Occupational Vehicle-related Particulate Exposure and Inflammatory Markers in Trucking Industry Workers

Abstract

Background: Previous studies have suggested an association between particulate air pollution and cardiovascular disease, but the mechanism is still unclear. Objective: We examined the association between workplace exposure to vehicle-related particles and cardiovascular disease related systemic inflammatory markers, C-reactive protein (hs-CRP), soluble intercellular adhesion molecule-1 (sICAM-1), and interleukin-6 (IL-6) in 137 trucking terminal workers (non-drivers) in the U.S. trucking industry. Methods: We visited two large trucking terminals in 2009 and measured vehicle-related elemental carbon (EC), organic carbon (OC), and particulate matter with aerodynamic diameter <= 2.5 mu m (PM2.5), for 5 days consecutively at the main work areas. Each participant provided a blood sample and completed a health questionnaire during the sampling period. Individual workplace exposure level was calculated by 12-h time weighted moving averages based on work shift. The association between each blood marker and exposure to each pollutant during 0-12, 12-24, 24-36, and 36-48 h before the blood draw was examined by multivariable regression analyses. Results: In general, OC and EC had a positive association with sICAM-1, especially for exposure periods 12-24 (lag(12-24)) and 24-36 (lag(24-36)) h prior to blood draw [beta=54.9 (95%CI: 12.3-97.5) for lag(12-24) and beta=46.5 (95%CI: 21.2-71.8) for lag(12-24); change in sICAM-1 (in ng/mL) corresponding to an IQR increase in OC]. A similar pattern was found for EC and PM2.5. We did not find an association between measured pollutants up to 48 h before blood draw and hs-CRP or IL-6. Conclusion: In this group of healthy workers, short-term exposure to vehicle-related air pollutants may be associated with sICAM-1. Our findings may be dependent on the exposure period studied.