Effect of hormone replacement therapy on intervertebral disc height.

OBJECTIVE: Intervertebral discs act as shock absorbers, thereby helping to reduce the risk of vertebral body fractures. Previous studies have shown that estrogen loss following menopause is associated with disc height reduction whereas treatment with hormone replacement therapy (HRT) helps to maintain disc height. This study reports the effect of HRT on disc height from a post hoc analysis of a prospective randomized clinical trial of the effect of HRT on bone density. METHODS: A total of 355 healthy postmenopausal women aged (mean ± standard deviation) 55.4 ± 4.8 years were randomized to HRT with oral 1 mg or 2 mg estradiol plus dydrogesterone or placebo. Dual-energy X-ray absorptiometry measurements (Lunar DPX) were obtained at baseline and following 2 years of treatment. Intervertebral disc height was measured in discs between T12 and L3 using the bone densitometer ruler. RESULTS: Compared with baseline, treatment with HRT resulted in a significant increase in total disc height with 1 mg estradiol (0.16 ± 0.65 cm, p = 0.015) and with 2 mg estradiol (0.21 ± 0.86 cm, p = 0.006) whilst there was no significant increase with placebo (0.13 ± 0.65 cm, p = 0.096). Between-group differences were not statistically significant. CONCLUSIONS: These results are consistent with previous findings of a beneficial effect of estrogen on discs. This may be in part responsible for the anti-fracture efficacy of HRT on vertebral fractures.

Cardiometabolic health in premature ovarian insufficiency.

Premature ovarian insufficiency (POI) is an increasing public health problem with a prevalence now approaching 4%. POI results in adverse effects on the skeleton and central nervous system as well as disturbances of metabolic and cardiological factors that predispose to a major increased risk of cardiovascular disease (CVD). This article reviews the effects of the premature loss of ovarian function on lipids and lipoproteins, glucose and insulin metabolism, body composition, hemostasis and blood pressure, together with effects on the development of metabolic syndrome and diabetes mellitus. The article examines the effects of POI on vascular endothelial function and inflammation that result in arterial disease, and reviews the effects of hormone replacement therapy (HRT) on these various metabolic processes and on cardiovascular outcomes. It is essential that women with POI receive hormonal treatment to help prevent the development of CVD, and that this treatment is continued at least until the normal age of menopause. It appears that HRT has a more favorable effect than the combined oral contraceptive, but larger clinical trials are needed to establish the optimal treatment. Other therapeutic measures may need to be added to correct existing metabolic abnormalities and, in particular, attention to lifestyle factors such as diet and exercise must be encouraged.

The menopausal hot flush: a review.

The hot flush is the most characteristic and often the most distressing symptom of the menopause. It is a unique feature and yet the mechanism and health implications are still not fully understood. This review summarizes some of the current thoughts on factors contributing to flushing, the physiological, vascular and neuroendocrine changes associated with flushing and the possible cardiovascular and other health implications for women experiencing hot flushes. Therapy is not discussed.

Cardiovascular risk assessment in women - an update.

Cardiovascular disease is the leading cause of morbidity and mortality in postmenopausal women. Although it is a disease of aging, vascular disease initiates much earlier in life. Thus, there is a need to be aware of the potential to prevent the development of the disease from an early age and continue this surveillance throughout life. The menopausal period and early menopause present an ideal opportunity to assess cardiovascular risk and plan accordingly. Generally in this period, women will be seen by primary health-care professionals and non-cardiovascular specialists. This review addresses female-specific risk factors that may contribute to the potential development of cardiovascular disease. It is important for all health-care professionals dealing with women in midlife and beyond to be cognisant of these risk factors and to initiate female-specific preventative measures or to refer to a cardiovascular specialist.

Conflicts of interest, smoke and mirrors.

Commercial funding of research studies may potentially influence or bias the findings and interpretation of results. An editorial on conflicts of interest suggested that funding from non-commercial sources, such as government agencies, may also represent a conflict of interest, and uses the Women's Health Initiative (WHI) as an example of how this might be. Two WHI investigators responded by claiming that the arguments put forward in the editorial were largely 'red herrings' and were aimed at disparaging the WHI results. But there is evidence of bias in the presentation and interpretation of WHI findings by some investigators which may be due to conflicts of interest. It is probably wise to declare all sources of external research funding, including industries, governments and charities, as conflicts of interest so that reviewers of such research studies are alerted to give them full scrutiny for evidence of external influences.

