Postmenopausal hormone therapy and the risk of cardiovascular disease: the epidemiologic evidence

[Hypertension and menopausal hormone therapy]

Can menopausal hormone therapy (HT) be used in hypertensive women? The group of experts of the French Society of Hypertension has carried out a review of the recent literature in order to answer this question, based on the most recent scientific publications. If use of oral HT is associated with a discreet increase in blood pressure, the transdermal route seems to be safer. The first results of major randomized trials of HT had alerted to an increase in cardiovascular events and breast cancer with the use of oral HT, generally, tipping the benefit-risk balance of the deleterious side. Complementary analyzes have shown the importance of the window of intervention (less than 10 years after the menopause) and the age of the woman to start the HT. On the contrary, they have shown a significant decrease of the coronary events. For woman suffering from hypertension and important climacteric symptoms, it is important to evaluate the whole cardiovascular risk in order to decide the possibility of prescribing a HT. Thus, the group of experts proposes a prescription assistance algorithm based on the stratification of cardiovascular risk, always favoring, when it is authorized, HT by transdermal route of administration.

Estrogen suppresses adipogenesis by inhibiting S100A16 expression

The aim of this study is to determine the effects of E2 on metabolic syndrome and the molecular mechanisms involving S100A16. Ovariectomized (OVX) rat models and mouse embryonic fibroblasts cell models were used. E2 loss in OVX rats induced body weight gain and central abdominal fat accumulation, which were ameliorated by E2 treatment under chow and high-fat diet (HFD) conditions. E2 decreased the expression of the adipocyte marker genes PPARγ, aP2, C/EBPα, and S100A16. E2 inhibited adipogenesis. Overexpression of S100A16 reversed the E2-induced adipogenesis effect. A luciferase assay showed that E2 inhibited the expression of S100A16. E2 treatment decreased body weight gain and central abdominal fat accumulation under both chow and HFD conditions. Also, E2 suppressed adipogenesis by inhibiting S100A16 expression.

ESTROGEN REPLACEMENT THERAPY FOR STROKE

Stroke is the third most common cause of death and severe disability among Western populations. Overall, the incidence of stroke is uniformly higher in men than in women. Stroke is rare in women during the reproductive years, and rapidly increases after menopause, strongly suggesting that estrogen (E2) plays an important role in the prevention of stroke. Ongoing studies are currently evaluating both the benefits and risks associated with E2 replacement therapy and hormone replacement therapy in stroke. Equally important is the role of E2 receptor (ER), as studies indicate that ER populations in several tissue sites may significantly change during stress and aging. Such changes may affect the patient's susceptibility to neurological disorders including stroke, and greatly affect the response to selective E2 receptor modulators (SERMs). Replacement therapies may be inefficient with low ER levels. The goal of this review paper is to discuss an animal model that will allow investigations of the potential therapeutic effects of E2 and its derivatives in stroke. We hypothesize that E2 neuroprotection is, in part, receptor mediated. This hypothesis is a proof of principle approach to demonstrate a role for specific ER subtypes in E2 neuroprotection. To accomplish this, we use a retroviral mediated gene transfer strategy that express subtypes of the ER gene in regions of the rat brain most susceptible to neuronal damage, namely the striatum and cortex. The animal model is exposed to experimental stroke conditions involving middle cerebral artery occlusion (MCAo) method, and eventually the extent of neuronal damage will be evaluated. A reduction in neuronal damage is expected when E2 is administered with specific ER subtypes. From this animal model, an optimal E2 dose and treatment regimen can be determined. The animal model can help identify potential E2-like therapeutics in stroke, and screen for beneficial or toxic additives present in commercial E2 preparations that are currently available. Such studies will be informative in designing drug therapies for stroke.

Menopausal hot flushes and vascular health

Hot flushes are complained of by approximately 75% of all postmenopausal women, and hormone therapy (HT) is the most effective way to alleviate them. Hot flushes are characterized by altered vascular function and sympathetic nervous system activity. Hot flushes occurred more often in women attending large, non-randomized observational studies (e.g. Nurses' Health Study), where HT use protected against cardiovascular disease (CVD). However, they were absent (or mild) in randomized HT trials where HT use was accompanied with an elevated risk for CVD. Hot flushes, if a factor for cardiovascular health, could partly explain the conflict between observational and randomized trials. Several cross-sectional studies imply that hot flushes are detrimental to the cardiovascular system. However, the data are not uniform, and hot flushes were recalled retrospectively or during HT use. In our prospective study hot flushes were accompanied with a vasodilatory effect during endothelial testing, and this was related to the severity of hot flushes. Night-time hot flushes were followed with transient rises in ambulatory blood pressure (BP). However, no effect of hot flushes on diurnal BP was detected. The use of estradiol showed no harmful effects on endothelial function in women with hot flushes, but in non-flushing women oral, but not transdermal, estradiol led to vasoconstrictive changes. Estradiol complemented with medroxyprogesterone acetate eliminated the vasoconstrictive effect of sole oral estradiol. Thus, both oral and transdermal estradiol are applicable in flushing women, whereas a transdermal route should be favored in non-flushing women if used e.g. for bone protection.

