PHOENIX – Oral estrogen therapy taken within 6 years after the onset of menopause significantly reduced progression of lipid deposition in the carotid arterial wall, compared with placebo. However, starting oral estrogen 10 years after menopause did not confer a similar benefit.
“The clinical practice of estradiol therapy has been nothing short of a roller coaster ride,” lead study author, said in an interview at the Epidemiology and Prevention/Lifestyle and Cardiometabolic Health meeting sponsored by the American Heart Association. “Clinicians have been sort of conservative in terms of prescribing estradiol therapy. But over the last 2 decades things have changed, and eventually the timing hypothesis evolved based on the final analysis of the Women’s Health Initiative results as well.”
The findings come from a secondary analysis of the Early Versus Late Intervention Trial With Estradiol (), which examined the effects of oral 17-beta-estradiol (estrogen) on the progression of early atherosclerosis and cognitive decline in healthy postmenopausal women.
In the original trial, 643 healthy postmenopausal women were randomized to receive 1 mg/day of estradiol or a placebo pill either within 6 years after the onset of menopause or more than a decade after menopause (). All study participants took estradiol or placebo daily for an average of 5 years. The study’s initial findings showed that the mean carotid intima-media thickness progression rate was decreased by 0.0034 mm per year with estradiol, compared with placebo, but only in women who initiated hormone therapy within 6 years of menopause onset.
For the current analysis, researchers led by Dr. Karim looked further into estradiol’s impact on heart health by using echogenicity to analyze lipids in the arterial wall among the ELITE participants. The main outcome of interest was gray-scale median (GSM, unitless), a qualitative measure of atherosclerosis based on echogenicity obtained by high-resolution ultrasonography of the common carotid arterial wall. Whereas higher GSM values result with plaques rich in calcium and fibrous tissue, lower GSM values indicate more lipid deposition.
Dr. Karim, an associate professor of clinical preventive medicine at the University of Southern California, Los Angeles, and colleagues assessed GSM and serum concentrations of estradiol every 6 months over a median 5-year trial period, and used linear mixed effects regression models to compare the rate of GSM progression between the randomized groups within time-since-menopause strata.
The researchers found that effect of estradiol on the annual rate of GSM progression significantly differed between women in the early and late postmenopause groups (P for interaction = .006). Specifically, the annual GSM progression rate among women in early postmenopause fell by 0.30 per year in women taking estradiol, compared with 1.41 per year in those in the placebo group (P less than .0001), indicating significantly more atherosclerosis in the placebo group. On the other hand, the annual GSM progression rate was not significantly different between the estradiol and placebo groups among the late postmenopausal women (P = .37).
“I think this should comfort clinicians in terms of prescribing estradiol therapy to women who don’t have any contraindications and who are within 6 years of menopause,” Dr. Karim said. “Accumulation of lipids is the key event for atherosclerosis progression.” She and her colleagues also observed that the positive association between mean on-trial serum estradiol levels and GSM progression rate was stronger and significant among early postmenopausal women (P = .008), compared with women in the late postmenopausal group (P = .003). However, this differential association between estradiol level and GSM progression rate was not statistically significant (P for interaction = .33).
“This study is important and raises a critical question: Is there a time period where getting hormone therapy would be most beneficial for the heart?”, medical director of the New York University women’s heart program and senior advisor for women’s health strategy at NYU Langone Health, said in an interview. “I think more studies and more analyses are needed, but we haven’t changed the indications for estradiol. We’re not giving estradiol to prevent progression of heart disease. We use estradiol hormone therapy as indicated for women who are having menopausal symptoms.”
Dr. Karim and colleagues plan to conduct a follow-up analysis from the same cohort of ELITE study participants to validate the findings by assessing lipid particles and markers of inflammation.
She reported having no financial disclosures. The study was funded by the National Institute on Aging.
SOURCE: Karim R et al. Epi/Lifestyle 2020, Abstract .