Long-term Exposure to PM₁₀Increases Lung Cancer Risks: A Cohort Analysis

Purpose Although lung cancer incidences in female never-smokers have increased, few studies focus on explicit investigation. We aimed to investigate the relationship between long-term exposure to ambient particulate matter sized 10 μm or less in diameter (PM₁₀) and the incidence of lung cancer within different genders and smoking status populations. Materials and Methods We included Seoul metropolitan residents, aged between 20 and 65 years, who underwent a national health screening examination from 2005-2007 and were followed up until 2015. Individual-level long-term exposure to PM₁₀was assessed based on subject home addresses. To assess the relationship between PM₁₀and lung cancer, we estimated hazard ratios (HRs) for increased lung cancer incidence from a 10 μg/m³increase in PM_10.Results Among 5,831,039 individuals, 36,225 (0.6%) developed lung cancer within the 7 years observed. In females, the majority (94.4%) of lung cancer development was found in never-smokers. In adjusted analyses, a significant relationship between lung cancer development and PM₁₀was observed in males, regardless of smoking status (never-smoker: HR, 1.14 [95% confidence interval (CI), 1.13 to 1.15]; ex-smoker: HR, 1.16 [95% CI, 1.14 to 1.17]; current smoker: HR, 1.18 [95% CI, 1.17 to 1.19]). We also found significant associations in female never- or ex-smokers with smaller HRs (never-smoker: HR, 1.06 [95% CI, 1.05 to 1.07]; ex-smoker: HR, 1.13 [95% CI, 1.02 to 1.23]; current smoker: HR, 1.04 [95% CI, 0.99 to 1.10]). Conclusion Our findings suggest that long-term exposure to PM₁₀is associated with lung cancer development. A novel approach to lung cancer screening needs to be considered depending on the exposed PM₁₀level.