The higher risk for sperm DNA damage in infertile men

Objectives: Supplementary assays are needed for determination of relationships between sperm biomarkers and fertility potential. Therefore, our research was designed to determine the extent of sperm DNA fragmentation (SDF) and establish a discriminating threshold of SDF for fertility potential. Material and methods: Semen characteristics were evaluated according to World Health Organization recommendations, and SDF was assessed by sperm chromatin dispersion test on ejaculated spermatozoa from infertile and healthy normozoospermic men. Results: A higher proportion of SDF was noted in infertile men (median 23.00%) than normozoospermic (median 14.00%). Significantly less subjects (17.03%) with low SDF level (≤ 15%) and more (35.17%) with high SDF level ( > 30%) were found for the infertile group vs the normooospermic (57.90% and 5.26%, respectively). Infertile group had significantly lower odds ratio (OR) for having a low SDF level (OR: 0.1493) and higher OR for having a high SDF level (OR: 9.7627). Receiver operating characteristic analysis [area under curve (AUC) = 0.785] revealed that 20% SDF is predictive value for discriminating between infertile and normozoospermic subjects. SDF was negatively correlated with the sperm number, morphology, progressive motility and vitality but positively with the teratozoospermia index. Conclusions: Our study demonstrates: (1) a significant difference in the extent of SDF and in the risk for having damaged sperm DNA between infertile and normozoospermic men, (2) > 20% SDF has negative predictive value for fertility potential, (3) coexistence of abnormal standard sperm parameters with sperm chromatin damages. Therefore, SDF should be considered as a highly valuable indicator of male fertility potential.