17beta-Estradiol modulates local cardiac renin-angiotensin system to prevent cardiac remodeling in the DOCA-salt model of hypertension in rats

Ventricular remodeling can play a detrimental role in the progression of cardiovascular diseases, leading to heart failure. The current study was designed to investigate the effects of 17beta-estradiol (E2) on cardiac remodeling. Cardiac fibrosis and hypertrophy were examined in deoxycorticosterone acetate (DOCA)-salt treated rats with chronic, six-week administration of two different doses of E2. Bilaterally ovariectomized (Ovex) female Sprague-Dawley rats were randomly assigned to one of the following groups: Ovex-control; Ovex-DOCA; Ovex-DOCA+low-dose E2 (1.66 microg/day); or Ovex-DOCA+high-dose E2 (2.38 microg/day). All DOCA-treated rats were uninephrectomized and drinking water was replaced by 0.15M NaCl solution for the remainder of the study period. DOCA-salt treatment resulted in a significant increase in blood pressure, which was not altered by estrogen replacement. Histological examinations revealed marked cardiac remodeling (both ventricular hypertrophy and interstitial fibrosis) with DOCA treatment, which was attenuated in animals receiving estrogen therapy. Western blot analysis demonstrated increased cardiac levels of angiotensin converting enzyme (ACE) with DOCA treatment, which was attenuated by E2 replacement. Furthermore, increased levels of cardiac angiotensin converting enzyme 2 (ACE2) protein were observed in animals receiving high-dose E2 replacement. These findings suggest that physiologically relevant estrogen replacement therapy has blood pressure-independent cardioprotective effects, which are possibly mediated through modulation of the cardiac renin-angiotensin system.

Effects of estrogen therapy on microalbuminuria in healthy post-menopausal women

OBJECTIVE

To evaluate the impact of estrogen therapy on microalbuminuria levels in healthy post-menopausal women.

METHODS

Sixty post-menopausal women were evaluated in a prospective, randomised, double-blind, placebo-controlled study. The patients were randomly allocated to one of two groups to take one pill orally per day containing either 1 mg of 17beta-estradiol (E(2) group) or placebo (placebo group). Prior to initiating treatment and at the end of the sixth treatment month, microalbumin was measured in a 12-h urine sample, and lipid profile (total cholesterol, HDL, LDL and triglycerides) and fasting glucose were evaluated. Comparative intra- and inter-group analyses between the initial and final laboratory parameters were performed using the t-test for paired samples and for independent samples, respectively.

RESULTS

Microalbuminuria levels remained within normal limits throughout the study and no statistically significant differences were found in the intra- or inter-group analyses. With respect to lipid profile, alterations characteristically encountered during use of estrogen replacement therapy were found. No statistically significant variation in glucose levels occurred during the study period.

CONCLUSION

Estrogen replacement therapy had no significant effect on microalbuminuria levels in healthy post-menopausal patients.

Approach to the patient with menopausal symptoms

Many women experience menopausal symptoms during the menopausal transition and postmenopausal years. Hot flashes, the most common symptom, typically resolve after several years, but for 15-20% of women, they interfere with quality of life. For these women, estrogen therapy, the most effective treatment for hot flashes, should be considered. The decision to use hormone therapy involves balancing the potential benefits of hormone therapy against its potential risks. Accumulating data suggest that initiation of estrogen many years after menopause is associated with excess coronary risk, whereas initiation soon after menopause is not. Therefore, most now agree that short-term estrogen therapy, using the lowest effective estrogen dose, is a reasonable option for recently menopausal women with moderate to severe symptoms who are in good cardiovascular health. Short-term therapy is considered to be not more than 4-5 yr because symptoms diminish after several years, whereas the risk of breast cancer increases with longer duration of hormone therapy. A minority of women may need long-term therapy for severe, persistent vasomotor symptoms after stopping hormone therapy. However, these women should first undergo trials of nonhormonal options such as gabapentin, selective serotonin reuptake inhibitors, or serotonin norepinephrine reuptake inhibitors, returning to estrogen only if these alternatives are ineffective or cause significant side effects. Low-dose vaginal estrogens are highly effective for genitourinary atrophy symptoms, with minimal systemic absorption and endometrial effects.

Selective estrogen receptor-beta agonists repress transcription of proinflammatory genes

In addition to their role in the development and function of the reproductive system, estrogens have significant anti-inflammatory properties. Although both estrogen receptors (ERs) can mediate anti-inflammatory actions, ERbeta is a more desirable therapeutic target because ERalpha mediates the proliferative effects of estrogens on the mammary gland and uterus. In fact, selective ERbeta agonists have beneficial effects in preclinical models involving inflammation without causing growth-promoting effects on the uterus or mammary gland. However, their mechanism of action is unclear. The purpose of this study was to use microarray analysis to determine whether ERbeta-selective compounds produce their anti-inflammatory effects by repressing transcription of proinflammatory genes. We identified 49 genes that were activated by TNF-alpha in human osteosarcoma U2OS cells expressing ERbeta. Estradiol treatment significantly reduced the activation by TNF-alpha on 18 genes via ERbeta or ERalpha. Most repressed genes were inflammatory genes, such as TNF-alpha, IL-6, and CSF2. Three ERbeta-selective compounds, ERB-041, WAY-202196, and WAY-214156, repressed the expression of these and other inflammatory genes. ERB-041 was the most ERbeta-selective compound, whereas WAY-202196 and WAY-214156 were the most potent. The ERbeta-selective compounds repressed inflammatory genes by recruiting the coactivator, SRC-2. ERB-041 also repressed cytokine genes in PBMCs, demonstrating that ERbeta-selective estrogens have anti-inflammatory properties in immune cells. Our study suggests that the anti-inflammatory effects of ERB-041 and other ERbeta-selective estrogens in animal models are due to transcriptional repression of proinflammatory genes. These compounds might represent a new class of drugs to treat inflammatory disorders.

