Effect of body weight on testosterone/estradiol ratio in oligozoospermic patients.

To evaluate the effect of body mass on the hormonal and semen profiles of subfertile men with oligozoospemia, sperm concentration and reproductive hormone levels were compared in two body mass index (BMI) groups: underweight or normal weight patients (BMI = 25 kg/m2) vs. overweight or obese patients (BMI > 25 kg/m2). The mean BMI was 27 +/- 4.6 kg/m2. The testosterone/estradiol ratio was significantly reduced in the high BMI group as compared to the low BMI group (17 +/- 4 vs. 12 +/- 3; p < 0.05). A similar difference was found in the sperm concentration (11.2 +/- 3.16 x 10(6)/ml vs. 8.1 +/- 2.6 x 10(6)/ml). A nonsignificant difference was found in the LH/FSH ratio (1.41 +/- 0.64 vs. 1.63 +/- 0.72). We concluded that obesity and the consequent estrogen excess decrease the sperm concentration by influencing the hypothalamo-pituitary system.