Oxidative stress and adverse cardiovascular effects among professional divers in Egypt.

Professional divers are exposed to unique multifactorial hazards in their working environment and adverse cardiovascular effects such as ischemia, arrhythmia, stroke, and death are associated with professional diving. Cardiovascular events are aggravated by diving-induced oxidative stress and account for one-fourth of diving fatalities. This study aimed to measure oxidative and cardiovascular stress in a group of professional divers in Alexandria, Egypt using a panel of biomarkers. A comparative cross-sectional study was conducted between June 2017 and May 2018 at the General Naval Hospital in Alexandria. A total of 50 professional divers and a comparison group of 50 marine seafarers sharing similar maritime environments were enrolled in the study. Participants were clinically evaluated by electrocardiography (ECG) and plasma measurement of trace metals (Fe+, Cu+, and Zn+), electrolytes (Na+, K+, Ca+), and oxidative stress biomarkers (OSBMs; MDA, TAS, GST, GSH, GR, GPx, SOD, and CAT). Significant ECG abnormalities including short corrected QT interval, sinus bradycardia, left ventricular hypertrophy, early repolarization, first-degree heart block, and intraventricular conduction defect were identified among divers. Biochemical analyses revealed high mean levels of FBG [89.0 ± 12.46 vs. 100.5 ± 29.03 mg/dl], LDH-C [41.46 ± 4.01 vs. 39.34 ± 4.34 mg/dl], electrolyte imbalance [higher Na+ (9.44 ± 0.52 vs. 9.19 ± 0.60 mmol/L), and lower Ca+ (141.72 ± 3.53 and 143.26 ± 3.99 mmol/L)], disturbed trace metals [Fe+ and Zn+ (101.1 ± 38.17 vs. 147.6 ± 38.08 and 85.52 ± 27.37 vs. 116.6 ± 21.95 µm/dl, respectively), higher Cu+ (271.3 ± 75.01 vs. 100.8 ± 30.20 µm/dl)], and higher OSBMs (high MDA and reduced CAT, GPx, GSH, GR, and GST enzyme levels) among professional divers compared to the marine seafarers (t-test p < 0.05). Oxidative stress and trace metal imbalance are associated with the pathophysiology of cardiovascular disease; this association, together with electrophysiological changes of ECG may serve as biomarkers for cardiovascular risk assessment in diver periodic medical examinations.

Assessment of oxidative stress among refueling workers in an Egyptian setting.

BACKGROUND: Unlike developing countries, in Egypt, gasoline is dispensed at dedicated stations by gasoline filling workers. This leads to high levels of exposure to the aromatic compounds in gasoline [principally benzene, toluene, ethyl benzene, and xylene (BTEX)] with the consequences of adverse health effects including oxidative stress. OBJECTIVE(S): To assess oxidative stress and trace metal levels among Egyptian gas filling workers. METHODS: A cross-sectional study was conducted among 50 gasoline filling station workers (exposed group) and a matched group of 50 clerical workers (non-exposed group). Trace metal levels (Cu, Zn, Fe, and Mn) and the activities of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx) were measured in sera of all enrolled participants using atomic absorption spectroscopy. BTEX levels were assessed in the environment of the studied gas filling stations using the MIRAN IR system. RESULTS: All the measured trace metal levels and antioxidant enzyme activities were significantly lower among the exposed workers than among the non-exposed workers. All trace metals decreased significantly in relation to SOD activity among the exposed workers, whereas only Zn and Cu decreased in relation to SOD and GPx activity among the non-exposed workers. The exposed workers did not comply with the use of the required personal protective equipment (PPE) to avoid the dangerous effects of BTEX exposure. Among BTEX components, benzene exceeded the allowable Egyptian TLV in the studied gasoline stations (110.4 mg/m3 versus 1.6 mg/m3, respectively). The hygienic effect (HE) of the BTEX pollutant mixture exceeded the allowed borderline HE in Egypt although it did not show a significant correlation with different oxidative stress biomarkers and trace metals. CONCLUSION: Exposure to BTEX at gasoline filling stations lowers the levels of antioxidant enzyme activities and trace metals due to the strong hygienic effect of BTEX. Individual protection using the proper PPE should therefore be enforced. Research assessing the need of providing refueling workers with supplements of necessary trace metals and antioxidants is warranted.