Obesity and cardiovascular disease: pathophysiology, evaluation, and effect of weight loss: an update of the 1997 American Heart Association Scientific Statement on Obesity and Heart Disease from the Obesity Committee of the Council on Nutrition, Physical Activity, and Metabolism

Metabolic syndrome, hyperinsulinemia, and cancer

The term metabolic syndrome describes the association between obesity, insulin resistance, and the risk of several prominent chronic diseases, including cancer. The causal link between many of these components remains unexplained, however. What is clear are the events that precede the development of the syndrome itself. In animal models, a fat-supplemented diet causes 1) lipid deposition in adipose depots, 2) insulin resistance of liver and skeletal muscle, and 3) hyperinsulinemia. One hypothesis relating fat deposition and insulin resistance involves enhanced lipolysis in the visceral depot, which leads to an increase in free fatty acid (FFA) flux. Increased mass of stored lipid and insulin resistance of visceral adipocytes favors lipolysis. Additionally, hypersensitivity of visceral adipose cells to sympathetic nervous system stimulation leads to increased lipolysis in the obese state. However, little evidence is available for enhanced plasma FFA concentrations in the fasting state. We measured FFA concentrations over a 24-h day in obese animals and found that plasma FFAs are elevated in the middle of the night, peaking at 0300. Therefore, it is possible that nocturnal lipolysis increases exposure of liver and muscle to FFAs at night, thus causing insulin resistance, which may play a role in hyperinsulinemic compensation to insulin resistance. Nocturnal lipolysis secondary to sympathetic stimulation may not only cause insulin resistance but also be responsible for hyperinsulinemia by stimulating secretion and reducing clearance of insulin by the liver. The resulting syndrome-elevated nocturnal FFAs and elevated insulin-may synergize and increase the risk of some cancers. This possible scenario needs further study.

Plasma osteopontin levels and expression in adipose tissue are increased in obesity

CONTEXT

Obesity acts as a cardiovascular risk factor by mechanisms that are not fully understood. Osteopontin (OPN) is a proinflammatory mediator involved in tissue remodeling that plays a role in atherosclerosis and diabetes.

OBJECTIVE

The aim of the present study was to compare the circulating concentrations of OPN and its mRNA expression in omental adipose tissue of lean, overweight, and obese individuals and to analyze the effect of weight loss.

SUBJECTS AND METHODS

Plasma concentrations of OPN were measured in 77 volunteers. OPN mRNA expression in omental adipose tissue obtained from 12 women was quantified by real-time PCR. In addition, the concentrations of OPN in 12 obese men were measured before and after weight loss following a dietetic program.

SETTING

The study was conducted at a University Hospital.

RESULTS

Obese and overweight patients exhibited significantly increased circulating OPN concentrations as compared with lean subjects (obese 72.6 +/- 28.5, overweight 68.2 +/- 20.8, lean 42.7 +/- 27.9 ng/ml; P < 0.001). A significant positive correlation was found between OPN levels and body fat (r = 0.45; P < 0.0001). Obese individuals showed significantly increased (P < 0.05) mRNA expression of OPN in omental adipose tissue as compared with lean volunteers, which was further increased in obese diabetic patients. Diet-induced weight loss significantly decreased OPN concentrations from 64.7 +/- 22.1 to 36.6 +/- 20.1 ng/ml (P = 0.006).

CONCLUSIONS

These findings represent the first observation that plasma OPN and mRNA expression of OPN in omental adipose tissue are increased in overweight/obese patients with the latter being further elevated in obesity-associated diabetes. Moreover, weight loss reduces OPN concentrations, which may contribute to the beneficial effects accompanying weight reduction. Measurement of OPN might be useful for evaluating the outcomes of various clinical interventions for obesity-related cardiovascular diseases.

Effect of angiotensin converting enzyme inhibitor enalapril on body weight and composition in young rats

Obesity is considered a worldwide public health problem showing an increased prevalence in developing countries, with urgent need for new and more efficient drugs and therapies. Enalapril, an angiotensin-I converting enzyme inhibitor (ACEi), is classically used in anti-hypertensive therapies, however, earlier publications have shown that this drug could also have significant impact on body weight in rats as well as in humans, besides reducing blood pressure. The effect of this drug in the white adipose tissue has been neglected for long time, even considering that most components of the renin-angiotensin and kallikrein-kinin system are expressed in this tissue. Furthermore, the adipose tissue is considered today as one of the most important sites for endocrine/inflammatory regulation of appetite and energy output and AngII has been linked to the metabolism in this tissue. Therefore, we analyzed the influence of chronic enalapril treatment in normotensive rats at earlier ages, evaluating body weight, energy homeostasis, lipid profile and serum levels of the hormones leptin and insulin, in the presence of a standard or a palatable hyperlipidic diet regimen for one month. Our results show that enalapril treatment is able to reduce body fat on both diets, without alteration in serum lipid profile. Furthermore, animals receiving enalapril showed reduction in food intake, leptin level and energy intake. In summary, these findings show for the first time that the ACEi enalapril reduces body fat in young normotensive rats and highlights a novel target to treat obesity and associated diseases.

Cardiac steatosis in diabetes mellitus: a 1H-magnetic resonance spectroscopy study

BACKGROUND

The risk of heart failure in type 2 diabetes mellitus is greater than can be accounted for by hypertension and coronary artery disease. Rodent studies indicate that in obesity and type 2 diabetes mellitus, lipid overstorage in cardiac myocytes produces lipotoxic intermediates that cause apoptosis, which leads to heart failure. In humans with diabetes mellitus, cardiac steatosis previously has been demonstrated in explanted hearts of patients with end-stage nonischemic cardiomyopathy. Whether cardiac steatosis precedes the onset of cardiomyopathy in individuals with impaired glucose tolerance or in patients with type 2 diabetes mellitus is unknown.

METHODS AND RESULTS

To represent the progressive stages in the natural history of type 2 diabetes mellitus, we stratified 134 individuals (age 45+/-12 years) into 1 of 4 groups: (1) lean normoglycemic (lean), (2) overweight and obese normoglycemic (obese), (3) impaired glucose tolerance, and (4) type 2 diabetes mellitus. Localized (1)H magnetic resonance spectroscopy and cardiac magnetic resonance imaging were used to quantify myocardial triglyceride content and left ventricular function, respectively. Compared with lean subjects, myocardial triglyceride content was 2.3-fold higher in those with impaired glucose tolerance and 2.1-fold higher in those with type 2 diabetes mellitus (P<0.05). Left ventricular ejection fraction was normal and comparable across all groups.

CONCLUSIONS

In humans, impaired glucose tolerance is accompanied by cardiac steatosis, which precedes the onset of type 2 diabetes mellitus and left ventricular systolic dysfunction. Thus, lipid overstorage in human cardiac myocytes is an early manifestation in the pathogenesis of type 2 diabetes mellitus and is evident in the absence of heart failure.

