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 .
Calcitriol does not prevent bone loss in patients with asthma receiving corticosteroid therapy: a double-blind placebo-controlled trial
Introduction Oral glucocorticoid therapy reduces bone mineral density ( BMD ) and increases fracture risk . It is uncertain whether inhaled glucocorticoids , the most commonly used long-term therapy for asthma , have a similar effect . If bone loss does occur , it is unclear whether this is preventable by calcitriol . Patients with asthma receiving inhalational plus intermittent oral glucocorticoids  lose bone , and treatment with 0.5 μg/day of calcitriol will prevent bone loss . Methods A 2-year r and omized double-blind placebo-controlled trial . One hundred eight patients with asthma were stratified by gender , age , and inhaled glucocorticoid dose and treated with calcitriol ( n=55 ) or placebo ( n=53 ) . There were 41 men ( mean age 53.2±1.7 years ) and 67 women ( mean age 49.1±1 years ) with moderate to severe asthma ( requiring ≥800 μg/day of beclomethasone dipropionate or equivalent maintenance therapy ) . BMD values at the lumbar spine ( LS ) and femoral neck ( FN ) were measured at baseline and at 6 , 12 , and 24 months using dual x-ray absorptiometry . Results Changes in LS and FN BMD . Bone loss occurred in both groups at the FN ( both p<0.03 ) and at the LS in the calcitriol ( p<0.001 ) , but not the control , group . Bone loss was not less in the calcitriol group at either site . Conclusion Patients with asthma receiving inhalational plus intermittent short courses of  oral glucocorticoids  lose bone . Calcitriol is unlikely to be appropriate therapy against this bone loss
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 .