Sex-related differences in bronchial epithelial changes associated with tobacco smoking

Background: Lung cancer is the most common cause of cancer death in North A merican women, Because smoking-related changes in the bronchial epithelium and in lung function have not been studied in detail in women, we used fluo rescence bronchoscopy-directed biopsy to determine the prevalence of high-g rade preinvasive lesions in former and current smokers of both sexes. Metho ds: Spirometry, white-light bronchoscopy, and fluorescence bronchoscopy wer e performed in 189 women and 212 men older than 40 years of age who had smo ked 20 pack-years or more (pack-years number of packs of cigarettes smoked per day x number of years of smoking). Results: Carcinoma in situ was found in 1.8% of the subjects, severe dysplasia was found in 6.5%, and moderate dysplasia was found in 14% (all preinvasive lesions). Compared with men, wo men had a lower prevalence of high-grade preinvasive lesions in the observe d airways (14% versus 31%; odds ratio = 0.18; 95% confidence interval = 0.0 4-0.88), and women with preinvasive lesions had fewer such lesions (two-sid ed P = .048), The prevalence of preinvasive lesions did not change substant ially for more than 10 years after cessation of smoking. Lung function was associated with the prevalence of preinvasive lesions, but the association was weaker in women than in men, If the presence of airflow obstruction was defined by an FEV1/FVC (forced expiratory volume in 1 second/forced vital capacity) value of 70% or less, only 56% of the men and 44% of the women wi th preinvasive lesions had abnormal lung function. Conclusion: In developin g strategies for chemoprevention or early detection of lung cancer in high- risk populations, it is important to consider the effect of sex and arbitra rily chosen lung function values on the prevalence of preinvasive airway le sions.