HRT as secondary prevention of cardiovascular disease

Objective: To review the evidence of the efficacy of postmenopausal hormone replacement therapy (HRT) in secondary prevention of coronary artery disease or stroke. Results: Although a number of rather large and prolonged non-randomized observational studies have produced convincing and consistent evidence of the efficacy of HRT in the prevention of recurrence of cardiac events, the first randomized, placebo controlled trial (RCT) on heart disease and estrogen replacement study (HERS) reported no benefit of conjugated equine estrogen (CEE) and medroxyprogesterone acetate (MPA) in secondary prevention of cardiac events in women with established coronary artery disease. This was supported by RCT reporting no effect of CEE or CEE + MPA on the progress of coronary sclerosis. Similarly, some nonrandomized observational studies have evaluated the risk of recurrent stroke in regard to the use of HRT, and the data are conflicting reporting a reduced or increased risk of recurrence for HRT users. One RCT has shown that low-dose estrogen treatment can only slow down the progression of carotid arteriosclerosis in high-risk postmenopausal women, whereas two other RCTs have shown no benefit (or risk) of using HRT for secondary prevention of ischemic stroke or progression of carotid atherosclerosis. Conclusion: The evidence accumutaed so far shows that HRT has no place in secondary prevention of coronary or carotic artery disease. Its use in these patients must be based on solid nonvascular indications and expected benefits from these causes.     

A clinical trial of estrogen-replacement therapy after ischemic stroke.

BACKGROUND: Observational studies have suggested that estrogen-replacement therapy may reduce a woman's risk of stroke and death. METHODS: We conducted a randomized, double-blind, placebo-controlled trial of estrogen therapy (1 mg of estradiol-17beta per day) in 664 postmenopausal women (mean age, 71 years) who had recently had an ischemic stroke or transient ischemic attack. Women were recruited from 21 hospitals in the United States and were followed for the occurrence of stroke or death. RESULTS: During a mean follow-up period of 2.8 years, there were 99 strokes or deaths among the women in the estradiol group, and 93 among those in the placebo group (relative risk in the estradiol group, 1.1; 95 percent confidence interval, 0.8 to 1.4). Estrogen therapy did not reduce the risk of death alone (relative risk, 1.2; 95 percent confidence interval, 0.8 to 1.8) or the risk of nonfatal stroke (relative risk, 1.0; 95 percent confidence interval, 0.7 to 1.4). The women who were randomly assigned to receive estrogen therapy had a higher risk of fatal stroke (relative risk, 2.9; 95 percent confidence interval, 0.9 to 9.0), and their nonfatal strokes were associated with slightly worse neurologic and functional deficits. CONCLUSIONS: Estradiol does not reduce mortality orthe recurrence of stroke in postmenopausal women with cerebrovascular disease. This therapy should not be prescribed for the secondary prevention of cerebrovascular disease.     

Coronary heart disease in menopausal women: implications of primary and secondary prevention trials of hormones

In direct contrast to the observational studies, both primary and secondary prevention trials of female reproductive hormones have found no benefit for coronary heart disease (CHD). Basic science studies have elucidated several mechanisms by which estrogen may improve coronary arterial physiology and prevent pathology, but have also found mechanisms by which estrogen might increase coagulation or inflammation, or might trigger coronary events in advanced lesions. Animal studies suggest that hormones may retard early atherosclerosis, while both animal studies and human angiographic trials are conclusive that hormones do not retard progression of raised lesions. Hormone use in the primary prevention observational studies would mostly have started at the age of menopause, in women whose arteries on average would be closer to normal than those of women in the clinical trials. One hypothesis worthy of further study is that estrogen may have a beneficial effect in normal or near-normal arteries, but the opposite effect in the presence of established atherosclerosis. However, at the average age of menopause, a substantial proportion of women has raised lesions, and a smaller proportion already has advanced lesions. Also, the apparent benefit of hormone use was found in secondary prevention observational studies, i.e., in women with compromised arteries. It is likely that uncorrected biases in the observational studies lead to an overestimation of any benefit of hormone use. On the other hand, endogenous estradiol may be responsible for the later onset of coronary disease in women compared to men; if so, then the appropriate test of the estrogen hypothesis would employ transdermal estradiol in a young population of menopausal women. Hormones are not indicated for the prevention of CHD, particularly in the light of the increased risk for stroke and venous thrombosis. Their use for other indications (menopausal symptoms, osteoporosis) needs to be tempered by the risk for cardiovascular disease (CVD).     