Factors Associated with Obstetrician-Gynecologists' Response to the Women's Health Initiative Trial of Combined Hormone Therapy

The Women's Health Initiative trial of combined estrogen and progestin (WHI E+P) ended prematurely after preliminary evidence indicated that harms exceeded benefits, with no cardiovascular benefit. There was controversy over the results and the decision to end the trial early, with many obstetrician-gynecologists expressing reservations about the evidence. The Research Department of the American College of Obstetricians and Gynecologists conducted a study regarding the WHI E+P, sending questionnaires to 2500 randomly selected Fellows; 703 Fellows returned usable surveys (28.1%). Despite almost universal awareness of the results of the WHI E+P (> 97%), almost half of the responding physicians did not find the results convincing and disagreed with the decision to stop the trial. In this further examination of the data, we identified characteristics of the respondents who were associated with either accepting or rejecting the WHI E+P. The year residency was completed, the relative importance a respondent attributed to randomized clinical trials (RCTs), concern about harms of action, and opinion of alternative therapies were significant factors. One of 5 respondents found the results convincing and agreed with the decision to end the trial (acceptors). One of 3 respondents did not find the results convincing and disagreed with the decision to end the trial (rejectors). Acceptors had completed residency more recently (1991 v. 1985, P = 0.001), rated evidence from RCTs as more important (P = 0.006), were more concerned with harms of action (22.4% v. 10.6%, P = 0.004), and were more likely to have a favorable opinion of alternative therapies to hormone therapy (64.1% v. 44.4%, P < 0.001).

Hormonal replacement therapy (HRT) in postmenopause: a reappraisal

Hormone replacement therapy (HRT) is the most effective treatment currently available for vasomotor and urogenital symptoms and decreased libido. Because harmful effects were evidenced in some clinical trials, health authorities now consider that risk-benefit considerations do not favour the use of HRT for prevention of cardiovascular diseases and bone fractures in postmenopausal women. However, experimental and clinical studies indicate that adverse effects of HRT may largely depend on the estrogen and progesterone/progestin formulation, dosage, mode of administration, patient's age, associated diseases, and duration of treatment. All estrogen formulations and modes of administration have similar beneficial effects on vasomotor and urogenital symptoms and on bone structure. But cardiovascular and invasive breast cancer risks are higher with oral estrogen than with transdermal estradiol, and also higher with many progestin compounds than with micronized progesterone. The combination of transdermal estradiol+micronized progesterone appears to be effective and relatively safe if elementary precautions are taken, and seems to be presently the best choice for HRT in most postmenopausal women. In the author's--heterodox--opinion, HRT may also be a good therapeutic choice to prevent bone loss, since alternative medications, including raloxifene and bisphosphonates, may have dramatic harmful effects in some patients. It might also have beneficial effects on the development of coronary disease in young postmenopausal women. HRT requires careful adjustment to each individual patient and continuous monitoring of clinical evolution. In the future, this adjustment could benefit from genetic screening to maximize in each individual the ratio between positive and adverse effects.

Discontinuing hormone replacement therapy: attenuating the effect on CVD risk with lifestyle changes

BACKGROUND

Concern about the potential risks associated with hormone replacement therapy (HRT) has left post-menopausal women and healthcare providers searching for safe and effective means for cardiovascular disease (CVD) risk factor reduction.

METHODS

The Woman On the Move through Activity and Nutrition study is a 5-year clinical trial (2002-2006) designed to test whether a lifestyle intervention will reduce measures of subclinical CVD. Participants were randomized at baseline to a health education or lifestyle change group. The impact of lifestyle intervention on CVD risk factors was examined in 240 women who were initially on HRT at baseline and either continued (n = 110) or discontinued (n = 130) by 18 months.

RESULTS

The lifestyle-change group significantly decreased weight, body mass index, waist circumference (all p<0.0001), total cholesterol (p=0.02), and LDL cholesterol (LDL-C) (p= 0.01), improved fat intake (p<0.0001), and increased leisure physical activity (p=0.005) when compared with the health education group. HRT discontinuation resulted in increased total cholesterol (p=0.04) and LDL-C (p=0.009). CVD risk factor changes were further explored by the HRT group, stratified by randomized group assignment. Within the health education arm, HRT discontinuers averaged over a 22-mg/dL increase in total cholesterol and LDL-C, while HRT continuers averaged less than 4 mg/dL (p=0.004 and 0.002, respectively). No such differences were noted in the lifestyle-change group (p=0.78 and 0.90, respectively).

