Low levels of vitamin D are associated with asthma severity, airway remodeling, and exacerbation rate increase, especially in nonatopic asthma. Reduced steroid responsiveness or impaired antimicrobial defense might be underlying mechanisms.
This double-blind, randomized, placebo-controlled trial investigated the effect of long-acting vitamin D3 (400,000 IU), single oral dose, on sputum neutrophils and eosinophils in 44 patients with nonatopic asthma with neutrophilic (≥53%) and/or eosinophilic (≥3%) airway inflammation.
In patients with eosinophil levels of 26% or more (median in patients with sputum eosinophilia, >3%), eosinophils decreased from a median of 41% to 11.8% after vitamin D treatment. It also resulted in slightly better Asthma Control Questionnaire scores (P = .08).
Vitamin D supplementation reduced eosinophilic airway inflammation in patients with nonatopic asthma with severe eosinophilic airway inflammation, but did not affect sputum neutrophils. These findings suggest that vitamin D might have potential as an add-on treatment option in eosinophilic asthma.
Vitamin D reduces eosinophilic airway inflammation in nonatopic asthma. Jantina C. de Groot et al. JACI, March 2015, Volume 135, Issue 3, Pages 670–675.e3.
The World Allergy Organization (WAO) Small Airways Working Group publishes a monthly "What's New?" summary and I have served as an editor since 2011. The summary features the top 3 asthma/small airways articles each month. The article above is a part of the project. The archive is here: http://www.worldallergy.org/small_airways_group/reviews/archive.php
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