Air pollution and incidence of lung cancer by histological type in Korean adults : a Korean national health insurance service health examinee cohort study = Air pollution and incidence of lung cancer by histological type in Korean adults : a Korean national health insurance service health examinee cohort study

다국어 초록 (Multilingual Abstract)

Background: Studies have reported the associations between long-term exposure to ambient air pollution and lung cancer. However, there have been inconsistent reports of associations for lung cancer by histological type. We aimed to assess the association between long-term exposure to particulate matter less than or equal to 10 μm in a diameter (PM10) and nitrogen dioxide (NO2) and lung cancer incidence by histological subtype in South Korea. Methods: This population- based longitudinal study included 6,567,909 cancer-free subjects from the Korean National Health Insurance Service (NHIS) database for 2006-2007. We linked population data to National Cancer Center cancer registry data to confirm lung cancer incidence for 2006-2013. Individual exposure to PM10 and NO2 were assessed as 5-year average concentrations predicted at subjects’ district-specific home addresses for 2002-2007. We divided these exposures into two categories based on the 75th percentile. Cox proportional hazards models were used to estimate hazard ratios (HRs) of lung cancer incidence for the upper 25% exposure compared to the low 75% by histological subtypes at diagnosis, adjusting for potential confounders. (Figure 1) Results: Incident lung cancer was higher in male (n=21,912) than female (n=5,606). The incidence of lung cancer was higher in males, smokers, frequent exercisers or drinkers, and subjects with chronic obstructive pulmonary disease. Overall, we did not find increased risk of lung cancer with higher exposure of PM10 or NO2. However, a marginal association (P<0.10) was found for non-small cell carcinoma (HR=1.05, 95% CI=0.99-1.11). Specifically, high exposure to PM10 was associated with increased risk of adenocarcinoma in comparison with lower exposure in male smokers (HR=1.14, 95% CI=1.03- 1.25). (Table1) Conclusion: This study showed that long-term air pollution exposures were associated with elevated risk of lung adenocarcinoma in male smokers in Korea.