High-calcium diet with whey protein attenuates body-weight gain in high-fat-fed C57Bl/6J mice

An inverse relationship between Ca intake and BMI has been found in several studies. It has been suggested that Ca affects adipocyte metabolism via suppressing 1,25-dihydroxycholecalciferol (1,25(OH)2-D3) and decreases fat absorption. We studied the effect of Ca and milk proteins (whey and casein) on body weight in C57Bl/6J mice. Male mice, age 9 weeks, were divided into three groups (ten mice per group) receiving modified high-fat (60% of energy) diets. Two groups received a high-Ca diet (1.8% calcium carbonate (CaCO3)), with casein or whey protein (18% of energy), and one group received a low-Ca diet (0.4% CaCO3) with casein for 21 weeks. Food intake was measured daily and body weight twice per week. Body fat content (by dual-energy X-ray absorptiometry) of all mice and faecal Ca and fat excretion of seven mice/group were measured twice during the study. Final body weight (44.1 (SEM 1.1) g) and body fat content (41.6 (SEM 0.6) %) were significantly lower (P < 0.05) in the high-Ca whey group than in the low-Ca casein group (48.1 (SEM 0.8) g and 44.9 (SEM 0.8) %). Body weight and body fat content of the high-Ca casein group did not differ significantly from the low-Ca casein group even though serum 1,25(OH)2-D3 levels were significantly lower (P < 0.001) in both high-Ca groups than in the low-Ca casein group. Thus changes in serum 1,25(OH)2-D3 do not seem to affect body weight in this animal model. There was a significant difference in fat excretion between the high-Ca whey and low-Ca casein groups (3.9 (SEM 0.9) % in the high-Ca whey v. 1.4 (SEM 0.2) % in the low-Ca casein group; P < 0.05), which may partly explain the effect on body weight.

A complex web of risks for metabolic syndrome: race/ethnicity, economics, and gender

BACKGROUND

Metabolic syndrome is a recognizable clinical cluster of risks known to be associated in combination and independently with an increased risk for cardiovascular disease (CVD). Identifying and treating metabolic syndrome is one promising strategy to reduce CVD. The intersection of race/ethnicity, gender, and economic status complicates our understanding of who is at risk for metabolic syndrome, but understanding this social patterning is important for the development of targeted interventions. This study examines the relationship between metabolic syndrome (and the underlying contributing risk factors) and race/ethnicity, economic status, and gender.

METHODS

National Health and Nutrition Examination Survey data collected from 1999 through 2002 were used; analysis was completed in 2006-2007. Metabolic syndrome was defined using the Adult Treatment Panel III definition. Economic status was measured using income as a percentage of the poverty level. Prevalence of metabolic syndrome and each of its contributing risk factors were determined by race/ethnicity and economic group. Logistic regressions were estimated. All analyses were stratified by gender.

RESULTS

Economic effects were seen for women, but not men. Women in the lowest economic group were more likely to be at risk in four of the five risk categories when compared with women in the highest economic group. Differences in the contributing risk profiles for metabolic syndrome were seen by race/ethnicity.

CONCLUSIONS

Strategies to reduce CVD must be built on a clear understanding of the differences in contributing risk factors for metabolic syndrome across subgroups. The findings from this study provide further information to guide the targeting of these strategies.

Diuretics in Obstructive Sleep Apnea With Diastolic Heart Failure

BACKGROUND

Upper airway edema might contribute to pharyngeal collapsibility and account for the high prevalence of obstructive sleep apnea (OSA) in patients with heart disease. The aim of this study was to evaluate if intensive unloading with diuretics improves sleep-disordered breathing and increases pharyngeal caliber in patients with severe OSA and diastolic heart failure.

METHODS

Fifteen patients with severe OSA, hypertension, and diastolic heart failure were hospitalized to receive IV furosemide, 20 mg, and spironolactone, 100 mg, bid for 3 days. Polysomnography was performed for assessment of apnea-hypopnea index (AHI), acoustic pharyngometry was performed for assessment of the oropharyngeal junction (OPJ) area, and forced midinspiratory flow (FIF(50)), forced midexpiratory flow (FEF(50))/FIF(50) percentage, and exhaled nitric oxide (FeNO) were measured before and after diuretic treatment.

RESULTS

Diuretic treatment produced a significant decrease in body weight, BP, and AHI (from 74.89 +/- 6.95 to 57.17 +/- 5.40/h, p < 0.001), associated with an improvement in OPJ area (from 1.33 +/- 0.10 to 1.78 +/- 0.16 cm(2), p = 0.007), FIF(50) (from 3.16 +/- 0.4 to 3.94 +/- 0.4 L/s, p = 0.006), and FEF(50)/FIF(50) percentage (from 117.9 +/- 11.8 to 93.15 +/- 10.1%, p = 0.002). Weight loss was significantly related to the decrease of AHI (R = 0.602; p = 0.018), to the increase of FIF(50) (R = 0.68; p = 0.005), and to the decrease of FEF(50)/FIF(50) (R = 0.635; p = 0.011).

CONCLUSIONS

These findings suggest that pharyngeal edema contributes to sleep-disordered breathing in obese patients with severe OSA, hypertension, and diastolic heart failure. Upper airway edema may contribute to the frequent occurrence of OSA in patients with heart disease.

Are physicians able to identify high-risk abdominally obese individuals? An analysis from the pan-European Survey of HDL-cholesterol

OBJECTIVES

Physician perception of the obesity status may influence the approach to the management of cardiometabolic risk factors. The objective of this study was to explore physicians' perceptions of the obesity status of their patients in comparison with objective measurements of generalised or abdominal obesity.

RESEARCH DESIGN AND METHODS

The pan-European Survey of high density lipoprotein (HDL)-cholesterol measured the prevalence of low HDL-cholesterol and other cardiometabolic risk factors in 8545 patients in 11 European countries. The survey also included a question, 'Is your patient obese?' with possible answers of 'Yes' or 'No'. Answers to this question were compared with actual obesity status, based on standard cut-off values for body mass index (BMI) and waist circumference.

MAIN OUTCOME MEASURES

Sensitivity and specificity of physicians' identification of obesity using receiver operating characteristics analysis.

RESULTS

All patients identified as non-obese were subsequently found to have BMI <30 kg/m(2). However, 38% of patients identified as obese by physicians did not have BMI > or =30 kg/m(2). It appeared that the presence of abdominal obesity (high waist circumference, present according to US criteria in about half of overweight patients) increased the likelihood of a patient being perceived as obese.

CONCLUSIONS

Physicians often overestimate obesity, especially in abdominally overweight patients. In practice, physicians tend to identify as obese a subset of patients at higher cardiovascular risk through high waist circumference.

Cardiovascular disease: strategies for risk assessment and modification

Cardiovascular disease is the leading cause of death among men and women in the United States. Silent myocardial ischemia, defined as documentation of ischemia in the absence of angina or anginal equivalents, affects up to 4 million Americans and carries a poor prognosis. The assessment of the presence of subclinical coronary atherosclerosis affords an opportunity to identify patients who may be at risk for coronary artery disease over the long term. In addition to traditional risk factors (such as lipid parameters, diabetes, hypertension, smoking, and age), a variety of novel factors (such as lipoprotein[a], homocysteine, and C-reactive protein) may enhance assessment of risk in specific populations. Risk modification should be aimed at achieving recommended levels of lipids and blood pressure, reducing obesity, facilitating optimal management of diabetes and the metabolic syndrome, and encouraging smoking cessation and physical activity. Clinicians should be knowledgeable regarding the application of national guidelines for the reduction of cardiovascular risk so as to maximize the prospects for both the primary and secondary prevention of coronary artery disease and associated adverse outcomes.

