testicular microvascular function in obese and non-obese, fertile and infertile men: a four-group comparative study

Background :obesity and infertility independently affect testicular function through hormonal disruption, oxidative stress, and endothelial dysfunction. testicular microvascular perfusion, assessable via doppler ultrasonography using resistive index (ri) and pulsatility index (pi), is critical for spermatogenesis and hormonal health. the combined effect of obesity and fertility status on testicular vascular and morphological parameters has not been systematically studied.objectives :this study aimed to evaluate the independent effects and statistical interaction between obesity and infertility on testicular microvascular function and volume. patients and methods :a total of 172 men aged 25 - 45 years were recruited and stratified into four groups: non-obese fertile (n = 64), non-obese infertile (n = 22), obese fertile (n = 45), and obese infertile (n = 41). testicular volume and vascular parameters (ri, pi) were measured using color doppler ultrasonography. non-parametric kruskal-wallis tests with post-hoc comparisons, robust linear regression for interaction effects, and spearman correlations were used for statistical analysis. results :the obese-infertile group had the highest median ri (0.77) and pi (1.61) and the lowest median testicular volume (9.8 ml). pi and testicular volume differed significantly across groups (p < 0.001), while ri showed borderline significance (p = 0.054). linear regression revealed a significant statistical interaction between obesity and infertility on pi (β = 0.318, p < 0.001), indicating that the association with higher pi was stronger in obese infertile men than would be expected from either factor alone. obese men with preserved fertility maintained relatively normal testicular volume and vascular indices. spearman correlation demonstrated a positive association between bmi and pi and a negative association between bmi and testicular volume (both p < 0.001). conclusion :the combination of obesity and infertility was associated with the highest pi values and the lowest testicular volume among the groups studied. pulsatility index and testicular volume are the most sensitive indicators of this dysfunction, while ri is less informative. obese men who remain fertile maintain relatively preserved testicular volume and vascular indices.