Effect of postmenopausal hormone therapy on glucose and insulin concentrations. PEPI Investigators. Postmenopausal Estrogen/Progestin Interventions

Postmenopausal hormone replacement improves proteinuria and impaired creatinine clearance in type 2 diabetes mellitus and hypertension

OBJECTIVE

To determine whether hormone replacement therapy can reverse established renal microvascular damage in type 2 diabetes and hypertension.

DESIGN

Prospective, single centre clinical trial.

SETTING

Outpatient clinics.

PARTICIPANTS

Sixteen diabetic and hypertensive postmenopausal women (age 47-57 years)

METHODS

Administration of a cyclic combination of oestradiol and norgestrel orally for 3.5 monthly cycles.

RESULTS

Comparing the baseline values, mean (SD) 24-hour urine protein excretion was reduced from 0.452 g (0039) to 0.370 g (0.047) (P < 0.01) and creatinine clearance was increased from 1.68 mL/sec (0.11) to 1.77 mL/sec (0.08) (P < 0.05). Fasting plasma glucose also improved from 6.92 mmol/L (0.47) to 6.51 mmol/L (0.28) (P < 0.05), as did serum total cholesterol from 7.26 mmol/L (0.28) to 6.65 mmol/L (0.14) (P < 0.05). Blood pressure did not change significantly. Univariate linear regression analysis showed no significant correlation between the individual changes in blood pressure, fasting plasma glucose or serum cholesterol and the individual changes in proteinuria or creatinine clearance.

CONCLUSIONS

This study shows that hormone replacement therapy may reduce proteinuria, and even improve creatinine clearance, in diabetic and hypertensive postmenopausal women. These effects are additive to nephroprotective therapy, and the mechanisms appear unrelated to conventional risk factors for vascular complications, such as high blood pressure, elevated plasma glucose or serum cholesterol.

Postmenopausal hormone use following a 3-year randomized clinical trial

Postmenopausal women often discontinue estrogen therapy within the first year. No studies have examined reasons why women continue or discontinue hormone replacement therapy (HRT) after several years of use, when hormone side effects have subsided. We wanted to identify determinants of estrogen use after participation in a 3-year randomized placebo-controlled trial. The Postmenopausal Estrogen/Progestin Intervention (PEPI) study compared the effects of estrogen alone or in combination with one of three progestogens with placebo. Post-PEPI use of hormone therapy was ascertained 1-4 years after the trial in 775 (90%) of the originally enrolled women. Potential correlates of treatment decisions were identified from sociodemographic characteristics, medical histories, and clinical measures ascertained at baseline and during and after the trial. Among women who had been assigned to placebo during PEPI, post-PEPI hormone use was significantly less common in women who were adherent to placebo during PEPI, older, or of non-Caucasian ethnicity. Hormone use was positively associated with hysterectomy. Among women assigned to an active regimen during PEPI, post-PEPI hormone use was significantly more common in women who used hormones before PEPI and in women who were adherent to hormones during PEPI. Older age, less education, and being non-Caucasian predicted less hormone use. Post-PEPI hormone use was highest in San Diego and lowest in Iowa City. Women on placebo who lost more bone mineral density (BMD) were more likely to begin hormones than women with less bone loss. Lipids, blood pressure, and other cardiovascular risk factors had relatively little influence on hormone use. The main predictors of post-PEPI hormone use were those associated with use in the general population (education, ethnicity, geographical region, hysterectomy, and prior use/adherence).

Acute effects of estradiol and progesterone on insulin, lipids and lipoproteins in postmenopausal women: a pilot study

OBJECTIVES

To examine the acute effects of estradiol-17beta (E(2)) and progesterone (P) on serum levels of insulin, lipids and lipoproteins in estrogen-deficient postmenopausal women, whereby, a direct cause-effect relationship could be established without the influence of lifestyle changes.

MATERIALS AND METHODS

Nine postmenopausal women were given oral E(2) (Estrace) 2 mg/day for 28 days and oral micronized P (Prometrium) 200 mg/day in the last 14 days of E(2) treatment. Fasting blood samples were obtained before starting E(2) (day 1) and P (day 15) and on day 29. Serum levels of insulin, triglycerides (TG), total cholesterol (TC), low density lipoprotein (LDL), high density lipoprotein (HDL) and lipoprotein (a) (Lp(a)) at the three time points were compared by Friedman analysis of variance (ANOVA). Corresponding levels of glucose, the apolipoproteins (Apo) A1 and B and serum androgen levels were also evaluated.

RESULTS

E(2) decreased while P increased fasting levels of insulin (32.45+/-3.57, 26.36+/-2.90 and 37.36+/-3.67 pmol/l on day 1, 15 and 29 respectively; P<0.01). Fasting glucose to insulin ratios changed inversely (P<0.01). E(2) increased HDL from 1.07+/-0.05 mmol/l on day 1 to 1.17+/-0.07 mmol/l on day 29 but decreased corresponding levels of Lp(a) from 261+/-93 to 211+/-83 U/l (P=0.03 for both). TC and LDL levels fell significantly after 14 days of E(2) treatment with no further decrease when P was added. Androgen levels remained unchanged during hormone treatment.

