Effects of oral and transdermal 17 beta-estradiol combined with progesterone on homocysteine metabolism in postmenopausal women: a randomised placebo-controlled trial

Acute Pulmonary Embolism and Immunity in Animal Models

Venous thromboembolism, encompassing acute pulmonary embolism (APE) and deep vein thrombosis (DVT), is a potentially fatal disease with complex pathophysiology. Traditionally, the Virchow triad provided a framework for understanding the pathogenic contributors to thrombus formation, which include endothelial dysfunction, alterations in blood flow and blood hypercoagulability. In the last years, it has become apparent that immunity plays a central role in thrombosis, interacting with classical prothrombotic mechanisms, oxidative stress and vascular factors. Thrombosis amplifies inflammation, and exaggerated inflammatory processes can trigger thrombosis mainly due to the activation of leukocytes, platelets, and endothelial cells. APE-related endothelium injury is a major trigger for immune system activation. Endothelium is also a key component mediating inflammatory reaction and it is relevant to maintain vascular permeability. Exaggerated right ventricular wall stress and overload, with coexisting systemic hypotension and hypoxemia, result in myocardial injury and necrosis. Hypoxia, tissue factor activation and cytokine storm are engaged in the thrombo-inflammatory processes. Thrombus development is characterized by inflammatory state vascular wall caused mainly by an early extravasation of leukocytes and intense selectins and cytokines production. Nevertheless, immunity of DVT is well described, little is known about potential chemokine and cellular differences between thrombus that develops in the vein and thrombus that detaches and lodges in the pulmonary circulation being a cause of APE. There is a paucity of data considering inflammatory state in the pulmonary artery wall during an acute episode of pulmonary embolism. The main aim of this review is to summarize the knowledge of immunity in acute phase of pulmonary embolism in experimental models.

Plasma and Aorta Biochemistry and MMPs Activities in Female Rabbit Fed Methionine Enriched Diet and Their Offspring

This study investigated whether a high Met diet influences biochemical parameters, MMPs activities in plasma, and biochemical and histological remodeling in aorta, in both pregnant female rabbits and their offspring. Four female rabbit groups are constituted (each n = 8), nonpregnant control (NPC), pregnant control (PC) that received normal commercial chow, nonpregnant Met (NPMet), and pregnant Met (PMet) that received the same diet supplemented with 0,35% L-methionine (w/w) for 3 months (500 mg/d). All pregnant females realize 3 successive pregnancies. Plasma results showed that Met excess increased Hcy, raised CRP in NPMet and decreased it in PMet, enhanced significantly proMMP-2 and proMMP-9 activities in NPMet, and reduced them in PMet. Aorta showed a rise in collagen level, essentially in PMet, a reduction of elastin content in both PMet and NPMet, and a significant decrease in lipid content in PMet, with histological changes that are more pronounced in NPMet than PMet. Met excess enhanced proMMP-9 activities in NPMet while it decreased them in PMet. PMet newborn presented increase in uremia and CRP and significant rise of active MMP-2 and MMP-9 forms. In aorta, media and adventitia thickness increased, total lipids content decreased, proMMP-9 activity decreased, and proMMP-2 activity increased.

Bioidentical hormones for women with vasomotor symptoms

BACKGROUND

Various hormone therapies (HT) are available to treat menopausal vasomotor symptoms. Bioidentical hormones are chemically identical to those produced by the human body, and several types are well-tested and available on prescription. Many women have opted for bioidentical hormone therapy (BHT) on the assumption that it is safer than other forms of HT. We evaluated the evidence.

OBJECTIVES

To determine the effectiveness and safety of bioidentical hormones compared to placebo or non-bioidentical hormones for the relief of vasomotor symptoms.

SEARCH METHODS

In July 2015 we searched the Cochrane Central Register of Controlled Trials, PubMed, Embase, Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), registers of ongoing trials and the reference lists of articles retrieved.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing bioidentical hormone therapy (BHT) versus placebo or non-bioidentical hormones.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by the Cochrane Collaboration. Our primary outcome was vasomotor symptoms (hot flushes and night sweats). We evaluated the overall quality of the evidence using Grading of Recommendations Assessment, Development and Evaluation criteria (GRADE).