Postmenopausal estrogen therapy and cardiovascular disease. Ten-year follow-up from the nurses' health study

BACKGROUND. The effect of postmenopausal estrogen therapy on the risk of cardiovascular disease remains controversial. Our 1985 report in the Journal, based on four years of follow-up, suggested that estrogen therapy reduced the risk of coronary heart disease, but a report published simultaneously from the Framingham Study suggested that the risk was increased. In addition, studies of the effect of estrogens on stroke have yielded conflicting results. METHODS. We followed 48,470 postmenopausal women, 30 to 63 years old, who were participants in the Nurses' Health Study, and who did not have a history of cancer or cardiovascular disease at base line. During up to 10 years of follow-up (337,854 person-years), we documented 224 strokes, 405 cases of major coronary disease (nonfatal myocardial infarctions or deaths from coronary causes), and 1263 deaths from all causes. RESULTS. After adjustment for age and other risk factors, the overall relative risk of major coronary disease in women currently taking estrogen was 0.56 (95 percent confidence interval, 0.40 to 0.80); the risk was significantly reduced among women with either natural or surgical menopause. We observed no effect of the duration of estrogen use independent of age. The findings were similar in analyses limited to women who had recently visited their physicians (relative risk, 0.45; 95 percent confidence interval, 0.31 to 0.66) and in a low-risk group that excluded women reporting current cigarette smoking, diabetes, hypertension, hypercholesterolemia, or a Quetelet index above the 90th percentile (relative risk, 0.53; 95 percent confidence interval, 0.31 to 0.91). The relative risk for current and former users of estrogen as compared with those who had never used it was 0.89 (95 percent confidence interval, 0.78 to 1.00) for total mortality and 0.72 (95 percent confidence interval, 0.55 to 0.95) for mortality from cardiovascular disease. The relative risk of stroke when current users were compared with those who had never used estrogen was 0.97 (95 percent confidence interval, 0.65 to 1.45), with no marked differences according to type of stroke. CONCLUSIONS. Current estrogen use is associated with a reduction in the incidence of coronary heart disease as well as in mortality from cardiovascular disease, but it is not associated with any change in the risk of stroke.     

Postmenopausal hormone therapy: new questions and the case for new clinical trials

Observational studies suggest that postmenopausal hormone therapy (HT) prevents coronary heart disease, whereas randomized clinical trials have not confirmed a cardioprotective effect. Although observational studies may have overestimated the coronary benefit conferred by postmenopausal hormone use, there are other plausible explanations for the apparent discrepancy between previous results and the less favorable findings from clinical trials such as the large Women's Health Initiative. There is now a critical mass of data to support the hypothesis that age or time since menopause may importantly influence the benefit-risk ratio associated with HT, especially with respect to cardiovascular outcomes, and that the method of administration, dose, and formulation of exogenous hormones may also be relevant. Although the weight of the evidence indicates that older women and those with subclinical or overt coronary heart disease should not take HT, estrogen remains the most effective treatment currently available for vasomotor symptoms, and its effects on the development of coronary disease in newly postmenopausal women remain unclear. Moreover, effects of HT on quality of life and cognitive function in recently postmenopausal women merit further study. These unresolved clinical issues provide the rationale for the design of the Kronos Early Estrogen Prevention Study, a 5-year randomized trial that will evaluate the effectiveness of low-dose oral estrogen and transdermal estradiol in preventing progression of atherosclerosis in recently postmenopausal women.     

