Relationship of waist and hip circumference with coagulation and fibrinolysis in postmenopausal women

Past, Present, and Future Perspectives of Plasminogen Activator Inhibitor 1 (PAI-1)

Plasminogen activator inhibitor 1 (PAI-1), a SERPIN inhibitor, is primarily known for its regulation of fibrinolysis. However, it is now known that this inhibitor functions and contributes to many (patho)physiological processes including inflammation, wound healing, cell adhesion, and tumor progression.This review discusses the past, present, and future roles of PAI-1, with a particular focus on the discovery of this inhibitor in the 1970s and subsequent characterization in health and disease. Throughout the past few decades diverse functions of this serpin have unraveled and it is now considered an important player in many disease processes. PAI-1 is expressed by numerous cell types, including megakaryocytes and platelets, adipocytes, endothelial cells, hepatocytes, and smooth muscle cells. In the circulation PAI-1 exists in two pools, within plasma itself and in platelet α-granules. Platelet PAI-1 is secreted following activation with retention of the inhibitor on the activated platelet membrane. Furthermore, these anucleate cells contain PAI-1 messenger ribonucleic acid to allow de novo synthesis.Outside of the traditional role of PAI-1 in fibrinolysis, this serpin has also been identified to play important roles in metabolic syndrome, obesity, diabetes, and most recently, acute respiratory distress syndrome, including coronavirus disease 2019 disease. This review highlights the complexity of PAI-1 and the requirement to ascertain a better understanding on how this complex serpin functions in (patho)physiological processes.

A Serpin With a Finger in Many PAIs: PAI-1's Central Function in Thromboinflammation and Cardiovascular Disease

Plasminogen activator inhibitor 1 (PAI-1) is a member of the serine protease inhibitor (serpin) superfamily. PAI-1 is the principal inhibitor of the plasminogen activators, tissue plasminogen activator (tPA), and urokinase-type plasminogen activator (uPA). Turbulence in the levels of PAI-1 tilts the balance of the hemostatic system resulting in bleeding or thrombotic complications. Not surprisingly, there is strong evidence that documents the role of PAI-1 in cardiovascular disease. The more recent uncovering of the coalition between the hemostatic and inflammatory pathways has exposed a distinct role for PAI-1. The storm of proinflammatory cytokines liberated during inflammation, including IL-6 and TNF-α, directly influence PAI-1 synthesis and increase circulating levels of this serpin. Consequently, elevated levels of PAI-1 are commonplace during infection and are frequently associated with a hypofibrinolytic state and thrombotic complications. Elevated PAI-1 levels are also a feature of metabolic syndrome, which is defined by a cluster of abnormalities including obesity, type 2 diabetes, hypertension, and elevated triglyceride. Metabolic syndrome is in itself defined as a proinflammatory state associated with elevated levels of cytokines. In addition, insulin has a direct impact on PAI-1 synthesis bridging these pathways. This review describes the key physiological functions of PAI-1 and how these become perturbed during disease processes. We focus on the direct relationship between PAI-1 and inflammation and the repercussion in terms of an ensuing hypofibrinolytic state and thromboembolic complications. Collectively, these observations strengthen the utility of PAI-1 as a viable drug target for the treatment of various diseases.

[Diagnostic and therapeutic management of venous thromboembolic disease in obese patients]

Despite the high proportion of obese patients this population remains understudied in the field of venous thromboembolic disease (VTE). Obesity is a risk factor for pulmonary embolism and/or deep vein thrombosis, especially when it is associated with other risk factors for VTE. Currently there is no validated diagnostic algorithm for VTE in the population of obese patients. Moreover, imaging examinations can be of poor quality and inconclusive. In the prevention of VTE, data concerning obese patients are mainly based on low-level studies. Apart from the context of bariatric surgery, an adjustment of heparin doses according to the weight of the patient is proposed only on a case-by-case basis. According to the current guidelines, therapeutic fixed dose oral anticoagulants should not be prescribed for patients with weights exceeding 120kg or a body mass index>40kg/m². Heparin doses should be weight adjusted and monitored with anti-Xa activity. Anti vitamin K can be prescribed but require INR monitoring. Therefore, new studies specifically dedicated to obese patients are required in the field of VTE for better diagnostic and therapeutic management.

