Effects of continuous low-dosage hormonal replacement therapy on lipoprotein metabolism in postmenopausal women

Peripheral vasodilation is reduced during exercise in perimenopausal women with elevated cardiovascular risk

OBJECTIVE

The menopausal transition has a negative effect on peripheral dilation in response to various stimuli including shear stress and exercise. Whether the presence of elevated traditional cardiovascular disease (CVD) risk factors in women going through menopause exacerbates the adverse effect on peripheral vasodilation is unclear.

METHODS

Forty-four perimenopausal women with relatively low CVD risk were divided into tertiles based on atherosclerotic CVD (ASCVD) 10-year risk scores (lowest: 0.1%-0.5%, middle: 0.6%-0.9%, higher: >1%). Comparisons were made across tertile groups for the femoral artery vascular conductance (FVC) response to single-leg knee extension exercise (0, 5, 10, 15 W) as measured using Doppler ultrasound.

RESULTS

At higher exercise intensities, FVC was lower in women in the tertile group with the highest ASCVD 10-year risk scores (10 W: 6 ± 2 mL/min/mm Hg, 15 W: 8 ± 3 mL/min/mm Hg) compared to women in the lowest tertile group (10 W: 9 ± 3 mL/min/mm Hg, P = 0.01; 15 W: 12 ± 3 mL/min/mm Hg, P < 0.01) and middle tertile group (10 W: 10 ± 4 mL/min/mm Hg, P < 0.01; 15 W: 12 ± 5 mL/min/mm Hg, P < 0.01). The overall increase in FVC during exercise from 0 to 15 W remained lower (P ≤ 0.01) in women with the highest ASCVD risk scores compared to the other two tertile groups even after adjustment for chronological age, arterial stiffness, and fat-free mass adjusted aerobic fitness level.

CONCLUSION

Our results show that the presence of mild differences in ASCVD risk scores may be associated with a blunted active limb blood flow during leg exercise in mid-life women transitioning through menopause.

The effects of progesterones on blood lipids in hormone replacement therapy

The safety of progestogens as a class has drawn much attention after the publication of data from the Women’s Health Initiative (WHI) trial, particularly with respect to cardiovascular disease. Depending on the chemical structure, pharmacokinetics, receptor affinity and potency of action, progestogens have a divergent range of properties that may translate to very different clinical effects. The purpose of this review is to describe the role of varied progestogens in hormone replacement therapy (HRT), especially focusing on blood lipids, which are the most important parameters for assessing cardiovascular disease risk.

SERUM LIPID PROFILE OF SPAYED AND NON-SPAYED FEMALE DOGS ASSOCIATED WITH THE BODY CONDITION SCORE

Neutering females may be associated to weight gain in dogs. In order to diagnose possible alterations, such as diabetes and hyperlipidemias, laboratory assessment of carbohydrate and lipid metabolism is important. The aim of this study was to verify glycemia and serum lipid profile in non-spayed and spayed female dogs, and associate these results with the body condition score. Thirty-two spayed (n=16) and non-spayed (n=16) female dogs had their blood collected for biochemical analysis, and were classified as to their body condition score (BCS). Nine had normal BCS, 10 were overweight, and 13 were obese. Little difference was observed among spayed and non-spayed dogs. Glycemia of spayed canine females is higher than that of non-spayed dogs, regardless of the body condition score. Likewise, total cholesterol levels are higher in non-spayed females. The HDL is higher in non-spayed obese dogs than in spayed dogs with the same body condition, this parameter did not differ in other weight groups. Contrary to what happens in post-menopausal women, spaying dogs does not seem to have such a strong effect on the metabolic parameters assessed. This study revealed unique results, where neither spaying nor weight group had a strong association with metabolic alterations.

Sex differences in lipid and lipoprotein metabolism: it's not just about sex hormones

It is commonly thought that sex hormones are important regulators of plasma lipid kinetics and are responsible for sexual dimorphism in the plasma lipid profile. Here we discuss the findings from studies evaluating lipid and lipoprotein kinetics in men and women in the context of what we know about the effects of exogenous sex hormone administration, and we conclude that it is more complicated than that. It has become clear that normal physiological alterations in the hormonal milieu (i.e. due to menopause or throughout the menstrual cycle) do not significantly affect plasma lipid homeostasis. Furthermore, parenterally administered estrogens have either no effect or only very small beneficial effects, whereas orally administered estrogens raise plasma triglyceride concentrations--a phenomenon that is not consistent with the observed sex differences and likely results from the hepatic "first-pass effect." The effects of progestogens and androgens mimic only in part the differences in plasma lipids between men and women. Thus, the underlying physiological modulators of plasma lipid metabolism responsible for the differences between men and women remain to be elucidated.

