Placebo-controlled trial of transdermal estrogen therapy alone in postmenopausal women: effects on arterial compliance and endothelial function

BACKGROUND: The cardiovascular effects of hormone replacement therapy (HRT) are controversial. Improvement in vascular function, potentially mediated, at least in part, via improvements in lipid profiles, is a proposed mechanism of estrogen action; however, there are few controlled human trials. We have studied the effects of HRT, independent of changes in lipid profile, with transdermal estrogen therapy, focusing on blood pressure, lipid profiles and vascular function, encompassing both biomechanical arterial properties (systemic arterial compliance and pulse wave velocity) and endothelial function (flow-mediated vasodilatation). METHODS: In this 2-year, double-blind, placebo-controlled, cross-over study, 34 healthy postmenopausal women were randomized to transdermal estrogen alone (Menorest, 50 micrograms) or placebo. After withdrawals, 25 women completed measurements at baseline, 6 weeks, 6 months and 12 months during both treatment phases. RESULTS: Transdermal estrogen did not improve blood pressure, lipid profiles or arterial function, compared with placebo. CONCLUSION: From this randomized, controlled trial, it appears that transdermal estrogen alone, in healthy postmenopausal women, does not improve lipid profiles or a spectrum of indices of arterial function, compared with placebo. These results would suggest that there might not be a beneficial effect of transdermal HRT on the vasculature in postmenopausal women.