Chronic obstructive lung diseases and risk of non-small cell lung cancer in women.

Introduction: The link between lung cancer and chronic obstructive lung diseases (COPD) has not been well studied in women even though lung cancer and COPD account for significant and growing morbidity and mortality among women.
Methods: We evaluated the relationship between COPD and non-small cell lung cancer in a population-based case-control study of women and constructed a time course of chronic lung diseases in relation to onset of lung cancer. Five hundred sixty-two women aged 18 to 74, diagnosed with non-small cell lung cancer and 564 population-based controls matched on race and age participated. Multivariable unconditional logistic regression models were used to estimate risk associated with a history of COPD, chronic bronchitis, or emphysema.
Results: Lung cancer risk increased significantly for white women with a history of COPD (odds ratios [OR] = 1.85; 95% confidence intervals [CI]: 1.21-2.81), but this was not seen in African American women. Risk associated with a history of chronic bronchitis was strongest when diagnosed at age 25 or earlier (OR = 2.35, 95% CI: 1.17-4.72); emphysema diagnosed within 9 years of lung cancer was also associated with substantial risk (OR = 6.36, 95% CI: 2.36-17.13). Race, pack-years of smoking, exposure to environmental tobacco smoke as an adult, childhood asthma, and exposure to asbestos were associated with a history of COPD among lung cancer cases.
Conclusions: In women, COPD is associated with risk of lung cancer differentially by race. Untangling whether COPD is in the causal pathway or simply shares risk factors will require future studies to focus on specific COPD features, while exploring underlying genetic susceptibility to these diseases.