Impact of a New Formulation of Low-Dose Micronised Medroxyprogesterone and 17-beta Estradiol on Lipid Profiles in Menopausal Women

OBJECTIVE

To evaluate the impact of cyclical low-dose micronised medroxyprogesterone (5 mg/day for the last 12 days of each 28-day cycle) in combination with 17-beta estradiol (2 mg/day continuously) on lipid profiles in postmenopausal women treated for 12 months.

DESIGN AND SETTING

Open, noncomparative, prospective study carried out in general practice.

PATIENTS AND RESULTS

98 female patients were enrolled; seven failed to meet entry criteria, 20 withdrew after developing adverse events, three were lost to follow up and one withdrew for personal reasons; 67 (67.3%) completed 12 months' treatment. Levels of total cholesterol (6.42 mmol/L at baseline) fell 8.4% (p = 0.0001) after 12 months' treatment, while total triglycerides (1.39 mmol/L at baseline) increased by 12.2% (p = 0.007), low density lipoprotein cholesterol (4.27 mmol/L at baseline) fell 18.3% (p = 0.0001) and high density lipoprotein (HDL) cholesterol (1.59 mmol/L at baseline) increased by 6.9% (p = 0.0001). The most frequently reported adverse events were menorrhagia, breast tenderness, cervical polyps or cysts, bloating, fatigue or lethargy, influenza or influenza-like syndrome, back pain and headaches.

CONCLUSIONS

Treatment with oral micronised 17-beta estradiol 2 mg/day continuously and medroxyprogesterone 5 mg/day for 12 days of each 28-day cycle lead to changes in lipid profiles in postmenopausal women that had favourable implications for the risk of development of coronary heart disease. The 17-beta estradiol-induced increase in the level of HDL cholesterol was maintained during combination with low-dose cyclical medroxyprogesterone for 12 months.

Appropriate use of hormones should alleviate concerns of cardiovascular and breast cancer risk

Since the publication of several recent randomized trials in the United States, prescriptions for hormonal therapy have dropped precipitously. This has been due, in large part, to the concerns about the increased risk of cardiovascular (CV) disease and breast cancer among the hormone users. This review takes the perspective that the appropriate use of hormones largely alleviates these concerns. The appropriate use of hormones pertains to treating younger, healthy women who have menopausal symptoms as well as using low-doses of hormones. In the randomized trials, suggesting an increased CV risk, the older women were largely asymptomatic and had other CV risk factors. Data are presented to suggest that there is no increased CV risk with hormonal therapy in younger, healthy women within 5 years of menopause. Moreover, a model is presented to attempt to explain the potential of preventing CV disease when estrogen is begun early, and the relative hazard associated with later use. The risk of breast cancer with hormonal therapy is put into perspective with the realization that this risk is related to hormonal dose and duration of use, and that the absolute risk remains small. Use of progestogens, in particular, appears to enhance this risk. The appropriate use of hormones also pertains to using lower-doses. Here data are presented showing efficacy with lower-doses and improved safety. With the use of lower-doses of estrogens, the progestogen dose, as required in women with a uterus, can be minimized.

Progestogens of varying androgenicity and cardiovascular risk factors in postmenopausal women receiving oestrogen replacement therapy

OBJECTIVE

Medroxyprogesterone (MP) was used as the progestogen in randomized clinical trials of postmenopausal hormone replacement on cardiovascular risk. To attempt to understand the lack of benefit in these trials, we have examined the effects of MP and two other progestogens, the less androgenic desogestrel (DG) and the more androgenic norethisterone (NE), on cardiovascular risk factors against a background of oestrogen therapy.

DESIGN AND MEASUREMENTS

Thirty-four women were treated with conjugated equine oestrogens (CEE) 0.625 mg daily alone for 12 weeks, followed in random order by each of the three progestogens (DG 75 microg, MP 10 mg and NE 1 mg daily) given sequentially for three 12-week cycles while maintaining the same CEE treatment. We measured serum lipoproteins, paraoxonase activity, C-reactive protein (CRP), fibrinogen, fasting glucose and insulin levels at baseline, at the end of the oestrogen-only phase and at the end of each of the combined oestrogen and progestogen phases.

RESULTS

The addition of progestogens to CEE maintained the oestrogen-induced reduction in apolipoprotein B (apo B) and lipoprotein (a) [Lp(a)], and further lowered total cholesterol (P < 0.01) and fibrinogen (P < 0.001). CEE raised serum triglyceride (P < 0.001) and CRP (P < 0.01) concentrations, which reverted towards pre-oestrogen levels with progestogens. Progestogens significantly reduced high density lipoprotein (HDL) cholesterol (P < 0.05). NE was associated with the greatest reduction in HDL cholesterol and apo A1, but was most effective in preserving paraoxonase activity and reducing the potentially unfavourable oestrogen-induced increases in triglycerides and CRP.

