An Ecologic Analysis of County-Level PM(2.5) Concentrations and Lung Cancer Incidence and Mortality

Few studies have explored the relationship between PM(2.5) and lung cancer incidence. Although results are mixed, some studies have demonstrated a positive relationship between PM(2.5) and lung cancer mortality. Using an ecologic study design, we examined the county-level associations between PM(2.5) concentrations (2002–2005) and lung cancer incidence and mortality in North Carolina (2002–2006). Positive trends were observed between PM(2.5) concentrations and lung cancer incidence and mortality; however, the R(2) for both were <0.10. The slopes for the relationship between PM(2.5) and lung cancer incidence and mortality were 1.26 (95% CI 0.31, 2.21, p-value 0.01) and 0.73 (95% CI 0.09, 1.36, p-value 0.03) per 1 μg/m(3) PM(2.5), respectively. These associations were slightly strengthened with the inclusion of variables representing socioeconomic status and smoking. Although variability is high, thus reflecting the importance of tobacco smoking and other etiologic agents that influence lung cancer incidence and mortality besides PM(2.5), a positive trend is observed between PM(2.5) and lung cancer incidence and mortality. This suggests the possibility of an association between PM(2.5) concentrations and lung cancer incidence and mortality.