CONCLUSIONS

Lifestyle modification was effective for CVD risk factor reduction in post-menopausal women. HRT discontinuation resulted in increased total cholesterol and LDL-C, which were successfully attenuated by a lifestyle intervention incorporating weight loss, physical activity, and dietary modification.

The Cardiovascular Effects of Selective Estrogen Receptor Modulators

Coronary artery disease (CAD) is the main contributor of mortality among postmenopausal women. Menopause-associated estrogen deficiency has both metabolic and vascular consequences that increase the risk for CAD. Hormone therapy (HT) has been reported to have a beneficial effect on metabolic and vascular factors influencing the incidence of CAD. Although observational studies have reported that HT reduces significantly the risk for CAD, randomized clinical trials (WHI, HERS, ERA) have questioned the efficacy of HT in primary and secondary CAD prevention despite confirming the lipid-lowering effect of HT. In the aftermath of the WHI, increased interest has been given to the action of selective estrogen receptor modulators (SERMs) and their effect on the cardiovascular system. The chemical structure of SERMs, either triphenylethilyn (tamoxifen) or benzothiophene (raloxifene) derivatives, differs from that of estrogens. SERMs are nonsteroidal molecules that bind, with high affinity, to the ER. SERMs induce conformational changes to the ligand-binding domain of the ER that modulate the ability of the ER to interact with coregulator proteins. The relative balance of coregulators within a cell determines the transcriptional activity of the receptor-ligand complex. SERMs therefore may express an estrogen-agonist or estrogen-antagonist effect depending on the tissue targeted. SERMs express variable effects on the metabolic and vascular factors influencing the incidence of CAD. SERMs have been reported to modulate favorably the lipid-lipoprotein profile. Toremifene expresses the most beneficial effect followed by tamoxifene and raloxifene, while ospexifene and HMR-3339 have the least effect and may even increase triglycerides. Raloxifene and tamoxifene decrease serum homocysteine levels and C-reactive proteins (CRP), which are both markers of CAD risk. Raloxifene has been reported to increase the nitric oxide (NO)-endothelin (ET)-1 ratio and, thus, contribute to proper endothelial function and vasodilation. Toremifene has no effect on the NO-ET-1 ratio. Finally, raloxifene decreases the vascular cell adhesion molecules and the inflammatory cytokines TNF-alpha and IL-6. Of the SERMs, raloxifene has had the most extensive evaluation regarding the effect on the vascular wall of endothelium. Although not confirmed by large clinical trials, raloxifene has been reported to have an effect on the cohesion of the intercellular junction (VE-cadherin) and the synthesis-degradation of extracellular matrix (MMP-2). The Multiple Outcomes Raloxifene Evaluation (MORE) study has reported that raloxifene may have a cardioprotective effect when administered to postmenopausal women at high risk for CAD disease.

Differential effect of hormone therapy and tibolone on lipids, lipoproteins, and the atherogenic index of plasma

The aim of our study was to assess the effect of various regimens and doses of hormone therapy and tibolone on the Atherogenic Index of Plasma (AIP). A total of 519 postmenopausal women attending our menopause clinic were studied in a prospective design. Women with climacteric symptoms were randomly assigned to receive 1 of the following regimens: tibolone 2.5 mg, conjugated equine estrogens 0.625 mg plus medroxyprogesterone acetate 5 mg (CEE/MPA), 17beta-estradiol 2 mg plus norethisterone acetate 1 mg (E2/NETA), or 17beta-estradiol 1 mg plus norethisterone acetate 0.5 mg (low E2/NETA). Serum parameters were assessed at baseline and after 6 months and included total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, apolipoprotein A1 and apolipoprotein B. The AIP was assessed as the log (triglycerides [mmol/L]/HDL-C [mmol/L]). CEE/MPA treatment associated with lower mean LDL-C but higher mean triglyceride levels (-15.5 mg/dL +/- 3.6, P = 0.0001; 12.6 mg/dL +/- 4.8, P = 0.01). Furthermore, CEE/MPA treatment resulted in higher AIP levels (0.073 +/- 0.021, P = 0.001). On the contrary, both E2/NETA regimens and tibolone associated with lower mean triglyceride and HDL-C levels (E2/NETA, triglycerides: -9.8 mg/dL +/- 5.0, P = 0.049; HDL-C: -4.9 mg/dL +/- 1.8, P = 0.01, low E2/NETA triglycerides: -12.5 mg/dL +/- 4.1, P = 0.003; HDL-C: -4.7 mg/dL +/- 1.3, P = 0.001; tibolone, triglycerides: -21.9 mg/dL +/- 2.7, P = 0.0001; HDL-C: -12.7 mg/dL +/- 1.1, P = 0.0001). None of the 3 regimens had any effect on AIP. The effect of a particular regimen of hormone therapy on the lipid-lipoprotein profile differs depending on the parameter assessed. The use of unified markers such as AIP will be helpful in evaluating the overall effect of lipid-lipoprotein modulation on the cardiovascular system. In fact, the concurrent assessment of the therapy effect on both LDL-C and AIP may be more dependable in evaluating the cardiovascular impact of a given regimen.

