Oxidative stress in youth and adolescents with elevated body mass index exposed to secondhand smoke

Introduction: Our objective was to investigate the relationships between secondhand smoke (SHS) exposure and oxidative stress in a group of youth and adolescents with elevated body mass index. Methods: Participants in this cross sectional study were healthy nonsmoking youth and adolescents ages 9 to 18 years old. Three-quarters of the participants were either overweight or obese. SHS exposure was determined by survey and hair nicotine level. Markers of oxidation were total antioxidant capacity and protein malondialdehyde adducts (MDA). Results: Ninety subjects were studied; adequate hair samples were available for 86. The mean hair nicotine level was 0.75 ng/mg, the median was 0.58 ng/mg and the range was 0.09-2.88 ng/ mg. There was a significant relationship between MDA and the three survey questions regarding smoke exposure ([mother smokes, r = 0.29, P = .006], [smoker lives in the home, r = 0.31, P = .004], and [number of smokers in the home, r = 0.36, P = .002]). There was a significant positive relationship between log-hair nicotine and MDA (Pearson r = 0.233, P = .031), which remained significant after controlling for age, sex, race, and method of insurance. No relationship was found between log-hair nicotine and total antioxidant capacity. However, there was a significant relationship between number of smokers in the home (r = 0.24, P = .042) and total antioxidant capacity. Conclusions: We have demonstrated a significant positive relationship hair nicotine level and MDA in a group of youth with a high proportion of overweight/obese subjects. Implications: We have shown a significant relationship between objectively measured SHS exposure and one marker of oxidative stress in a sample of youth and adolescents with a high proportion of overweight/obese subjects, and who were nonsmokers with relatively low tobacco exposure. This finding remains significant after controlling for age, sex, race, and type of medical insurance. Since the cardiovascular effects of SHS exposure are related to oxidative stress, this finding adds to our knowledge that the sequence of deleterious effects of tobacco exposure on the cardiovascular system begins long before clinical disease is evident.