Associations among sex hormone binding globulin concentrations and characteristics of the metabolic syndrome in obese women.

The aim of this study was to determine sex hormone binding globulin (SHBG) concentrations in premenopausal obese women who were otherwise healthy, and to evaluate the relationships between SHBG concentrations and features of the metabolic syndrome; 307 premenopausal women (mean age 30.9+/-10.2 years) were studied. Subjects were divided into two groups according to the BMI: Group I, women with BMI <30 kg/m2 (n=69) and Group II, women with BMI > or = 30 kg/m2 (n=238). Insulin resistance was determined according to the Homeostasis Model Assessment (HOMA) formula. Median SHBG concentration of Group I was 75.9 nmol/l. Group II was divided into two subgroups according to the median SHBG concentration of Group I; women with high SHBG (SHBG concentration > or = median level of the control group, i.e. > or = 76 nmol/l) and women with low SHBG (i.e. <76 nmol/l). The low SHBG group was significantly younger, with higher waist-to-hip ratio (WHR). Triglycerides, uric acid, insulin and HOMA values were significantly higher and HDL-cholesterol was significantly lower in the low SHBG group. Multiple regression analysis revealed that age and uric acid concentrations were significant independent predictors of SHBG concentrations in the whole group (regression summary, adjusted r2=0.1414, F=10.5627, p<0.001). It is concluded that low SHBG concentrations may indicate a severe degree of insulin resistance in premenopausal obese women.