Redox imbalance is thought to contribute to the pathogenesis of both lung cancer and obstructive airways disease. We hypothesized that airway antioxidants would be associated with high-grade sputum dysplasia and a higher risk of airflow obstruction. One hundred seventeen research subjects (41 never-smokers, 40 former smokers, and 36 current smokers) underwent BAL, spirometry, and venous blood sampling. The antioxidants urate, glutathione (reduced and oxidized), and ascorbate were measured by high-pressure liquid chromatography with electrochemical detection. Total protein and total nitrites were assayed by colorimetric detection. Median concentrations (10th and 90th percentile) for selected BAL markers are listed in Table 1
. There was a statistically significant correlation between airflow obstruction and BAL protein (p = 0.03), total nitrite (p = 0.02), and oxidized glutathione (p = 0.01). In a stepwise multiple regression model with age and pack-years of smoking, only total nitrites and oxidized glutathione remained in the model for airflow obstruction. Carcinoma or high-grade dysplasia on sputum cytology was associated with higher concentrations of protein (p = 0.03), total nitrites (p = 0.01), and urate (p = 0.02), but not in a stepwise logistic regression model. Antioxidants and markers of oxidative stress are elevated in persons with airflow obstruction and high-grade sputum dysplasia; however, these measurements are not as good predictors as pack-years of smoking. The increase in airways antioxidants may be a response to elevated oxidative stress from tobacco smoke.