The neurology of menopause

BACKGROUND

Menopause is a normal milestone experienced annually by 2 million American women each year, and many women are concerned about the relation between menopause and health. Associated hormonal changes have the potential to influence neurologic disease, as do hormonal therapies prescribed for menopausal symptoms or other conditions. The objective of this article is to increase neurologists' awareness of the relation between menopause and neurologic illness.

REVIEW SUMMARY

This was a focused review of 4 common neurologic disorders potentially influenced by menopause or by estrogen-containing hormone therapy: stroke, epilepsy, Parkinson disease, and Alzheimer disease. Hormonal effects are germane to each illness, although clinical implications are clearer for stroke and Alzheimer disease than for epilepsy and Parkinson disease. For women with epilepsy, few clinical data directly address the role of menopause or estrogen-containing hormone therapy on seizure frequency. Relevant clinical research findings on Parkinson disease are inconsistent and provide an inadequate basis for practice guidelines. There is clinical trial evidence that hormone therapy does not reduce stroke incidence and may increase risk of ischemic stroke; hormone therapy cannot be recommended for stroke prevention. The natural menopausal transition is not characterized by objective memory loss. There is clinical trial evidence that hormone therapy should not be used for the postmenopausal woman age 65 years or older for the preservation of cognitive skills, prevention of dementia, or treatment of dementia due to Alzheimer disease. Long-term cognitive consequences of short-term hormone therapy used by younger women for menopausal symptoms remains an important area of uncertainty.

CONCLUSIONS

Increased awareness of hormonal influences on neurologic illness is important for the practicing neurologist.

Hormone therapy and coronary heart disease: the role of time since menopause and age at hormone initiation

BACKGROUND

Apparently discrepant findings have been reported by the Women's Health Initiative (WHI) trial compared with observational studies of postmenopausal hormone therapy (HT) and coronary heart disease (CHD).

METHODS

We prospectively examined the relation of HT to CHD, according to timing of hormone initiation relative to age and time since menopause. Participants were postmenopausal women in the Nurses' Health Study, with follow-up from 1976 to 2000. Information on hormone use was ascertained in biennial, mailed questionnaires. We used proportional hazards models to calculate multivariable adjusted relative risks (RR) and 95% confidence intervals (CI). We also conducted sensitivity analyses to determine the possible influence of incomplete capture of coronary events occurring shortly after initiation of HT.

RESULTS

Women beginning HT near menopause had a significantly reduced risk of CHD (RR = 0.66, 95% CI 0.54-0.80 for estrogen alone; RR = 0.72, 95% CI 0.56-0.92 for estrogen with progestin). In the subgroup of women demographically similar to those in the WHI, we found no significant relation between HT and CHD among women who initiated therapy at least 10 years after menopause (RR = 0.87, 95% CI 0.69-1.10 for estrogen alone; RR = 0.90, 95% CI 0.62-1.29 for estrogen with progestin). Among women who began taking hormones at older ages, we also found no relation between current use of estrogen alone and CHD (for women aged 60+ years, RR = 1.07, 95% CI 0.65-1.78), although there was a suggestion of possible reduced risk for combined HT (RR = 0.65, 95% CI 0.31-1.38). In sensitivity analyses, we found that the incomplete capture of coronary events occurring shortly after initiation of HT could not explain our observation of a reduced risk of coronary disease for current users of HT.

CONCLUSIONS

These data support the possibility that timing of HT initiation in relation to menopause onset or to age might influence coronary risk.

The impact of menopause and lifestyle factors on blood and bone lead levels among female former smelter workers: the Bunker Hill Study

OBJECTIVE

The Bunker Hill mine in Idaho operated from 1886 to 1981. In the 60's and 70's it provided approximately 25% of the primary lead in the United States. Women first began working on the production and maintenance lines in 1972. This study examines the impact of menopause and several occupational and lifestyle factors as determinants of blood and bone lead levels among 73 female former smelter workers.

METHODS

Blood lead levels were analyzed using graphite furnace atomic absorption spectroscopy. The (109)Cd K X-ray fluorescence system was used to measure calcaneus and tibia bone lead content. Information was obtained on reproductive history, alcohol and cigarette consumption, education, and hormone replacement therapy (HRT).

RESULTS

Postmenopausal women (n = 47) had significantly (P < 0.002) higher blood lead levels (3.48 microg/dl) than did premenopausal women (n = 26) (2.19 microg/dl). The best predictors of blood lead levels were smoking (>10 or < or =10 cigarettes/day), natural menopause, technical or community college education, manager or technical worker, and past or present use of HRT. The best predictors of calcaneus bone lead levels (P < 0.2) were technical workers, such as miner; natural menopause; and smoking >10 cigarettes/day; level of education; 1-2 pregnancies; and age (>60 years).

CONCLUSIONS

Lead exposure results in higher blood lead levels especially during menopause.

