Abstract
Background: The most common lung cancer among non-smokers is adenocarcinoma (AC). Most studies find an increased risk of lung AC associated with particulate air pollution but few studies have assessed the association among non-smokers.
Objectives: To assess the association between ambient PM2.5 and risk of lung AC, in single and two-pollutant models with ozone (O3) using the Adventist Health and Smog Study-2 (AHSMOG-2), a cohort study where 80% are never smokers.
Methods: A total of 79,950 AHSMOG-2 non-smoking subjects were followed for an average of 7.7 years with respect to incident lung AC identified through U.S. state cancer registries. Ambient air pollution levels at subjects' residence was estimated for the years 2000 and 2001, immediately prior to study start.
Results: A total of 164 incident AC of the lung occurred during 615,826 person-years of follow-up. Multivariable adjusted hazard ratio (HR) with 95% confidence interval (CI) for incident AC of the lung for each increment of 10 µg/m3 in PM2.5 was 1.46 (0.99, 2.15) in single-pollutant and 1.45 (0.98, 2.16) in two-pollutant models with 24-hour ozone (O3). A significant interaction (p=0.0159) was observed between PM2.5 and prevalent non-melanoma skin cancer (NMSC). Excluding those with prevalent NMSC from the analysis, strengthened the association between PM2.5 and AC (HR=1.74, 95% CI,1.10, 2.77) in the two-pollutant model.
Conclusions: Increasing levels of ambient PM2.5 are associated with increasing incidence of AC of the lung. Non-melanoma skin cancer modifies the effect of ambient PM2.5 and excluding prevalent NMSC strengthened the HR.
- Copyright ©the authors 2016
