Short-term personal traffic-related exposures and biomarkers of nitro-PAH exposure and oxidative DNA damage

Abstract

Background: Traffic attributed exposures including diesel exhaust exposures have been associated with cardiac-related health outcomes, respiratory disease, lung cancer, and overall mortality. However, few biomarker indicators of exposure have been identified. Nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) have been considered as diesel exhaust specific compounds. Their metabolites, amino-PAHs, may be used as biomarkers of diesel exhaust exposure. Aim: Assess relationships between urinary amino-PAHs and vehicle exhaust exposures to examine their efficacy as biomarkers of internal dose, and relationships with oxidative DNA damage. Methods: Urine samples were collected pre- and post-shift, at the beginning and end of a work week from 95 male U.S trucking industry workers. We used repeated-measures analysis to assess total 1- and 2-aminonaphthalene (1-AN & 2-AN) and 1-aminopyrene (1-AP) urinary concentrations with concurrent microenvironment particulate matter (PM­2.5), elemental and organic carbon (EC & OC), and urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG). Results: There was a suggestive association between daily PM2.5 ­­­levels and post-shift urinary 1 & 2-AN levels with a 115.0 pg/ml increase (95% CI:-0.5, 230.1) associated with every IQR increase in PM­2.5, but there were no other associations with daily or mean PM­2.5, EC, or OC . There were significant associations between pre-shift levels of 1 & 2-AN and post-shift 8-OHdG levels and between concurrent 1-AP and 8-OHdG levels with 4.64 (95% CI: 0.81, 8.45) and 3.29 (95% CI: 0.05, 6.59) µg/g urine creatinine increases in 8-OHdG levels per IQR increase in exposure biomarkers, respectively. Conclusions: Our findings suggest only weak associations of the urinary amino-PAHs with PM2.5 in this trucking industry population. However, amino-PAHs were significantly associated with 8-OHdG, suggesting that the internal dose markers may be more relevant to oxidative DNA damage than external measures of vehicular exhaust.