Chronic obstructive pulmonary disease (COPD) is a term used to describe chronic lung conditions characterized by airflow limitation, most commonly chronic bronchitis and emphysema. These conditions are strongly associated with cigarette smoking and often occur together.
A study published in Lung (2006; 184(2):51–55) examined markers of oxidative stress and antioxidant status in several groups: 30 smokers without diagnosed lung disease, 30 healthy nonsmokers, 71 patients with stable COPD, and 31 patients experiencing an acute exacerbation of COPD. The investigators measured plasma malondialdehyde (MDA), a marker of lipid peroxidation and oxidative stress, and superoxide dismutase (SOD) activity in red blood cells, an important endogenous antioxidant enzyme.
Plasma MDA levels were lower in smokers than in healthy nonsmokers, but were higher in patients with COPD compared with nonsmokers. SOD activity was markedly elevated in patients experiencing COPD exacerbations compared with all other groups. Based on these findings, the authors reported differences in oxidative and antioxidant markers among smokers and patients with COPD relative to healthy nonsmokers, consistent with an imbalance in oxidative stress and antioxidant defenses in COPD.
