RESUMEN
OBJECTIVES: The aim of this study was to investigate the associations between urinary arsenic, oxidative stress, assessed by thiol/disulphide homeostasis, and lung diseases in firefighters. METHODS: The study conducted among the municipality-based male firefighters (n = 100) who were admitted to occupational diseases clinic for periodic medical examination. The control group consisted of non-exposed male office workers (n = 50). Urinary arsenic levels, thiol/disulphide homeostasis parameters of participants were determined. Also, lung diseases were assessed by chest X-ray and pulmonary function tests. RESULTS: The mean age and work year did not differ in the study and control group. The median urinary arsenic concentration of firefighters was significantly higher than in the control group: 15.65 (2.5-246) µg/L and 3 (0.10-6) µg/L, respectively (p < 0.001). The parameters of pulmonary function tests (PFT) FVC (%), FEV1 (%), FEV1/FVC ratio and FEF 25-75 (%) were all significantly lower in firefighters compared to controls. A significant increase in mean serum disulphide concentration (17.10 ± 8.31 µmol/L vs. 7.48 ± 5.91) (Fig. 1) and disulphide/native thiol % ratio: 3.63 (0.53-11.43) vs. 1.51 (0.03-7.65) (p < 0.001) were found between exposed group and controls. The Spearman's correlation analysis revealed a positive correlation between urinary arsenic and disulphide (r = 0.422, p < 0.001), disulphide/native thiol % ratio (r = 0.409, p < 0.001). Nevertheless, urinary arsenic correlated negatively with all PFT parameters including FVC (%), FEV1 (%), FEV1/FVC and FEF 25-75 (%) (p < 0.001). CONCLUSION: We showed the arsenic-induced oxidative stress in firefighters with impairments of several lung functions determined by thiol/disulphide homeostasis using a novel method.