Swetland Faculty Affiliate, Kristie Ross, MD, is a co-author on a new article in the prestigious Journal of the American Medical Association. This study evaluates the effectiveness of Vitamin D Supplementation for the prevention of acute asthma attacks among children 6-16 years old, who are at high risk for having a severe asthma attack. Dr. Ross and her colleagues identified children with low vitamin D levels in their blood (less than 30 ng/mL) who were requiring chronic use of inhaled steroids to ward off asthma attacks. Half of these 192 children were randomly selected to receive a vitamin D supplement (4000IU of Vitamin D each day) and the other half received placebo pills. All of the participants kept taking steroids throughout the study. After following these children for 48 weeks they found no difference in the time to severe asthma attack between the two groups.
This is an important study because the authors evaluated children who were known to be deficient in Vitamin D at the start of the study. Failing to measure baseline levels has been a problem in nutritional research (details here) but the authors’ thoughtful design addresses this problem. While no single study can provide a definitive, universally applicable, answer to research questions, this study indicates that Vitamin D supplements (of this specific type and dose) did not help these 6 to 16 year-old children who were taking inhaled steroids. In other words, for this specific group of patients, this supplement was not an effective treatment. A number of questions remain, and while some of these can be answered with clinical trials of Vitamin D supplements, some of them cannot be. The strongest near-term asthma triggers are allergen, irritant, or infection exposures, and other factors are more distal (long term) players in the complex system that produces: 1) chronic susceptibility and 2) acute symptoms. In this light, it still is not clear how early life and concurrent Vitamin D levels might interact to affect the risk of developing asthma, transient wheezing, or respiratory infections. If habitually sufficient Vitamin D, obtained via foods and/or sunlight, lowers the risk of developing asthma and asthma attacks, this will be hard to study with clinical trials and other study designs may be needed. Read more here.
Though the findings were negative, this study in JAMA takes us one step closer to understanding how to reduce the burden of asthma in our communities.