Chronic Effects of High Fine Particulate Matter Exposure on Lung Cancer in China

Rationale: Limited cohort studies have evaluated chronic effects of high fine particulate matter (particulate matter with an aerodynamic diameter ≤2.5 μm [PM_2.5]) exposure on lung cancer.Objectives: To investigate the response pattern of lung cancer associated with high PM_2.5 exposure.Methods: A Chinese cohort of 118,551 participants was followed up from 1992 to 2015. By incorporating PM_2.5 exposure at 1 km spatial resolution generated using the satellite-based model during 2000-2015, we estimated the association between lung cancer and time-weighted average PM_2.5 concentration using Cox proportional hazard models.Measurements and Main Results: A total of 844 incident lung cancer cases were identified during 915,053 person-years of follow-up. Among them, 701 lung cancer deaths occurred later. The exposure-response curves for lung cancer associated with PM_2.5 exposure were nonlinear, with steeper slopes at the higher concentrations. Adjusted for age, sex, geographical region, urbanization, education level, smoking status, alcohol consumption, work-related physical activity, and body mass index, participants exposed to the second-fifth quintiles of PM_2.5 had higher risk for lung cancer incidence than those exposed to the first quintile, with hazard ratios of 1.44 (95% confidence interval [CI], 1.10-1.88), 1.49 (95% CI, 1.12-1.99), 2.08 (95% CI, 1.42-3.04), and 2.45 (95% CI, 1.83-3.29), respectively. The corresponding hazard ratios for lung cancer mortality were 1.83 (95% CI, 1.33-2.50), 1.80 (95% CI, 1.29-2.53), 2.50 (95% CI, 1.62-3.86), and 2.95 (95% CI, 2.09-4.17), respectively.Conclusions: We provide strong evidence that high PM_2.5 exposure leads to an elevated risk of lung cancer incidence and mortality, highlighting that remarkable public health benefits could be obtained from the improvement of air quality in highly polluted regions.