Study on the Correlation between Sperm DNA Fragmentation Index and Age, BMI, and Varicocele in Male Fertility

doi:10.3969/j.issn.1004-5775.2025.02.019

Abstract：Objective: To investigate the correlation between sperm DNA fragmentation index and age, body mass index (BMI), and varicocele in male fertility. Methods: A total of 120 infertile men who visited the Department of Reproductive Medicine at Nanyang City First People's Hospital from July to December 2023 were selected as the study subjects, including 108 cases without varicocele and 12 cases with varicocele. Ultrasound was used to detect varicocele; the sperm chromatin dispersion (SCD) method was applied to detect the sperm DNA fragmentation index. The relationship between age and sperm DNA fragmentation index in infertile men was analyzed; the relationship between BMI and sperm DNA fragmentation index was analyzed; the relationship between varicocele and sperm DNA fragmentation index was analyzed. Results: The proportion of patients with a sperm DNA fragmentation index ≤15% decreased with increasing age, while the proportion of patients with a sperm DNA fragmentation index ≥30% increased with increasing age, with statistically significant differences (χ2=10.871, 13.030, P<0.05). There was a positive correlation between age and sperm DNA fragmentation index in infertile men (r=0.615, P<0.05). The proportion of patients with a sperm DNA fragmentation index ≤15% decreased with increasing BMI, while the proportion of patients with a sperm DNA fragmentation index ≥30% increased with increasing BMI, with statistically significant differences (χ2=6.345, 2.287, P<0.05). There was a positive correlation between BMI and sperm DNA fragmentation index in infertile men (r=0.576, P<0.05). The sperm DNA fragmentation index of non-varicocele patients was (19.78±3.07)%, which was significantly lower than that of varicocele patients (25.89±4.11)% (t=6.312, P<0.05). The sperm DNA fragmentation index of patients with grade I varicocele was (21.88±2.09)%, which was significantly lower than that of grade II (28.05±4.23)% and grade III (29.45±5.10)% varicocele patients (F=5.007, P<0.05). However, there was no statistically significant difference between grade II and III varicocele patients (t=0.399, P>0.05). Conclusion: There is a positive correlation between age, BMI, and sperm DNA fragmentation index in infertile men. Moreover, there is an inseparable relationship between varicocele and sperm DNA fragmentation index. Clinical detection of the sperm DNA fragmentation index can be used to evaluate male fertility.