Oxidative stress and DNA damage in a long-term hexavalent chromium-exposed population in North China: a cross-sectional study

• Published in: BMJ open Vol. 8; no. 6; p. e021470
• Main Authors: Xu, Jing, Zhao, Meiduo, Pei, Lu, Zhang, Ruiming, Liu, Xiaolin, Wei, Lanping, Yang, Mingan, Xu, Qun
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group LTD 01.06.2018; BMJ Publishing Group
• Subjects: 8-Hydroxy-2'-Deoxyguanosine; Aged; Alcohol; Alcohol Drinking - adverse effects; Antioxidants; Biomarkers - blood; Biomarkers - urine; Case-Control Studies; China - epidemiology; Chromium; Chromium Compounds - blood; Chromium Compounds - toxicity; Chromium Compounds - urine; Cross-Sectional Studies; Deoxyguanosine - analogs & derivatives; Deoxyguanosine - urine; Deoxyribonucleic acid; DNA; DNA Damage; Environmental Exposure - adverse effects; Epidemiology; Ethanol; Female; Free radicals; Glutathione Peroxidase - blood; Health risk assessment; Heavy metals; Humans; Lipid peroxidation; Lipids; Lung cancer; Male; Malondialdehyde - blood; Metals; Middle Aged; Multivariate Analysis; Oxidation; Oxidative Stress; Population; Regression Analysis; Smoking - adverse effects; Software; Superoxide Dismutase - blood; Towns; Wood preservatives; China; oxidative damage; hexavalent chromium; oxidative stress; dna damage
• ISSN: 2044-6055; 2044-6055
• DOI: 10.1136/bmjopen-2017-021470

ObjectiveThe International Agency for Research on Cancer classifies hexavalent chromium (Cr(VI)) as a human carcinogen. As reported, cancer mortality was higher in Cr(VI)-contaminated areas. Scientists have recommended studying its health impact on people living in contaminated areas. This study aims to evaluate the health risk for people living in Cr(VI)-contaminated areas.DesignWe conducted a cross-sectional study in rural areas of north-eastern China. Malondialdehyde (MDA), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) were used as oxidative stress parameters, and 8-hydroxy-2 deoxyguanosine (8-OHdG) as a DNA damage biomarker. We collected information on demographics, lifestyles and length of residence from all participants using a questionnaire. Biological specimens and environmental media samples were collected on the same day as the survey was done. We used t-test, χ2 test, Wilcoxon rank-sum test and multivariate linear regression analysis.ParticipantsThe study included 319 participants exposed to Cr(VI) and 307 unexposed participants, with 447 women and 179 men. These participants met the following criteria: (1) living in the areas for more than 10 years; (2) age older than 18 years; and (3) without occupational chromium exposure.ResultsOur study revealed that serum concentration of MDA (p<0.001), serum activities of CAT (p<0.001) and GSH-Px (p<0.001), as well as urine concentration of 8-OHdG (p=0.008) in the exposed group were significantly higher than those in the unexposed group. However, serum SOD activity was significantly lower in the exposed group, compared with that in the unexposed group (p<0.001). Cr(VI) exposure and smoking have an interaction effect on GSH-Px activity (p<0.05). Cr(VI) exposure and alcohol drinking also have an interaction effect on GSH-Px activity (p<0.05). Longer residence in the exposed areas increased the oxidative levels (p<0.05).ConclusionsThe findings of this study showed elevated oxidative stress and DNA damage in people exposed to Cr(VI).