TY - EJOU AU - Du, Guowei AU - Chen, Jianhuai AU - Wang, Heng AU - Chen, Shanshan AU - Wang, Yanting AU - Wang, Jing AU - Yang, Guangzhao AU - Liu, Siwen AU - Chen, Xuanyi TI - Interaction effects of age and abstinence duration on semen quality T2 - Canadian Journal of Urology PY - VL - IS - SN - 1488-5581 AB - Objective: Given that the interactive effects of age and abstinence duration on semen quality remain unclear and current guidelines lack age-specific recommendations, this study aimed to evaluate the independent and interactive effects of these factors on semen parameters and to identify the optimal abstinence period for semen analysis across different age groups. Methods: A retrospective analysis was conducted on 1480 men who underwent semen analysis according to the WHO 5th edition guidelines. Participants were stratified by age (20–34 vs. 35–58 years) and abstinence duration (1–3, 4–6, and 7–11 days). A comprehensive set of semen parameters was analyzed, and statistically significant indicators were reported, including semen volume, sperm concentration, total sperm number, motility-related parameters, morphological indices, and functional indices. Statistical analyses included Mann–Whitney U, Kruskal–Wallis, Spearman correlation, Scheirer–Ray–Hare two-way nonparametric ANOVA, and simple effect analysis. Results: Only 23.04% had normal semen quality; asthenozoospermia (52.77%) and teratozoospermia (56.35%) were most common. Older age was associated with lower semen volume, total sperm count, and progressive motility, and higher immotile sperm percentage, TZI, and SDI (all p < 0.05). Longer abstinence increased sperm count and concentration but decreased progressive motility (p = 0.001) and increased SDI (p = 0.017). No significant Age × Abstinence interactions were found for any parameter (all p > 0.05); both factors exerted independent main effects. Age-stratified descriptive data showed that 4–6 days of abstinence optimized sperm quantity while preserving motility in both age groups. Conclusions: Age and abstinence duration independently influence semen quality without significant interaction. We recommend a uniform abstinence period of 4–6 days for semen analysis in Chinese men, balancing sperm quantity and quality across age groups without need for age-specific adjustments. KW - Semen analysis; age; abstinence duration; sperm motility; sperm morphology; teratozoospermia DO - 10.32604/cju.2026.079848