Serum catalase, thiol and myeloperoxidase levels in children passively exposed to cigarette smoke

Background: Free radicals found in cigarette smoke can harm all tissues and cellular structures in the human body. Passive smoking increases free radical production, leads to the depletion of antioxidants and increases oxidative stress which causes lipid peroxidation. Many studies have been conducted to determine the effects of passive smoking on antioxidant enzymes and lipid levels in adults, but pediatric studies on this topic are few. In our study, we compared the levels of antioxidants, oxidants, total and LDL cholesterol in children exposed to passive cigarette smoking with a healthy control group that was not exposed to passive smoking. Methods: A total of 41 children (4-17years of age, 24 girls and 17 boys) exposed to passive smoking and 18 healthy girls and 12 healthy boys were included in this study. Secondhand smoking was confirmed via measurement of the cotinine/creatinine ratio. Various sociodemographic characteristics of patients were recorded. The levels of catalase, thiol, myeloperoxidase were measured to determine the antioxidant and oxidant levels in children, while the levels of total cholesterol and LDL cholesterol were measured to determine the alterations in lipid profile. Results: The groups were similar in regard to demographic characteristics. Myeloperoxidase levels were significantly higher in the passive cigarette smoking group compared to the non-exposure group; however, catalase and thiol levels were similar. In regard to lipid profile, the levels of total cholesterol and LDL cholesterol were also similar in those with and without exposure to passive smoking. Conclusions: Our findings suggest that the effects of passive smoking initially influence oxidants (MPO), but not antioxidants (thiol and catalase). However, it is apparent that passive smoking adversely affects oxidative balance in children and this may lead to the development of various diseases which could cause significant morbidity and mortality.