PLASMA FLUORESCENT OXIDATION PRODUCTS AND SHORT-TERM AMBIENT AND OCCUPATIONAL PARTICULATE EXPOSURES

Abstract

Background and Aims:Experimental evidence suggests that exposure to fine particulate air pollution results in oxidative induced tissue damage. To assess whether ambient and occupational particulate exposure in humans results in systemic oxidative stress, we used a novel fluorescent oxidation products (FLOx) assay measured in plasma samples. Methods:Blood samples were collected from a total of 236 nonsmoking, Caucasian, male trucking industry workers either before, during, or after their work shifts. FLOx was measured as relative fluorescent intensity (FI) units per milliliter (FI/ml) of plasma. County-level ambient PM2.5 exposures on the day of blood draw and the proceeding two days were determined based on US EPA monitors. Occupational exposures to PM2.5 were based on job-specific area-level sampling, weighted by time worked prior to blood draw. Generalized linear models were used to determine associations between FLOP levels and the ambient and occupational exposures, adjusted for each other and age, alcohol consumption, aspirin, and cholesterol medications. Results:Participants were 51.0 (SD=8.8) years old on average, had mean FLOx levels of 265.9 FI/ml (SD=96.0), and spent an average of 5 hours (range 0 to 17 hours) working prior to blood draw. Ambient PM2.5 levels on the day of blood draw varied from 3.6 to 18.8µg/m (mean=10.2µg/m) and occupational PM2.5 levels varied from 0 to 87.0µg/m(mean=16.4µg/m). Only 40 of the workers came in before work (occupational PM2.5=0µg/m3). In fully adjusted models, FLOx was positively associated with average ambient PM2.5 levels on the day of blood draw, increasing 3.1 Fl/ml (95%CI:0.6, 5.5) for each 1µg/m3 increase in PM2.5. No associations were observed between FLOx and occupational PM2.5 levels. Conclusions: Our results suggest a small, but positive association of recent ambient exposure to PM2.5 with this novel marker of systemic oxidative stress. However, we did not observe the same relationship with occupational PM2.5 exposures.