Low-Level Human Epididymis Protein 4 in Seminal Plasma Is an Independent Risk Factor for Poor Semen Liquefaction: A Case Control Study.

OBJECTIVE: The aim of this study was to investigate the relationship between human epididymis protein 4 (HE4) levels in seminal plasma and semen liquefaction in males. METHODS: A total of 314 healthy men from the andrology department were included. The correlations between HE4 levels and prostate-specific antigen (PSA) levels as well as conventional semen parameters (sperm density, the proportion of non-progressively motile spermatozoa, seminal liquefaction time) were analyzed, and logistic regression was further employed to examine the association between HE4 levels and the risk of poor semen liquefaction. RESULTS: The level of HE4 in seminal plasma was negatively correlated with semen liquefaction time (r = -0.207, p < 0.001) and positively correlated with seminal plasma PSA levels (r = 0.280, p < 0.001), suggesting a potential link to the process of semen liquefaction. Continuous HE4 levels were standardized by dividing by 100, and participants were then categorized into quartiles (Q1-Q4) based on the standardized HE4 values. After adjusting for confounding factors, the risk of poor semen liquefaction in the Q3, Q2, and Q1 groups of the lower HE4 level was 4.024 times (95% CI: 1.908-8.485; p < 0.001), 6.320 times (95% CI: 2.818-14.175; p < 0.001), and 5.190 times (95% CI: 2.217-12.15; p < 0.001) higher, respectively, compared to the highest HE4 quartile (Q4). CONCLUSION: This suggests that a low level of HE4 in seminal plasma is an independent risk factor for poor semen liquefaction.