Low-dose hormone therapy and carbohydrate metabolism.

Objective: To evaluate the influence by two low doses of oral continuous-combined formulations of 17 beta-estradiol (E(2)) 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) E(2) 1 mg/NETA 0.25 mg group (n = 40); (2) E(2) 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 E(2)/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 E(2)/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 E(2) 1 mg/NETA 0.5 mg regimen did not impair carbohydrate metabolism, but seemed to improve insulin sensitivity in healthy postmenopausal women.