Influence of excess fat on cardiac morphology and function: study in uncomplicated obesity

OBJECTIVE: To evaluate whether or not "uncomplicated" obesity (without associated comorbidities) is really associated with cardiac abnormalities. RESEARCH METHODS AND PROCEDURES: We evaluated cardiac parameters in obese subjects with long-term obesity, normal glucose tolerance, normal blood pressure, and regular plasma lipids. We selected 75 obese patients [body mass index (BMI) >30 kg/m(2)], who included 58 women and 17 men (mean age, 33.7 +/- 11.9 years; BMI, 37.8 +/- 5.5 kg/m(2)) with a > or =10-year history of excess fat, and 60 age-matched normal-weight controls, who included 47 women and 13 men (mean age, 32.7 +/- 10.4 years; BMI, 23.1 +/- 1.4 kg/m(2)). Each subject underwent an oral glucose tolerance test to exclude impaired glucose tolerance or diabetes mellitus, bioelectrical impedance analysis to calculate fat mass and fat-free mass, and echocardiography. RESULTS: Obese patients presented diastolic function impairment, hyperkinetic systole, and greater aortic root and left atrium compared with normal subjects. No statistically significant differences between obese subjects and normal subjects were found in indexed left ventricular mass (LVM/body surface area, LVM/height(2.7), and LVM/fat-free mass(kg)), and no changes in left ventricular geometry were observed. No statistically significant differences in cardiac parameters between extreme (BMI > 40 kg/m(2)) and mild obesity (BMI < 35 kg/m(2)) were observed. DISCUSSION: In conclusion, our data showed that obesity, in the absence of glucose intolerance, hypertension, and dyslipidemia, seems to be associated only with an impairment of diastolic function and hyperkinetic systole, and not with left ventricular hypertrophy.     

Prevalence of uncomplicated obesity in an Italian obese population

OBJECTIVE: The existence of healthy obese subjects has been suggested but not clearly reported. We sought to address the prevalence of uncomplicated obesity and adverse risk factors in a large Italian obese population. RESEARCH METHODS AND PROCEDURES: This was a cross-sectional study of a population of consecutive Italian obese subjects. We studied 681 obese subjects (514 women and 167 men), with a mean age of 41.1+/-13.9 years (range, 16 to 77 years), mean BMI of 40.2+/-7.6 kg/m2 (range, 30 to 89.8 kg/m2), and a history of obesity for 20.5+/-7 years (range, 10.5 to 30 years). Anthropometric, metabolic, cardiac, and obesity-related risk factors were evaluated. RESULTS: The prevalence of uncomplicated subjects was 27.5%, independent of BMI and duration of obesity. The youngest group of obese subjects showed a higher, but not statistically significantly higher, prevalence of uncomplicated obesity. No statistical difference for the prevalence of impaired fasting glucose, glucose intolerance, high triglycerides, high total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol among BMI categories (from mild to extremely severe obesity degree) was found. Obese subjects with BMI>50 kg/m2 showed a higher prevalence of high blood pressure only when they were compared with the group with a BMI of 30 to 35 kg/m2 (p<0.01). Obese subjects with BMI>40 kg/m2 showed a higher prevalence of hyperinsulinemia than subjects with BMI 30 to 35 kg/m2 (p<0.01). DISCUSSION: This study shows that a substantial part of an Italian obese population has uncomplicated obesity, and the prevalence of adverse risk factors in this sample is unexpectedly low and partially independent of obesity degree. Uncomplicated obesity could represent a well-defined clinical entity.     

Resting metabolic rate in severely obese diabetic and nondiabetic subjects

OBJECTIVES: To compare the resting metabolic rate (RMR) between diabetic and nondiabetic obese subjects and to develop a predictive equation of RMR for these subjects. RESEARCH METHODS AND PROCEDURES: Obese adults (1088; mean age = 44.9 +/- 12.7 years) with BMI > or = 35 kg/m2 (mean BMI = 46.4 +/- 8.4 kg/m2) were recruited. One hundred forty-two subjects (61 men, 81 women) were diagnosed with type 2 diabetes (DM), giving the prevalence of DM in this clinic population as 13.7%. RMR was measured by indirect calorimetry, and several multivariate linear regression models were performed using age, gender, weight, height, BMI, fat mass, fat mass percentage, and fat-free mass as independent variables. RESULTS: The severely obese patients with DM had consistently higher RMR after adjustment for all other variables. The best predictive equation for the severely obese was RMR = 71.767 - 2.337 x age + 257.293 x gender (women = 0 and men = 1) + 9.996 x weight (in kilograms) + 4.132 x height (in centimeters) + 145.959 x DM (nondiabetic = 0 and diabetic = 1). The age, weight, and height-adjusted least square means of RMR between diabetic and nondiabetic groups were significantly different in both genders. DISCUSSION: Severely obese patients with type 2 diabetes had higher RMR than those without diabetes. The RMR of severely obese subjects was best predicted by an equation using age, gender, weight, height, and DM as variables.     

