Body mass index and central adiposity are associated with sperm quality in men of subfertile couples

BACKGROUND The incidence of overweight and obesity in men of reproductive ages is rising, which may affect fertility. Therefore, this study aims to assess the associations between BMI, central adiposity and sperm parameters in men of subfertile couples. METHODS Ejaculate volume (ml), sperm concentration (millions per ml), percentage of progressive motile and immotile spermatozoa and total motile sperm count (millions) were measured in 450 men of subfertile couples visiting a tertiary outpatient clinic for reproductive treatment and preconception counseling. RESULTS Overweight was negatively associated with the percentage of progressive motility type A [β −0.32 (SE 0.2), P = 0.036] and positively associated with the percentage of immotility type C [β 0.21 (SE 0.07), P = 0.002]. Obesity was negatively associated with ejaculate volume [β −0.23 (SE 0.1), P = 0.02], sperm concentration [β −0.77 (SE 0.3), P = 0.006] and total motile sperm count [β −0.91 (SE 0.3), P = 0.007]. Waist circumference ≥102 cm, a measure for central adiposity, was inversely associated with sperm concentration [β −0.69 (SE 0.2), P = 0.001] and total motile sperm count [β −0.62 (SE 0.3), P = 0.02]. All associations remained significant after adjustment for age, ethnicity, active and passive smoking, alcohol and medication use and folate status. CONCLUSIONS This study shows that in particular, sperm concentration and total motile sperm count in men of subfertile couples are detrimentally affected by a high BMI and central adiposity. The effect of weight loss on sperm quality and fertility needs further investigation.