MAIN RESULTS

We included 23 RCTs (5779 participants). Most studies (20/23) included only women with moderate to severe hot flushes. All studies compared unopposed 17 beta-estradiol (beta-estradiol) versus placebo or conjugated equine estrogens (CEE). None of the studies reported night sweats as a separate outcome. BHT patch versus placebo Frequency of hot flushesFour RCTs reported data suitable for analysis. There were fewer hot flushes in the BHT group, with a moderate to large effect size (SMD -0.68, 95% CI -0.83 to -0.53, four RCTs, 793 women, I(2) = 67%, low quality evidence). There was moderate heterogeneity, but a consistent direction of effect. Seven RCTs reported data unsuitable for analysis; all reported a benefit in the intervention group. Symptom intensityTwo RCTs reported analysable data. Measured on a 0-100 visual analogue scale (VAS), hot flush intensity was lower in the BHT group (MD -19.94 points, 95% CI -24.86 to -15.02, two RCTs, 393 women, I(2) = 54%, low quality evidence). There was moderate heterogeneity, but a consistent direction of effect. Adverse effectsAdverse events (such as headache, vaginal bleeding, breast tenderness and skin reactions) were more common in the intervention group (odds ratio (OR) 2.14, 95% CI 1.29 to 3.54, 9 RCTs, 1822 women, I(2) = 73%, low quality evidence). There was moderate heterogeneity, but a consistent direction of effect. In one study, five women in the intervention group developed endometrial hyperplasia. BHT gel versus placebo Hot flush frequencyThree RCTs reported this outcome, but the data were unsuitable for analysis. All reported a benefit in the BHT group. Adverse effectsAdverse events were more common in the BHT group (OR 1.41, 95% CI 1.09 to 1.83, 3 RCTs, 1086 women, I(2) = 0%, moderate quality evidence). Oral BHT versus placebo Hot flush frequencyTwo studies reported analysable data. There were fewer hot flushes in the BHT group, with a moderate to large effect size (SMD -0.80, 95% CI -1.03 to -0.57, two RCTs, 356 women, I(2) = 14%, low quality evidence). Adverse effectsThere was no evidence of a difference between the groups (OR 1.28, 95% CI 0.84 to 1.96, 3 RCTs, 433 women, I(2) = 0%, low quality evidence). Topical BHT emulsion versus placebo Hot flush frequencyOne study with data unsuitable for analysis reported a benefit in the intervention group. Adverse effectsThere was no evidence of a difference between the groups (OR 1.46, 95% CI 0.80 to 2.66, one RCT, 200 women, low quality evidence). Intranasal BHT versus placebo Hot flush frequencyOnly one study reported analysable data. There were fewer hot flushes per day in the BHT group (MD -3.04 95% CI -4.05 to -2.03, one study, 458 women, moderate quality evidence) Adverse effectsAdverse events (such as headache, breast tenderness, arthralgia and nausea) were more common in the intervention group (OR 1.96, 95% CI 1.26 to 3.03, one RCT, 458 women, moderate quality evidence). Subgroup analysesSubgroup analyses by dose of BHT suggested that higher doses of BHT may be associated with more effectiveness but also higher risk of adverse effects. BHT patch versus 0.625 mg CEETwo RCTs reported this comparison, but the data were unsuitable for analysis. Hot flush frequencyBoth RCTs reported no evidence of a difference between the groups. Adverse effectsFindings were inconsistent. In one comparison (0.1 mg BHT versus CEE), breast pain and vaginal bleeding were more frequent in the BHT group. Oral BHT versus 0.625 mg CEE Hot flush frequencyOne study with data unsuitable for analysis reported no evidence of a difference between the groups. Adverse effectsThere was no evidence of a difference between the groups (OR 1.20, 95% CI 0.50 to 2.87, one RCT, 103 women, very low quality evidence).

