Objectives Chronic occupational exposure to chromium can result in a broad range of adverse effects including multiple organ damage, genotoxicity and carcinogenesis. However, the metabolic consequences of chromium exposure have not been fully investigated. This study was designed to examine vitamin B12, folate and homocysteine metabolic changes in workers chronically exposed to chromate. The potential association between metabolic alteration and renal impairment induced by chromate exposure was also assessed.
Methods The level of chromium exposure was evaluated by measuring chromium concentrations in red blood cells (RBC-Cr) and urine (U-Cr). Renal impairment was assessed with serum cystatin C (Cys-C) and urinary β2-microglobulin (β2M). Serum vitamin B12, folate and plasma total homocysteine (tHcy) were measured and correlations analysed.
Results Significant increases in RBC-Cr, U-Cr, serum Cys-C, plasma tHcy and urinary β2M concentrations were observed in workers chronically exposed to chromate compared to controls. In the exposed workers, serum vitamin B12 and folate levels were decreased and significantly inversely correlated with RBC-Cr concentrations, and increased plasma tHcy concentrations were mirrored by decreased serum vitamin B12 and folate levels. Elevated plasma tHcy concentrations were positively related to serum Cys-C concentrations.
Conclusions Hyperhomocysteinemia in chronically exposed workers was primarily induced by vitamin B12 and folate deficiency. This metabolic change might be associated with renal dysfunction in chromate processing workers after long term exposure.
- vitamin B12
- renal impairment
- hygiene/occupational hygiene
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Funding This research was supported by the National Natural Science Foundation of China (Major Project No. 30571550 and 81072281) and grants from the Ministry of Science and Technology of China (Project No. 2006BAI06B02 and Project 200902006).
Competing interests None.
Ethics approval This study was conducted with the approval of the Health Science Center, Peking University and the Center for Disease Control and Prevention of Jinan City, Jinan, Shandong Province, China.
Provenance and peer review Not commissioned; externally peer reviewed.
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