Association Between Residual Platelet Reactivity on Clopidogrel Treatment and Severity of Coronary Atherosclerosis: Intrinsic Hypercoagulability as a Mediator

INTRODUCTION

High on-treatment residual platelet reactivity (HRPR) was associated with greater atherosclerosis burden. We examined whether intrinsic hypercoagulability (IHC) could be attributed to that association in patients treated by drug-eluting stents.

METHODS

This retrospective observation enrolled a total of 891 coronary artery disease (CAD) subjects. Platelet and coagulant reactivity was measured by thrombelastography. At least 24 h after a 300-mg dose of clopidogrel, adenosine diphosphate (ADP)-induced maximum amplitude of clot strength (MA_adp) > 47 mm represented HRPR. Thrombin-induced platelet-fibrin clot strength (MA_thrombin) and blood fibrinogen surrogated intrinsic coagulability. Using mediation analysis to evaluate the effect of IHC on the relationship between the number of narrowed coronaries and HRPR on clopidogrel.

RESULTS

More HRPR on clopidogrel and higher intrinsic coagulability were observed in more severe coronary atherosclerosis, especially in the three-vessel disease. After adjustment for confounding factors, the number of narrowed coronaries (OR_adj = 1.343, 95% CI 1.063-1.695, p = 0.013), MA_thrombin (OR_adj = 1.106, 95% CI 1.058-1.157, p < 0.001), and fibrinogen (OR_adj = 1.003, 95% CI 1.001-1.005, p = 0.012) were all independent positive predictors for HRPR. MA_thrombin and fibrinogen were meaningful mediators for the significant positive association of the number of narrowed vessels and HRPR on clopidogrel, which were enhanced by around 30% and 43%, respectively, for this effect.

CONCLUSIONS

This is the first study to demonstrate that the positive correlation between the number of stenotic coronaries and HRPR on clopidogrel may be partly attributed to IHC, which may enhance the risk stratification, guide more precise coagulation in multi-vessel disease after drug-eluting stents, and therefore deserve further study.

Influence of skeletal muscle mass and fat mass on the metabolic and inflammatory profile in sarcopenic and non-sarcopenic overfat elderly

BACKGROUND

Sarcopenic elderly present low muscle mass and strength, however, it is not clear if the inflammatory and metabolic profile is more related to low lean mass or high fat mass in sarcopenic and non-sarcopenic overfat elderly.

AIM

To verify the difference in inflammatory and metabolic responses in sarcopenic and non-sarcopenic overfat elderly and the relationship between these markers, body composition, and strength in this population.

METHODS

Fifty-seven elderly were divided into two groups: sarcopenic (n = 30) and non-sarcopenic (n = 27). Body composition was evaluated with octopolar bioimpedance. Total cholesterol, high-density lipoprotein cholesterol, triacylglycerol, glucose, cortisol, leptin, adiponectin, Plasminogen activator inhibitor-1 (PAI-1), TNF-α, IL-6, IL-8, and IL-10 were assessed. The handgrip test was used to evaluate strength.

RESULTS

When comparing the inflammatory profile, sarcopenic individuals showed greater adiponectin concentration (p = 0.019), adiponectin/fat mass ratio (p < 0.001), adiponectin/visceral fat (p < 0.001), and higher PAI-1 (p = 0.019) than non-sarcopenic overfat elderly. After adjusting the inflammatory profile by skeletal muscle mass the significant differences between groups were maintained (p < 0.05) but no significant differences between groups were observed when adjusting by fat mass, despite a tendency to a significant difference for adiponectin concentration (p = 0.06). In addition, after adjusting leptin by fat mass there was a statistically significant lower concentration in the sarcopenic compared to non-sarcopenic overfat elderly.