Adiposity and Alzheimer's disease

The objective of this manuscript is to provide a comprehensive review of the relation between adiposity and Alzheimer's disease (AD), its potential mechanisms, and issues in its study. Adiposity represents the body fat tissue content. When the degree of adiposity increases it can be defined as being overweight or obese by measures such as the body mass index. Being overweight or obese is a cause of hyperinsulinemia and diabetes, both of which are risk factors for AD. However, the epidemiologic evidence linking the degree of adiposity and AD is conflicting. Traditional adiposity measures such as body mass index have decreased validity in the elderly. Increased adiposity in early or middle adult life leads to hyperinsulinemia which may lead to diabetes later in life. Thus, the timing of ascertainment of adiposity and its related factors is critical in understanding how it might fit into the pathogenesis of AD. We believe that the most plausible mechanism relating adiposity to AD is hyperinsulinemia, but it is unclear whether specific products of adipose tissue also have a role. Being overweight or obese is increasing in children and adults, thus understanding the association between adiposity and AD has important public health implications.

Anthropometric predictors for the risk of chronic disease in non-diabetic, non-hypertensive young Mexican women

OBJECTIVES

To assess the ability of anthropometric measurements to identify young women at risk of developing diabetes, hypertension and heart disease in the future and to compare cut-off points for common anthropometric measures established with receiver-operating characteristic (ROC) curves with those reported in the literature.

DESIGN

Cross-sectional study.

SUBJECTS

Eight hundred and two young Mexican women living in semi-urban poverty. MEASUREMENTS/METHODS: The ability of anthropometric measures of fatness and fat distribution (body mass index (BMI), summed skinfold thickness (SST), waist circumference (WC), waist-to-hip ratio (WHR), conicity index (CI), abdominal volume index (AVI)) to predict risk of future disease (pre-diabetes: fasting blood glucose 100-126 mg dl-1; pre-hypertension: systolic blood pressure 120-139 mmHg and/or diastolic blood pressure 80-89 mmHg; hypertriglyceridaemia: triglycerides > or =150 mg dl-1; or a combination of risk factors) was assessed using ROC curve analysis.

RESULTS

Twenty-three of the 802 women who were interviewed had incomplete data and 50 (6.4%) were eliminated from the analysis due to hypertension and/or diabetes. Mean age of the remaining 729 women was 29.6 +/- 5.4 years and mean BMI was 27.7 +/- 4.5 kg m-2. There were no significant differences in the area under the ROC curve for BMI, WC, AVI or SST for any of the four outcomes. However, these indices performed significantly better than WHR and CI (P < 0.05). The BMI cut-off points that maximised sensitivity and specificity for the four outcomes were in the range of 27.7-28.4 kg m-2, and for WC were 89.3-91.2 cm. To detect 90% of the cases of any metabolic alteration, the necessary BMI cut-off was 26.1 kg m-2. Younger women (<25 years) were at greater risk than older women for a given BMI increment (P < 0.05).

CONCLUSIONS

We found that BMI and WC cut-off points commonly used for the identification of risk of existing disease were also appropriate in this population for the identification of risk in the future among women without diabetes or hypertension. The early identification of at-risk individuals, prior to the onset of disease, is fundamental particularly in the context of a country with scarce resources that is rapidly undergoing nutrition transition.

The relationship of sterol regulatory element-binding protein cleavage-activation protein and apolipoprotein E gene polymorphisms with metabolic changes during weight reduction

Sterol regulatory element-binding protein cleavage-activating protein (SCAP) and apolipoprotein E (apo E) regulate cellular and plasma lipid metabolism. Therefore, variations in the corresponding genes might influence weight reduction and obesity-associated metabolic changes. We investigated the relationships of SCAP (Ile796Val) and apo E polymorphisms on metabolic changes during weight reduction by using a 12-week very low-energy diet. Body composition, serum lipids, plasma glucose, and insulin were assessed in 78 healthy premenopausal women (initial body mass index, 34 +/- 4 kg/m(2); age, 40 +/- 4 years) before and after the intervention. The SCAP genotype groups did not differ in the responses of any parameters measured during weight reduction. Apo E did not differentiate the weight loss, but the changes in total and low-density lipoprotein cholesterol for the genotype groups apo E epsilon2/3, epsilon3/3, as well as epsilon3/4 and epsilon4/4 combined were -0.94 +/- 0.56 and -0.59 +/- 0.32, -0.71 +/- 0.49 and -0.49 +/- 0.45, and -0.55 +/- 0.47 and -0.37 +/- 0.39 mmol/L, respectively (P < .05 for both). In conclusion, neither the SCAP Ile796Val nor the apo E polymorphism was associated with weight loss in obese premenopausal women. However, the apo E-but not SCAP genotype-seems to be one of the modifying factors for serum cholesterol concentrations during very low-energy diet in obese premenopausal women.

Cardiovascular effects of sibutramine in the treatment of obese adolescents: results of a randomized, double-blind, placebo-controlled study

BACKGROUND

Adolescent obesity is a major public health problem. Treatment options in addition to behavioral therapy could include pharmacotherapy with sibutramine.

OBJECTIVES

Concerns regarding increases in blood pressure and heart rate after sibutramine treatment in some adult patients precipitated the present analysis, which evaluated the cardiovascular safety of sibutramine plus a behavioral therapy program in obese adolescents.

PATIENTS AND METHODS

With this 12-month, randomized, double-blind, placebo-controlled trial in 33 US clinics we studied 498 adolescents aged 12 to 16 years with multiethnic backgrounds and BMIs of 28.1 to 46.3 kg/m2.

RESULTS

The subjects were randomly assigned to behavioral therapy plus 10 mg of sibutramine or behavioral therapy plus placebo daily. At the end point, there was a mean treatment group difference in BMI of 2.6 kg/m2 in favor of sibutramine. Small mean decreases in blood pressure and pulse rate were seen in both sibutramine and placebo groups at the end point (systolic blood pressure: -2.1 vs -2.1 mmHg; diastolic blood pressure: -0.1 vs -1.1 mmHg; pulse rate: -0.2 vs -1.8 bpm). In both treatment groups, these reductions in vital signs were greater at the end point when BMI reduction was > or = 5% compared with < 5%.

CONCLUSIONS

Sibutramine may have some direct cardiovascular effects on obese adolescents. These cardiovascular effects may be balanced by a reduction in BMI, which, in adolescents, seems to be greater than that observed in adults.

Metabolic syndrome, its preeminent clusters, incident coronary heart disease and all-cause mortality--results of prospective analysis for the Atherosclerosis Risk in Communities study

OBJECTIVE

To investigate the prospective association between Metabolic Syndrome (MetS) and coronary heart disease (CHD) and all-cause mortality.

