Sex hormones in obese premenopausal women and their relationships to body fat mass and distribution, B cell function and diet composition

Abstract

We examined sex hormone blood concentrations in a group of 33 obese non-hirsute premenopausal women with normal menses and in 14 age-matched normal-weight controls, and evaluated their relationship with anthropometric parameters, dietary habits and insulin levels. Obese women showed lower than control sex hormone-binding globulin (24.9 ± 14.6 vs 38.6 ± 12.5 nmol/I; p < 0.005) and 5α-dihydrotestosterone (13.7 ± 5.4 vs 18.2 ± 4.8 ng/dl; p < 0.005) values. Despite their consensual behavior, the correlation coefficient between 5α-dihydrotestosterone and sex hormone-binding globulin was not significant in the obese while in controls it was 0.68 (p < 0.01). This suggests that mechanisms operating to lower the plasma levels of these compounds may be regulated differently in obesity. Body Mass Index, per cent body fat and its distribution showed a highly significant negative correlation with sex-hormone binding-globulin and 5α-dihydrotestosterone values. Insulin levels did not appear to be correlated with sex hormone values. On the contrary, in the obese women we found a highly significant correlation between dietary lipids and sex-hormone-binding-globulin levels (r = −0.54; p < 0.005) and between dietary carbohydrates and estrone values (r = 0.47; p < 0.005); all these relationships were independent of body weight. These results confirm that in premenopausal women obesity may be characterized by detectable changes in sex steroid metabolism and suggest a possible causal role not only of the excessive quantity of metabolically active adipose tissue but also of specific dietary factors.