Waist-to-Hip Ratio, BMI, and Sperm Parameters: A Correlation Study

Objective: Male obesity and infertility are growing health concerns, yet the relationship between obesity and sperm parameters remains controversial. This study aimed to investigate the association between waist-to-hip ratio (WHR), body mass index (BMI), and sperm parameters in adult males at a selected center in the Colombo district, Sri Lanka.
Methods: A descriptive study was conducted from September to November 2023 at Colombo South Teaching Hospital (CSTH) with 104 male volunteers. Waist, hip, weight, and height were measured following standard protocols and semen samples were collected after three days of abstinence. WHR categories were ≤0.9 (normal) and >0.9 (obese), while BMI was categorized as normal (18.5-24.9 kg/m²), overweight (25.0-29.9 kg/m²), and obese (>30 kg/m²). Sperm parameters assessed included volume, viability, count, motility, and morphology. Statistical analysis using SPSS 27.0, employed t-tests, correlation, and regression analysis, with significance at P < 0.05.  
Results: Males with a WHR>0.9 showed higher semen volume (1.82±0.74 ml), sperm concentration (85.42±55.20 million/ml), sperm count (163.28±142.47 million/ml), and normal sperm morphology (11.04±5.99 %) compared to those with a WHR≤0.9. No consistent linear trend was observed for BMI with sperm concentration (p=0.42), count (p=0.61) or viability (p=0.89). Sperm motility showed slight variations across BMI categories; however, it was statistically non-significant (p=0.95, p=0.617). WHR showed a potential positive association with sperm morphology (r²=0.06, p=0.05) and was identified as an independent risk factor for sperm morphology in multivariate analysis (95% CI: 48.3–1.08, p=0.041).
Conclusions: WHR and BMI showed no significant correlations with most sperm parameters, however, WHR positively influenced normal sperm morphology, warranting validation in larger studies.