AUTHORS' CONCLUSIONS

There was low to moderate quality evidence that BHT in various forms and doses is more effective than placebo for treating moderate to severe menopausal hot flushes. There was low to moderate quality evidence of higher rates of adverse effects such as headache, vaginal bleeding, breast tenderness and skin reactions in the BHT group. There was some evidence to suggest that higher doses of BHT are associated with greater effectiveness but also with higher risk of adverse effects. Although all the included studies used unopposed estrogen, it is recommended best practice to use progestogen therapy in women with a uterus taking estrogen in order to avoid endometrial hyperplasia, regardless of the source of the estrogen. No data are yet available about the safety of BHT with regard to long-term outcomes such as heart attack, stroke and breast cancer.There was no good evidence of a difference in effectiveness between BHT and CEE, and findings with regard to adverse effects were inconsistent. The quality of the evidence was too low to reach any firm conclusions.The main limitations in the quality of the evidence were study risk of bias (mainly due to poor reporting of methods), imprecision and lack of data suitable for analysis.

Guidelines for the diagnosis and treatment of cobalamin and folate disorders

The clinical picture is the most important factor in assessing the significance of test results assessing cobalamin status because there is no 'gold standard' test to define deficiency. Serum cobalamin currently remains the first-line test, with additional second-line plasma methylmalonic acid to help clarify uncertainties of underlying biochemical/functional deficiencies. Serum holotranscobalamin has the potential as a first-line test, but an indeterminate 'grey area' may still exist. Plasma homocysteine may be helpful as a second-line test, but is less specific than methylmalonic acid. The availability of these second-line tests is currently limited. Definitive cut-off points to define clinical and subclinical deficiency states are not possible, given the variety of methodologies used and technical issues, and local reference ranges should be established. In the presence of discordance between the test result and strong clinical features of deficiency, treatment should not be delayed to avoid neurological impairment. Treatment of cobalamin deficiency is recommended in line with the British National Formulary. Oral therapy may be suitable and acceptable provided appropriate doses are taken and compliance is not an issue. Serum folate offers equivalent diagnostic capability to red cell folate and is the first-line test of choice to assess folate status.

Effects of early initiated oestrogen replacement therapy on plasma homocysteine levels in women in surgically induced menopause

OBJECTIVE

The aim of this study was to investigate and to compare the effects on serum homocysteine levels of early initiated oral and transdermal oestrogen replacement therapies (ERTs) given to women without a uterus who had undergone surgically induced menopause. Homocysteine levels are considered one of the predictors of cardiovascular disease risk.

METHODS

This study included 45 women with surgical menopause. Of 45 women, 15 received oral ERT, (oestradiol hemihydrate 2 mg/day, Estrofem®), 15 received transdermal ERT (oestradiol hemihydrate 0.1% gel 1.5 mg/day, Estreva®) and 15 received no hormone therapy. Blood samples were collected from all women to measure homocysteine levels at the mean time of 15 weeks after surgical menopause. Obtained results of the groups were compared.

RESULTS

There were no significant differences in age, height, weight, body mass index (BMI), waist circumference and time elapsing since menopause between the three groups. The duration of ERT was not significantly different between the therapy groups. There was no significant difference in homocysteine levels between the groups (p>0.05). No significant correlation was found between weight, BMI and homocysteine levels (p>0.05).

CONCLUSION

Considering that homocysteine is a predictor of risk for cardiovascular disease, the results of this study showed that early initiation of ERT in healthy surgically induced menopausal women neither protects nor deteriorates cardiovascular disease.

The effect of postmenopausal hormone therapy with or without folic acid supplementation on serum homocysteine level

OBJECTIVE

To evaluate the effects of postmenopausal hormone therapy (HT) with or without the addition of folic acid (FA) on serum homocysteine levels in a randomized, placebo-controlled design. Additionally, a non-randomized control group with no treatment was included.

