Background: Vitamin D deficiency has been suggested to play a role in the pathophysiology of asthma. Several suggested mechanisms have been proposed including airway remodelling. The aim of our study was to investigate the role of vitamin D serum level in the pathophysiology of airway remodelling in severe refractory asthma.
Subjects and methods: The present study was conducted on 20 severe, 10 non-severe asthma patients and 15 control subjects. Pulmonary function tests, sputum matrix metalloproteinase-9 (MMP-9) and serum vitamin D3 were measured in all subjects. Patients with airway obstruction (Forced expiratory volume in one second (FEV1) <80%) performed bronchodilator reversibility testing.
Results:Vitamin D deficiency was prevalent among all our asthma patients. Although there was no significant difference in serum vitamin D levels between severe and non-severe asthmatic patients, serum vitamin D levels were positively correlated with the degree of current clinical control, as measured by Asthma Control Test (ACT). Serum vitamin D levels were negatively correlated with sputum MMP-9 levels in our asthma patients. The degree of bronchodilator reversibility was positively correlated with serum vitamin D and negatively correlated with sputum MMP-9 levels. Accordingly, we suggest that vitamin D may have a beneficial role in the prevention of airway remodelling in asthma patients.