Hormone replacement therapy and acute myocardial infarction: a large observational study exploring the influence of age

BACKGROUND

We examined whether the discrepancy between observational studies and randomized clinical trials (RCTs) on the effect of hormone replacement therapy (HRT) on myocardial infarction (MI) could be explained by differences in age of participants at the time of either HRT initiation or the MI event.

METHODS

A matched case-control study was performed using the General Practice Research Database. Cases (n = 22 225) had a first diagnosis of MI between 1987 and 2001; up to six controls (n = 144 085) were matched to each case based on age, sex, and practice. Conditional logistic regression was performed adjusting for traditional cardiovascular risk factors, as well as, cardiovascular drug use and consultation rate.

RESULTS

HRT users had a lower overall risk of MI compared with never users [odds ratio (OR): 0.76; 95% confidence interval (95% CI) 0.68-0.86); results were similar for opposed (OR: 0.73; 95% CI 0.68-0.86) and unopposed (OR: 0.79; 95% CI 0.66-0.96) therapy. This apparent benefit increased with older age at HRT initiation(18-44 years: OR = 0.99; 95% CI 0.74-1.33; 45-54 years: OR = 0.84; 95% CI 0.71-1.00; 55-64 years: OR = 0.67; 95% CI 0.54-0.82; 65-74 years: OR = 0.50; 95% CI 0.34-0.74; >75 years: OR = 0.55; 95% CI 0.23-1.32). Moreover, the cardioprotective effect was greater for MIs occurring at older ages (P-value for interaction = 0.003).

CONCLUSION

The effect of HRT on MI becomes more pronounced with older age at initiation and at older ages at the time of an MI event. These findings contradict the hypothesis that the apparent protection seen in observational studies was due to the inclusion of younger participants.

Toremifene: an evaluation of its safety profile

Toremifene has been in clinical use for 8 years for the treatment of advanced hormone-sensitive breast cancer and the adjuvant treatment of early breast cancer. More than 350,000 patient treatment years have accumulated, sufficient to allow evaluation of its longer-term safety profile in comparison with tamoxifen and, where possible, with raloxifene and aromatase inhibitors. We reviewed all preclinical and clinical safety data from 1978 to 2004 and comparative clinical safety data between October 1995 and the end of 2004. Secondary endometrial cancer incidence was lower with toremifene than with tamoxifen and was similar to that with raloxifene. It is speculated that toremifene may unmask existing endometrial tumors rather than induce new events. The risk of stroke, pulmonary embolism, and cataract may be lower with toremifene than with tamoxifen and the risk of pulmonary embolism and deep vein thrombosis lower than with raloxifene. Beneficial estrogen agonistic effects were equivalent to those of tamoxifen regarding bone mineral density and superior regarding lipid profiles.

Effects of raloxifene, hormone therapy, and soy isoflavone on serum high-sensitive C-reactive protein in postmenopausal women

OBJECTIVE

To compare the effects of raloxifene, estradiol valerate plus dienogest, and soy isoflavones (genistein) on serum concentrations of high-sensitive C-reactive protein in healthy postmenopausal women.

METHODS

The 80 healthy postmenopausal women enrolled in the study were randomly allocated to receive 60 mg of raloxifene, 2 mg of estradiol valerate plus dienogest, 40 mg of genistein, or placebo (n=20 in each group). Blood samples were collected at the start of the study and at 3 and 6 months. Lipid profile was also determined.

RESULTS

Only the group receiving estradiol valerate plus dienogest showed an increase in serum levels of high-sensitive C-reactive protein compared with baseline values and values in the control and other groups. All 3 treatments resulted in an increase in high-density lipoprotein cholesterol levels and a decrease in total, low-density, and very-low-density lipoprotein cholesterol levels.

CONCLUSIONS

Estradiol valerate plus dienogest, but not raloxifene and genistein, increase serum high-sensitive C-reactive protein levels. All 3 treatments, however, have an estrogen-like effect on serum lipid profile.

Calcitropic hormones, bone turnover, and lead exposure among female smelter workers

To study the association between levels of lead in blood and bone among female former smelter workers in Bunker Hill, Idaho, the authors performed a longitudinal study using homeostatic regulators of calcium and biomarkers of bone turnover. The authors measured participants' blood lead levels (by means of a graphite furnace atomic absorption spectrophotometer) and tibia-bone lead levels (by means of the 109Cd K x-ray fluorescence system) in 1994 and again in 2000; serum ionized calcium, parathyroid hormone, osteocalcin, urinary deoxypyridinoline, pyridinoline, and 1, 25-dihydroxyvitamin D were measured. After controlling for weight and age, significant predictors of changes in blood lead levels from 1994 to 2000 in postmenopausal women were duration of employment, higher ionized calcium levels, alcohol consumption, and higher parathyroid hormone levels. Predictors of change in tibia-bone lead levels in the same group of women were employment in a technical job such as mining and higher urinary pyridinoline levels (p < .05). Changes in blood and bone lead levels over time were associated with increased bone resorption, especially among postmenopausal women.

