Changes in lipid and lipoprotein profile in postmenopausal women receiving low-dose combinations of 17 beta-estradiol and norethisterone acetate

Objective: To evaluate the modification of lipid and lipoprotein by use of low doses of continuous-combined formulations of 17beta-estradiol (E-2) and norethisterone acetate (NETA) in healthy postmenopausal women. Design: The study was designed as a double-blind, randomized, placebo-controlled trial. A total of 120 healthy postmenopausal women were randomized to one of three treatment arms: (1) placebo group (n = 40); (2) E-2/NETA 0.25-mg group-subjects receiving oral continuous-combined E-2 1 mg and NETA 0.25 mg (n = 40); (3) E2/NETA 0.5-mg group-women who were treated with E-2 1 mg and NETA 0.5 mg (n = 40). The duration of study was 12 months. Plasma levels of total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and very low-density lipoprotein (VLDL) cholesterol, triglycerides, lipoprotein(a), apolipoprotein A and apolipoprotein B were determined on four occasions (i.e., baseline, 3-, 6-, and 12-month visits). Results: There were no differences in the baseline characteristics among the three groups. A total of 102 women completed the study, resulting in a compliance rate of 85%. There was a significant reduction of total cholesterol, LDL cholesterol, and lipoprotein(a) in both combined groups when compared with placebo. The level of apolipoprotein B declined significantly only in the E-2/NETA 0.25-mg group. Decrements were observed within 3 months of treatment and maintained thereafter. No significant changes were found in triglycerides, VLDL cholesterol, HDL cholesterol, apolipoprotein A, and LDL/HDL ratio. Between the two active combined groups, no statistically significant differences were noted. Conclusion: Favorable changes in lipids and lipoproteins were associated with the low dose of E-2/NETA combinations. These effects may contribute to the reduction or prevention of atherogenesis in postmenopausal women