25-Hydroxyvitamin D, biomarkers of eosinophilic inflammation, and airway remodeling in children with newly diagnosed untreated asthma.

Abstract Low 25-hydroxyvitamin D (25[OH]D) and asthma development may be related to airway remodeling and eosinophilia. Periostin is proposed as a key molecule that links remodeling and eosinophilic inflammation. We evaluated the association of 25(OH)D concentration with periostin, peripheral blood eosinophil counts, and immunoglobulin E (IgE) in children with newly diagnosed asthma. The study included 150 children: 110 with atopic asthma and 40 constituted a reference group. Fasting blood was collected for cell counts and serum for measurements of 25(OH)D, periostin, IgE, and C-reactive protein (CRP) concentrations. Significantly lower 25(OH)D, elevated IgE concentrations, and eosinophil counts were found in children with asthma compared with the reference group (p = 0.0001). A lower forced expiratory volume in the first second of expiration percentage predicted value was associated with a lower 25(OH)D value in children with asthma. The bronchodilator reversibility was inversely related to serum 25(OH)D concentrations (R = -0.45, p = 0.029). The children with asthma and with a 25(OH)D deficient concentration (≤20 ng/mL) had higher concentrations of periostin (p = 0.035) and CRP (p = 0.01) than those with a sufficient 25(OH)D concentration (≥30 ng/L). Additional analysis revealed statistically significant differences (p = 0.013) when comparing periostin concentrations between subjects with a 25(OH)D deficient concentration (≤20 ng/mL) and subjects who did not have a deficient concentration (>20 ng/mL). In individuals with asthma, a 25(OH)D concentration of