SUBJECTS AND DESIGN

A bi-racial cohort of 14 699 middle-aged Americans from the Atherosclerosis Risk in Communities study were followed for the development of new CHD and death over a period of 9 years. MetS, using the original ATP-III criteria, was defined as having at least three of the following components: elevated blood pressure (BP), elevated plasma glucose, elevated blood triglyceride (TG), increased waist circumference, and low HDL cholesterol (HDL-c). Incident CHD cases included hospitalized myocardial infarction (MI), fatal CHD, revascularization procedures, and silent MI as detected by EKG.

RESULTS

The prevalence of the MetS at baseline was 29%, 30%, 40% and 26% among CHD-free white women, white men, black women, and black men, respectively. There were 1018 incident CHD cases and 1039 deaths. The relative risk (RR) and 95% confidence interval (CI) of incident CHD associated with MetS was 2.46 (1.99, 3.03) for women and 1.86 (1.59, 2.18) for men. Clear dose-response relationship between the number of MetS components and incidence of CHD was found (P for linear trend <0.001). The following three clusters of MetS components posed the highest risk for CHD: (i) the elevated BP and glucose and low HDL-c group [RR = 5.68 (3.44, 9.37)]; (ii) the elevated BP and glucose and TG group [RR = 5.08 (2.96, 8.70)]; and (iii) the elevated BP and TG and low HDL-c group [RR = 3.98 (2.75, 5.77)]. When all five components co-existed, the risk was the highest [RR = 6.24 (4.65, 8.36)]. Similar results with attenuated RR were found for all-cause mortality.

CONCLUSIONS

Individuals, especially women, with the MetS have significantly higher risk of developing CHD. The riskiest combination is high-BP and glucose clustered with low HDL-c or high TG. These data highlight the importance of targeting MetS in the prevention of CHD and premature death.

Effect of gastric bypass operation on Framingham and actual risk of cardiovascular events in class II to III obesity

BACKGROUND

Obesity is known to be a major risk factor for cardiovascular diseases. There are few studies in the literature assessing the effect of bariatric procedures on longterm risk of cardiovascular events. The aim of this study was to determine the effect of gastric bypass operation on actual and Framingham risk of coronary heart disease (CHD) events in class II to III obesity.

STUDY DESIGN

In a cohort of subjects with class II to III obesity, we used the observed change in CHD risk factors and risk models derived from the Framingham data equation to calculate the predicted 10-year absolute and relative risk of CHD after gastric bypass operation. The risk predicted by the Framingham model was then compared with the actual incidence of CHD events of the cohort.

RESULTS

Five-hundred patients were included in the study. The 1-year mean excess body weight loss was 68.7% +/- 22%. There was a substantial reduction in prevalence of diabetes from 28% to 6% (p = 0.001). Compared with baseline, the average 10-year absolute risk of cardiac events decreased from 5.4% at baseline to 2.7% at 1 year after operation (p = 0.001). A similar risk reduction was observed in subgroups defined by diabetes status and gender. Gastric bypass decreased absolute risk of cardiac events by a mean of 63% (p = 0.0001) in diabetics and 56% (p = 0.001) in male patients. The cohort actual rate of CHD events was 1% (5 of 500). At the 5-year horizon, this was considerably (p = 0.001) lower than the predicted rate before gastric bypass operation.

CONCLUSIONS

Gastric bypass operation is effective in reducing actual and the 10-year Framingham risk of CHD events in individuals with class II to III obesity. The major estimated risk reduction was observed in male patients with type 2 diabetes.

Androgens, obesity, and sleep-disordered breathing in men

Impaired gonadal function, obesity, metabolic syndrome, and obstructive sleep apnea commonly occur together in men. We propose that this arises due to two interlinked cycles. Understanding the molecular mechanisms by which these relationships occur may lead to novel therapeutic strategies. Although obesity is not gender specific and the effectiveness of current antiobesity interventions have predominantly been verified in women, promoting weight loss in men is an urgent concern because men are have proportionally worse health consequences. In addition, avoiding excessive weight may maintain optimal male reproductive health.

Concentrations of urinary phthalate metabolites are associated with increased waist circumference and insulin resistance in adult U.S. males

BACKGROUND

Phthalates impair rodent testicular function and have been associated with anti-androgenic effects in humans, including decreased testosterone levels. Low testosterone in adult human males has been associated with increased prevalence of obesity, insulin resistance, and diabetes.

OBJECTIVES

Our objective in this study was to investigate phthalate exposure and its associations with abdominal obesity and insulin resistance.

METHODS

Subjects were adult U.S. male participants in the National Health and Nutrition Examination Survey (NHANES) 1999-2002. We modeled six phthalate metabolites with prevalent exposure and known or suspected antiandrogenic activity as predictors of waist circumference and log-transformed homeostatic model assessment (HOMA; a measure of insulin resistance) using multiple linear regression, adjusted for age, race/ethnicity, fat and total calorie consumption, physical activity level, serum cotinine, and urine creatinine (model 1); and adjusted for model 1 covariates plus measures of renal and hepatic function (model 2). Metabolites were mono-butyl phthalates (MBP), mono-ethyl phthalate (MEP), mono-(2-ethyl)-hexyl phthalate (MEHP), mono-benzyl phthalate (MBzP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), and mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP).

RESULTS

In model 1, four metabolites were associated with increased waist circumference (MBzP, MEHHP, MEOHP, and MEP; p-values </= 0.013) and three with increased HOMA (MBP, MBzP, and MEP; p-values </= 0.011). When we also adjusted for renal and hepatic function, parameter estimates declined but all significant results remained so except HOMA-MBP.

CONCLUSIONS

In this national cross-section of U.S. men, concentrations of several prevalent phthalate metabolites showed statistically significant correlations with abdominal obesity and insulin resistance. If confirmed by longitudinal studies, our findings would suggest that exposure to these phthalates may contribute to the population burden of obesity, insulin resistance, and related clinical disorders.

Biliopancreatic diversion reduces QT interval and dispersion in severely obese patients

OBJECTIVES

The objectives were to evaluate QT interval (QTc) and QT-interval dispersion (QTd) in severely obese individuals and to determine the effects of biliopancreatic diversion (BPD) and weight loss after BPD on ventricular repolarization parameters.

BACKGROUND

People with severe obesity (SO) have a 50% to 100% increased risk of death associated with a 1.6-fold increased risk of sudden death. BPD surgery induces rapid and considerable weight loss through severe lipid malabsorption, thus achieving long-term weight control.

RESEARCH METHODS AND PROCEDURES

A total of 85 subjects with SO (age, 42 +/- 12 years; 66 females; mean body weight, 120 +/- 29 kg; BMI, 45 +/- 11 kg/m(2)) of 330 who had a bariatric surgical consultation between January 2001 and July 2002 were enrolled. Inclusion criteria were sinus rhythm, unremarkable 12 leads surface electrocardiogram, no atrioventricular blocks and/or bundle branch blocks, normal serum electrolyte profile, and no medical therapies exerting known effects on QTc. Exclusion criteria were previous diagnosis of coronary artery disease, known cardiovascular disease, atrial fibrillation or any other known cardiac arrhythmias, cancer, or renal dysfunction.

