Updated evidence suggests that supplementation with vitamin D or its hydroxylated metabolites does not reduce the risk for asthma exacerbations, according to a study published in the Cochrane Database of Systematic Reviews. Anne M. Williamson and colleagues examined the effectiveness and safety of administration of vitamin D or its hydroxylated metabolites for reducing the risk for asthma exacerbations and improving asthma symptom control in a review of 20 studies: 15 with 1,155 children and five with 1,070 adults. The proportion of participants experiencing one or more asthma exacerbations treated with systemic corticosteroids was not affected by administration of vitamin D or its hydroxylated metabolites. Vitamin D supplementation also had no effect on the rate of exacerbations requiring systemic corticosteroids or the time to first exacerbation. No evidence of effect modification was seen by baseline vitamin D status, vitamin D dose, frequency of dosing regimen, or age. “In contrast to our previous Cochrane review on this topic, this updated review does not find that vitamin D offers protection against asthma
attacks or improves control of asthma symptoms,” a coauthor said in a statement.