Low doses of 17 beta-estradiol and norethisterone acetate as continuous combined replacement therapy in postmenopausal women: Lipid metabolic effects

Our objective was to investigate the effects on serum and lipoprotein lipids of low doses of 17 beta-estradiol (E(2)) and norethisterone acetate (NETA) administered as continuous combined hormone replacement therapy (HRT) in postmenopausal women. A one-center prospective randomized double-blind comparison of three hormone replacement combinations was carried out during 12 months. Subjects were 60 healthy postmenopausal women with climacteric symptoms, Treatment was continuous combined regimens as one tablet every day given to three treatment groups denoted group A (1 mg E(2) + 0.25 mg NETA), group B (1 mg E(2) + 0.5 mg NETA), and group C (2 mg E(2) + 1 mg NETA). A significant decrease in total cholesterol (0.4-0.61 mmol/L) and low-density lipoprotein (LDL)-cholesterol (0.12-0.33 mmol/L) was found in all groups. High-density lipoprotein (HDL)-cholesterol decreased (0.11-0.15 mmol/L) after 12 months but the HDL/LDL ratio remained unchanged. Serum triglyceride levels were reduced in all groups (0.07-0.31 mmol/L) but the reduction did not reach statistical significance. The levels of serum lipoprotein(a) showed a slight reduction at the end of the study (10-14 mg/L). Small changes occurred in apolipoprotein-A1 levels. Apolipoprotein-B increased in group B (p < 0.05) and was unchanged in groups A and C. Low doses of E(2) and NETA as continuous combined HRT induced small metabolic effects. No significant differences were observed between the treatment groups, The significance of the changes in lipid metabolism in elderly women on long-term therapy cannot be fully evaluated from our study but has to be confirmed further in larger epidemiological studies.