Bisphosphonate drug holidays--when, why and for how long?

Bisphosphonates are first-line agents used for the treatment of osteoporosis in postmenopausal women and men. Although their efficacy in the reduction of vertebral, non-vertebral and hip fracture risk has been established, some concerns have arisen associated with their long-term use. These include osteonecrosis of the jaw and atypical (subtrochanteric and femoral shaft) fractures. The latter may result from accumulation of fatigue damage due to oversuppression of bone turnover in susceptible individuals. In this respect, the concept of a 'drug holiday' after completion of a reasonable period of bisphosphonate therapy has emerged. Theoretically, this allows bone turnover to increase and permits normal skeletal maintenance and repair, although there is as yet no good evidence that bisphosphonate discontinuation will reduce the risk of these adverse events. Current data derive from studies in postmenopausal women and support a beneficial effect of alendronate or zolendronate continuation in high-risk groups, such as those with T-score < -2.5 or prevalent vertebral fractures after completion of 5 or 3 years, respectively. The optimal length of a 'drug holiday' has not been established but existing data suggest up to 5 years with alendronate, 3 years with zoledronate and 1 year with risedronate. A decision to recommence therapy should then probably be based on regular reassessment of bone mineral density and fracture risk.

Validation of three geolocation strategies for health-facility attendees for research and public health surveillance in a rural setting in western Kenya.

Understanding the spatial distribution of disease is critical for effective disease control. Where formal address networks do not exist, tracking spatial patterns of clinical disease is difficult. Geolocation strategies were tested at rural health facilities in western Kenya. Methods included geocoding residence by head of compound, participatory mapping and recording the self-reported nearest landmark. Geocoding was able to locate 72·9% [95% confidence interval (CI) 67·7-77·6] of individuals to within 250 m of the true compound location. The participatory mapping exercise was able to correctly locate 82·0% of compounds (95% CI 78·9-84·8) to a 2 × 2·5 km area with a 500 m buffer. The self-reported nearest landmark was able to locate 78·1% (95% CI 73·8-82·1) of compounds to the correct catchment area. These strategies tested provide options for quickly obtaining spatial information on individuals presenting at health facilities.

Risks and benefits of hormone therapy: has medical dogma now been overturned?

BACKGROUND: In an integrated overview of the benefits and risks of menopausal hormone therapy (HT), the Women's Health Initiative (WHI) investigators have claimed that their 'findings … do not support use of this therapy for chronic disease prevention'. In an accompanying editorial, it was claimed that 'the WHI overturned medical dogma regarding menopausal [HT]'. OBJECTIVES: To evaluate those claims. METHODS: Epidemiological criteria of causation were applied to the evidence. RESULTS: A 'global index' purporting to summarize the overall benefit versus the risk of HT was not valid, and it was biased. For coronary heart disease, an increased risk in users of estrogen plus progestogen (E + P), previously reported by the WHI, was not confirmed. The WHI study did not establish that E+ P increases the risk of breast cancer; the findings suggest that unopposed estrogen therapy (ET) does not increase the risk, and may even reduce it. The findings for stroke and pulmonary embolism were compatible with an increased risk, and among E+ P users there were credible reductions in the risk of colorectal and endometrial cancer. For E+ P and ET users, there were credible reductions in the risk of hip fracture. Under 'worst case' and 'best case' assumptions, the changes in the incidence of the outcomes attributable to HT were minor. CONCLUSIONS: Over-interpretation and misrepresentation of the WHI findings have damaged the health and well-being of menopausal women by convincing them and their health professionals that the risks of HT outweigh the benefits.

The WHI: the effect of hormone replacement therapy on fracture prevention.

The Women's Health Initiative (WHI) randomized, controlled trial was the first study to prove that hormone replacement therapy (HRT) reduces the incidence of all osteoporosis-related fractures in postmenopausal women, even those at low risk of fracture. The study authors concluded that the bone-friendly aspect of HRT was limited in clinical practice as possible adverse effects outweighed possible benefit. On the strength of these publications, regulatory authorities downgraded the use of HRT for the prevention of fracture to second-line therapy. This article examines the original and subsequent evidence presented by the WHI study and concludes that the restrictions placed on HRT as a bone-specific drug by regulatory bodies have not withstood the test of time and are not supported by the data of the WHI.