CONCLUSION

The sequential, acute effects of E(2) and micronized P on insulin and lipids confirm a direct cause-effect relationship. The acute effects of P on insulin in particular, highlights the importance of standardizing the medication days according to estrogen and progestin in the clinical evaluation of their true metabolic impact in longer-term studies and may influence the choice of progestin type, dose and duration in hormone replacement.

Hormone replacement therapy and coronary heart disease. A new debate

Hormone replacement therapy is extensively used in the United States, especially for the possible prevention of heart disease, osteoporotic fractures, and, more recently, dementia. The results of recent clinical trials have raised new questions about the risk and benefits of estrogen or estrogen/progesterone therapy to prevent heart attacks, the choice of specific drug therapy such as specialized estrogen receptor modulation (SERM). The change in risk factors, especially weight gain or obesity, may determine the risks and benefits of hormone replacement therapy.

Hormone replacement therapy and glucose tolerance in EPIC-Norfolk: a population-based study

BACKGROUND

Hormone replacement therapy (HRT) can affect glucose homeostasis in postmenopausal women but it is unclear whether long-term use is associated with changes in glucose tolerance. The objective was to examine the relationship of glycated haemoglobin (HbA(1C)) concentration with HRT use in non-diabetic postmenopausal women.

METHODS

A cross-sectional analysis of baseline data on 2753 postmenopausal women, aged 45-74 years who were recruited to the EPIC-Norfolk study between 1995 and 1998 was performed. Women completed a health and lifestyle questionnaire from which information on HRT use was obtained and gave blood for HbA(1C) assay.

RESULTS

Of the women, 23% were current HRT users and 14% were former users. Mean HbA(1C) was significantly lower in current users compared to former and never users. This difference was independent of age, body mass index (BMI), waist-to-hip ratio (WHR), family history of diabetes, educational status, employment status, smoking history, history of alcohol consumption, parity, known illness and hysterectomy status. Compared to never users of HRT, the unadjusted odds ratio (OR) for being in the highest quintile of HbA(1C) distribution as opposed to the lowest was 0.28 (95% CI 0.20-0.39) for current users and 0.41 (0.32-0.53) for ever users. After adjustment for confounders, the OR were 0.52 (0.34-0.79) and 0.72 (0. 51-1.03) for current and ever users, respectively.

CONCLUSION

Women currently using HRT have lower HbA(1C) levels not explained by known confounders though we cannot completely exclude a healthy user effect. Nevertheless, this population study suggest that current use of HRT was not associated with impairment of glucose tolerance in postmenopausal women.

Hormone replacement therapy and cardiovascular disease

This year's work on hormone replacement therapy (HRT) and cardiovascular disease has been remarkable for the publication of the first randomised controlled trial of HRT use, the Heart Estrogen Replacement Study (HERS). The findings go against not only the trend of previous observational epidemiological studies, but also against findings in the very many studies which have previously shown and continue to show this year a beneficial effect of HRT on a large variety of cardiovascular risk factors, including endothelial function, here reviewed. The aspect of the effect of HRT on clotting variables is clearly crucial given the increased risk of venous thrombosis, and also increased number of cardiac events in the first 4 months of the HERS. Prothrombotic factors increase with age in women, and HRT alters these, particularly fibrinogen, factor VII, and PAI (less change with transdermal HRT) and antithrombin III. In normal women therefore the balance should be towards fibrinolysis rather than coagulation. Work has been presented in abstract for clarifying the effects of HRT on coagulation markers and grasping the problem of differences according to its route of administration. The full publications on this work are expected shortly. We are still awaiting evidence from randomized controlled trials of HRT in primary prevention; one is now recruited but will not report until 2005.

Obesity, weight change, fasting insulin, proinsulin, C-peptide, and insulin-like growth factor-1 levels in women with and without breast cancer: the Rancho Bernardo Study

Postmenopausal overweight women have an increased risk of breast cancer. The link between obesity and breast cancer could be mediated through hyperinsulinemia. Insulin and insulin-like growth factor-1 (IGF-1) stimulate mammary cell proliferation in vitro, and cell proliferation is directly linked to the risk of breast cancer. Our objective was to investigate the relationship between breast cancer and body composition, IGF-1, proinsulin, C-peptide, and fasting insulin. A case-control study was conducted of 438 community-dwelling women aged 53-90 years in 1992-1994 who had no history of cancer at the baseline visit in 1972-1974. Women were excluded who were using estrogen replacement therapy (ERT) or tamoxifen at the 1992-1994 visit, when IGF-1, proinsulin, fasting insulin, and C-peptide levels were measured. Prior ERT, alcohol and tobacco use, exercise, and reproductive history were recorded. Weight, height, and waist/hip ratio were measured. The 45 women with breast cancer had similar baseline body mass indices to the 393 women without breast cancer but had gained significantly more weight between the baseline visit in 1972-1974 and 1992-1994, (age-adjusted relative risk [RR] 1.05/kg, 95% confidence interval [CI] 1.01-1.09, p = 0.016). Proinsulin, fasting insulin, and C-peptide were each significantly positively correlated with both current weight and weight gain. However, levels of these hormones and IGF-1 did not differ significantly between women with and without breast cancer (all 95% CI within 0.996-1.004). Past ERT was significantly more common among women with breast cancer (p = 0.015), and duration of use was significantly longer (age-adjusted RR 1.13 per year of use, 95% CI 1.08-1.18, p = 0.000). The risk of breast cancer was significantly increased in women who had gained weight or used ERT. This increased risk was not associated with circulating levels of IGF-1, fasting insulin, proinsulin, or C-peptide.

