Gender Differences in Susceptibility to Smoking among Patients with Lung Cancer

Background/Aims: To determine whether female smokers are more or less susceptible to the detrimental pulmonary-function effects of smoking when compared to male smokers among patients with lung cancer. Methods: Pack-years and pulmonary function indices were compared between 1,594 men and women with lung cancer who were smokers or had a history of smoking. Differences in individual susceptibility to smoking were estimated using a susceptibility index formula. Results: Of the patients, 959 (92.8%) men and 74 (7.2%) women were current smokers. Common histological types of lung cancer were squamous cell carcinoma, adenocarcinoma, and small cell carcinoma, among others. Women had a lower number of pack-years, forced expiratory volume in 1 second ($FEV_{1}$, liters), forced vital capacity (FVC, liters), and total lung capacity (TLC, liters) compared to those of men (25.0 ${\pm}$ 19.2 vs. 42.9 ${\pm}$ 21.7 for pack-years; 1.4 ${\pm}$ 0.5 vs. 2.0 ${\pm}$ 0.6 for $FEV_{1}$; 3.0 ${\pm}$ 0.7 vs. 2.0 ${\pm}$ 0.6 for FVC; 4.5 ${\pm}$ 0.8 vs. 5.7 ${\pm}$ 1.0 for TLC; all p < 0.001). The susceptibility index for women was significantly higher compared to that of men (1.1 ${\pm}$ 4.1 vs. 0.7 ${\pm}$ 1.1; p = 0.001). A significant inverse association was shown between the susceptibility index and TLC and FVC (r = -0.200 for TLC, -0.273 for FVC; all p < 0.001). Conclusions: The results suggest that the detrimental effects of smoking on pulmonary function are greater in women, as compared to those in men, among patients with lung cancer.