RESULTS

A total of 86% of patients had QTc >440 ms and/or QTd >60 ms. Subjects with SO showed a mean maximum QTc of 446 +/- 28 ms and a mean QTd of 52 +/- 20 ms. A close correlation was found between QTc and QTd (p < 0.0001; R(2) = 0.33). One month after BPD, mean QTc was 420 ms and remained stable at follow-up; QTd was 32 ms at 1 and 6 months and became 35 ms at 1 year.

CONCLUSIONS

Ventricular repolarization abnormalities are significantly increased in subjects with SO. Reduction of QT abnormalities after BPD is independent of weight loss and is caused by the 100% reduction of glucose plasma shortly after surgery. This effect may be related to surgical interruption of the entero-insular axis.

Serum insulin and inflammatory markers in overweight individuals with and without dyslipidemia

CONTEXT

The worldwide epidemic of overweight and obesity is setting the scene for a new wave of premature cardiovascular disease.

OBJECTIVE

The objective of this study was to define relationships between dyslipidemia and other metabolic abnormalities in overweight subjects.

DESIGN

This study included comparison of overweight subjects with and without dyslipidemia.

SETTING

The setting was an institutional practice.

PATIENTS

Dyslipidemic subjects (n = 715) had plasma triglyceride greater than or equal to the 75th percentile in combination with high-density lipoprotein cholesterol (HDL-C) less than or equal to the 25th percentile. Unrelated, normolipidemic controls (n = 1073) had HDL-C higher than the median and triglyceride lower than the median. It was a requirement for the control subjects to have a body mass index (BMI) greater than 25 kg/m(2).

MAIN OUTCOME MEASURES

The main outcome measures included BMI, inflammatory markers, adipokines, blood pressure, and fasting plasma glucose and insulin.

RESULTS

The mean BMI in the subjects and controls was 28.7 and 28.2 kg/m(2), respectively. Subjects had higher levels of plasma high-sensitivity C-reactive protein (3.0 vs. 2.0 mg/liter; P < 0.001), lower levels of adiponectin (4.7 vs. 6.6 mg/liter; P < 0.001), and, after adjustment for age, BMI, gender, smoking, statin, and beta-blocker use, higher systolic (P = 0.001) and diastolic (P = 0.05) blood pressures. Fasting plasma glucose, insulin, and homeostasis model of assessment-insulin resistance were all significantly higher in subjects than controls (P < 0.0001).

CONCLUSIONS

Identification of people solely on the basis of an elevated plasma triglyceride and a low HDL-C uncovers an overweight group of people who have a generalized metabolic disorder. In contrast, overweight people with normal plasma lipids have normal glucose and insulin metabolism, low levels of inflammatory markers, and normal blood pressure. Such people may thus be at relatively low risk of developing diabetes and cardiovascular disease despite being overweight.

Core components of cardiac rehabilitation/secondary prevention programs: 2007 update: a scientific statement from the American Heart Association Exercise, Cardiac Rehabilitation, and Prevention Committee, the Council on Clinical Cardiology; the Councils on Cardiovascular Nursing, Epidemiology and Prevention, and Nutrition, Physical Activity, and Metabolism; and the American Association of Cardiovascular and Pulmonary Rehabilitation

The American Heart Association and the American Association of Cardiovascular and Pulmonary Rehabilitation recognize that all cardiac rehabilitation/secondary prevention programs should contain specific core components that aim to optimize cardiovascular risk reduction, foster healthy behaviors and compliance to these behaviors, reduce disability, and promote an active lifestyle for patients with cardiovascular disease. This update to the previous statement presents current information on the evaluation, interventions, and expected outcomes in each of the core components of cardiac rehabilitation/secondary prevention programs, in agreement with the 2006 update of the American Heart Association/American College of Cardiology Secondary Prevention Guidelines, including baseline patient assessment, nutritional counseling, risk factor management (lipids, blood pressure, weight, diabetes mellitus, and smoking), psychosocial interventions, and physical activity counseling and exercise training.

Impact of obesity and bariatric surgery on cardiovascular disease

Morbid obesity is a growing public health concern with multiple associated cardiovascular comorbidities. Bariatric surgery has emerged as a safe and effective treatment for morbidly obese patients at risk for, or already suffering from, cardiovascular disease. Weight loss induced by the surgery has been shown to improve cardiovascular risk factors, cardiac structure and function, and the clinical course of established cardiovascular disease. The role of adipocyte-derived cytokines in mediating cardiovascular pathophysiology in obesity-and its modulation after weight loss-is under active investigation.

Aggressive Management of Obesity in Children and Young Adults: The Known Challenges and Potential Opportunities

The world is confronted with an impending epidemic of premature cardiovascular disease (CVD) that is being fueled by an increase in the prevalence of central obesity.

Core Components of Cardiac Rehabilitation/Secondary Prevention Programs: 2007 Update

The American Heart Association and the American Association of Cardiovascular and Pulmonary Rehabilitation recognize that all cardiac rehabilitation/secondary prevention programs should contain specific core components that aim to optimize cardiovascular risk reduction, foster healthy behaviors and compliance to these behaviors, reduce disability, and promote an active lifestyle for patients with cardiovascular disease. This update to the previous statement presents current information on the evaluation, interventions, and expected outcomes in each of the core components of cardiac rehabilitation/secondary prevention programs, in agreement with the 2006 update of the American Heart Association/American College of Cardiology Secondary Prevention Guidelines, including baseline patient assessment, nutritional counseling, risk factor management (lipids, blood pressure, weight, diabetes mellitus, and smoking), psychosocial interventions, and physical activity counseling and exercise training.

Diet-induced obese mice have increased mortality and altered immune responses when infected with influenza virus

Obesity is associated with an impaired immune response, an increased susceptibility to bacterial infection, and a chronic increase in proinflammatory cytokines such as IL-6 and TNFalpha. However, few studies have examined the effect of obesity on the immune response to viral infections. Because infection with influenza is a leading cause of morbidity and mortality worldwide, we investigated the effect of obesity on early immune responses to influenza virus exposure. Diet-induced obese and lean control C57BL/6 mice were infected with influenza A/PR8/34, and lung pathology and immune responses were examined at d 0 (uninfected), 3, and 6, postinfection. Following infection, diet-induced obese mice had a significantly higher mortality rate than the lean controls and elevated lung pathology. Antiviral and proinflammatory cytokine mRNA production in the lungs of the infected mice was markedly different between obese and lean mice. IFNalpha and beta were only minimally expressed in the infected lungs of obese mice and there was a notable delay in expression of the proinflammatory cytokines IL-6 and TNFalpha. Additionally, obese mice had a substantial reduction in NK cell cytotoxicity. These data indicate that obesity inhibits the ability of the immune system to appropriately respond to influenza infection and suggests that obesity may lead to increased morbidity and mortality from viral infections.

