title: Urinary trans, trans-muconic acid and S-phenylmercapturic acid are indicative of exposure to urban benzene pollution during childhood.
abstract: The aims of the study were to evaluate the feasibility of urinary trans, trans-muconic acid (u-t,t-MA) and urinary S-phenylmercapturic acid (u-SPMA) as markers of exposure to urban benzene pollution for biomonitoring studies performed on children and to investigate the impact that creatinine correction may have on the classification of children exposure status. U-t,t-MA, u-SPMA, u-cotinine, and u-creatinine levels were measured in urine samples of 396 Italian children (5-11 years) living in three areas with different degrees of urbanisation (very, fairly and non-urban). The median u-SPMA levels significantly increased with increased urbanisation: non-urban (0.19 μg/L; 0.22 μg/g creatinine)<fairly urban (0.28 μg/L; 0.28 μg/g creatinine)<very urban group (0.92 μg/L; 0.90 μg/g creatinine). Differences in the levels of u-t,t-MA excretion related to the degree of urbanisation were revealed only by multivariate analyses. Neither u-SPMA nor u-t,t-MA levels were influenced by environmental tobacco smoke (ETS) exposure. Athletic activity during the sampling day was negatively associated with u-SPMA in the model built with u-SPMA adjusted for creatinine, but not in the model where unadjusted u-SPMA was used. This finding demonstrates that u-creatinine correction may alter the results when an independent variable is unrelated to the chemical concentration itself but is related to the u-creatinine levels. These results suggest that both u-SPMA and u-t,t-MA are indicative for assessing environmental benzene exposure in children (exposed and unexposed to ETS) when urine sample is collected at the end of the day. However, u-SPMA is more reliable because u-t,t-MA, also a metabolite of sorbic acid, is less specific for exposure to low levels of benzene. To avoid the possible confounding effect of creatinine correction, it is better to use u-creatinine as additional independent variable in multiple linear regression analyses for evaluating the independent role of the covariates on the variability of u-t,t-MA and u-SPMA levels.
authors: Department of Public Health and Infectious Diseases, P.le Aldo Moro 5, 00185, Sapienza University, Rome, Italy. carmela.protano@uniroma1.it
authors: Carmela
authors: C
authors: Protano
authors: Roberta
authors: R
authors: Andreoli
authors: Paola
authors: P
authors: Manini
authors: Matteo
authors: M
authors: Vitali
mesh_terms: D000111:Acetylcysteine / Q000031:analogs & derivatives* / Q000652:urine; D001554:Benzene / Q000633:toxicity*; D015415:Biomarkers / Q000652:urine; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000378:metabolism / Q000652:urine; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D006801:Humans; D008297:Male; D013011:Sorbic Acid / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D013177:Sports / Q000502:physiology; D014028:Tobacco Smoke Pollution; D014507:Urbanization
chemical_list: D015415:Biomarkers; D004785:Environmental Pollutants; D014028:Tobacco Smoke Pollution; C005939:muconic acid; C053003:S-phenyl-N-acetylcysteine; D003404:Creatinine; D001554:Benzene; D000111:Acetylcysteine; D013011:Sorbic Acid