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 .
The Vitamin D Antenatal Asthma Reduction Trial (VDAART): rationale, design, and methods of a randomized, controlled trial of vitamin D supplementation in pregnancy for the primary prevention of asthma and allergies in children.
There is intense interest in the role of vitamin D in the development of asthma and allergies . However , studies differ on whether a higher vitamin D intake or status in pregnancy or at birth is protective against asthma and allergies . To address this uncertainty , the Vitamin D Antenatal Asthma Reduction Trial ( VDAART ) was developed . VDAART is a r and omized , double-blind , placebo-controlled trial of vitamin D supplementation  in pregnant women to determine whether prenatal supplementation can prevent the development of  asthma and allergies in women 's offspring . A secondary aim is to determine whether vitamin D supplementation can prevent the development of pregnancy complications , such as preeclampsia , preterm birth , and gestational diabetes .  Women were r and omized to the treatment arm of 4000IU/day of vitamin D3 plus a daily multivitamin that contained 400IU of vitamin D3 or the placebo arm of placebo plus a multivitamin that contained 400IU daily of vitamin D3 . Women who were between the gestational ages of 10 and 18 weeks were r and omized from three clinical centers across the United States - Boston Medical Center , Washington University in St. Louis , and Kaiser Permanente Southern California Region ( San Diego , CA ) . Supplementation took place throughout pregnancy . Monthly monitoring of urinary calcium to creatinine ratio was performed in addition to medical record review for adverse events . Offspring are being evaluated quarterly through question naires and yearly during in-person visits until the 3rd birthday of the child . Ancillary studies will investigate neonatal T-regulatory cell function , maternal vaginal flora , and maternal and child intestinal flora
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 .