Effects of the estrogen replacement therapy on different biochemical markers of endothelial reactivity in recent postmenopausal healthy women

The risk of cardiovascular disease significantly increases after menopause. Accordingly, many evidences suggest that estrogens may positively affect the production of different vasoactive factors, such as nitric oxide, prostacyclin, endothelin-1 and catecholamines and induce favourable changes in lipid profile. However, although observational data indicate that hormone replacement therapy (HRT) reduces significantly the cardiovascular risk, recent results have added controversial data to the institution of HRT in postmenopausal women. These last studies present numerous bias, related to inclusion of a single combination HRT regimen, recruitment women of older age groups who began treatment years after menopause and generally with pre-existing coronary artery disease. In fact, it is known that aging and atherosclerotic injury may induce estrogen receptors depletion, endothelial dysfunction and thrombosis, thus potentially decreasing HRT efficacy. Therefore, particular attention must be paid to the age of the woman and the complexity of atheroscleriotic lesions as determinants of the response to HRT for each patient. Moreover, the maintenance of an healthy and normal functioning endothelium after menopause emerges as a major target to retain maximal cardiovascular benefit from this treatment.     

Estrogen-containing hormone therapy and Alzheimer's disease risk: understanding discrepant inferences from observational and experimental research

Estrogen has the potential to influence brain processes implicated in Alzheimer's disease pathogenesis. With the loss of ovarian estrogen production after menopause, estrogen-containing hormone therapy might be expected to influence the risk of Alzheimer's disease. Observational data link use of hormone therapy to reductions in Alzheimer risk, but experimental evidence from the Women's Health Initiative Memory Study trial demonstrates that oral estrogen, with or without a progestin, increases the incidence of dementia for postmenopausal women age 65 years or older. Mechanisms of harm in this setting are unknown. Bias and unrecognized confounding in observational research are leading candidates for discrepant results between observational studies and the Women's Health Initiative Memory Study trial. Studies are also distinguished by differences in outcome measures, hormone therapy formulations, prevalence of menopausal symptoms among study participants, and participant age. Finally, Women's Health Initiative Memory Study findings may not generalize to estrogen use by relatively young women during the menopausal transition or early postmenopause, a class of women who were ineligible for the Women's Health Initiative Memory Study trial. In observational studies, hormone therapy exposure often included use by younger women for menopausal vasomotor symptoms. Although there is no clinical trial evidence that hormone therapy at any age protects against Alzheimer's disease, it remains to be determined whether the age at which hormone exposure occurs or the timing of hormone therapy initiation in relation to the menopause (the critical window hypothesis) modifies treatment outcomes on dementia risk.     

Controversies about HRT--lessons from monkey models

Lessons from monkey models contribute significantly to a better understanding of the controversies in reconciling the differences in postmenopausal hormone treatment outcomes between observational and randomized trial data. Monkey studies brought attention to premenopausal estrogen deficiency with resulting premature coronary artery atherosclerosis. Recently, those monkey studies were confirmed for premenopausal women in the NHLBI-sponsored Women's Ischemia Syndrome Evaluation (WISE) Study. Monkey studies have provided convincing evidence for the primary prevention of coronary artery atherosclerosis when estrogens are administered soon after the development of estrogen deficiency. Equally convincing are the data from monkey studies indicating the total loss of these estrogens beneficial effects if treatment is delayed for a period equal to six postmenopausal years for women. An attempt has been made using the monkey model to identify the hormone treatment regimen most effective in preventing the progression of coronary artery atherosclerosis. By a substantial margin, the most effective approach is that of using estrogen containing oral contraceptive during the perimenopausal transition, followed directly by hormone replacement therapy postmenopausally. Because of similarities between human and nonhuman breast, monkeys have had a major role in clarifying controversies surrounding the breast cancer risk of estrogen only versus estrogen plus progestin therapies. The results of monkey studies suggest little or no effects of estrogen only treatment; whereas, estrogen+progestin clearly increases breast cancer risk.     

