Low- and standard-estrogen dosage in oral therapy: dose-dependent effects on insulin and lipid metabolism in healthy postmenopausal women

Abstract

Objective To evaluate the influences of different doses of daily oral unopposed 17β-estradiol compared with placebo, both on glucose tolerance and lipid metabolism in healthy postmenopausal women.

Patients and methods Forty-eight normoinsulinemic postmenopausal women were enrolled in the study. Patients were assigned to receive randomly 1 mg (group A) or 2 mg (group B) of oral micronized estradiol therapy daily or to the placebo (group C), for 12 weeks.

Results The low-dose estradiol treatment determined an improvement of the peripheral insulin sensitivity, made evident by a significant increase both in the metabolic index and oral glucose insulin sensitivity index (p < 0.01 and p < 0.05, respectively) as well as a decrease in the homeostasis model assessment-estimated insulin resistance (p < 0.01). Conversely, in the standard-dose group, the metabolic index significantly decreased (p < 0.05), showing a slight deterioration in insulin sensitivity. For lipid metabolism, the 1 mg dose showed a neutral effect, while 2 mg had a beneficial effect on low density lipoprotein cholesterol, but caused an increase in triglycerides (p < 0.01 and p < 0.05, respectively).

Conclusions The oral low dose of unopposed estradiol therapy had a favorable effect on glycoinsulinemic metabolism in healthy postmenopausal women; however, the standard dose caused a slight but significant deterioration in insulin sensitivity.

Key words:

• Estrogen
• Carbohydrate Metabolism
• Postmenopausal Women
• Lipid Metabolism
• Insulin Sensitivity