Hypertension and impaired renal function accompany juvenile obesity: the effect of prenatal diet

Obesity has been suggested to have a detrimental impact on kidney structure and function, leading to focal glomerulosclerosis and hypertension. It is also associated with hyperleptinemia and elevated renal sympathetic nerve activity. Prenatal undernutrition promotes postnatal obesity, hypertension, and an altered renal structure and function. In this study, we examined the effects of prenatal nutrient restriction and juvenile obesity in sheep. We found that juvenile obesity led to chronic hyperleptinemia and reduced renal function as assessed by nuclear scintigraphy. Additional factors include hypertension, glomerulosclerosis, and increased kidney apoptosis. Prenatal undernutrition, synchronous with early kidney development, coupled postnatally with juvenile obesity had no effect on systemic pathophysiological sequalae associated with obesity per se. Hypertension, hyperleptinemia, and poor renal function were all observed in this group. All indices of renal pathology such as increased expression of proinflammatory cytokines, angiotensin II, glucocorticoid receptors, and increased apoptosis and glomerulosclerosis were entirely absent in obese prenatally undernourished offspring. Our data indicate that juvenile obesity per se leads to systemic hypertension and renal structural and functional pathology. Prenatal undernutrition effectively abolishes any renal histopathology associated with juvenile obesity.

Obesity did not diminish the efficacy of percutaneous ablation for hepatocellular carcinoma

BACKGROUND

Overweight and hepatic steatosis can increase the risk of hepatocarcinogenesis. In addition, overweight may affect the treatment efficacy of ultrasound-guided percutaneous ablation. We evaluated the impact of overweight on the safety and efficacy of percutaneous ablation to hepatocellular carcinoma (HCC).

METHODS

We enrolled 743 patients with naïve HCC who were treated by percutaneous ablation including ethanol injection, microwave coagulation, and radiofrequency ablation (RFA) between 1995 and 2003. Patients were divided into two groups by body mass index (BMI): 219 overweight patients with BMI>25 kg/m2 and 524 control patients with BMI<or=25 kg/m2. The effects of BMI on complications of percutaneous ablation, HCC recurrence, and overall survival were analyzed, together with others including tumor and liver function-related factors.

RESULTS

The overweight group required a significantly larger number of sessions by RFA (P=0.01). Major complications were identified in 8.7% in the overweight group and 7.6% in the control group (P=0.94). There was no significant difference in cumulative recurrence rate and local tumor-progression rate between the two groups (P=0.63 and 0.44). Cumulative survival rates at 1, 3, and 5 years were 95.4%, 75.7%, and 57.8%, respectively, in the overweight group and 94.1%, 78.0%, and 58.8% in the control group (P=0.99).

CONCLUSIONS

The results indicated that overweight did not increase complications nor affect HCC recurrence and overall survival. However, the number of sessions of RFA was significantly greater in overweight patients, suggesting that overweight was associated with minor technical difficulties.

Fatness is related to blunted vascular stress responsivity, independent of cardiorespiratory fitness in normal and overweight men

Obesity is associated with disturbed cardiovascular responsivity to mental stress, which may mediate psychosocial disease pathways. Whether being aerobically fit is protective against psychophysiological dysfunction in the presence of overweight or obesity is undetermined. Peripheral blood flow, blood pressure, and cardiac responses were measured during a 2-min mental stress task in 48 healthy men (aged 18-32 years). Mental stress-evoked increases in mean arterial pressure and heart rate, forearm vasodilatation, and cardiac parasympathetic withdrawal. Multiple linear regression analyses adjusted for age, peak oxygen uptake, and baseline forearm vascular resistance, revealed that greater fatness was related to a blunted vasodilatation response to mental stress (beta=-.31, p<.05). There were no interactive effects of fitness and fatness. Fitness does not appear to moderate the association between fatness and impaired vascular stress responsivity in normal and overweight men.

Opposing effects of adiponectin receptors 1 and 2 on energy metabolism

The adipocyte-derived hormone adiponectin regulates glucose and lipid metabolism and influences the risk for developing obesity, type 2 diabetes, and cardiovascular disease. Adiponectin binds to two different seven-transmembrane domain receptors termed AdipoR1 and AdipoR2. To study the physiological importance of these receptors, AdipoR1 gene knockout mice (AdipoR1(-/-)) and AdipoR2 gene knockout mice (AdipoR2(-/-)) were generated. AdipoR1(-/-) mice showed increased adiposity associated with decreased glucose tolerance, spontaneous locomotor activity, and energy expenditure. However, AdipoR2(-/-) mice were lean and resistant to high-fat diet-induced obesity associated with improved glucose tolerance and higher spontaneous locomotor activity and energy expenditure and reduced plasma cholesterol levels. Thus, AdipoR1 and AdipoR2 are clearly involved in energy metabolism but have opposing effects.

Anthropometric measures in middle age after exposure to famine during gestation: evidence from the Dutch famine

BACKGROUND

Few studies in humans have related maternal undernutrition to the size of the adult offspring.

OBJECTIVE

The objective was to assess whether reductions in food intake by pregnant women during the Dutch famine of 1944-1945 were related to offspring length, weight, and indexes of adiposity in middle age.

DESIGN

We recruited 1) exposed persons born in western Netherlands between January 1945 and March 1946 whose mothers experienced famine during or immediately preceding pregnancy, 2) unexposed persons born in the same 3 institutions during 1943 or 1947 whose mothers did not experience famine during this pregnancy, and 3) unexposed same-sex siblings of persons in series 1 or 2. Anthropometric measurements (n = 427 males and 529 females) were obtained between 2003 and 2005. We defined 4 windows of gestational exposure (by ordinal weeks 1-10, 11-20, 21-30, and 31 through delivery) on the basis of exposure to a ration of <900 kcal/d during the whole 10-wk interval.

RESULTS

Exposure to reduced rations was associated with increased weight and greater indexes of fat deposition at several tissue sites in women but not in men (P for interaction <0.01). Measures of length and linear proportion were not associated with exposure to famine.

CONCLUSION

Reduced food availability may lead to increased adiposity later in life in female offspring.

Effect of weight loss on predicted cardiovascular risk: change in cardiac risk after bariatric surgery

OBJECTIVE

Our goal was to assess the effect of bariatric surgery on cardiovascular risk estimations of preventable, long-term adverse outcomes.

RESEARCH METHODS AND PROCEDURES

We performed a population-based, historical cohort study between 1990 and 2003 of 197 consecutive patients from Olmsted County, MN, with Class II to III obesity (defined as BMI > or = 35 kg/m2) treated with Roux-en-Y gastric bypass and 163 non-operative patients assessed in a weight-reduction program. We used the observed change in cardiovascular risk factors and risk models derived from data from the National Health and Nutrition Examination Survey (NHANES) I and the NHANES I Epidemiological Follow-up Study (NHEFS) to calculate the predicted impact on cardiovascular events and mortality for the operative and non-operative groups.