HRT and breast cancer risk: a realistic perspective.

A new analysis from the Women's Health Initiative included data on breast cancer incidence over a 11-year period from the randomized trial of conjugated equine estrogens (CEE) plus medroxyprogesterone acetate (MPA) and a subsequent observational follow-up. The conclusions were that CEE/MPA use was associated with an increase in both breast cancer incidence and mortality. We have concerns over the validity of their statistical analyses, as adjustments for baseline characteristics or for multiple comparisons demonstrate no significant differences in incidence between those allocated to CEE/MPA or placebo. We suspect that the apparent increase in mortality is the result of surveillance and detection bias rather than a true cause and effect. Even if such an effect were true, mortality from breast cancer would still be a very rare event. We also question the clinical relevance and applicability of their findings. The data over the 11 years show no increased risk of breast cancer with CEE/MPA in women who had not previously used hormone replacement therapy (HRT), and the vast majority of women on HRT would not be prior users at initiation. It should be remembered that women using CEE alone showed a significant decrease in breast cancer risk in the WHI trial and follow-up. Even if combined estrogen?progestogen HRT did cause an increase in breast cancer risk, and this is not proven, the magnitude of that risk is small, and less than that risk seen with many lifestyle factors. HRT is a benefit, not a risk, for those women requiring it.

Type and route of estrogen administration.

Hormone replacement therapy (HRT) can be administered orally and non-orally. Providing equivalent doses are given, all forms of HRT can equally relieve menopausal symptoms and prevent bone loss and osteoporosis. Different routes of administration will have differing metabolic effects, with oral HRT producing a hepatic first-pass effect not seen with non-oral HRT. The first-pass effect can produce benefits including larger reductions in low density lipoprotein cholesterol, lipoprotein(a) and insulin resistance, and larger increases in high density lipoprotein cholesterol. Unwanted effects are seen in increases in triglycerides and in coagulation activation. Cardiovascular effects of oral and transdermal HRT appear to be fairly similar, with improvements in vascular endothelial function, angiotensin-converting-enzyme activity, and in most markers of inflammation. There is a paucity of studies on the effects of transdermal HRT on cardiovascular outcomes, but the few data available suggest similar effects to oral HRT, and dose rather than route of administration is probably more important in this respect. Oral HRT may be preferred in women with evidence of insulin resistance, such as in metabolic syndrome or maturity-onset diabetes mellitus. Transdermal HRT may be preferred in women with coagulation disturbances. But, for the majority of women, personal preference should determine their choice of HRT route.

Regional and total skeletal measurements in the early postmenopause.

In a cross-sectional study of 70 early postmenopausal women, regional bone measurements were compared with total body calcium (TBCa). Spinal and forearm trabecular bone were mainly related to age and time since menopause. In contrast, TBCa and forearm integral (cortical and trabecular) and cortical bone were unrelated to age, although the time since menopause also had some influence. Forearm integral and cortical bone measurements were quite well correlated with TBCa (r = 0.84 and 0.73, respectively, P less than 0.001). The correlation between spinal bone measurements and any of the forearm measurements, even purely trabecular bone, was weak (r less than 0.52, P less than 0.001). Our results show quite clearly that forearm bone measurements cannot be used to predict bone density in the vertebrae. Loss of ovarian function affects bone in general, and trabecular bone in particular. Bone measurements at specific anatomical sites are clearly necessary for studies of metabolic bone diseases and their response to treatment.

Stimulation of 1,25-dihydroxycholecalciferol production by prolactin and related peptides in intact renal cell preparations in vitro.

Ovine prolactin stimulated the 1 alpha-hydroxylase activity in isolated renal tubules and especially in primary kidney cell cultures, both prepared from vitamin D-deficient chicks. In primary chick kidney cell cultures, treated for 48 h with 1,25-dihydroxycholecalciferol (to induce the 24-hydroxylase activity) ovine prolactin, after a 1 h incubation period, stimulated the 1 alpha-hydroxylase activity without affecting the 24-hydroxylase activity. Similar results were obtained with related peptide hormones such as human growth hormone, chicken growth hormone, and human placental lactogen. These observations are discussed in relation to the possible role of these peptide hormones as modulators of 1,25-dihydroxycholecalciferol production in physiological situations of calcium stress, such as pregnancy, lactation, growth in mammals and egg laying in birds.

