Abstract-Although several studies have shown that exogenous estrogens have beneficial effects on arterial characteristics, the effect of endogenous estrogen on the vascular system is still unknown. In this study, distensibility, an indicator of arterial elasticity, of the common carotid artery was compared in pre-and postmenopausal women. The study comprised 93 premenopausal and 93 postmenopausal women of similar age (range, 43 to 55 years). Women were selected from respondents to a mailed questionnaire about the menopause, which was sent to all women aged 40 to 60 years in the Dutch town of Zoetermeer (nϭ12 675). Postmenopausal women who were at least 3 years past natural menopause or whose menses had stopped naturally before age 48, were age-matched with premenopausal women with regular menses and without menopausal complaints. The selection aimed at maximizing the contrast in estrogen status between pre-and postmenopausal women of the same age. Distensibility of the carotid artery was measured noninvasively with B-mode ultrasound and a vessel wall movement detector system. Arterial distensibility is expressed as the change in arterial diameter (distension, ⌬D) with the cardiac cycle, adjusted for lumen diameter, pulse pressure, and mean arterial blood pressure. Key Words: menopause Ⅲ distensibility Ⅲ stiffness Ⅲ carotid artery Ⅲ cardiovascular disease T he incidence of cardiovascular disease in women rises sharply after middle age, and menopause is thought to be a major determinant of this increase. 1-3 The mechanism through which menopause exerts its effect on the cardiovascular system remains largely unexplained. Unfavorable effects on lipid metabolism have been considered a major intermediary. However, recent studies have increasingly emphasized the direct beneficial effects of estrogens on the arterial wall. In experimental studies in animals, estrogen replacement had direct vasodilatory effects 4 -6 and was shown to affect the structure and mechanical properties of large arteries. Improved endothelial function has been shown after hormone replacement therapy in women 7-9 and after estrogen use in transsexual men. 10,11 Use of estrogens in premenopausal women with coronary artery disease had a beneficial effect on exercise induced myocardial ischemia. 12 Few studies have addressed the effects of endogenous estrogens and natural menopause on the dynamic characteristics of the arterial system. Although changes in distensibility were not found during the menstrual cycle, 13 going through menopause has shown to negatively affect the elastic properties of the aortic root in hypertensive women, 14 and time since menopause was inversely related to the pulsatility index in the carotid arteries 15 and several parameters of aortic flow. 16 In the current study, we examined the relation between natural menopause and arterial distension in the common carotid artery.
Methods
Study PopulationSelection of participants in this study was aimed at maximizing the contrast in estrogen status in pre-and postmenopausal women o...