Serum Oxidant and Antioxidant Levels in Diesel Exposed Toll Collectors

Abstract

It has been suggested that exposure to diesel exhaust may lead to adverse effects due to the generation of oxidants. To evaluate the end products of oxidative stress in DE exposure, toll collectors who are considered a high risk group in regard to occupational toxins were compared to controls who had office-based occupations in the same company in this cross sectional study. A total of 38 toll collectors constituted the study group. All subjects were male. The toll collectors and 29 controls were similar regarding age, smoking status and duration of work. All subjects underwent a clinical examination and an interviewer-administrated questionnaire regarding respiratory symptoms, past medical and occupational history, and pulmonary function tests were performed in all subjects. Serum malondialdehyde (MDA), nitrite+nitrate and vitamin E levels were measured. Toll collectors showed higher serum MDA (5.76 ± 2.15 μmol/L vs. 3.07 ± 0.76 μmol/L, p=0.0001) and nitrite+nitrate levels (96.50 ± 45.54 μmol/L vs. 19.32 ± 11.77 μmol/L, p=0.0001) than controls. Vitamin E levels were similar in toll collectors and controls (10.57 ± 3.44 mg/L and 9.72 ± 2.44 mg/L, respectively, p=0.267). There was no difference between groups in terms of the findings of clinical examinations and respiratory symptoms. In pulmonary function parameters, only peak expiratory flow (PEF) in toll collectors was significantly lower than that of controls (88.9% predicted and 104.2% predicted, respectively, p=0.012). In conclusion, we suggest that serum MDA and nitrite+nitrate levels may be used as biological markers of oxidative stress related to DE exposure, but prospective controlled clinical studies are necessary to clarify the possible association between concentrations of MDA and nitrite+nitrate and pulmonary diseases related to DE exposure.