Effect of hormone replacement therapy on age-related increase in carotid artery intima-media thickness in postmenopausal women

The aim of this study was to determine the changes in carotid artery intima -media thickness as measured by B-mode ultrasound in postmenopausal women r eceiving hormone replacement therapy (HRT) or not. One hundred and fifty-ni ne healthy postmenopausal women aged 45-65 years were recruited from our me nopause clinic. All the selected women were free of cardio-vascular disease s and had no cardio-vascular risk factors. None of the women were receiving lipid-lowering or antihypertensive drugs. Because carotid artery intima-me dia thickness was shown to be strongly and positively correlated with age i n women aged 55 years and older but not before, women were divided into fou r groups according to age (< 55 vs. <greater than or equal to> 55 years) an d use of HRT (current users vs. never users). All the treated women receive d non-oral 17 beta -estradiol with a non-androgenic progestin and had start ed HRT within the first year after menopause. Scanning of the right common carotid artery was performed with a B-mode ultrasound imager and thickness of the intima-media complex as well as luminal diameter of the artery were determined using an automated computerized procedure. Within each age group (i.e. < 55 or <greater than or equal to> 55 years), women had comparable d emographic characteristics and only differed by HRT use. long-term treated women had significantly lower total cholesterol Levels than untreated women (P=0.005). Triglycerides, low-density lipids (LDL)-cholesterol and high-de nsity lipids (HDL)cholesterol levels, systolic and diastolic blood pressure were not significantly different between users and non-users. In women < 5 5 years, no significant difference in carotid intima-media thickness was fo und between current users (mean 2.5 +/- 1.4 years) and non users. In older women, the mean values of carotid intima-media thickness were significantly smaller in current users (mean 6.9 +/- 3.3 years) than in never treated wo men: 0.50 +/- 0.05 versus 0.56 +/- 0.07 mm, P < 0.0001. Carotid artery inti ma-media thickness was significantly correlated to age in never users (r = 0.5, P < 0.0001) but not in women who were currently receiving HRT (r = 0.2 , ns). These findings suggest an apparent protective effect of long-term HR T on age-related thickening of the intima-media of the right common carotid artery. This may contribute to explain the apparent cardio-protective effe ct of HRT after the menopause. (C) 2000 Elsevier Science Ireland Ltd. All r ights reserved.