RESUMEN
<p><b>OBJECTIVE</b>To investigate the semen quality and its influencing factors in preconception males in Nanjing area so as to provide some evidence for working out effective intervention measures.</p><p><b>METHODS</b>Totally 687 men receiving preconceptional physical examination were enrolled in this study. A questionnaire survey was conducted among the subjects along with an analysis of their semen quality.</p><p><b>RESULTS</b>The median of sperm concentration was 63.3 x 10(6)/ml (95% CI [19.88-119] x 10(6)/ml). The median of grade a sperm was 33.03% (95% CI [19.38-55.05]%), that of grade a + b sperm was 52.08% (95% CI [39.53-69.37]%), and that of teratosperm was 91.75% (95% CI [69-100]%). The median concentration of seminal plasma PMN-elastase was 195.55 ng/ml (95% CI [76.16-3330.38] ng/ml) and that of seminal plasma zinc was 7.62 μmol/L (95% CI [1.5-23, 45] μmol/L). The positive rates of Ureaplasma urealyticum (UU), Chlamydia trachomatis (CT), and Gardnerella vaginalis (GV) were 42.4%, 0.3%, and 2.4%, respectively. The median of sperm DNA fragmentation index (DFI) of those whose wives had a history of adverse pregnancy was 20.25% (95% CI [2.15-68.25]%). Multivariate logistic regression analysis suggested that mental stress (OR 1.567, 95% CI [1.081-2.27]) and sedentariness (OR 1.772, 95% CI [1.211-2.592]) were independent risk factors for asthenospermia.</p><p><b>CONCLUSION</b>The sperm quality of preconception males in Nanjing area is not encouraging, and it can be improved by changing undesirable lifestyle and reducing mental stress.</p>