17beta-oestradiol enhances release of matrix metalloproteinase-2 from human vascular smooth muscle cells.

Vascular remodelling occurs during all stages of atherosclerotic progression. Anti-atherosclerotic drugs may function by restoring regulation of the processes involved in remodelling of the extracellular matrix. A key group of enzymes involved in these processes are the matrix metalloproteinases (MMPs). Oestrogens have been demonstrated to possess anti-atherosclerotic properties at low concentrations while being associated with lesion formation at high concentrations. We examined the effect of 17beta-oestradiol on MMP-2 expression in human coronary artery (CAVSMC) and umbilical artery vascular smooth muscle cells (UAVSMC). MMP-2 expression was measured by chemiluminescent immunoblotting and quantified by laser densitometry. pro-MMP-2 was secreted by VSMCs and increasing levels of 17beta-oestradiol, from physiological through supraphysiological, were associated with significant dose-dependent increases in MMP-2 levels in culture media. This effect was dependent on de novo protein synthesis and could be antagonised by the oestrogen receptor antagonist, tamoxifen, and the specific receptor antagonist ICI 182, 780. 17beta-Oestradiol appears to be a specific stimulator of MMP-2 release from human vascular cells. The concentration dependence of this effect suggests a basis for the differential effects of low and high oestrogen levels on vascular integrity.

Hemostatic risk factors and insulin sensitivity, regional body fat distribution, and the metabolic syndrome.

Disturbances in the thrombotic and fibrinolytic systems are a feature of insulin resistance, obesity, and the metabolic syndrome. However, there are few studies in which these relationships have been explored in mainly asymptomatic individuals using sophisticated measures of insulin sensitivity and regional adiposity. Variables of the hemostatic system were measured in 106 men (aged 32-68 yr; body mass index, 20-34 kg/m(2)). Insulin sensitivity was measured by minimal model analysis and regional adiposity by dual energy x-ray absorptiometry. Clustering of intercorrelated variables was assessed by the statistical technique of factor analysis. Plasma levels of procoagulant factors VII and X, anticoagulant proteins C and S, and plasminogen activator inhibitor-1 correlated positively with total and percent central body fat (r = 0.25-0.38; P < 0.05) and negatively with insulin sensitivity (except protein S; r = -0.24 to -0.35; P < 0.05). On factor analysis, procoagulant factors VII and X, proteins C and S, and plasminogen activator inhibitor-1 were components of the cluster of variables that explained the greatest proportion of the variance in the data (39.2%). Other variables included in this cluster were those typical of the metabolic syndrome and also serum gamma-glutamyl transferase activity. These results suggest that factors VII and X and proteins C and S are features of the intercorrelated disturbances of the metabolic syndrome. Associations with adiposity and liver enzyme activity suggest the involvement of hepatic fat deposition.

Insulin resistance, lipoproteins, body fat and hemostasis in nonobese men with angina and a normal or abnormal coronary angiogram.

OBJECTIVES: The aim of this study was to compare metabolic risk factors in men with anginal chest pain and a normal or abnormal coronary angiogram with those in healthy men. BACKGROUND: Risk factors for coronary heart disease, including lipoprotein abnormalities, hypertension and adiposity, may be metabolically interlinked, with insulin resistance and hyperinsulinemia being pivotal to these disturbances. METHODS: Glucose and insulin metabolism, lipids and lipoproteins, hemostasis, blood pressure and body fat distribution were measured in 77 nonobese middle-aged men who had anginal chest pain (39 with an abnormal coronary angiogram and 38 with no detectable angiographic abnormality) and were compared with those of 40 healthy men of similar age and body mass index. RESULTS: Patients with chest pain had higher insulin responses to an intravenous glucose challenge, lower insulin sensitivity, lower high density lipoprotein (HDL) and subfraction 2 cholesterol, lower apolipoprotein AI, higher triglycerides, greater android fat and higher systolic blood pressure at rest compared with levels in healthy control subjects (p < 0.05). Those with an abnormal coronary angiogram had lower tissue plasminogen activator levels, higher plasminogen activator inhibitor 1 levels and more android fat than did those with a normal angiogram (p < 0.05). Insulin sensitivity correlated positively with HDL (p < 0.05) and subfraction 2 (p < 0.001) cholesterol and negatively with triglycerides (p < 0.01), android fat proportion (p < 0.01) and systolic blood pressure (p < 0.05), whereas insulin response showed converse correlations. CONCLUSIONS: These findings provide new evidence of the central role of insulin resistance and hyperinsulinemia in the development of risk factors associated with coronary heart disease.