CONCLUSION

Non-sarcopenic overfat elderly presented lower anti-inflammatory and anti-atherogenic responses than sarcopenic elderly. Furthermore, fat mass but not skeletal muscle mass seem to change these responses.

The contribution of different adipose tissue depots to plasma plasminogen activator inhibitor-1 (PAI-1) levels

Increased plasma plasminogen activator inhibitor-1 (PAI-1) level is considered a mechanistic pathway through which obesity contributes to increased cardiovascular disease risk. Abdominal adipose tissue specifically, is a major PAI-1 source with visceral adipose tissue (VAT), an ectopic fat depot, generally considered to produce more PAI-1 than subcutaneous adipose tissue. However, this does not necessarily lead to increased plasma PAI-1 levels. This review provides an overview of studies investigating the association between body fat distribution and plasma PAI-1 levels. It discusses factors that influence this relationship and also considers the contribution of other tissue to plasma PAI-1 levels, placing the relative contribution of adipose tissue into perspective. In conclusion, the relationship between VAT and plasma PAI-1 levels is not fixed but can be modulated by a number of factors such as the size of the subcutaneous adipose tissue depot, ethnicity, possibly genetics and other obesity-related metabolic abnormalities.

Obesity and lower limb venous disease - The epidemic of phlebesity

Introduction Lower limb venous disease affects up to one half, and obesity up to one quarter, of the adult population. Many people are therefore affected by, and present to health services for the treatment of both conditions. This article reviews the available evidence of pathophysiological and clinical relationship between obesity and varicose veins, chronic venous insufficiency and ulceration and deep vein thrombosis. Methods A literature search of PubMed and Cochrane libraries was performed in accordance with PRISMA statement from 1946 to 2015, with further article identification from following cited references for articles examining the relationship between obesity and venous disease. Search terms included obesity, overweight, thrombosis, varicose veins, CEAP, chronic venous insufficiency, treatment, endovenous, endothermal, sclerotherapy, bariatric surgery and deep vein thrombosis. Results The proportion of the population suffering from lower limb venous disease and obesity is increasing. Obesity is an important risk factor for all types of lower limb venous disease, and obese patients with lower limb venous disease are more likely to be symptomatic as a result of their lower limb venous disease. The clinical diagnosis, investigation, imaging and treatment of lower limb venous disease in obese people present a number of challenges. The evidence base underpinning medical, surgical and endovenous management of lower limb venous disease in obese people is limited and such treatment may be associated with worse outcomes and increased risks when compared to patients with a normal body mass index. Conclusion Lower limb venous disease and obesity are both increasingly common. As such, phlebologists will be treating ever greater numbers of obese patients with lower limb venous disease, and clinicians in many other specialties are going to be treating a wide range of obesity-related health problems in people with or at risk of lower limb venous disease. Unfortunately, obese people have been specifically excluded from many, if not most, of the pivotal studies. As such, many basic questions remain unanswered and there is an urgent need for research in this challenging and increasingly prevalent patient group.

Effect of a 12-month exercise intervention on serum biomarkers of angiogenesis in postmenopausal women: a randomized controlled trial

BACKGROUND

Increased physical activity is associated with decreased risk of several types of cancer, but underlying mechanisms are poorly understood. Angiogenesis, in which new blood vessels are formed, is common to adipose tissue formation/remodeling and tumor vascularization.

METHODS

We examined effects of a 12-month 45 minutes/day, 5 days/week moderate-intensity aerobic exercise intervention on four serum markers of angiogenesis in 173 sedentary, overweight, postmenopausal women, 50 to 75 years, randomized to intervention versus stretching control. Circulating levels of positive regulators of angiogenesis [VEGF, osteopontin (OPN), plasminogen activator inhibitor-1 (PAI-1)], and the negative regulator pigment epithelium-derived factor (PEDF), were measured by immunoassay at baseline and 12 months. Changes were compared using generalized estimating equations, adjusting for baseline levels of analytes and body mass index (BMI).

