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

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/l; p less than 0.005) and 5 alpha-dihydrotestosterone (13.7 +/- 5.4 vs 18.2 +/- 4.8 ng/dl; p less than 0.005) values. Despite their consensual behavior, the correlation coefficient between 5 alpha-dihydrotestosterone and sex hormone-binding globulin was not significant in the obese while in controls it was 0.68 (p less than 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 5 alpha-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 less than 0.005) and between dietary carbohydrates and estrone values (r = 0.47; p less than 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.