Poster - #UCLAFSPH-29 - Keywords: Air pollution; Oxidative Stress; Pregnancy

Fine particulate matter metal composition with oxidative potential and oxidative stress biomarkers among pregnant women in Los Angeles

Qi Meng, Jonathan Liu, Jiaqi Shen, Irish Del Rosario, Pascale S. J. Lakey, Manabu Shiraiwa, Scott Weichenthal, Yifang Zhu, Farzan Oroumiyeh, Sudipto Banerjee, Suzanne E. Paulson, Michael Jerrett, Beate Ritz
Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles, CA 90095, USA Department of Environmental Health Sciences, Fielding School of Public Health, University of California, Los Angeles, CA 90095, USA Department of Atmospheric & Oceanic Sciences, University of California, Los Angeles, CA 90095, USA Department of Chemistry, University of California, Irvine, CA 92697, USA Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec H3A 1A2, Canada Department of Biostatistics, Fielding School of Public Health, University of California, Los Angeles, CA 90095, USA

ABSTRACT:
Background/Aims: Oxidative stress generation has been suggested as one of the main mechanisms by which particulate matter exposure from traffic may contribute to adverse pregnancy outcomes. Few epidemiological studies to date have evaluated speciated fine particulate matter (PM2.5) exposures or employed biomarkers. Here, we investigate whether measures of ambient air PM2.5 oxidative potential or brake and tire wear derived metal exposures affect levels of oxidative stress biomarkers in the urine of pregnant women. Methods: We measured two oxidative stress biomarkers -malondialdehyde (MDA) representing lipid peroxidation and 8-hydroxy-2’-deoxyguanosine (8-OHdG) indicating DNA damage - in up to three urine samples collected during pregnancy in 156 women during 2016-2019 enrolled at antenatal clinics of University of California Los Angeles. We employed land use regression models with cokriging to estimate average PM2.5 mass and PM2.5 components related to brake (barium) and tire wear (zinc), oxidative potential (including 2-hour modeled ROS based on measured concentrations of PM2.5 iron and PM2.5 copper (OPmROS), hydroxyl radical formation (OPOH), and dithiothreitol loss (OPDTT)) as well as black carbon during the 4 weeks prior to the date of urine sample collection. Using linear mixed models, we estimated the percentage change (%) and 95% confidence interval (CI) for MDA and 8-OHdG with each exposure measure (continuous, scaled by the interquartile range (IQR)). Results: Per IQR increase of brake and tire wear markers (barium and zinc) and oxidative potential (OPmROS, OPOH and OPDTT) was associated with higher MDA but not 8-OHdG levels, and these changes were robust to adjustment for PM2.5 mass. 8-OHdG increases were associated with black carbon and PM2.5 mass only in the second sample collection (18-29 gestational week) of pregnancy samples. Conclusion: Our findings provide evidence for oxidative stress being a potential mechanism for adverse pregnancy outcomes attributed to traffic related air pollution exposures.