A new potential biomarker in early diagnosis of firefighter lung function impairment: dynamic thiol/disulphide homeostasis.

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.