RESULTS

VEGF, OPN, or PAI-1 levels did not differ by intervention arm. Participants randomized to exercise significantly reduced PEDF (-3.7%) versus controls (+3.0%; P = 0.009). Reductions in fat mass were significantly associated with reductions in PAI-1 (Ptrend = 0.03; Ptrend = 0.02) and PEDF (Ptrend = 0.002; Ptrend = 0.01) compared with controls, or to those who gained any fat mass respectively. There was a significant association between decreases in VO2max, and increased reductions in PEDF (Ptrend = 0.03), compared with participants who increased their level of fitness.

CONCLUSIONS

Fat loss reduces circulating PAI-1 and PEDF. Changes in VO2max are associated with alterations in PEDF, but these associations are complex.

IMPACT

Unexpected reductions in PEDF with decreasing fat mass, and with decreasing VO2max, warrant further study, including examining the effects of different types and intensities of exercise; and role of dietary weight-loss with and without exercise.

Relationship of body mass index and waist-to-hip ratio with fibrinolytic activity measured as D-dimer

SUMMARY

BACKGROUND/AIMS

Increased coagulability or impaired fibrinolysis may partly explain how obesity increases cardiovascular disease risk. However, there has been some controversy regarding the relationship of anthropometric measures, like body mass index (BMI) and waist-to-hip ratio (WHR), and D-dimers. We aimed to determine the relationship of general and visceral obesity to D-dimer in a group of outpatients with different BMI and WHR ranges.

METHODS

We performed a cross-sectional study with adult patients from an outpatient primary health service. BMI, WHR and triceps skin fold were measured. Blood samples were collected from all patients and D-dimer levels were obtained.

RESULTS

A total of 66 patients were included in the analysis. The patients had a mean age of 54.6 ± 15.3 years. Fifty-three (80.3%) patients were female and 13 (19.7%) were male. The mean BMI, WHR and triceps skin fold were 30.1 ± 6.9 kg/m(2), 0.88 ± 0.08, 20.9 ± 7.6 mm, respectively. For all the study group, D-dimers were positively correlated only with WHR (r = 0.27, p = 0.038). D-Dimers values were not related to BMI and to triceps skin fold. D-Dimers were moderately correlated with WHR in women (r = 0.40, p = 0.021), but not in male patients (r = 0.18, p = 0.601).

CONCLUSIONS

Our results suggest that abdominal obesity may lead to disturbances in hemostasis, at least in female patients.

Clinical markers of the hypercoagulable state by rotational thrombelastometry in obese patients submitted to bariatric surgery

BACKGROUND

Metabolic and inflammatory disturbances associated with obesity are considered important trigger factors for venous thromboembolism (VTE). Identification of clinical markers indicating a hypercoagulability state could define a group of high-risk patients in the surgical setting. This study aimed to identify these markers using rotational thrombelastometry (ROTEM) analysis, an established method for hemostasis testing that can detect hyperfunctional stages of the clotting process.

METHODS

From June to December 2010, this study investigated 109 consecutive obese patients (28 women and 22 men, mean age 46 years, body mass index 46.6 ± 7 kg/m(2)) with no history of VTE who were candidates for bariatric surgery. Preoperative clinical and metabolic characteristics and ROTEM analysis were recorded. Hypercoagulable risk was defined when patients showed a clot strength (G) of ≥11 dynes/cm(2).

