Effect of postmenopause and hormone replacement therapy on serum adiponectin levels

Little is known about the effects of menopause and hormone replacement therapy (HRT) on adiponectin production. The objectives of the study were to compare levels of serum adiponectin in post- and premenopausal women, to test whether adiponectin levels are related to endogenous estradiol and sex hormone-binding globulin (SHBG) levels, to determine whether HRT influences serum adiponectin, and to investigate relationships of adiponectin levels with cardiovascular risk factors. One hundred four women matched for body mass index were enrolled in this study, and among them were 34 postmenopausal HRT nonusers, 34 postmenopausal HRT users, and 36 premenopausal healthy women with regular menstrual cycles. We evaluated waist circumference and waist-to-hip ratio (WHR) in each women. Serum was assayed for adiponectin, estradiol, SHBG, triglycerides (TGs), total cholesterol, high-density lipoprotein cholesterol, and fasting glucose levels. Post- and premenopausal women showed no significant differences in adiponectin and SHBG concentrations. There were no differences in serum adiponectin levels between postmenopusal HRT nonusers and users; however, SHBG concentrations were higher in HRT users. The simple linear regression analyses of all studied women indicated that serum adiponectin was negatively correlated with body mass index, waist circumference, WHR, and TG levels. Positive correlation was observed between adiponectin and high-density lipoprotein cholesterol as well as between adiponectin and SHBG levels. There were no relationships between adiponectin and estradiol levels in all studied women and among subgroups. Multiple regression analysis showed that WHR and TG were significant independent predictors of serum adiponectin. In conclusion, serum adiponectin levels are not influenced by menopausal status or serum estradiol levels. Exogenous estrogen treatment does not significantly affect serum adiponectin concentrations.