RESULTS

Mean follow-up was 3.3 years. Hypertension, diabetes, and dyslipidemia all improved after bariatric surgery. The estimated 10-year risk for cardiovascular events for the operative group decreased from 37% at baseline to 18% at follow-up, while the estimated risk for the non-operative group did not change from 30% at baseline to 30% at follow-up. Risk modeling to predict 10-year outcomes estimated 4 overall deaths and 16 cardiovascular events prevented by bariatric surgery per 100 patients compared with the non-operative group.

CONCLUSIONS

Bariatric surgery induces an improvement in cardiovascular risk factors in patients with Class II to III obesity. Weight loss predicts a major, 10-year reduction in cardiovascular events and deaths. Bariatric surgery should be considered as an alternative approach to reduce cardiovascular risk in patients with Class II to III obesity.

Glomerular hyperfiltration: a new marker of metabolic risk

Chronic kidney disease coexists with metabolic syndrome and this relationship may be apparent before overt manifestations of cardiovascular disease. To investigate early stages of the natural history of associations between renal function and metabolic syndrome, we phenotyped 1572 young (mean age=18.4 years), apparently healthy men for metabolic risk factors and estimated their creatinine clearance based on the Cockcroft-Gault equation. High metabolic risk (clustering of at least three metabolic risk factors) was revealed in 8.7% (137) of the subjects and was associated with a 6.9-fold increase in the odds of glomerular hyperfiltration (95% confidence interval (CI): 3.9-11.5) when compared to reference (from none to two metabolic risk factors). Overweight, elevated blood pressure, and low high-density lipoprotein (HDL) cholesterol increased the multivariate-adjusted odds ratio of glomerular hyperfiltration to 6.6 (95% CI: 3.8-11.6), 1.8 (95% CI: 1.0-3.0), and 2.5 (95% CI: 1.5-4.3), respectively. Systolic and diastolic blood pressures clustered together with leptin in the factor analysis and this blood pressure-adiposity component correlated with estimated creatinine clearance (r=0.329, P<0.0001) and explained on its own 10.2% of the variance in the estimated renal function. Our data reveal the silent epidemics of metabolic risk among young, apparently healthy men. Furthermore, the results indicate that high metabolic risk is associated with glomerular hyperfiltration before overt manifestations of cardiovascular disease.

T-cell accumulation and regulated on activation, normal T cell expressed and secreted upregulation in adipose tissue in obesity

BACKGROUND

Obesity is associated with chronic inflammation, which includes increased macrophage accumulation in adipose tissue (AT) and upregulation of chemokines and cytokines. T cells also play important roles in chronic inflammatory diseases such as atherosclerosis but have not been well studied in obesity.

METHODS AND RESULTS

Flow cytometric analysis showed higher numbers of T cells and macrophages in AT of diet-induced obese insulin-resistant male mice than in lean mice and obese females (P<0.05). RNase protection assay, ELISA, and flow cytometry indicated gender-dependent upregulation of mRNA and protein levels of regulated on activation, normal T cell expressed and secreted (RANTES) and its receptor CCR5 in AT of obese mice. Adipocytes, stromal/vascular cells from mouse AT, and human and murine adipocytes expressed RANTES. RANTES mRNA levels were negatively correlated with adiponectin in mouse AT. Adiponectin-deficient mice fed high-fat diet showed higher RANTES mRNA levels in AT than wild-type mice. Activated T cells coincubated with preadipocytes in vitro significantly suppressed preadipocyte-to-adipocyte differentiation. Obese humans with metabolic syndrome had higher mRNA levels of RANTES and CCR5 in subcutaneous AT than lean humans. RANTES and CCR5 mRNA levels were significantly higher in visceral than subcutaneous AT of morbidly obese humans. RANTES mRNA levels were positively correlated with CD3 and CD11b in human visceral AT.

CONCLUSIONS

Obesity is associated with increased accumulation of T cells and macrophages in AT, which may play important roles in obesity-related disease by influencing preadipocyte/adipocyte functions. RANTES is an adipokine that is upregulated in AT by obesity in both mice and humans.

Obesity-induced upregulation of myocardial endothelin-1 expression is mediated by leptin

Several studies have shown that leptin, the product of the obese gene, may link obesity with cardiovascular diseases, and in particular with cardiac hypertrophy. In vitro studies suggest that the mechanism by which leptin causes cardiac hypertrophy involves the upregulation of endogenous endothelin-1 (ET-1), a potent vasoconstrictor and mitogen. Whether obesity-associated hyperleptinemia causes an increase in myocardial ET-1 expression in vivo remains unclear. To address this issue, we fed mice with a high-fat diet and analyzed serum levels of ET-1 and ET-1 mRNA in the heart. We found that in mice fed a high-fat diet, serum ET-1, myocardial ET-1, leptin and leptin receptor mRNA were all elevated. In contrast, in leptin-deficient obese (ob/ob) mice, both serum and myocardial ET-1 levels were not higher than in wild type mice. These findings suggest that upregulation of myocardial ET-1 by obesity is mediated by leptin.

The Obesity Epidemic: Current and Future Pharmacological Treatments

The unabated rise in the prevalence of obesity is a challenge for global health care systems. Efforts to reverse this trend by dietary or behavioral counseling have not been successful, which has stimulated efforts to find a role for pharmacotherapy. Currently only a small number of antiobesity drugs are approved for long-term use and only a few compounds are in clinical development. Despite recent progress in the understanding of the regulation of energy balance, drug discovery has been less productive than expected. In the present review, the clinically available antiobesity agents are discussed. Examples of drug candidates that are currently in development are given and the possible future range of antiobesity agents is illustrated by the targets being addressed in drug discovery. Finally, the efficacy of antiobesity agents and their value in the treatment of obesity are assessed in comparison with other therapeutic approaches, such as surgery and changes in lifestyle.

Mechanisms linking obesity with cardiovascular disease

Obesity increases the risk of cardiovascular disease and premature death. Adipose tissue releases a large number of bioactive mediators that influence not only body weight homeostasis but also insulin resistance - the core feature of type 2 diabetes - as well as alterations in lipids, blood pressure, coagulation, fibrinolysis and inflammation, leading to endothelial dysfunction and atherosclerosis. We are now beginning to understand the underlying mechanisms as well as the ways in which smoking and dyslipidaemia increase, and physical activity attenuates, the adverse effects of obesity on cardiovascular health.

An obesity paradox in acute heart failure: analysis of body mass index and inhospital mortality for 108,927 patients in the Acute Decompensated Heart Failure National Registry

BACKGROUND

Prior studies on chronic systolic heart failure (HF) have demonstrated that body mass index (BMI) is inversely associated with mortality, the so-called obesity paradox. The aim of this study was to determine whether BMI influences the mortality risk in acute decompensated HF, a subject not previously studied.

METHODS

The Acute Decompensated Heart Failure National Registry was analyzed for acute HF hospitalizations in 263 hospitals in the United States from October 2001 through December 2004. Patients with documented height and weight were divided into BMI (measured in kilograms per square meter) quartiles. Inhospital mortality by BMI quartile for all the patients and for those with reduced (n = 43,255) and preserved (n = 37,901) systolic function was assessed.

