Factors affecting the frequency of micronuclei in asthmatic and healthy children from Ostrava.

A higher incidence of asthma is one of the serious problems confronting urban populations worldwide. The aim of the present study was to analyze the effect of age, gender, smoking, vitamin intake, genetic polymorphisms in genes related to the metabolic activation of polycyclic aromatic hydrocarbons (PAHs) and their detoxification and oxidative damage to DNA, lipids and proteins on the frequency of micronuclei (MN) in a group of 175 children (81 with bronchial asthma and 94 healthy controls) aged 6-15 years. The study group from the most polluted region of the Czech Republic, Ostrava, was followed in November 2008, when the mean concentration of benzo[a]pyrene (B[a]P) measured by stationary monitoring was 11.4±9.8ng/m(3). The results of cotinine analysis revealed active smoking in 15 children. The frequency of MN per 1000 binucleated cells (MN/1000 BNC), measured by automated image analysis, indicated a significant risk for smoking children with asthma in comparison with smoking control children (4.25±1.54 and 3.00±0.77, respectively, p<0.05). Girls in the control group had 16% higher levels of MN in comparison with boys. Markers of oxidative damage to DNA, proteins and lipids were not associated with asthma in this study. Higher levels of MN were associated with increased levels of protein carbonyl groups. We conclude that smoking asthmatic children are at higher risk of DNA damage measured as the frequency of micronuclei in peripheral blood lymphocytes.