pregnant women at 27 weeks gestation to either  no vitamin D , 800 IU ergocalciferol daily until delivery or single oral bolus of 200,000 IU cholecalciferol  , in an ethnically stratified , r and omised controlled trial . Supplementation improved but did not optimise vitamin D status . Research ers blind to allocation assessed offspring at 3 years . Primary outcome was any history of wheeze assessed by vali date d question naire . Secondary outcomes included atopy , respiratory infection , impulse oscillometry and exhaled nitric oxide . Primary analyses used logistic and linear regression . Results We evaluated 158 of 180 ( 88 % ) offspring at age 3 years for the primary outcome . Atopy was assessed by skin test for 95 children ( 53 % ) , serum IgE for 86 ( 48 % ) , exhaled nitric oxide for 62 ( 34 % ) and impulse oscillometry of acceptable quality for 51 ( 28 % ) . We found no difference between supplemented and control groups in risk of wheeze  [ no vitamin D : 14/50 ( 28 % ) ; any vitamin D : 26/108 ( 24 % ) ( risk ratio 0.86 ; 95 % confidence interval 0.49 , 1.50 ; P = 0.69 ) ] . There was no significant difference in atopy , eczema risk , lung function or exhaled nitric oxide between supplemented groups and controls . Conclusion Prenatal vitamin D supplementation in late pregnancy that had a modest effect on cord blood vitamin D level , was not associated with decreased wheezing in offspring at age three years . Trial Registration Controlled-Trials.com IS RCT
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 .