Meta- analysis of a modest number of trials in people with predominantly mild to moderate asthma suggests that vitamin D is likely to reduce both the risk of severe asthma exacerbation and healthcare use .
Children and people with frequent severe asthma exacerbations were under-represented ; additional primary trials are needed to establish whether vitamin D can reduce the risk of severe asthma exacerbation in these groups
BACKGROUND Several clinical trials of vitamin D to prevent  asthma exacerbation  and improve  asthma control  have been conducted in children and adults , but a meta- analysis restricted to double-blind , r and omised , placebo-controlled trials of this intervention is lacking .
OBJECTIVES To evaluate the efficacy of administration of vitamin D and its hydroxylated metabolites in reducing the risk of severe asthma exacerbations ( defined as those requiring treatment with systemic corticosteroids ) and improving asthma symptom control .
Vitamin D intervention in preschoolers with viral-induced asthma (DIVA): a pilot randomised controlled trial
Background Trials in school-aged children suggest vitamin D supplementation reduces asthma exacerbations . Primary aim : to examine whether vitamin D3 ( 100,000 IU ) rapidly raises serum 25-hydroxyvitamin D ( 25OHD ) ≥75 nmol/L in asthmatic preschoolers . Methods In a double-blind , r and omised , placebo-controlled trial , preschool-aged children with asthma received 100,000 IU vitamin D3 ( intervention ) or placebo ( control ) , followed by 400 IU vitamin D3 daily for 6 months . Serum 25OHD was measured at baseline , 10 days , 3 and 6 months . Outcomes included the group difference in 25OHD change from baseline at 3 months ( Δ25OHD ) ; the proportion of children with 25OHD ≥75 nmol/L at 3 months ; the pattern in serum vitamin D over 6 months ; the proportion of children with hypercalciuria at any time point ( safety ) ; and group rates for oral corticosteroids . Continuous outcomes were analysed using generalised linear mixed models and group rate ratios of events per child were assessed using a Poisson distribution model . Results Twenty-two children were r and omised ( intervention:11 ; control:11 ) during winter . At 3 months , the group difference in Δ25OHD ( 7.2 nmol/L ; 95 % CI : -13.7 , 28.1 ) was not significant ; yet , 100 % versus 54.5 % ( intervention versus control ) had serum 25OHD ≥75 nmol/L. There was a significant group difference in Δ25OHD at 10 days ( 110.3 nmol/L ; 95 % CI : 64.0 , 156.6 ) . One child in each group had transient hypercalciuria at 10 days . Group oral corticosteroids rates were 0.82 and 1.18/child , intervention versus control ( rate ratio = 0.68 ; 95 % CI : 0.30 , 1.62 ; non-significant ) . Conclusions Following 100,000 IU vitamin D3 , all children reached serum 25OHD ≥75 nmol/L , compared with half who received placebo . Daily supplementation , sun exposure and insufficient power may explain the absence of a significant 3-month group difference in Δ25OHD . No clinical ly important alterations in bone metabolism biomarkers occurred . Group oral corticosteroid rates will inform sample size calculations for the larger trial . ( NCT01999907 , 25 November 2013 )
Meta- analysis of a modest number of trials in people with predominantly mild to moderate asthma suggests that vitamin D is likely to reduce both the risk of severe asthma exacerbation and healthcare use .
Children and people with frequent severe asthma exacerbations were under-represented ; additional primary trials are needed to establish whether vitamin D can reduce the risk of severe asthma exacerbation in these groups
BACKGROUND Several clinical trials of vitamin D to prevent  asthma exacerbation  and improve  asthma control  have been conducted in children and adults , but a meta- analysis restricted to double-blind , r and omised , placebo-controlled trials of this intervention is lacking .
OBJECTIVES To evaluate the efficacy of administration of vitamin D and its hydroxylated metabolites in reducing the risk of severe asthma exacerbations ( defined as those requiring treatment with systemic corticosteroids ) and improving asthma symptom control .