Antioxidant action and potential antidiabetic properties of an isoflavonoid-containing soyabean phytochemical extract (SPE)

The potential role of oestrogenic agents, antioxidants and intestinal glucose-uptake inhibitors in the treatment of diabetes is briefly reviewed. Reports in the literature suggest that oestrogen replacement therapy may favourably modulate glucose homeostasis. A soya phytochemical extract (SPE) containing the isoflavone phytoestrogens genistein and daidzein (mostly in their glycone forms as genistin and daidzin) was investigated as an antioxidant and modulator of intestinal glucose-transport. In the present study, SPE was found to protect against glucose-induced oxidation of human low density lipoproteins (LDL) in vitro. Equol (a gut bacterial metabolite of daidzein) was a more effective antioxidant than daidzein or genistein in this system and was of similar antioxidant potency to the dietary flavonols quercetin and kaempferol and to the endogenous antioxidant 17beta-oestradiol. SPE was found to be an inhibitor of glucose uptake into rabbit intestinal brush border membrane vesicles in vitro, though of weaker potency than the classical sodium dependent glucose transporter (SGLT) inhibitor, phlorizin. Thus SPE displays a range of properties which may be of benefit in diabetes, namely as an oestrogenic agent, an inhibitor of intestinal glucose-uptake and a preventive agent for glucose-induced lipid peroxidation.

Long-term effects of oral estradiol and dydrogesterone on carbohydrate metabolism in postmenopausal women

OBJECTIVE

To determine in postmenopausal women the long-term effects on carbohydrate metabolism of the administration of oral micronized 17 beta-estradiol (2 mg/day continuously) and cyclical dydrogesterone (10 mg/day for 14 days per 28-day cycle).

METHODS

A 2-year open-label prospective, non-comparative study was carried out of 13 healthy postmenopausal women receiving cyclical estradiol and dydrogesterone and serving as their own controls. Concentrations of blood glucose, plasma insulin, C-peptide, glucagon and free fatty acids (FFAs) were determined before treatment (base-line) and at 6, 12 and 24 months of hormone replacement therapy under fasting conditions and during a standard 75-g, 3-h, oral glucose tolerance test (OGTT).

RESULTS

Fasting blood glucose levels were unchanged throughout the study, and the mean areas under the curves (AUCs) for glucose response increased slightly but non-significantly versus baseline; fasting plasma insulin levels tended a decrease, and AUCs for insulin responses to the glucose load fell by 23% from baseline (not significant); fasting C-peptide levels and AUCs were unchanged; plasma glucagon fasting levels and responses were in the normal range and stable throughout the study; and plasma FFA fasting levels decreased significantly, as well as FFA AUCs during OGTTs, at the 12th and 24th months of the study.

CONCLUSIONS

During a 2-year treatment with oral estradiol and cyclical dydrogesterone, a direct progesterone derivative, tolerance to glucose was unchanged, fasting plasma insulin and insulin response to repeated glucose loads were decreased, and C-peptide levels remained unchanged, indicating a potential improvement in insulin sensitivity and clearance, as in younger women; additionally, a slightly enhanced antilipolytic activity of insulin was observed.

Cardiovascular disease in the diabetic woman

The incidence of cardiovascular disease (CVD) with age is increasing in the United States, and elderly women constitute a disproportional component of the aging population. Elderly women also have a relatively high incidence of diabetes, which contributes to this relatively high CVD risk. Although CVD is less common in premenopausal women than in men, this difference begins to disappear after the onset of menopause, presumably related to decreased levels of female sex hormones (estrogen and/or progesterone). Diabetes mellitus removes the normal premenopausal gender-related differences in the prevalence of CVD by mechanisms that are not clearly defined, including metabolic and hemodynamic factors associated with diabetes. Dyslipidemia in diabetes mellitus consists of low high density lipoprotein cholesterol, elevated triglyceride levels, and a small, dense, more atherogenic low density lipoprotein particle (i.e. oxidized). Dyslipidemia interacts with associated hemodynamic (i.e. hypertension) and metabolic abnormalities (i.e. increased platelet aggregation and plasminogen activator inhibitor-1 levels) to promote CVD risks in diabetic women. Recent controlled trials underscore the critical importance of aggressively treating CVD risk factors, especially dyslipidemia, in women with diabetes.