A study conducted by the Atherosclerosis Research Unit at Keck School of Medicine suggests that hormone therapy, when taken within six years of menopause, may slow the buildup of plaque in the arteries.

This is the first study to directly examine the hypothesis that the cardiovascular effects of postmenopausal hormone therapy vary with the timing of hormone therapy initiation, according to Howard N. Hodis, MD, director of the Atherosclerosis Research Unit and principle investigator of the study.

The study, titled “Vascular Effects of Early versus Late Postmenopausal Treatment with Estradiol,” was published in the March 31 issue of the New England Journal of Medicine.

To gather data, researchers conducted the Early versus Late Intervention Trial with Estradiol (ELITE), an NIH-funded study. Over 600 postmenopausal women with no history of cardiovascular disease or diabetes were stratified into two groups: early postmenopause (women who were within six years of menopause) and late postmenopause (women who were 10 years or more beyond menopause). Women in each group were randomly assigned to receive either oral estradiol or a placebo Every six months, subclinical atherosclerosis, or the buildup of plaque in the arteries, was assessed with measurement of carotid artery intima-media thickness (CIMT).

After a median of five years, women in the early postmenopausal group who were taking estradiol showed significantly slower rates of CIMT progression, meaning they developed less build-up within the arteries, when measured against those taking the placebo. However, the late postmenopausal group showed essentially the same rates of CIMT progression between those taking estradiol and those taking the placebo.

“ELITE provides proof of concept and first direct evidence from human investigation that timing of hormone therapy is imperative for success in the prevention of atherosclerosis progression, the primary underlying pathway that leads to heart disease and stroke,” Hodis said. “The stratification of participants into early and late postmenopause was a unique feature of ELITE. We believe that applying this design to further examination of heart disease prevention could ultimately prove immensely fruitful for women’s health.”

Building from these data, the ELITE researchers intend to investigate why hormone therapy is more effective in the earlier stages of postmenopause and whether or not non-hormonal therapies provide the same effect. In doing so, they hope to contribute to the development of more effective, precise and target-driven therapies to prevent heart disease in women.

— Mary Dacuma