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Elevated urinary mutagenicity among those exposed to bituminous coal combustion emissions or diesel engine exhaust
Citation:
Wong, J., R. Vermeulen, Y. Dai, W. Hu, W. Martin, S. Warren, H. Liberatore, D. Ren, H. Duan, Y. Niu, J. Xu, W. Fu, K. Meliefste, J. Yang, M. Ye, X. Jia, T. Meng, B. Bassig, H. Hosgood, J. Choi, M. Rahman, D. Walker, Y. Zheng, J. Mumford, D. Silverman, N. Rothman, D. DeMarini, AND Q. Lan. Elevated urinary mutagenicity among those exposed to bituminous coal combustion emissions or diesel engine exhaust. Society for Epidemiologic Research, NA, Virtual, June 22 - 25, 2021.
Impact/Purpose:
In this study, we investigated associations between exposure to coal combustion emissions (CCE) or diesel engine exhaust (DEE) and urinary mutagenicity. Smoky coal users had significantly higher average urinary mutagenicity levels compared to smokeless coal users and significant exposure-response relationships with 5-methylchrysene and benzo[a]pyrene. DEE-exposed workers had significantly higher urinary mutagenicity levels compared to unexposed controls and a significant exposure-response relationship with elemental carbon. Exposure to CCE and DEE is associated with urinary mutagenicity, suggesting systemic exposure to mutagens. Measurement of additional exposure biomarkers and comprehensive identification of chemical constituents of air samples would improve understanding of the potential risk(s) of these exposures.
Description:
Urinary mutagenicity reflects systemic exposure to complex mixtures of DNA-damaging agents and has been linked to tumor development. Coal combustion emissions (CCE) and diesel engine exhaust (DEE) are prominent environmental risk factors for lung cancer, but their influence on urinary mutagenicity is unclear. We investigated associations between exposure to CCE or DEE and urinary mutagenicity. In two separate cross-sectional studies of non-smokers, organic extracts of urine were evaluated for mutagenicity levels using strain YG1041 in the Salmonella (Ames) mutagenicity assay. First, we compared levels among 10 bituminous (smoky) coal users from Laibin, Xuanwei, China, and 10 anthracite (smokeless) coal users. We estimated exposure-response relationships using concentrations of two lung carcinogens, 5-methylchrysene (5MC) and benzo[a]pyrene (B[a]P), from indoor air samples. Second, we compared levels among 20 highly exposed diesel factory workers and 15 unexposed controls, along with evaluating exposure-response relationships using elemental carbon (EC) as a DEE-surrogate. Age-adjusted linear regression was used to estimate associations. Laibin smoky coal users had significantly higher average urinary mutagenicity levels compared to smokeless coal users (28.4 ± 14.0 SD vs. 0.9 ± 2.8 SD rev/ml-eq, p = 2 x 10-5) and significant exposure-response relationships with 5MC (p = 7 x 10-4) and B[a]P (p = 0.05). DEE-exposed workers had significantly higher urinary mutagenicity levels compared to unexposed controls (13.0 ± 10.1 SD vs. 5.6 ± 4.4 SD rev/ml-eq, p = 0.02) and a significant exposure-response relationship with EC (p-trend = 2 x 10-4). Exposure to CCE and DEE is associated with urinary mutagenicity, suggesting systemic exposure to mutagens.