Elevated seminal plasma leptin may correlate with varicocele presence and BMI

Male infertility affects 20-30 % of infertile couples worldwide, and varicocele being a common cause. The relationship between leptin, a hormone involved in energy homeostasis and reproduction, and male fertility parameters remains incompletely understood, particularly in the context of varicocele and obesity. Thus, the current study sought to assess the associations between seminal plasma leptin and other clinical and demographic data of infertile patients.

In this cross-sectional study, 90 men (29 with varicocele, 61 without) were evaluated from November 2023 to March 2024. Seminal plasma leptin levels were measured using ELISA. Study subjects were classified into three weight classifications using body mass index (BMI) measurements: normal weight, overweight, and obese. Semen analysis, reproductive hormones assessment, and correlation analyses were performed to examine relationships between leptin levels and various clinical parameters.

Patients with varicocele demonstrated significantly higher seminal plasma leptin levels compared to those without (9.27 vs. 7.65 ng/mL, p<0.05), this association persisted following statistical adjustment for demographic and clinical variables. In addition, BMI was the strongest independent predictor of seminal plasma leptin levels (β=0.26, p<0.01). Interestingly, overweight individuals showed higher leptin levels than both normal weight and obese participants. A significant inverse relationship found between leptin concentrations and luteinizing hormone levels (ρ=-0.375, p<0.05), while a positive association was found with progressive motility of sperm (ρ=0.225, p<0.05).

Higher levels of leptin were found in seminal specimens of varicocele-diagnosed subjects and strongly correlate with BMI in this Middle Eastern population. These results together propose that leptin's level in semen could be useful as a biological indicator for varicocele-associated male fertility issues.