Long-term Exposure to PM10 Increases Lung Cancer Risks: A Cohort Analysis

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.

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 PM10 was assessed based on subject home addresses. To assess the relationship between PM10 and lung cancer, we estimated hazard ratios (HRs) for increased lung cancer incidence from a 10 µg/m3 increase in PM10.

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 PM10 was 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]).

Our findings suggest that long-term exposure to PM10 is associated with lung cancer development. A novel approach to lung cancer screening needs to be considered depending on the exposed PM10 level.