RESULTS

Of the 109 patients, 20 (18%) were hypercoagulable according to ROTEM analysis. Metabolic/inflammatory biomarkers such as leptin, C-reactive protein, fibrinogen levels, and platelet count were significantly higher in the high-risk patients. In the multivariate analysis, fibrinogen was an independent predictor of G ≥ 11 dynes/cm(2) [odds ratio (OR) 2.92, 95 % confidence interval (CI) 1.80-5.21, p = 0.023]. After adjustment to other data, only waist circumference affected the prediction [OR 4.42, 95 % CI 2.27-6.71, p = 0.009]. Receiver operating characteristic curve analysis showed that 3.95 g/l was the best cutoff point for fibrinogen predictability (sensitivity 100 %, specificity 41%).

CONCLUSION

A hypercoagulability state in obese patients is associated with central obesity and high fibrinogen levels, which should be considered clinical hallmarks of this state. More aggressive perioperative prophylaxis for VTE should be recommended when these hallmarks are present in obese patients.

Young Hispanics at risk of type 2 diabetes display endothelial activation, subclinical inflammation and alterations of coagulation and fibrinolysis

BACKGROUND

Hispanics have a high rate of diabetes that exposes them to an increased risk of cardiovascular disease. We hypothesized that many of the pathophysiological mechanisms that cause atherosclerotic disease may be present in young Hispanics who do not have clinical diabetes but are at increased risk of developing it.

METHODS

We studied 36 young Hispanic adults without diabetes (ages 18-40). Seventeen participants were at increased risk of developing type 2 diabetes given by overweight and a family history of diabetes on one or both parents (at risk group). Nineteen participants with normal body-mass index and no parental history of diabetes constituted the control group. We measured and compared plasma markers of endothelial dysfunction, disturbed coagulation and fibrinolysis, subclinical inflammation and adipose tissue dysfunction in the at risk and control groups.

RESULTS

Participants at risk of diabetes were more insulin-resistant according to different indicators, and had significantly higher levels of soluble intercellular adhesion molecule-1 (sICAM-1), tissue plasminogen activator (tPA), inhibitor of plasminogen activator-1 (PAi-1), high sensitivity C-reactive protein and free fatty acids, signaling the presence of multiple proatherogenic alterations despite the absence of overt diabetes. Levels of the prothrombotic molecule PAi-1 were most elevated in participants who were not only at risk of diabetes by the study definition, but also abdominally obese.

CONCLUSIONS

Young adult Hispanics at risk of type 2 diabetes but without overt disease already bear considerably high levels of markers reflecting processes that lead to the development of atherosclerotic cardiovascular disease.

Dydrogesterone does not reverse the cardiovascular benefits of percutaneous estradiol

OBJECTIVE

To evaluate the influence of dydrogesterone on estimated cardiovascular risk of users of hormone replacement therapy (HRT) (with percutaneous 17β-estradiol in monotherapy and in combination with dydrogesterone) and HRT non-users through the Framingham score tool for a period of 2 years.

METHODS

Framingham scores were calculated from the medical records of patients treated for at least 2 years with 17β-estradiol alone or in combination with dydrogesterone, along with HRT non-users, through the analysis of patient medical records, followed for at least 2 years at Instituto Estadual de Diabetes e Endocrinologia Luiz Capriglione.

RESULTS

Improvements in lipid profile, glucose and blood pressure levels, which reduced the estimated cardiovascular risk, were observed in the 17β-estradiol group. Similar changes were observed in the users of 17β-estradiol + dydrogesterone, suggesting that this progestogen does not attenuate the effects caused by 17β-estradiol.

CONCLUSIONS

Both HRT groups showed a reduction in their Framingham score. In contrast to data from other HRT investigations on cardiovascular risk, these formulations proved to be safe, even in the first year of use.