RESULTS

Body mass index quartiles in the 108,927 hospitalizations were QI (16.0-23.6 kg/m2), QII (23.7-27.7 kg/m2), QIII (27.8-33.3 kg/m2), and QIV (33.4-60.0 kg/m2). Patients in the higher BMI quartiles were younger, had more diabetes, and had a higher left ventricular ejection fraction. Inhospital mortality rates decreased in a near-linear fashion across successively higher BMI quartiles. After adjustments for age, sex, blood urea nitrogen, blood pressure, creatinine, sodium, heart rate, and dyspnea at rest, BMI quartile still predicted mortality risk. For every 5-U increase in BMI, the odds of risk-adjusted mortality was 10% lower (95% CI 0.88-0.93, P < .0001).

CONCLUSIONS

In this cohort of hospitalized patients with HF, higher BMI was associated with lower inhospital mortality risk. The relationship between BMI and adverse outcomes in HF appears to be complex and deserving of further study.

Body weight and weight change in relation to blood pressure in normotensive men

We examined blood pressure (BP) in association with weight change since age 20, body mass index (BMI) at different ages and fat distribution in normotensive individuals using baseline survey data collected in the Shanghai Men's Health Study, an ongoing population-based prospective cohort study of Chinese men aged 40-74 years. All anthropometric and BP measurements were performed by medical professionals. Included in this analysis were 25 619 men who had no prior history of hypertension, diabetes or cardiovascular disease, never took any antihypertensive medication and had both normal systolic BP (SBP) and diastolic BP (DBP) (<140/90 mm Hg). Both SBP and DBP increased linearly across the whole range of weight gain since age 20. The adjusted mean differences between the highest and the lowest quintiles of weight gain were 6.0 mm Hg (95% confidence interval (CI): 5.6, 6.5) for SBP and 3.9 (95% CI: 3.6, 4.2) for DBP. When accounting for BMI at age 20, the multivariate-adjusted odds ratio of prehypertension (SBP, 120-139 and/or DBP, 80-89 mm Hg) was 4.1 (95% CI: 3.7, 4.5; P for trend <0.0001) comparing the extreme quintiles of weight gain. Similar positive associations were also observed for BMI at age 40, current BMI, circumferences of the waist and hips and waist-to-hip ratio. In conclusion, these data suggest that weight gain since age 20 and elevated adiposity may contribute significantly to the rise in BP in normotensive individuals, emphasizing the importance of weight control throughout adulthood in preventing high BP.

Impact of weight-loss medications on the cardiovascular system: focus on current and future anti-obesity drugs

Overweight and obesity have been rising dramatically worldwide and are associated with numerous co-morbidities such as cardiovascular disease (CVD), type 2 diabetes mellitus, hypertension, certain cancers, and sleep apnea. In fact, obesity is an independent risk factor for CVD and CVD risks have also been documented in obese children. The majority of overweight and obese patients who achieve a significant short-term weight loss do not maintain their lower bodyweight in the long term. This may be due to a lack of intensive counseling and support from a facilitating environment including dedicated healthcare professionals such as nutritionists, kinesiologists, and behavior specialists. As a result, there has been a considerable focus on the role of adjunctive therapy such as pharmacotherapy for long-term weight loss and weight maintenance. Beyond an unfavorable risk factor profile, overweight and obesity also impact upon heart structure and function. Since the beginning, the quest for weight loss drugs has encountered warnings from regulatory agencies and the withdrawal from the market of efficient but unsafe medications. Fenfluramine was withdrawn from the market because of unacceptable pulmonary and cardiac adverse effects. Nevertheless, there is extensive research directed at the development of new anti-obesity compounds. The effect of these molecules on CVD risk factors has been studied and reported but information regarding their impact on the cardiovascular system is sparse. Thus, instead of looking at the benefit of weight loss on metabolism and risk factor management, this article discusses the impact of weight loss medications on the cardiovascular system. The potential interaction of available and potential new weight loss drugs with heart function and structure is reviewed.

Type 2 diabetes and cardiovascular disease: getting to the fat of the matterThis paper is one of a selection of papers published in this Special Issue, entitled Young Investigators' Forum

The increasing national prevalence of obesity is a major public health concern and a substantial burden on the health care resources of Canada. In addition to the direct health impact of obesity, this condition is a well-established risk factor for the development of various prevalent comorbidities including type 2 diabetes, hypertension, and cardiovascular disease. Historically, adipose tissue has been regarded primarily as an organ for energy storage. However, the discovery of leptin in the mid 1990’s revolutionized our understanding of this tissue and has focused attention on the endocrine function of adipose tissue as a source of secreted bioactive peptides. These compounds, collectively termed adipokines, regulate a number of biological functions including appetite and energy balance, insulin sensitivity, lipid metabolism, blood pressure, and inflammation. The physiological importance of adipokines has led to the hypothesis that changes in the synthesis and secretion of these compounds in the obese are a causative factor contributing to the development of obesity and obesity-related diseases in these individuals. Following from this it has been proposed that pharmacologic manipulation of adipokine levels may provide novel effective therapeutic strategies to treat and prevent obesity, type 2 diabetes, and cardiovascular disease.

Macrophages block insulin action in adipocytes by altering expression of signaling and glucose transport proteins

Obesity leads to a proinflammatory state with immune responses that include infiltration of adipose tissue with macrophages. These macrophages are believed to alter insulin sensitivity in adipocytes, but the mechanisms that underlie this effect have not been characterized. We have explored the interaction between macrophages and adipocytes in the context of both indirect and direct coculture. Macrophage-secreted factors blocked insulin action in adipocytes via downregulation of GLUT4 and IRS-1, leading to a decrease in Akt phosphorylation and impaired insulin-stimulated GLUT4 translocation to the plasma membrane. GLUT1 was upregulated with a concomitant increase in basal glucose uptake. These changes recapitulate those seen in adipose tissue from insulin-resistant humans and animal models. TNF-alpha-neutralizing antibodies partially reversed the insulin resistance produced by macrophage-conditioned media. Peritoneal macrophages and macrophage-enriched stromal vascular cells from adipose tissue also attenuated responsiveness to insulin in a manner correlating with inflammatory cytokine secretion. Adipose tissue macrophages from obese mice have an F4/80(+)CD11b(+)CD68(+)CD14(-) phenotype and form long cellular extensions in culture. Peritoneal macrophages take on similar characteristics in direct coculture with adipocytes and induce proinflammatory cytokines, suggesting that macrophage activation state is influenced by contact with adipocytes. Thus both indirect/secreted and direct/cell contact-mediated factors derived from macrophages influence insulin sensitivity in adipocytes.

Lifestyle Intervention for Prevention and Treatment of Type 2 Diabetes

Evidence exists that lifestyle interventions in the prevention and treatment of type 2 diabetes are effective. The present challenge is to translate the evidence into policies and practices that maximize the potential health benefits for the largest number of individuals. Translational efforts are urgently needed to identify how best to identify individuals for lifestyle prevention efforts, prepare health care systems for treatment delivery, and design public health policies that support healthy weight through healthy opportunities for eating and physical activity.