Low-dose hormone therapy and carbohydrate metabolism

Objective To evaluate the influence by two low doses of oral continuous-combined formulations of 17 β-estradiol (E2) and norethisterone acetate (NETA) on carbohydrate metabolism in healthy postmenopausal women. Design A double-blind, randomized, placebo-controlled trial. Setting Volunteers at a university hospital. Subject One hundred twenty healthy postmenopausal women. Intervention(s) One hundred twenty women were randomized to three treatment arms: (1) E2 1 mg/NETA 0.25 mg group (n = 40); (2) E2 1 mg/NETA 0.5 mg group (n = 40); (3) placebo group (n = 40). A total of 102 women completed 12 months of treatment. An oral glucose tolerance test (OGTT) was performed at baseline and at 3, 6, and 12 months. Main outcome measure(s) Fasting glucose, fasting insulin, total area under the curve (AUC) and insulin/glucose index during OGTT. Result(s) Fasting levels of glucose and insulin declined significantly in the E2/NETA 0.5 mg group. At OGTT, the total AUC for insulin declined in both active arms. The curve for glucose increased significantly in the E2/NETA 0.25 mg group. A lower insulin/glucose index was observed during OGTT in both active regimens when compared with placebo. In the active treatment groups, a significant reduction of fasting glucose and/or fasting insulin was encountered in women with higher basal fasting levels (fasting glucose >4.2 mmol/L or log-fasting insulin >0.87). Conclusion(s) Oral low-dose E2 1 mg/NETA 0.5 mg regimen did not impair carbohydrate metabolism, but seemed to improve insulin sensitivity in healthy postmenopausal women.