Association between the oxidative status, Vitamin D levels and respiratory function in asthmatic children

AIM: We studied the relationship between plasma concentrations of oxidative system markers, vitamin D, and respiratory functions in children with asthma. MATERIALS AND METHODS: Ninety one children aged 6-17 years with stable asthma seen in the clinic had the serum concentrations of oxidative system markers [total antioxidant capacity (TAC), total oxidative status (TOS), paraoxonase-1 activity (PON-1), and 25-hydroxyvitamin D3] and respiratory functions were measured. RESULTS: There was no statistical correlation between TAC and age and FEV1. There was a significant positive correlation between TAC and 25(OH)D3 (r = 0.214, P = 0.021), TAC and TOS (r = 0.218, P = 0.007), TAC and PON-1 (r = 0.230, P = 0.028), TAC and IgE (r = 0.194, P = 0.033), and inverse correlation between TAC and PEF (r = -0.208, P = 0.024). In the backward multiple regression analysis, 25(OH)D3 (t = 2.613, P = 0.011), age (t = -2.158, P = 0.034), TOS (t = 2.158, P = 0.000), and OSI index (t = -13.859 P = 0.000) maintained an independent relationship with TAC (r = 0.858, r2 = 0.737, F = 21.436, P = 0.000). CONCLUSION: Oxidative stress correlates with the serum vitamin D concentrations. Clinical trials are required to confirm that increasing serum 25OHD may improve asthma control, as measured by clinical and oxidative stress markers.