Altered oxidative state in schoolchildren with asthma and allergic rhinitis.

Oxidative stress may be defined as a disruption of the balance between the level of oxidants and reductants (antioxidants), and oxidative state in children may influence the risk of asthma and allergic disease. We investigated serum antioxidant levels: selenium, vitamin E, bilirubin, albumin, uric acid and transferrin as well as the oxidant ferritin and their association with asthma and allergic rhinitis. Children of 7-12 yr with asthma (n = 50) and no asthma (controls) (n = 52) underwent skin prick test, lung function, fractional exhaled nitric oxide (FeNO) measurements and blood sampling. Allergic rhinitis was found in 23 children, 19 with asthma and four controls. Healthy children were controls without rhinitis. Asthma was associated with reduced albumin (g/l), adjusted odds ratio (aOR) (95% CI) 0.81 (0.66, 0.99) (p = 0.048) compared with healthy children in a regression analysis adjusted for age and gender. Asthma with high FeNO ≥20 ppb was associated with reduced albumin, aOR 0.60 (0.40, 0.89) (p = 0.012) compared to controls with FeNO <20. Asthma with allergic rhinitis had reduced albumin, aOR = 0.70 (0.50, 0.99) (p = 0.04), and higher ferritin levels (mg/l) [aOR = 1.04 (1.00, 1.09) p = 0.03] compared to healthy children. Poorly controlled asthma was associated with lower vitamin E levels, aOR 0.79 (0.65, 0.95) (p = 0.02), lower transferrin levels, aOR 0.72 (0.57, 0.92) (p < 0.01), and higher albumin levels, aOR 1.53 (1.03, 2.28) (p = 0.04), compared to well controlled asthma. In conclusion, schoolchildren with asthma and rhinitis had reduced levels of the major serum antioxidant albumin, and poorly controlled asthma was associated with decreased vitamin E and transferrin levels. Reduced albumin was associated with increased FeNO, a marker of allergic inflammation in asthma, although the discriminatory value of this finding should be further assessed in population studies.