There has been some debate in recent times about the association between vitamin D levels and the risk of developing certain conditions such as diabetes, colon cancer, arthritis and infections. Studies show conflicting results. But when it comes to asthma, vitamin D may indeed protect against severe bouts of the illness.
A Cochrane review published today shows that asthmatics given vitamin D had fewer severe asthma attacks that needed treatment with anti-inflammatory tablets, known as oral corticosteroids.
For those taking vitamin D, the average number of attacks per person per year went down from 0.44 to 0.22. This is a clinically relevant reduction, meaning it is significant enough to justify a change in treatment.
The Cochrane Library contains in-depth reviews, known as meta-analyses, that independently study the best available evidence generated through previous research in the field.
The Cochrane review also showed vitamin D reduced the likelihood of attending hospital for an acute asthma attack from six per 100 patients to around three per 100. However, vitamin D had little or no effect on day-to-day asthma symptoms or breathing tests.
No serious side-effects of vitamin D occurred at the doses tested and the evidence reviewed was graded as of high quality.
The meta-analysis included a comprehensive review of published and unpublished trials up to January 2016. The studies included compared children or adults with asthma who were randomly chosen to receive either vitamin D or identical dummy tablets (placebo) for at least 12 weeks.
Seven trials involving 435 children and two trials involving 658 adults contributed to a pooled analysis of the results. Most of the patients included had mild or moderate asthma.