Short-term effects of low-dose estradiol on endothelial function and blood viscosity in nondiabetic postmenopausal overweight women: a double-blind, placebo-controlled study.

OBJECTIVE: The beneficial effects of estrogen on endothelial function depend on its integrity. This study evaluates the short-term effects of low-dose transdermal estradiol on endothelial function, insulin sensitivity, and blood viscosity in nondiabetic overweight/obese women. METHODS: Forty-four nondiabetic overweight/obese women with a history of recent menopause were randomly allocated, in a double-blind fashion, to receive transdermal estradiol (1 mg/d, n = 22) or placebo (n = 22). The following parameters were assessed: endothelial reactivity (venous occlusion plethysmography and nailfold videocapillaroscopy), plasma levels of soluble adhesion molecules, insulin sensitivity (homeostasis model assessment of insulin resistance and areas under the curve of insulin and glucose during an oral glucose tolerance test), and blood and plasma viscosity. Data were expressed as means ±â€ŠSD or medians [first to third quartiles]. RESULTS: Participants were aged 51.8 ±â€Š2.3 years with a body mass index of 31.5 ±â€Š2.5 kg/m and time since menopause was 3 [2-5] years. At baseline, no differences between the groups were observed; however, after 3 months of treatment, the following changes were observed in the estradiol group compared with the placebo group: a decrease in the forearm vascular resistance at baseline (36.37 [24.9-51.27] vs 51.3 [40.88-70.03] mm Hg/mL per min 100 mL tissue, P < 0.01) and during the postocclusive reactive hyperemia response (15.93 [11.32-22.29] vs 22.13 [16.46-29.7] mm Hg/mL per min 100 mL tissue, P < 0.01), and an increase in red blood cell velocity at rest (0.316 [0.309-0.326] vs 0.303 [0.293-0.308] mm/s, P < 0.001) and during postocclusive reactive hyperemia response (0.374 [0.353-0.376] vs 0.341 [0.333-0.355] mm/s, P < 0.001). Furthermore, blood viscosity was lower in the estradiol group than in the placebo group (3.57 ±â€Š0.12 vs 3.76 ±â€Š0.22 mPa.s; P < 0.01). CONCLUSIONS: Short-term use of low-dose transdermal estradiol in nondiabetic overweight/obese women with a history of recent menopause improved endothelial function and decreased blood viscosity compared with placebo.