SHBG levels correlate with insulin resistance in postmenopausal women

Abstract

Background: Overweight or central obesity is generally associated with increases in fasting insulin levels, insulin resistance, and glucose intolerance and has been identified as a target for new therapeutic strategies, including early change in lifestyle. Early biochemical markers for identifying at-risk patients will be useful for prevention studies. The aim of this study is to investigate whether or not SHBG level is a useful index of hyperinsulinemia and/or insulin resistance in pre- and postmenopausal obese women. At the same time, the relationship between SHBG concentrations and features of the metabolic syndrome were evaluated. Methods: 229 women were eligible for this study. MetS was defined by using a modification of the ATP III guidelines. All patients were euthyroid, obese and overweight, 25 to 69 years of age. Subjects were divided into groups of premenopausal women (n = 125) and postmenopausal women (n = 104). Various fatness and fat distribution parameters, SHBG, sex hormones, FSH, LH, thyroid hormones, serum levels of fasting and postprandial glucose, lipid profile, uric acid and serum insulin, and blood pressure were measured. Results: No significant difference was found in mean SHBG levels between pre- and postmenopausal obese women in this study (p = 0.866). In premenopausal obese women, SHBG correlated negatively with BMI, waist circumference, fasting glucose, uric acid levels and FAI. In postmenopausal obese women, SHBG correlated negatively with fasting glucose, postprandial plasma glucose, fasting insulin, HOMA-IR and FAI and positively with HDL. SHBG had a significant inverse association with MetS parameters only in postmenopausal women, also after adjusting for BMI, age and estradiol. Conclusions: Obesity may influence the levels of endogenous sex steroid, especially after menopause. SHBG concentrations are correlated with features of the metabolic syndrome, particularly in postmenopausal obese women. These results suggest that SHBG may be an index of insulin resistance in postmenopausal obese women. © 2008 European Federation of Internal Medicine.