Menopause and ischaemic stroke: basic,clinical and epidemiological considerations. The role of hormone replacement

Stroke is a leading cause of disability and death in women, despite progress in its prevention and treatment. As with coronary artery disease, the incidence of stroke rises after the menopause, in parallel with metabolic changes that add up to create an unfavourable risk factor profile for cardiovascular disease. The menopause metabolic syndrome, which includes weight gain and changes in lipids, insulin resistance, endothelial dysfunction, increased levels of homocysteine, lipoprotein (a) and several coagulation factors, may in part be attributable to estrogen deficiency, and may be reversible with hormone replacement therapy (HRT). As for blood pressure, a major detrimental risk factor for stroke, it is probably not affected by either the menopause per se or by HRT. Abundant experimental data exist indicating that estrogens have both anti-atherosclerotic and neuroprotective effects. The width or thickness of the carotid wall is a good indicator of carotid atherosclerosis; it increases after the menopause transition, and decreases with HRT. Estrogens may enhance cerebral blood flow and reduce vascular resistance. In animal models of stroke, estrogen induced anti-ischaemic effects. Several large-scale epidemiological studies have verified the concept of primary protection of stroke by HRT, though others have failed to do so. In light of these contradictory data, several recent reports were highly significant (Nurses' Health Study, HERS Study, Cancer Prevention II Trial, WEST Trial). Despite the known neural and vascular benefits of estrogen, it is uncertain whether HRT is associated with stroke protection. At present, prevention of stroke should involve proven risk reduction strategies.     

Potential age-dependent effects of estrogen on neural injury

In 2000, approximately 10 million women were receiving hormone replacement therapy (HRT) for alleviation of menopausal symptoms. A number of prior animal studies suggested that HRT may be neuroprotective and cardioprotective. Then, in 2003, reports from the Women's Health Initiative (WHI) indicated that long-term estrogen/progestin supplementation led to increased incidence of stroke. A second branch of the WHI in women with prior hysterectomy found an even stronger correlation between estrogen supplementation alone and stroke incidence. Follow-up analyses of the data, as well as data from other smaller clinical trials, have also demonstrated increased stroke severity in women receiving HRT or estrogen alone. This review examines the studies indicating that estrogen is neuroprotectant in animal models and explores potential reasons why this may not be true in postmenopausal women. Specifically, age-related differences in estrogen receptors and estrogenic actions in the brain are discussed, with the conclusion that animal models of disease must closely mimic human disease to produce clinically relevant results.     

Osteoporosis,osteopenia, and atherosclerotic vascular disease

Older women with low bone mineral density (BMD) have a higher prevalence of atherosclerotic vascular disease (coronary artery disease, ischemic stroke, or peripheral arterial disease) than older women with normal BMD. Three coronary angiographic studies have shown that low BMD is associated with obstructive coronary artery disease. Low BMD has been shown to be associated with stress test-induced myocardial ischemia, reduced exercise capacity, and with aortic valve calcification. Women with osteoporosis have an increased risk for cardiovascular events. Treatment of osteoporosis or osteopenia should include therapeutic measures to prevent cardiovascular events.     

Hormone therapy and cerebrovascular events: a population-based nested case-control study

OBJECTIVE: The relationship between postmenopausal hormone therapy (HT) and cerebrovascular disease has been examined in several epidemiological studies and clinical trials with conflicting results. The authors aimed to evaluate the association between the use of HT and the incidence of first cerebrovascular event. DESIGN: The study cohort comprised 158,031 women 50 to 69 years old registered in the U.K. General Practice Research Database between 1991 and 1997. The authors conducted a nested case-control analysis using all 920 confirmed cases of cerebrovascular events identified during the follow-up (536 of transient ischemic attack [TIA]; 259 of ischemic stroke; 125 of hemorrhagic stroke) and 10,000 controls. RESULTS: The odds ratios of TIA, ischemic stroke, and hemorrhagic stroke among women currently using HT were 1.48 (95% CI, 1.17-1.87), 1.12 (95% CI, 0.78-1.59) and 1.21 (95% CI, 0.76-1.93), respectively, compared to never users. The overall risk estimate for having a cerebrovascular event was 1.34 (95% CI, 1.11-1.61). The risk of TIA was greater (1.96) among women using high doses of estrogen (95% CI, 1.34-2.87). CONCLUSION: Overall, a small increased risk of stroke associated with HT use of comparable magnitude to the one observed in recent clinical trials was found. The increased risk was more apparent for TIA than for stroke and was greater at higher doses.     