Strategies for managing breast cancer risk after the menopause

Postmenopausal women in Western societies are conscious of breast cancer as a potential cause of death and ill health, which they wish to avoid with the advice of their doctors. Yet many factors that predispose women to the development of cancer will have been laid down before the menopause, in their genetic makeup or during their adolescent years. Even in middle age it is important to take account of the intrinsic level of risk, and to give women advice tailored to their own individual risk level. This results from their family history, previous diseases such as benign breast disease, and previous treatment for breast cancer or Hodgkin's disease. For those at the highest level of risk, strategies will include regular screening, prophylactic mastectomy, and the use of chemoprevention agents, such as tamoxifen. These women should avoid hormone replacement therapy (HRT) and control their menopausal symptoms and osteoporosis through the use of other agents now available - venlafaxine for menopausal symptoms and bisphosphonates for osteoporosis. Raloxifene is an agent under trial that may be valuable for breast cancer control as well as for osteoporosis. Women at standard population risk will require less robust preventive strategies, which will include screening and lifestyle modification. Their decisions regarding HRT should now be modified by recent evidence of associated risks. Recent studies show that tibolone causes less mammographic density and has a lower relative risk of breast cancer than combined estrogen/progestogen preparations. There is limited evidence that controlling obesity, participating in exercise and adopting a diet low in fats and high in fruit and vegetables will alter risk at this age. These precautions will, however, reduce the risk of other diseases common in this age group, such as hypertension, heart disease, stroke, and type 2 diabetes mellitus. Alcohol, even in small amounts, is a risk factor for breast cancer. Given the cardioprotective effect of moderate alcohol intake, advice on alcohol must reflect the individual relative risk of cardiovascular disease and breast cancer. Personal risk assessment is relevant for all women. Screening and a healthy lifestyle are worthwhile approaches for all, with the more aggressive approaches such as chemoprevention and prophylactic surgery reserved for those who have substantially elevated levels of risk. Once the menopause has passed, screening is probably the most effective evidence-based tool for breast cancer control by early diagnosis.

Gender influences endothelial-dependent arterial dilatation via arterial size in youth

BACKGROUND

Reduced endothelial-dependent arterial dilatation (EDAD) has been suggested as an early marker of arteriosclerosis, since it has been reported to correlate with known cardiovascular disease (CVD) risk factors. It is unclear, however, whether gender plays a mediating or a moderating role in these relationships. The aim of this study was to evaluate the influence of gender on EDAD in youth at risk for CVD.

METHODS

The sample population of 261 individuals (mean age, 20 yr; SD, 3 yr) consisted of 148 African Americans, 113 European Americans, 133 males, and 128 females, all with a verified family history of CVD (ie, hypertension, myocardial infarction). Anthropometrics, sociometrics, hemodynamics, brachial artery diameter, left ventricular mass, and relative wall thickness were measured and used as independent variables. EDAD (dependent variable) was expressed as percent (%) change of brachial artery diameter to reactive hyperemia induced by pressure cuff occlusion and release. Artery diameters were calculated via an automated border detection system.

RESULTS

Percent EDAD change was inversely related to initial diameter of the brachial artery. Mean percent EDAD change was 14.37% for female subjects compared with 10.48% for male subjects. The gender difference was a function of smaller initial artery size in the female subjects. When initial diameter and gender were considered simultaneously within a multivariate model, the gender effect was eliminated. Although a large prediameter effect remained, the relationship between prediameter and EDAD was greater in female than in male subjects (ie, interaction/moderating effect).

CONCLUSION

The data suggest that the smaller the artery is, the more it will dilate. Further EDAD investigations are needed to predict arteriosclerosis, taking into account of the gender difference in vessel size.

Serum lipids and lipoproteins in relation to endogenous and exogenous female sex steroids and age

BACKGROUND

Different studies have presented conflicting results concerning the effect of menopause on lipid levels.

AIMS

To describe the serum lipid profile and the prevalence of hyperlipidemia in women aged 50-60 and the perceived relation to endogenous and exogenous hormones and age.

METHODS

Out of a total population of 10,766 women aged 50-59 years, 6908 (64%) participated in a health assessment program, including a lipid profile evaluation. The women were grouped according to hormonal status into pre-menopausal (PM), post-menopausal without hormone replacement therapy (PM0) (HRT) and post-menopausal with hormone replacement therapy (PMT). Age groups used were 50-54, 55-59 and >60 years.

RESULTS

Serum cholesterol and triglycerides increased significantly by age in PM0 (P < 0.0001) and triglycerides also in PMT (P < 0.0001). Serum high-density lipoprotein cholesterol (HDL) levels decreased significantly by age in PMT (P = 0.002) and low-density lipoprotein cholesterol (LDL) increased in PM0 (P < 0.0001) and PMT (P = 0.007). The co-prevalence of levels of cholesterol >7 and triglycerides >2 mmol/l decreased by age in PM, but increased by age in PM0 and PMT. The prevalence of high-risk lipid levels and the prevalence of coexisting additional two metabolic risk factors were higher in the PM0 compared to the PMT group. The prevalence of serum triglycerides >1.5 and serum cholesterol >5 mmol/l were increasing by age in each of the hormonal groups.

CONCLUSIONS

These data suggest that loss of endogenous sex steroids contribute substantially to an increased atherogenic lipid profile. Hormone replacement therapy may partly reverse these differences.