Insulin resistance in chronic heart failure: relation to severity and etiology of heart failure.

OBJECTIVES: We attempted to assess insulin sensitivity in patients with chronic heart failure (CHF) and its relation to disease severity. BACKGROUND: Peripheral muscular changes influence the progression of heart failure. This effect may be due to chronic disturbances of insulin and glucose metabolism that affect the energy status of skeletal and myocardial muscle. METHODS: We investigated insulin sensitivity in 79 men-38 patients with CHF, 21 patients with angiographic evidence of coronary artery disease without CHF and 20 healthy control subjects-and assessed its relation to disease severity, etiology and hormonal status (all subjects had a similar age and body mass index). Insulin sensitivity was estimated by minimal modeling analysis of the glucose and insulin and profiles during a 0.5 g/kg body weight intravenous glucose tolerance test. RESULTS: Compared with control subjects, patients with CHF had similar mean fasting glucose but increased insulin levels (67 vs. 29 pmol/liter, p < 0.002) and a 58% reduced mean insulin sensitivity (2.01 vs. 4.84 min-1/pmol/ml x 10(5), p < 0.0001). Peak oxygen consumption (VO2) (r = 0.63), fasting triglycerides (r = -0.62) and age (r = -0.46, all p < 0.001) predicted insulin sensitivity independently. Rest norepinephrine and epinephrine levels, left ventricular ejection fraction and heart failure etiology were not related to insulin sensitivity. Patients with coronary artery disease but no CHF had an intermediate mean insulin sensitivity (3.30 min-1/pmol/ml x 10(5) [-32%, p = 0.042 vs. control subjects; +113%, p = 0.0023 vs. patients with CHF due to ischemic heart disease]). In multivariate analyses of all 79 subjects, age (p = 0.0006), triglycerides (p = 0.0023), fasting insulin (p = 0.0037) and the presence of CHF (p = 0.018) were independent predictors of impaired insulin sensitivity (adjusted joint R2 = 0.53, p < 0.0001). CONCLUSIONS: CHF is associated with marked insulin resistance, characterized by both fasting and stimulated hyperinsulinemia. Advanced heart failure (in terms of reduced peak VO2) is related to increased insulin resistance, but this is not directly mediated through ventricular dysfunction or increased catecholamine levels.

Estrogen receptors and human bone cells: immunocytochemical studies.

In this immunocytochemical study we have probed a number of human bone cell types and bone preparations for the presence of the estrogen receptor (ER) with two distinct monoclonal antibodies. Using a well-validated antibody (H222) that recognizes human ER and standard peroxidase-antiperoxidase methodology, we were unable to demonstrate nuclear staining for ER in cultured primary or transformed human bone-derived cells or in fetal bone sections. Attempts to visualize ER in osteosarcoma cell lines (TE85C and HTB96) using a silver enhancement procedure were also unsuccessful. Additionally, we failed to detect immunocytochemical staining for the progesterone receptor (using monoclonal antibody mPR1) in control or estrogen-treated human bone cell cultures. Estrogen and progesterone receptor staining was readily detectable in MCF7 human breast cancer cells. In contrast, with a monoclonal antibody that recognizes a 29 kDa cytoplasmic component (p29) closely related to human ER, we observed specific staining in all the osteoblastlike cells studied. Cytoplasmic staining for this p29 antigen was most intense in primary cultures of human bone-derived cells. It is possible that the relatively abundant but as yet undefined p29 antigen may act as a sensitive marker for the presence of ER in cells at levels below the detection limit of the anti-ER monoclonal antibody. If so, our results are consistent with the presence of ER in osteoblastlike cells at very low concentrations.