Difficulties in diagnosing pulmonary embolism in the obese patient: a literature review

Several of the signs and symptoms of pulmonary embolism, such as dyspnea, tachypnea, and tachycardia, are common in the obese population, so these patients are frequently suspected of having a pulmonary embolism. Establishing an accurate diagnosis in this situation is often difficult. We performed a review of the literature examining the difficulty of diagnosing pulmonary embolism in obese patients. Several factors compromise the ability of clinicians to accurately diagnose pulmonary embolism in obese patients. When patients weigh over 350 lbs (159 kg), thoracic imaging often cannot be performed because of the weight limitations of the scanning equipment. If equipment is available that can scan these patients, image quality is often poor. The literature that is available to guide the clinician in this difficult clinical scenario is sparse. Access to radiology equipment that can image morbidly obese patients is improving, but questions about image quality remain. Further research on both imaging and outcomes is needed.

Nutrition and human health from a sex-gender perspective

Nutrition exerts a life-long impact on human health, and the interaction between nutrition and health has been known for centuries. The recent literature has suggested that nutrition could differently influence the health of male and female individuals. Until the last decade of the 20th century, research on women has been neglected, and the results obtained in men have been directly translated to women in both the medicine and nutrition fields. Consequently, most modern guidelines are based on studies predominantly conducted on men. However, there are many sex-gender differences that are the result of multifactorial inputs, including gene repertoires, sex steroid hormones, and environmental factors (e.g., food components). The effects of these different inputs in male and female physiology will be different in different periods of ontogenetic development as well as during pregnancy and the ovarian cycle in females, which are also age dependent. As a result, different strategies have evolved to maintain male and female body homeostasis, which, in turn, implies that there are important differences in the bioavailability, metabolism, distribution, and elimination of foods and beverages in males and females. This article will review some of these differences underlying the impact of food components on the risk of developing diseases from a sex-gender perspective.

Inverse association of serum carotenoids with prevalence of metabolic syndrome among Japanese

BACKGROUND & AIMS

Several epidemiological studies have shown that circulating antioxidant levels are inversely associated with metabolic syndrome status. The purpose of this study was to examine the association of serum carotenoid levels, which have potent antioxidant effects, with metabolic syndrome and metabolic syndrome components in Japanese subjects.

METHODS

We conducted a cross-sectional study of 931 subjects (318 men and 613 women), aged 39-70 years, who attended a health examination. Metabolic syndrome was defined according to the diagnostic definition from the Japanese Examination Committee of Criteria for Metabolic Syndrome, which was released in 2005. Serum carotenoids were measured by high-performance liquid chromatography.

RESULTS

A significantly lower odds ratio (OR) for metabolic syndrome was observed in the highest tertile of serum β-cryptoxanthin (OR:0.45; 95% CI:0.22-0.93 in men and 0.41; 0.17-0.93 in women) and β-carotene (OR:0.45; 95% CI:0.21-0.95 in men and 0.37; 0.15-0.83 in women) compared to the lowest tertiles, in both sexes, but no significant association was found in male smokers. In women, moreover, OR for metabolic syndrome in the highest tertile of serum zeaxanthin/lutein (OR:0.37; 95% CI:0.16-0.84) was significantly lower than in the lowest tertile. Serum levels of β-cryptoxanthin, α-carotene, and β-carotene were significantly decreased with an increasing number of metabolic syndrome components in both sexes.

CONCLUSIONS

These findings indicate that carotenoids may be important factors in the prevention of metabolic syndrome in nonsmokers, but further studies are required in smokers.

Coronary heart disease and body fat distribution

Larger waist circumference or waist-hip ratio, as crude indicators of visceral fat mass, are associated with adverse metabolic profile, but their role in predicting future coronary heart disease (CHD) events has been less investigated. Recent epidemiologic findings suggest that these simple and inexpensive measures of abdominal fat distribution predict CHD independently of body mass index, and, to a certain extent, cardiovascular disease risk factors. The magnitude and shape of the association between abdominal adiposity and CHD have been shown to vary with age, gender, and ethnicity. Studies have also suggested that lower body fat is associated with reduced CHD risk, although the clinical relevance for this finding needs further elucidation. Assessing body fat distribution may be useful for improving CHD risk assessment, although more studies are needed to assess consistency in CHD risk predictions across populations. A consensus is also needed to define the clinically relevant cut-off points for waist circumference or waist-hip ratio.

