Seminal Biomarkers and Oxidative Stress Parameters in Infertile Cigarette Smokers: A Study from Port Harcourt, Nigeria

Abstract

Background: Cigarette smoking is a common lifestyle exposure among infertile men; however, its effects on seminal antioxidant status in Nigerian populations are not well documented. Aim: To compare seminal biomarkers (zinc and fructose), inflammatory cytokines [interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α)], antioxidant biomarkers [superoxide dismutase (SOD) and reduced glutathione (GSH)], and the oxidative DNA-damage marker 8-hydroxy-2′-deoxyguanosine (8-OHdG) between cigarette-smoking and non-smoking infertile men attending the Rivers State University Teaching Hospital (RSUTH), Port Harcourt. Methods: This cross-sectional analysis included 84 men with abnormal semen parameters recruited from the fertility clinic of RSUTH. Participants were classified by current cigarette-smoking status as smokers (n = 27) or non-smokers (n = 57). Seminal plasma zinc, fructose, IL-6, TNF-α, SOD, GSH, and 8-OHdG were quantified by competitive enzyme-linked immunosorbent assay (ELISA). Data were analysed using an independent-samples t-test in the Statistical Package for the Social Sciences (SPSS), version 27, with statistical significance set at p ≤ 0.05. Results: Twenty-seven of the 84 infertile men (32.1%) reported current cigarette smoking. Mean seminal zinc concentration was significantly lower in smokers than in non-smokers (3.52 ± 0.97 vs 4.15 ± 0.67 µmol/L; p = 0.049), representing an approximate 15.2% reduction. SOD activity (12.12 ± 2.45 vs 15.72 ± 2.90 U/mL; p = 0.047) and GSH concentration (1.14 ± 0.30 vs 1.44 ± 0.29 µmol/L; p = 0.023) were also significantly lower in smokers. Fructose, IL-6, TNF-α, and 8-OHdG did not differ significantly by smoking status (p > 0.05). Conclusion: Among the infertile men studied, cigarette smoking was associated with lower seminal zinc, SOD, and GSH, whereas fructose, IL-6, TNF-α, and 8-OHdG did not differ significantly between smokers and non-smokers. These findings indicate an association between cigarette smoking and reduced seminal antioxidant status in this study population.