METHODS

Forty non-hysterectomized healthy postmenopausal women were randomly allocated to receive either oral continuous combined HT (0.625 mg conjugated equine estrogen with 2.5 mg medroxyprogesterone acetate daily) and oral folic acid (5 mg/day, n = 20) or HT and placebo (n = 20) for 3 months. A control group (n = 15) did not receive any study medication and was followed in the same manner. The fasting total serum homocysteine level was measured by fluorescence polarization immunoassay with a sensitivity of < 0.5 micromol/l. Serum levels of folate, estrogen and lipid profile were also followed.

RESULTS

The mean age of the postmenopausal women was 52 +/- 6 years. Baseline homocysteine level was the highest in the HT + FA group (9.96 +/- 2.82 micromol/l), compared to HT + placebo (9.64 +/- 1.89 micromol/l) and control groups (9.01 +/- 1.83 micromol/l) (ANCOVA, p = 0.022). Low baseline folate and vitamin B12 levels contributed significantly to the high level of baseline homocysteine in the HT + FA group. The addition of FA to HT led to a significant decrease in the serum homocysteine level from the baseline level of 9.96 +/- 2.82 micromol/l to the final level of 8.92 +/- 2.53 micromol/l (p = 0.023). On the other hand, HT alone (HT + placebo group) significantly increased the serum homocysteine level from 9.64 +/- 1.89 micromol/l to 10.22 +/- 1.77 micromol/l without a decline in serum folate level (p = 0.045). The serum homocysteine level in the control group did not change significantly (from 9.01 +/- 1.83 micromol/l to 9.58 +/- 2.05 micromol/l, p = 0.29).

CONCLUSIONS

Three months of oral continuous combined HT increased the fasting total serum homocysteine level without affecting the serum folate level. Lowering the homocysteine level in postmenopausal woman on HT is achievable by folic acid supplementation.

Hemostatic markers in healthy postmenopausal women during intranasal and oral hormone therapy

OBJECTIVE

To study changes in the hemostatic balance during intranasal compared with oral administration of 17beta-estradiol (E2) and norethisterone (NET) or NET acetate in postmenopausal women. A wide range of markers of coagulation and fibrinolysis associated with coronary artery disease was tested.

DESIGN

In a two-center, randomized, double-blind, comparative trial, 90 healthy postmenopausal women (aged 56.6 +/- 4.7 y) received daily continuous combined hormone therapy, either E2/NET 175 microg/275 mug intranasally as a spray (n = 47) or E2/NET acetate 1 mg/0.5 mg orally as a capsule (n = 43) for 1 year. Hemostatic markers were measured in blood samples taken at baseline and after 12, 24, and 52 weeks of treatment.

RESULTS

After 52 weeks of treatment, changes in the intranasal group in markers of coagulation-fibrinogen (-1.3%), factor VII activity (-14.0%), and prothrombin fragment 1 + 2 (+5.8%)-were significantly less (P < 0.05) than the changes in the oral group for these parameters (-6.5%, -20.3%, and +19.0%, respectively). Changes in activated factor VII did not differ between the groups. Neither group showed significant changes in thrombin-antithrombin complex. In the intranasal group, decreases in markers of fibrinolysis-tissue-type plasminogen activator (-10.4%) and plasminogen activator inhibitor-1 antigen (-13.8%)-were significantly less (P < 0.05) than the decreases in the oral group (-17.8% and -38.0%, respectively). A decrease in plasminogen activator inhibitor-1 activity and increases in D-dimer and plasmin-alpha2-antiplasmin complex did not differ between the groups. No differences were found between the groups in homocysteine, which overall was unaltered in both groups.

CONCLUSIONS

During intranasal E2/NET therapy, changes in the coagulatory and fibrinolytic markers were to some extent less than those observed during oral therapy.

Low-dose continuous combinations of hormone therapy and biochemical surrogate markers for vascular tone and inflammation: transdermal versus oral application

OBJECTIVE

To compare the effects of low-dose transdermal estradiol (E2)/norethisterone acetate (NETA) patches (Estalis 25/125) with low-dose oral E2/NETA (Activelle) on cardiovascular biochemical markers after 12 and 52 weeks of treatment in postmenopausal women with intact uteri.