Hormones and cardiovascular health in women

Cardiovascular diseases (CVDs) may have their origin beforebirth: the combination of being small at birth and having anoverly rich post-natal diet increases the likelihood of obesityand of acquiring a specific metabolic syndrome in adulthoodthat carries an increased risk of CVD. The incidence of CVDand mortality is very low in women of reproductive age but risesto a significant level in older women. In this article, we discussCVD in relation to hormonal contraception, pregnancy and polycysticovarian syndrome (PCOS) in younger women and menopause in olderwomen. Women with PCOS have a higher risk of diabetes and hypertension,but studies to date have not shown an effect on CVD events.Use of combined hormonal contraception has only small effectson CVD because of the low baseline incidence of myocardial infarction(MI), stroke and venous thromboembolism (VTE) among young women.Women with existing risk factors or existing CVD, however, shouldconsider alternative contraception. In pregnancy, CVD is rare,although, in the West, it now accounts for a significant proportionof maternal mortality as the frequency of obstetrical causesof mortality has substantially declined. The frequency of VTEis 15 per 10 000 during pregnancy and the post-partum period.In older women, menopause causes a slightly higher risk of MIafter allowing for age, although there is substantial heterogeneityin the results of studies on menopause and age at menopauseand MI. A larger effect might have been expected, because estrogenreduces the risk of developing atherosclerosis in premenopausalwomen, whereas in post-menopausal women who may have establishedatherosclerotic disease, estrogen increases the risk of myocardialdisease through the effects on plaque stability and clot formation.Recent trial results indicate that hormone treatment in menopausedoes not favourably affect the risk of MI, stroke or other vasculardisease. Thus, prevention of CVD should rely on diet and fitness,low-dose aspirin and treatment of hypertension, hyperglycaemiaand hyperlipidaemia.     

Interaction between menopausal status and obesity in affecting breast cancer risk

Obesity has a complex relationship to breast cancer risk that differs in premenopausal and postmenopausal women. Before the menopause, the level of adiposity is inversely related to risk, indicative of a protective effect, whereas in postmenopausal women, particularly the elderly, the association is a positive one, consistent with obesity being a risk factor. The importance of high estrogen production in adipose tissue, with consequent elevation of circulating biologically available estradiol, in the promotional effect of obesity on postmenopausal breast carcinogenesis is well established; the resulting tumors express both estrogen and progesterone receptors. The mechanism(s) for the protective effect in premenopausal women is less well understood, but the breast cancers that do develop in the presence of obesity are most often estrogen and progesterone receptor negative, consistent with the selection of non-estrogen-dependent tumor cells which are dependent on growth factors such as insulin, insulin-like growth factor-I and some adipokines. The influence of menopausal status on the relationships between adiposity and breast cancer appears to be modified within each category by age; the protective effect before the menopause may be limited to younger women (<35 years), and the adverse effect was found to apply specifically to older postmenopausal women. Although randomized trials of weight reduction for postmenopausal breast cancer prevention have not been performed, observational studies suggested that risk reduction does occur; in addition, other health benefits of weight control need to be considered regardless of menopausal status.     

The effect of menopause on the relation between weight gain and mortality among women

OBJECTIVE: To examine the effect of menopause on the relation between weight gain and all-cause mortality. DESIGN: Prospective cohort study of 6,030 adults (ages 25-82 years) who never smoked cigarettes, had no history of coronary heart disease, cancer, or stroke, and were enrolled in a 29-year follow-up in which anthropometric data were given at baseline and at 17 years after baseline. RESULTS: Weight gain that occurred over a 17-year interval (baseline to 17 years after baseline) increased the mortality risk of men and middle-aged women, but decreased the mortality risk of older women. Further study of the women revealed that a strong protective effect of weight gains was only evident among the leanest (25 kg/m2) postmenopausal women [HR (95% CI) = 0.81 (0.41, 1.58)] or for premenopausal women [HR (95% CI) = 1.05 (0.49, 2.25) for 25 kg/m2]. We found that the protective effect of weight gain among the leanest postmenopausal women was primarily due to a more than threefold decrease in cardiovascular disease mortality risk. One possible explanation for these findings is that weight gain increases the level of adipose-tissue-derived estrogen among lean postmenopausal women. CONCLUSION: Moderate menopausal weight gain may be well tolerated in lean women.     

