Outdoor Air Pollution Exposure and Lung Cancer Incidence in Korea: A Nationwide Population-Based Cohort Study

摘要

Background/Aim: The International Agency for Research on Cancer (IARC) has concluded that exposure to outdoor air pollution causes lung cancer. Epidemiological studies on air pollution associated with lung cancer played a crucial role in their decision. However, most of the epidemiological evidence is limited to western countries. We aimed to investigate the association between long-term exposure to outdoor air pollutants and lung cancer incidence in Korea. Methods: National Sample Cohort data from 2002 to 2013 were obtained from National Health Insurance Service in Korea. The study population included a total of 28,090 subjects without preexisting cancer at baseline. The district level annual-average concentration of particulate matter with a diameter ≤ 10 mm (PM10), nitrogen dioxide (NO2), and ozone (O3) were assigned to each individual based on residential address which is updated annually. Cox-proportional hazard regression model was used to estimate the effects of long-term exposure to air pollution on the incidence of lung cancer. Different exposure matrices and lag years were considered. Results: During 263,178 person-years, 160 incident cases of lung cancer were observed. Increasing yearly mean exposure in 10 ppb 03 was associated incident lung cancer (hazard ratio [HR]: 1.61, 95% CI: 1.07-2.41]). The results showed no association between lung cancer and PM10 (HR: 0.91, 95% CI: 0.72-1.15) or NO2 (HR: 0.84, 95% CI: 0.63-1.10). Each follow-up period average exposure and average cumulative exposure to O3 before censoring were also marginally associated with lung cancer. Conclusion: Lung cancer incidence was most strongly associated with long-term O3 exposure in this Korean study. Further investigation is required to provide strong evidence, however, our study suggests that annual guideline for O3 is recommended in Korea.