DESIGN

Participants were randomly assigned to receive either transdermal E2/NETA (delivering daily doses of 25 microg E2 and 125 microg NETA, applied every 3-4 d) or oral E2/NETA (1 mg E2 and 0.5 mg NETA, given daily) in this open-label study. The following markers or their stable metabolites in serum or urine were assessed: P-selectin, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, monocyte chemoattractant protein-1, matrix metalloproteinase-9, homocysteine, cyclic guanosine monophosphate, serotonin, prostacyclin, thromboxane, and urodilatin.

RESULTS

Significant decreases were found for P-selectin, intercellular adhesion molecule-1, monocyte chemoattractant protein-1, and homocysteine for both hormone therapy (HT) regimens compared with baseline. Matrix metalloproteinase-9 was increased only by oral HT. The urinary concentrations of cyclic guanosine monophosphate, the ratio of prostacyclin to thromboxane metabolite, and the serotonin metabolite were significantly increased for both HT application modes, although the oral treatment showed a significantly greater increase than the transdermal one with respect to baseline. Urodilatin excretion was increased only by the oral regimen.

CONCLUSIONS

Low-dose transdermal and oral HTs using E2 and NETA elicit favorable effects on cardiovascular biochemical markers. For most markers the magnitude of changes found were similar with respect to baseline; however, in some cases oral HT led to a significantly greater change, whereas in other cases the transdermal formulations seemed to provide greater benefits. Whether these differences may be attributed to the different administration routes or to different pharmacokinetic properties remains an open question. Overall low-dose transdermal HT seems to provoke the same benefit on the cardiovascular system as oral HT, as suggested by the results on vascular markers.

Effects of non-oral postmenopausal hormone therapy on markers of cardiovascular risk: a systematic review

OBJECTIVE

To review the effects of non-oral administration of postmenopausal hormone therapy (HT) on risk markers for atherosclerotic and venous thromboembolic disease.Non-oral postmenopausal HT appears not to increase venous thromboembolic risk, whereas the effect on coronary heart disease risk is less clear.

DESIGN

Systematic review of literature obtained from MEDLINE, EMBASE, and CENTRAL databases from 1980 until and including April 2006. Terms for "postmenopausal hormone therapy" and for "non-oral administration" were combined in the search.

SETTING

Randomized clinical trials.

PATIENT(S)

Postmenopausal women, both healthy and with established cardiovascular disease or specified cardiovascular risk factors

INTERVENTION(S)

Non-oral HT (e.g., transdermal or intranasal) compared with oral HT or no treatment/placebo.

MAIN OUTCOME MEASURE(S)

Lipoprotein(a), homocysteine, C-reactive protein (CRP), cell adhesion molecules, markers of endothelial dysfunction, coagulation, and fibrinolysis.

RESULT(S)

Seventy-two studies investigating either transdermal or intranasal administration were included. For non-oral HT, decreases in lipoprotein(a), cell adhesion molecules, and factor VII generally were significant, resistance to activated protein C (APCr) was slightly increased, and other markers including CRP and homocysteine did not change. Compared with oral HT, changes in CRP and APCr were smaller, changes in cell adhesion molecules and some fibrinolytic parameters tended to be smaller, whereas changes in other factors including lipoprotein(a) and homocysteine did not differ.

CONCLUSION(S)

Potentially unfavorable changes seen with oral HT on two important markers, CRP and APCr, are substantially smaller with non-oral HT. Non-oral HT has minor effects on the other cardiovascular risk markers studied. Therefore, compared with oral HT, non-oral HT appears be safer with respect to atherosclerotic and venous thromboembolic disease risk.

A comparison of the effects of sequential transdermal versus continuous orally administered hormone replacement therapies on plasma total homocysteine levels in postmenopausal women: A randomized, placebo-controlled study

OBJECTIVE

The objective was to determine the effects of transdermal and oral hormone replacement therapies on plasma total homocysteine levels in postmenopausal women.

