Objectives: To evaluate the lipid profile, insulin resistance and vasomotricity, and the interaction between these factors, in postmenopausal women receiving hormone therapy.
Methods: A prospective, randomized, double-blind study was carried out in which 77 postmenopausal women received one of the three treatment regimens: (A) 2mg oral micronized estradiol (E2) (n=25); (B) 2mg oral E2+1mg oral norethisterone acetate (NETA) (n=28); or C) placebo (n=24), daily for 6 months. Evaluations were carried out at baseline and at the end of treatment on lipid and lipoprotein profiles, homeostasis model assessment of insulin resistance (HOMA-IR) and pulsatility index (PI) of the internal carotid artery by Doppler ultrasonography.
Results: Mean increases of 15.6% and 2.4% and a reduction of 6.4% in high-density lipoprotein (HDL) levels were found for the E2, E2+NETA and placebo groups, respectively. Reductions of 9.5% and 3.7% and an increase of 12.1% in low-density lipoprotein (LDL), and reductions of 20.0% and 3.8% and an increase of 28.8% in the LDL:HDL ratio were found for the E2, E2+NETA and placebo groups, respectively (p<0.001 in all cases). Insulin levels and HOMA-IR decreased 12.8% and 12.3% in the E2 group and increased 12.9% and 16.0% in the E2+NETA group (p<0.05), respectively. Carotid PI following treatment was 1.18+/-0.23, 1.38+/-0.20 and 1.41+/-0.21 for the E2, E2+NETA and placebo groups, respectively (p=0.0006).
Conclusions: Oral estrogen therapy led to an improvement in lipid profile, insulin resistance and carotid blood flow, which was cancelled when NETA was associated.