High-Ambient Air Pollution Exposure Among Never Smokers Versus Ever Smokers With Lung Cancer

IntroductionAir pollution may play an important role in the development of lung cancer in people who have never smoked, especially among East Asian women. The aim of this study was to compare cumulative ambient air pollution exposure between ever and never smokers with lung cancer.MethodsA consecutive case series of never and ever smokers with newly diagnosed lung cancer were compared regarding their sex, race, and outdoor and household air pollution exposure. Using individual residential history, cumulative exposure to outdoor particulate matter (PM_2.5) in a period of 20 years was quantified with a high-spatial resolution global exposure model.ResultsOf the 1005 patients with lung cancer, 56% were females and 33% were never smokers. Compared with ever smokers with lung cancer, never smokers with lung cancer were significantly younger, more frequently Asian, less likely to have chronic obstructive pulmonary disease or a family history of lung cancer, and had higher exposure to outdoor PM_2.5 but lower exposure to secondhand smoke. Multivariable logistic regression analysis revealed a significant association with never-smoking patients with lung cancer and being female (OR = 4.01, 95% confidence interval [CI]: 2.76–5.82, p < 0.001), being Asian (OR_{Asian versus non-Asian} = 6.48, 95% CI: 4.42–9.50, p < 0.001), and having greater exposure to air pollution (OR_{ln_PM2.5} = 1.79, 95% CI: 1.10–7.2.90, p = 0.019).ConclusionsCompared with ever-smoking patients with lung cancer, never-smoking patients had strong associations with being female, being Asian, and having air pollution exposures. Our results suggest that incorporation of cumulative exposure to ambient air pollutants be considered when assessing lung cancer risk in combination with traditional risk factors.