MATERIAL AND METHODS

One hundred and ten postmenopausal patients were enrolled in the study. Participants were randomized into three groups: in Group A (n = 31) oral continuous combined therapy and in Group B (n = 30) transdermal sequential hormone replacement therapy were given for 6 months. A placebo was administered orally to the control group (Group C, n = 30). Serum homocysteine levels were studied prior to and after 6 months of treatment in all groups.

RESULTS

There were no statistical significant differences in mean serum homocysteine levels among the groups prior to the study. The mean homocysteine levels after 6 months in Groups A-C were also similar.

CONCLUSIONS

Serum homocysteine levels alter with neither oral continuous nor sequential transdermal hormone replacement therapy.

Hyperhomocysteinemia and cardiovascular risk in postmenopausal women: the role of folate supplementation

In the postmenopausal period, cardiovascular diseases are a frequent chronic condition leading to high risk of myocardial infarction and death. Recently hyperhomocysteinemia and even mildly elevated plasma concentrations of homocysteine have been recognized as independent risk factors for vascular damage predisposing to arteriosclerosis. Elevated plasma levels of homocysteine induce vascular endothelial damage and are frequently associated with low folate levels.

In this review we evaluate literature data on some aspects related to menopause and homocysteine metabolism. In particular, we show the effect of folic acid supplementation on homocysteine concentrations and on homocysteine-related thiols, such as cysteine and cysteine-glycine, as well as the relationship with glucose, insulin, and lipidic metabolism in postmenopausal women. We also analyze the influence of folate supplementation on endothelial function, by brachial artery flow-mediated dilatation (endothelium-dependent) and nitroglycerine-induced dilatation (endothelium-independent) before and after a methionine load.

Folate administration in postmenopausal women is able to reduce high plasma homocysteine levels and to modify impaired endothelial function induced by hyperhomocysteinemia.

Clin Chem Lab Med 2007;45:130–5.

Biochemical markers surrogating on vascular effects of sex steroid hormones

The main mechanism of possible cardioprotection by estrogens appears to be a direct effect on the vasculature, resulting in an improvement of endothelial function and inhibition of atherogenesis. Numerous observational and experimental studies have demonstrated a positive correlation between estrogens and various biochemical markers surrogating direct vascular effects. In general, most markers are influenced in a similar way by oral and transdermal hormone therapy, although oral therapy may have a faster and more pronounced effect. The main difference between oral and transdermal administration may be confined to markers that are mainly or exclusively produced in the liver. Clinical studies demonstrate that progestogen addition can have an impact on the beneficial estrogen-induced changes of biochemical markers. Concerning the effects of tibolone, inconsistent data have been found. Overall, tibolone-induced beneficial changes on the various biochemical markers appear to be less marked compared with those of hormone therapy. The few data available on the direct effects of androgens on the vascular wall indicate a less favorable action of androgens on biochemical markers than of estrogens. The practical relevance of marker measurements is currently under discussion. Although evidence strongly supports some of these markers as predictors of acute events, it remains to be established whether modifying circulating levels of these markers will influence outcomes.

The Effect of Hormone Replacement Therapy and Simvastatin on Plasma Homocysteine

BACKGROUND

Homocysteine may be an independent risk factor for coronary artery disease (CAD), and the risk is at least as strong for women as for men. Homocysteine levels are lower in women compared with men, and homocysteine is lower during pregnancy and higher during menopause.

PURPOSE

To investigate the effects of hormone replacement therapy (HRT), simvastatin, and their combination on plasma homocysteine levels, we treated 16 postmenopausal, hypercholesterolemic women with CAD with HRT (0.625 mg conjugated equine estrogens [CEE] combined continuously with 2.5 mg medroxyprogesterone), 20 mg simvastatin, and their combination in a randomized, placebo-controlled study. Each treatment period was 8 weeks long, with a 4-week washout interval. Plasma homocysteine levels were evaluated at the end of each treatment period.

