Association Between Zinc Ion Concentrations in Seminal Plasma and Sperm Quality: A Chinese Cross-Sectional Study

This study investigates the impacts of zinc ion concentration in in seminal plasma and the total amount of Zn2+ per ejaculation on sperm quality evaluation parameters. In addition, we assessed the reliability of using zinc content in seminal plasma to evaluate sperm quality. We analyzed semen from 964 men and found that men over 40 years old had significantly lower concentrations of Zn2+ in ejaculated semen compared to other age groups (p < 0.05), with no significant difference in Zn2+ concentrations among other age groups (p > 0.05). The total amount of Zn2+ in one ejaculation did not show a statistical difference between the normal semen and the abnormal semen groups (p > 0.05). Statistical differences were observed in sperm kinetic parameters and DNA fragmentation index between the normal Zn2+ total amount group and the abnormal group (p < 0.05). However, there was no statistical difference in morphological parameters (p > 0.05). Spearman correlation analysis showed a negative correlation between Zn2+ concentrations in seminal plasma, age, and sperm fructose and a positive correlation between semen volume, abstinence time, sperm concentration, neutral alpha-glycosidase, and citric acid content (p < 0.05). The receiver operating characteristic curve analysis demonstrated that Zn2+ concentrations had poor accuracy and specificity in assessing sperm quality (p > 0.05). Although there is a partial correlation between Zn2+ concentrations in seminal plasma and certain semen quality parameters, relying solely on Zn2+ concentrations to evaluate sperm quality lacks accuracy and specificity.