Oral contraceptives, menopause hormone replacement therapy, and risk of stroke

OBJECTIVES

To review available evidence from observational and intervention studies on oral contraceptives (OC), menopause hormone replacement therapy (HRT) and stroke.

METHODS

Qualitative literature review.

RESULTS

High dose OC were associated to elevated risk of stroke. However, the use of low oestrogen OC preparations by non-hypertensive women not at high baseline risk is not related to an appreciable risk of stroke. With reference to HRT, randomised clinical trials showed an excess risk of stroke among users of combined therapy.

CONCLUSIONS

In non-hypertensive women below age 35 stroke is not materially related to the use of low dose OC. HRT is associated to a moderate excess risk in randomised studies, and should therefore not be used for the prevention of stroke.

“Rise and fall” of hormone therapy in postmenopausal women with cardiovascular disease

Whereas observational data for postmenopausal women using hormone therapy (HT) have shown a protective effect against cardiovascular disease, prospective, randomized trials have demonstrated a harmful effect on the vascular system. This study describes the effects of HT on lipids, hemostatic parameters, inflammation, and the vascular wall. Reasons for the different results of observational and experimental studies of HT are postulated. The timing of hormonal supplementation seems crucial. Used chronically, HT has no harmful effects; however, first-time use of HT after a recent cardiovascular event results in an early increase in adverse cardiovascular events. In most observational studies, women started HT for postmenopausal symptoms, whereas in experimental studies, women started HT 10 to 20 years or longer after menopause. Cumulative evidence supports the hypothesis that HT has more effect in maintaining vascular health than in alleviating endothelial dysfunction. HT has not proven beneficial in the long term in women at risk of a cardiovascular event. The interval between menopause and the start of HT plays a crucial role in the effectiveness of HT in the vascular system.

Cardiovascular responses to hypocretin-1 in nucleus ambiguus of the ovariectomized female rat

Experiments were done to investigate the effect of chronic estrogen (E; 30 pg/ml plasma) treatment (15-25 days) in the ovariectomized (OVX) female Wistar rat on the cardiovascular responses to hypocretin-1 (hcrt-1) in the nucleus ambiguus (Amb). Microinjections of hcrt-1 (0.5-2.5 pmol) into the external formation of Amb (Ambe) in the urethane anaesthetized, E treated OVX animal or OVX only animal, elicited a dose-related decrease in heart rate (HR). On the other hand, hcrt-1 injections into Ambe did not elicit consistent changes in mean arterial pressure (MAP). The HR response was mediated by vagal excitation as ipsilateral vagotomy abolished the bradycardia response. The bradycardia responses were consistently of greater magnitude and longer duration in the OVX+E animals compared to the OVX only female animals. Finally, it was found that the reflex bradycardia to activation of arterial baroreceptors, as a result of increasing systemic arterial pressure with phenylephrine, was only significantly potentiated in the OVX+E animals. These data suggest that hcrt-1 in the Ambe of the female elicits an increase in vagal cardiomotor neuronal activity to the heart, and that the circulating level of E alters not only the sensitivity of Ambe neurons to hcrt-1 but also the sensitivity of these neurons during activation of baroreceptor afferent inputs.

Estrogen alters the bradycardia response to hypocretin-1 in the nucleus tractus solitarius of the ovariectomized female

Experiments were performed to investigate the effect of 17beta-estradiol (E; 30 pg/ml plasma) treatment (15-25 days) in the ovariectomized (OVX) female Wistar rat on the cardiovascular responses to hypocretin-1 (hcrt-1) in the nucleus tractus solitarius (NTS). In an initial series of experiments, the distribution of hcrt-1-like immunoreactivity within the region of the NTS was mapped in both OVX only and OVX+E animals. Hcrt-1 immunoreactivity was found throughout the NTS region in both groups of females, predominantly within the caudal interstitial, commissural, medial and lateral subnuclei of the NTS. The relative density of hcrt-1 immunoreactivity in all NTS subnuclei was similar in both female groups. Microinjections of hcrt-1 (0.5-10 pmol) into the caudal lateral and medial subnuclei of the NTS complex of the alpha-chloralose of the urethane-anaesthetized E-treated OVX rat elicited a dose-related decrease in heart rate (HR). On the other hand, although a dose-response effect on arterial pressure was evident, significant arterial pressure responses were observed only at the higher dose of hcrt-1 (>2.5 pmol). In the OVX only female rat, microinjection of hcrt-1 into similar NTS sites elicited a bradycardia and depressor response only at the highest dose of hcrt-1, and these responses were significantly smaller in magnitude than those elicited in the OVX+E animal. In addition, in the OVX only animals, a few sites within the caudal commissural subnucleus of the NTS complex were found at which hcrt-1 elicited tachycardia and pressor responses. Finally, it was found that the reflex bradycardia to the activation of arterial baroreceptors as a result of increasing systemic arterial pressure with phenylephrine (2-4 microg/kg) was significantly potentiated in the OVX+E animals only. These data suggest that hcrt-1 in the NTS of the female activates a neuronal circuit that controls the circulation and that the circulating level of E alters the sensitivity of these cardiovascular circuits to hcrt-1.