The effect of hormone therapy on the risk for age-related maculopathy in postmenopausal women

OBJECTIVE: To evaluate the effect of postmenopausal hormone therapy (HT) as well as the use of oral contraceptives and lifetime endogenous hormone exposure on the risk for age-related maculopathy (ARM) in postmenopausal women. DESIGN: This was a cross-sectional, controlled study. A total of 102 women from 60 to 80 years of age who were receiving HT and 100 controls underwent a detailed clinical funduscopic evaluation and stereoscopic fundus photography for the presence and grading of ARM. All participants completed a standardized questionnaire regarding vascular risk factors, HT, and lifetime exogenous and endogenous estrogen and progesterone exposure. Statistical analysis was performed using Student's t test, chi2 test, and a multivariate logistic regression model. RESULTS: The HT and the non-HT groups did not differ in terms of early (11% v 15%), late (6% v 6%), or wet (2% v 2%) ARM prevalence rates. Women with ARM were significantly older than controls (69 v 66 years; P = 0.001, 95% CI = 0.008 - 0.027) and were more likely to have ischemic heart disease (21% v 9%; OR = 2.86, P = 0.03, 95% CI = 0.020 - 0.360). Lifetime exogenous and endogenous hormone exposures and other cardiovascular risk factors were not significantly different among women with ARM as compared with controls. CONCLUSION: Postmenopausal HT may not affect the risk for either early or late ARM in women aged 60 to 80 years. The risk for both entities is not necessarily affected by either exogenous or endogenous lifetime hormone exposure. A history of ischemic heart disease may be associated with an increased risk for ARM.     

Older age and markers of inflammation are strong predictors of clinical events in women with asymptomatic carotid lesions

OBJECTIVE: Limited information exists regarding the association between markers of inflammation, such as high-sensitivity C-reactive protein (hs-CRP) and fibrinogen, and adverse events in postmenopausal women with subclinical atherosclerosis. Therefore, we investigated the prognostic impact of traditional risk factors and inflammation on adverse cardiac events in women with asymptomatic carotid lesions. DESIGN: We studied 250 postmenopausal women who were free of cardiovascular disease. Traditional cardiovascular risk factors were investigated, and laboratory analysis included measurement of plasma lipids, fibrinogen, and hs-CRP. The early phases of carotid atherosclerosis were assessed by B-mode ultrasonography. Women were asked about symptoms or a previous history of coronary artery disease and were followed for a period of 5 years. RESULTS: We found that the increment in age (in quintiles) was significantly associated with higher incidence of current smokers (P = 0.0286), hypertension (P = 0.0230), family history of coronary artery disease (P = 0.0216), dyslipidemia (P = 0.0330), and higher levels of fibrinogen (P = 0.0158). Moreover, older women had a higher prevalence of carotid lesions (P < 0.0001). After the follow-up, cardio- and cerebrovascular events were registered in 22% of the women. Using multivariate analysis, we observed that older age (odds ratio [OR], 1.7; 95% CI, 1.3-2.2; P < 0.0001), fibrinogen (OR, 1.6; 95% CI, 1.2-2.0; P < 0.0001), the presence of carotid lesions (OR, 2.0; 95% CI, 1.4-3.0; P = 0.0002), and hs-CRP (OR, 1.3; 95% CI, 1.2-2.0; P = 0.0175) were predictors of adverse events during the follow-up. CONCLUSIONS: Adverse events occurred more frequently in women with higher levels of fibrinogen and hs-CRP. The significance of these results requires confirmation in other studies, but they may have important implications for screening subjects at risk for cardiovascular disease and identifying candidates for anti-inflammatory therapy.     

雌激素防治骨质疏松症的研究进展

１９４１年Ａｌｂｒｉｇｈｔ首先提出绝经与骨质疏松之间的关系，５０多年来，大量的临床与实验研究证实，雌激素缺乏是绝经后骨质疏松的重要发病因素。低雌激素状态或绝经后补充雌激素，可以预防雌激素低下引起的骨丢失，并对绝经后的多种改变有防治作用，例如绝经后症状...