Sex hormone-binding globulin and glucose tolerance in postmenopausal women - The Rancho Bernardo study

OBJECTIVE - Sex hormone-binding globulin (SHBG) has been shown to be associated with several diabetes risk factors, including total body fat, central obesity, and hyperinsulinemic insulin resistance. We examined the cross-sectional association between SHBG and impaired glucose tolerance (IGT) and NIDDM. RESEARCH DESIGN AND METHODS - We conducted a cross-sectional study including 657 postmenopausal women, aged greater than or equal to 50 years, who were not using hormone replacement therapy. Blood for SHBG and fasting plasma glucose was obtained concurrently in the morning; all women had a 75-g oral glucose tolerance test and measurement of BMI and waist-to-hip ratio (WHR). RESULTS - SHBG was significantly associated with age, BMI, and WHR but not with smoking, physical activity, or alcohol intake. In these women, SHBG was significantly and independently inversely associated with IGT and with NIDDM. CONCLUSIONS - These data strongly support an association between SHBG, or androgenicity, and diabetes in postmenopausal women. Because of the cross-sectional nature of this study, however, the directionality of the association is uncertain.