Body composition as determinant of thrombin generation in plasma: the Hoorn study

OBJECTIVE

The association between obesity and cardiovascular disease and venous thromboembolism might, at least partially, be explained by a hypercoagulable state. The extent to which body fat mass and its distribution contribute to a hypercoagulable state is unknown. In this study, we investigated the association between body composition and thrombin generation and evaluated the potential mediating role of low-grade inflammation.

METHODS AND RESULTS

We studied 586 individuals from the Hoorn Study (mean age, 69.7 ± 6.5 years, 298 women) in whom body composition was assessed by whole body dual-energy absorptiometry. Thrombin generation was measured using the calibrated automated thrombogram. Multiple regression analyses showed a positive association between total body fat and thrombin generation in women but not in men. In addition, detailed analyses of regional body composition showed that central but not peripheral fat mass was associated with greater thrombin generation and that there was a trend toward an inverse association with peripheral lean mass. The reported positive associations were partially attenuated by low-grade inflammation, however.

CONCLUSIONS

Body fat mass, in particular a central pattern of fat distribution, is associated with higher levels of thrombin generation in elderly women but not in men. This association may partially be explained by adiposity-related low-grade inflammation, but this hypothesis needs to be further investigated in mechanistic/prospective studies.

Distribution of body fat and risk of coronary heart disease in men and women

PURPOSE OF REVIEW

Earlier studies investigating the risk of developing coronary heart disease in relation to body fat distribution showed inconsistent results, and any sex-related difference in disease risk has not been adequately examined. This review aims to assess current findings on the prospective association between body fat distribution measures and coronary heart disease in men and women.

RECENT FINDINGS

Current epidemiologic evidence suggests that waist circumference and waist-hip ratio, as indicators of abdominal adiposity, are positively related to coronary heart disease in men and women independently of body mass index and conventional coronary heart disease risk factors. But the magnitude and shape of the associations for these abdominal adiposity indices varied with adjustments for mediating and confounding factors. Interestingly, hip waist circumference was inversely associated with coronary heart disease after adjusting for waist circumference. Because waist and hips are positively correlated but have separate and opposite associations with coronary disease, using waist circumference alone may provide underestimated risk estimate if hip girth is not accounted for in the calculation of this risk.

SUMMARY

For adipose tissue distribution assessment to be clinically useful, the ideal adiposity phenotype should provide a single risk estimate that captures the separate 'effects' of abdominal and peripheral adiposity. Although far from perfect, waist-hip ratio may capture separate effects of central and peripheral adiposity. This simple and inexpensive measure could be used to help improve coronary heart disease risk assessment.

Sex differences in obesity and the regulation of energy homeostasis

Obesity prevalence is generally higher in women than in men, and there is also a sex difference in body fat distribution. Sex differences in obesity can be explained in part by the influence of gonadal steroids on body composition and appetite; however, behavioural, socio-cultural and chromosomal factors may also play a role. This review, which evolved from the 2008 Stock Conference on sex differences in obesity, summarizes current research and recommendations related to hormonal and neuroendocrine influences on energy balance and fat distribution. A number of important gaps in the research are identified, including a need for more studies on chromosomal sex effects on energy balance, the role of socio-cultural (i.e. gender) factors in obesity and the potential deleterious effects of high-fat diets during pregnancy on the foetus. Furthermore, there is a paucity of clinical trials examining sex-specific approaches and outcomes of obesity treatment (lifestyle-based or pharmacological), and research is urgently needed to determine whether current weight loss programmes, largely developed and tested on women, are appropriate for men. Last, it is important that both animal and clinical research on obesity be designed and analysed in such a way that data can be separately examined in both men and women.