Severe Asthma Attacks Reduced by Vitamin D

Individuals who take an oral vitamin D supplement in addition to their standard asthma medication had a reduction in severe asthma attacks, according to a new review published in the Cochrane Library.

There has been a link between low blood levels of vitamin D and the increased risk of asthma attacks in children and adults with asthma. This link has spurred a growing interest in the potential role vitamin D plays in asthma management, because it may help reduce upper respiratory infections that can lead to exacerbations of asthma, and several clinical trials have tested this theory.

For the review, a team of Cochrane researchers examined 7 trials that involved 435 children, and 2 studies that involved 658 adults, who were ethnically diverse. A majority of patients recruited into these studies had mild-to-moderate asthma, and a minority had severe asthma.

The studies last between 6 and 12 months, and most of the patients continued to take their usual asthma medication while participating. After analyzing study data, the researchers found that giving patients an oral vitamin D supplement reduced the risk of severe asthma attacks that required hospital or emergency department admission from 6% to about 3%.

Furthermore, vitamin D supplementation reduced the rate of asthma attacks that needed treatment with steroid tablets. These results were largely based on trials in adults.

An additional finding showed that vitamin D did not improve lung function or day-to-day asthma symptoms, nor did it increase the risk of side effects at the doses that were tested.

“We found that taking a vitamin D supplement in addition to standard asthma treatment significantly reduced the risk of severe asthma attack, without causing side effects,” said lead review author Adrian Martineau. This is an exciting result, but some caution is warranted.”

Martineau noted that the findings on severe asthma attacks were from 3 trials, with the majority of patients comprised of adults with mild or moderate asthma. Martineau added that further trials examining vitamin D in children and adults with severe asthma are needed to determine the benefit.

Martineau also noted it is unclear whether vitamin D supplements can decrease the risk of severe asthma attacks among all patient groups, or if it just applies to individuals who start with low vitamin D levels.

The Cochrane Review findings were presented at the European Respiratory Society (ERS) Congress in London.