Lung Cancer Risk and Residential Exposure to Air Pollution: A Korean Population-Based Case-Control Study

PURPOSE: To investigate the association between long-term exposure to ambient air pollution and lung cancer incidence in Koreans. MATERIALS AND METHODS: This was a population-based case-control study covering 908 lung cancer patients and 908 controls selected from a random sample of people within each Korean province and matched according to age, sex, and smoking status. We developed land-use regression models to estimate annual residential exposure to particulate matter (PM₁₀) and nitrogen dioxide (NO₂) over a 20-year exposure period. Logistic regression was used to estimate odds ratios (ORs) and their corresponding 95% confidence intervals (CI). RESULTS: Increases in lung cancer incidence (expressed as adjusted OR) were 1.09 (95% CI: 0.96-1.23) with a ten-unit increase in PM₁₀ (μg/m³) and 1.10 (95% CI: 1.00-1.22) with a ten-unit increase in NO₂ (ppb). Tendencies for stronger associations between air pollution and lung cancer incidence were noted among never smokers, among those with low fruit consumption, and among those with a higher education level. Air pollution was more strongly associated with squamous cell and small cell carcinomas than with adenocarcinoma of the lung. CONCLUSION: This study provides evidence that PM10 and NO₂ contribute to lung cancer incidence in Korea.