CONCLUSION

Preconceptions that more androgenic progestogens necessarily have more unfavourable effects on cardiovascular risk factors may require revision.

Perfil lipoprotéico de cadelas submetidas à ovário-histerectomia com e sem reposição estrogênica

Doze cadelas mestiças, adultas, foram submetidas à ovário-histerectomia e posteriormente distribuídas em dois grupos de seis animais. Um dos grupos recebeu estrógenos naturais conjugados na dose de 0,01mg/kg, via oral, a cada 48 horas, durante 12 meses, e o outro serviu como controle. A cada 60 dias foram realizadas colheitas de sangue e obtidos os valores de colesterol total, triglicerídeos, HDL, LDL e VLDL. Houve elevação do colesterol total e do LDL nas fêmeas sem reposição de hormônio. No grupo que recebeu estrógenos houve elevação do HDL. A ovário-histerectomia influenciou significativamente o perfil lipoprotéico; a reposição com estrógenos foi capaz de preservar esse perfil nas cadelas castradas.

The effect of sodium monofluorophosphate therapy on lipid and lipoprotein metabolism in postmenopausal women

OBJECTIVE

To investigate the effect of a low dose of fluoride, combined with hormone replacement therapy (HRT) or alone, on serum lipids and lipoproteins in postmenopause.

STUDY DESIGN

One hundred and thirty-five healthy postmenopausal women were enrolled in this prospective study and randomly assigned to: (1) oral monofluorophosphate (MFP, 25 mg per day); or (2) HRT (a combination of oral conjugated estrogen 0.625 mg in conjunction with medroxyprogesterone acetate 5 mg daily); or (3) HRT + MFP; or (4) placebo, for 18 months. Serum lipid and lipoprotein levels were measured at enrollment and at the end of the study period.

RESULTS

Total cholesterol was not significantly different among groups, with a decrease in the HRT and the HRT + MFP groups (respectively, -7.8 and -7.9%), and a small increase in the MFP group (0.4%). LDL-C did not differ significantly in the groups, with a decrease in the HRT and HRT + MFP groups (respectively, -10.3 and -10.4%), and a slight increase in the MFP group (0.8%). TG decreased with -12 and 11.8% in the HRT and HRT + MFP groups (P = 0.052 and 0.055, respectively), but a slight increase was seen in the MFP group (1.4%). For HDL-C, both HRT and HRT+MFP groups showed a small increase (respectively, 3.5 and 3.6%), whereas MFP group showed a slight decrease (-0.9%, NS).

CONCLUSION

We conclude that long-term use of a low dose of fluoride had no significant adverse changes in the lipid and lipoprotein profile in postmenopause. It neither attenuated nor potentiated the effect of HRT on lipids and lipoproteins.

Effects of postmenopausal hormone replacement therapy on lipid, lipoprotein, and apolipoprotein (a) concentrations: analysis of studies published from 1974-2000

OBJECTIVE

To establish reference estimates of the effects of different hormone replacement therapy (HRT) regimens on lipid and lipoprotein levels.

DESIGN

Review and pooled analysis of prospective studies published up until the year 2000.

SETTING

Clinical trials centers, hospitals, menopause clinics.

PATIENT(S)

Healthy postmenopausal women.

INTERVENTION(S)

Estrogen alone, estrogen plus progestogen, tibolone, or raloxifene in the treatment of menopausal symptoms.

MAIN OUTCOME MEASURE(S)

Serum high- and low-density lipoprotein (HDL and LDL) cholesterol, total cholesterol, triglycerides, and lipoprotein (a).

RESULT(S)

Two-hundred forty-eight studies provided information on the effects of 42 different HRT regimens. All estrogen alone regimens raised HDL cholesterol and lowered LDL and total cholesterol. Oral estrogens raised triglycerides. Transdermal estradiol 17-beta lowered triglycerides. Progestogens had little effect on estrogen-induced reductions in LDL and total cholesterol. Estrogen-induced increases in HDL and triglycerides were opposed according to type of progestogen, in the order from least to greatest effect: dydrogesterone and medrogestone, progesterone, cyproterone acetate, medroxyprogesterone acetate, transdermal norethindrone acetate, norgestrel, and oral norethindrone acetate. Tibolone decreased HDL cholesterol and triglyceride levels. Raloxifene reduced LDL cholesterol levels. In 41 studies of 20 different formulations, HRT generally lowered lipoprotein (a).

