Menopausal estrogen therapy counteracts normal aging effects on intima thickness, media thickness and intima/media ratio in carotid and femoral arteries. An investigation using noninvasive high-frequency ultrasound.

BACKGROUND

Estrogen therapy that is started at the time of menopause seems to protect against the development of atherosclerosis and cardiovascular diseases, in contrast to the initial increased cardiovascular risk when hormone therapy is initiated in older women. With increased aging and degree of atherosclerosis, the thickness of the artery intima increases and that of the media decreases. These changes can be noninvasively estimated using high-frequency ultrasound.

METHODS AND RESULTS

The thickness of carotid and femoral artery intima and media was assessed, using noninvasive high-frequency ultrasound (25MHz). Long-term estrogen users (mean treatment duration 20 years) had a significantly thinner mean carotid intima layer (-25%; P=0.0002), a thicker media layer (+74%; P=0.0002) and a substantially lower intima/media thickness ratio (-54%; P<0.0001) than 17 age-matched nonusers, with values closer to those in 20 premenopausal women. Similar but less pronounced differences between the postmenopausal groups were found for the femoral artery.

CONCLUSIONS

A preserved thin artery wall intima and a low intima/media thickness ratio, at values close to those in young women might be partially responsible for the beneficial cardiovascular effects of estrogen therapy when it is initiated at the time of menopause.