RESULTS

Only HRT, alone and in combination with simvastatin, significantly reduced homocysteine levels compared with placebo (11.82 +/- 0.74 and 12.22 +/- 0.71 vs 13.58 +/- 0.83 micromol/L, respectively, p < 0.05). Simvastatin had no effect (13.02 +/- 0.94 micromol/L), and the combination therapy was not better that monotherapy with HRT.

CONCLUSIONS

Oral HRT reduces homocysteine plasma levels, whereas simvastatin has no effect. If confirmed by randomized, prospective studies with clinical end points, HRT may be considered for women with mild hypercholesterolemia and high homocysteine levels.

Oestrogen and progestogen hormone replacement therapy for peri-menopausal and post-menopausal women: weight and body fat distribution

BACKGROUND

Hormone replacement therapy (HRT) is commonly prescribed to treat menopausal symptoms and to prevent post-menopausal bone loss. However, many women are concerned about hormonal replacement therapy because they believe that such treatment will result in weight gain. The effect of HRT on weight and body fat distribution has not yet been examined in systematic reviews. It is an important topic since many women decline oestrogen therapy due to their concerns about resultant weight gain, and thus forego its potential therapeutic benefits.

OBJECTIVES

To evaluate the effect of unopposed oestrogen or combined oestrogen and progestogen hormone replacement therapy (HRT) upon the weight and body fat distribution of perimenopausal and postmenopausal women.

SEARCH STRATEGY

The search strategy of the Menstrual Disorders and Subfertility Group was used for the identification of randomised controlled trials (RCTs). Computerised searches of MEDLINE, EMBASE, Current Contents, Biological Abstracts and CINAHL were performed. Attempts were made to identify trials from citation lists of review articles and relevant papers already obtained. In most cases, first authors of each eligible trial were contacted for additional information. All those trials that had been located as at August 1998 were examined for eligibility.

SELECTION CRITERIA

All randomised, placebo or no treatment controlled trials that detailed the effect of HRT on weight or body fat distribution, including studies where HRT was combined with other therapy such as diet, supplements or exercise. Studies were eligible for consideration even though the main focus of the trial may have been on another aspect of HRT. Previous HRT use should have ceased at least one month (in the case of patches, cream or gel) or three months (for oral preparations or subcutaneous pellets) before commencement of the study.

DATA COLLECTION AND ANALYSIS

Twenty two RCTs were identified that fulfilled the inclusion criteria for this review. The results of one trial were not available in a form that allowed it to be included in the meta-analysis; however, it has been included in the text of the review for discussion. Twenty four RCTs are awaiting assessment pending additional information from first authors. Two reviewers extracted the data independently, and the weighted mean differences for continuous outcomes were estimated from the data. Results for unopposed oestrogen and combined oestrogen were analysed separately, and the effect of each treatment regimen on body weight, BMI, waist-hip ratio, fat mass and skinfold measurement was examined where available. The effect of differing dosage levels on these parameters was also examined.

MAIN RESULTS

Outcomes were evaluated separately for unopposed oestrogen and oestrogen/progestogen regimens. Statistical analysis was performed using the weighted mean difference for continuous outcomes as recommended by the Cochrane Menstrual Disorders and Subfertility Group. No statistically significant difference was found in mean weight gain between those using unopposed oestrogen and non-HRT users (0.66 kg, 95% CI -0.62, 1.93). No significant difference was found in mean weight gain between those using oestrogen/progestogen therapy and non-HRT users (-0.47 kg, 95% CI -1.63, 0.69). Insufficient data exist to enable meta-analysis of the effect of unopposed oestrogen on BMI. The reviewers found no statistically significant difference in mean BMI increase between those using oestrogen/progestogen and non-HRT users (-0.50, 95% CI -1.06, 0.06). Insufficient data exist to enable meta-analysis of the effect of HRT on waist-hip ratio, fat mass or skinfold thickness.

REVIEWER'S CONCLUSIONS

There is evidence of no effect of unopposed oestrogen or combined oestrogen on body weight, indicating that these regimens do not cause extra weight gain in addition to that normally gained at menopause. (ABSTRACT TRUNCATED)