Effect of short-term estrogen therapy on endothelial function: a double-blinded, randomized, controlled trial

Abstract

Objective: To evaluate the effect of short-term hormone replacement therapy with 0.625 mg conjugated estrogens daily on endothelial function of healthy postmenopausal women, using flow-mediated dilation (FMD) of the brachial artery.

Methods: We performed a double-blinded, randomized, controlled trial over 3 years. Randomization was performed using computer-generated sorting. All participants were blinded to the use of conjugated equine estrogens (CEE) or placebo and FMD was assessed by a blinded examiner, before and after 28 days of medication. A total of 64 healthy postmenopausal women were selected and randomly assigned into two groups of treatment: 0.625 mg of CEE or placebo.

Results: FMD values were statistically different between the groups (p = 0.025): the group receiving CEE showed a FMD value of 0.011 compared to the placebo group (FMD = −0.082). The two groups were additionally evaluated for homogeneity through the Shapiro–Wilk test in respect to variables that could interfere with endothelial function such as age (p = 0.729), body mass index (p = 0.891), and time since menopause (p = 0.724). Other variables were excluded during selection of the participants such as chronic vascular conditions, smoking, and sedentary lifestyle.

Conclusion: Our results demonstrate that the administration of 0.625 mg CEE for 28 days is effective in improving vascular nitric oxide-dependent dilation assessed by FMD of the brachial artery in postmenopausal women.

Clinical trial registration: NCT01482416

Keywords:

• Estrogen
• postmenopausal
• flow-mediated dilation
• brachial artery
• endothelial function

Conflict of interest

The authors report no conflict of interest. The authors alone are responsible for the content and writing of this paper.

Source of funding

S. G. receives a grant from the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).