CONCLUSION(S)

Route of estrogen administration and type of progestogen determined differential effects of HRT on lipid and lipoprotein levels. Future work will focus on the interpretation of the clinical significance of these changes.

The effects of hormone replacement therapy on plasma lipids in type II diabetes

OBJECTIVES

The effects of hormone replacement therapy on cardiovascular risk factors in postmenopausal women with non-insulin dependent diabetes mellitus (type II diabetes) is uncertain.

METHODS

The effects of estrogen replacement therapy (ERT, conjugated equine estrogen0.625mg orally daily), combined estrogen and continuous progestogen therapy (HRT, 0.625 mg of conjugated equine estrogens plus medroxyprogesterone acetate 5 mg daily) or placebo was compared in 20 postmenopausal type II diabetic women and 20 normal postmenopausal women in a double blind, randomised, crossover study. Patients receiving insulin were excluded from the study and all lipid modifying drugs were ceased at least 4 weeks prior to randomisation. Other medication including oral hypoglycaemics was kept constant for the duration of the study.

RESULTS

Women with type II diabetes were a similar age (58.7+/-1.3 years) to the non-diabetic women (59.6+/-1.6 years) but they had a significantly greater body mass index, a higher incidence of treated hypertension, higher fasting plasma glucose levels, higher triglycerides and lower HDL cholesterol levels than non-diabetic women. ERT reduced total cholesterol and LDL cholesterol by a similar extent (8.9-12.3%) in normal and type II diabetic women and increased HDL cholesterol to a similar extent in both groups (11.0 and 8.9% respectively). ERT did not significantly alter fasting triglyceride levels in either group. The addition of medroxyprogesterone acetate 5 mg daily abolished the increase in HDL cholesterol associated with ERT in both groups but did not significantly affect any of the other lipid measurements. ERT and HRT did not significantly alter fasting insulin levels nor alter fasting glucose levels in either non-diabetic women or women with type II diabetes.

CONCLUSIONS

ERT and HRT have similar effects on lipids in women with type II diabetes and non-diabetic women after 1 month of therapy.

Phyto-oestrogens: where are we now?

Phyto-oestrogens have emerged from their esoteric role in animal husbandry following the hypothesis that the human Western diet is relatively deficient in these substances compared with societies where large amounts of plant foods and legumes are eaten. Evidence is beginning to accrue that they may begin to offer protection against a wide range of human conditions, including breast, bowel, prostate and other cancers, cardiovascular disease, brain function, alcohol abuse, osteoporosis and menopausal symptoms. Of the two main classes of these weak oestrogens, the isoflavones are under intensive investigation due to their high levels in soyabean. Like the 'anti-oestrogen' Tamoxifen, these seem to have oestrogenic effects in human subjects in the cardiovascular system and bone. Although previously only available from food, isoflavones are now being marketed in health-food supplements or drinks, and tablets may soon be available over the counter as 'natural' hormone-replacement therapy. In cancer, anti-oestrogenic effects are thought to be important, although genistein especially has been shown to induce wide-ranging anti-cancer effects in cell lines independent of any hormone-related influence. There are few indications of harmful effects at present, although possible proliferative effects have been reported. In infants, the effects of high levels in soya milk formulas are uncertain. The second group, lignans, have been less investigated despite their known antioestrogenic effects and more widespread occurrence in foods. Investigation of the possible benefits of phyto-oestrogens is hampered by lack of analytical standards and, hence, inadequate methods for the measurement of low levels in most foods. This problem may prove to be a major dilemma for regulatory authorities, clinicians and others wishing to advise the general public on whether these compounds really do have the health benefits attributed to them.

Initiation of hormone replacement therapy after diagnosis of osteoporosis by bone densitometry

The effect of osteoporosis, as diagnosed by bone densitometry, on general practitioners' decisions to initiate hormone replacement therapy (HRT) was assessed. Data for the study were collected by questionnaire from 147 women (> 40 years), previously referred for measurement of bone mineral density (BMD) at the proximal forearm. Among the women, at the time of BMD measurement, current and ever use of HRT was 35% and 50% respectively, and 25.2% were osteoporotic on the basis of their BMD level. HRT was more likely to be initiated by women who were told that their BMD was low (ODR 3.4; 95% CI 1.2-9.7); 37% of all women with osteoporosis were using HRT compared with 78% who were taking calcium supplements. Potential reasons for the low HRT prescription may include the nature of the BMD report, patient aversion to HRT and doctors' concern with the long-term side-effects of HRT.