Perimenopausal transdermal estradiol replacement reduces serum HDL cholesterol efflux capacity but improves cardiovascular risk factors

BACKGROUND: The cardiovascular (CV) safety of estrogen replacement therapy (ERT) in perimenopausal women remains uncertain. Although exogenous estrogens increase HDL cholesterol (HDL-C), estrogen-mediated effects on alternative metrics of HDL that may better predict CV risk are unknown. OBJECTIVE: To determine the effects of transdermal ERT on HDL composition and cholesterol efflux capacity (CEC), as well as the relationships between these metrics and CV risk factors. METHODS: Fasting plasma samples were analyzed from 101 healthy, perimenopausal women randomized to receive either transdermal placebo or transdermal estradiol (100 mu g/24 h) with intermittent micronized progesterone. At baseline and after 6 months of treatment, serum HDL CEC, HDL particle concentration, HDL protein composition, insulin resistance and brachial artery flow-mediated dilatation (FMD) were measured. RESULTS: No difference between groups was found for change in plasma HDL-C (p = 0.69). Between-group differences were found for changes in serum HDL total CEC [median change from baseline -5.4 (-17.3,+8.4)% ERT group versus +5.8 (-6.3,+16.9)% placebo group, p = 0.01] and ABCA1-specific CEC [median change from baseline -5.3 (-10.7,+6.7)% ERT group versus +7.4 (-1.5,+18.1)% placebo group, p = 0.0002]. Relative to placebo, transdermal ERT led to reductions in LDL-C (p < 0.0001) and insulin resistance (p = 0.0002). An inverse correlation was found between changes in serum HDL total CEC and FMD (b = -0.26, p = 0.004). CONCLUSIONS: Natural menopause leads to an increase in serum HDL CEC, an effect that is abrogated by transdermal ERT. However, transdermal ERT leads to favorable changes in major CV risk factors. (C) 2020 National Lipid Association. All rights reserved.

Automated summary

This study found that transdermal ERT led to reductions in LDL-C and insulin resistance compared to placebo, but had a negative impact on serum HDL total CEC. In addition, there was a negative correlation between changes in serum HDL total CEC and brachial artery flow-mediated dilatation.