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.