Obesity has a detrimental impact on temporal decline of sperm quality in normospermic patients: insights from a cross-sectional study of 2,430 patients over 14 years

Obesity is a known factor influencing sperm quality through hormonal imbalances and oxidative stress, contributing to male infertility.This study examines the association between obesity and temporal declines in sperm quality in normospermic men over 14 years. We conducted a retrospective analysis of 2,430 normospermic men who underwent fertility evaluation between 2010 and 2024. BMI categories were defined per WHO criteria, and semen analysis was performed following WHO guidelines. The study found that higher BMI correlated with declines in sperm quality. In normal-weight men, significant decreases were observed in total sperm count (r= -0.0020, p = 0.004), motility AB (r= -0.0396, p < 0.001), volume (r= -0.2007, p = 0.001), and morphology (r= -0.0210, p = 0.005). Overweight men showed reductions in sperm motility (A + B) (r= -0.0246, p = 0.009) and volume (r= -0.1616, p = 0.015), while obese men exhibited notable declines in TSC (r= -0.0029, p = 0.010) and volume (r= -0.2238, p = 0.009). Overall, obesity was associated with progressive declines in key sperm parameters over time. Obesity negatively impacts sperm quality in normospermic men, with significant declines in TSC, motility, and morphology. These findings underscore the importance of maintaining a healthy BMI to support male reproductive health and suggest the need for interventions targeting obesity-related fertility issues.