Relationship of insulin sensitivity and left ventricular mass in uncomplicated obesity

OBJECTIVE: We studied uncomplicated obesity as a model to evaluate the influence of insulin sensitivity per se on left ventricular mass (LVM) and geometry. RESEARCH METHODS AND PROCEDURES: We selected 50 obese subjects (BMI > 30 kg/m(2); 38 women and 12 men; mean age, 38.4 +/- 10 years; BMI, 36.4 +/- 10.5 kg/m(2)) with normal blood pressure, glucose tolerance, and plasmatic lipid levels. Thirty lean subjects formed the control group. Each subject underwent euglycemic insulin clamp (7 pmol/min per kg) to evaluate whole body glucose use (M index) and echocardiogram to calculate LVM and indexed LVM. RESULTS: Insulin-resistant obese subjects had higher LVM, LVM/h(2.7), LVM/body surface area, and LVM/fat-free mass(kg) (p = 0.001; p = <0.001 p = 0.001, and p = 0.04, respectively) than obese subjects with normal insulin sensitivity. Multivariate regression analysis showed that M index was the strongest independent correlate of LVM (r(2) = 0.34; p = 0.03). DISCUSSION: Our findings showed that insulin resistance, in uncomplicated obesity, is associated with an increased LVM and precocious changes of left ventricular geometry, whereas preserved insulin sensitivity is not associated with increased LVM.     

Muscle strength in obese elderly women: effect of recreational physical activity in a cross-sectional study

BACKGROUND: Muscle strength (MS) may be impaired in obese persons, and this impairment may be a consequence of both obesity and low physical fitness. OBJECTIVE: We investigated whether MS differed between obese [body mass index (BMI; in kg/m2 > 29], normal-weight (BMI = 24-29), and lean (BMI < 24) elderly subjects and compared the MS of sedentary and active subjects according to their BMI group. DESIGN: The study included 215 obese [ (+/- SD) age: 80.0 +/- 3.5 y; BMI: 31.9 +/- 2.6], 630 normal-weight (age: 80.2 +/- 3.7 y; BMI: 26.3 +/- 1.4), and 598 lean (age: 80.7 +/- 3.5 y; BMI: 21.6 +/- 1.8) women with good functional ability. A cross-sectional design was used. Anthropometric measures (weight, height); measures of appendicular skeletal muscle mass (by dual-energy X-ray absorptiometry), isometric knee and elbow extension (by statergometer), and isometric handgrip strength (by dynamometer); and data on health status and self-reported recreational physical activity (RPA: walking, gymnastics, cycling, swimming, gardening) were collected. RESULTS: Absolute (unadjusted) MS was higher in obese than in lean women (P < 0.01), except for handgrip strength (P > 0.05). When adjusted for age, height, RPA, pain, depression, and appendicular skeletal muscle mass, MS did not differ significantly between obese, normal-weight, and lean subjects, except for knee extension (significant interaction effect with RPA; P = 0.01). With increasing BMI, lower limb strength did not change in the sedentary women but increased in active (> or = 1 h/wk in > or = 1 RPA for > or = 1 mo) women. All adjusted MS measures in active participants were significantly higher (P < 0.001) than those in their sedentary peers. CONCLUSION: The adjusted MS of elderly women is not associated with obesity but is higher in active subjects than in sedentary ones, especially in the lower limbs of obese subjects.     

Air displacement plethysmography: validation in overweight and obese subjects

OBJECTIVE: Patients with moderate and severe obesity, because of their physical size, often cannot be evaluated with conventional body composition measurement systems. The BOD POD air displacement plethysmography (ADP) system can accommodate a large body volume and may provide an opportunity for measuring body density (D(b)) in obese subjects. D(b) can be used in two- or three-compartment body composition models for estimating total body fat in patients with severe obesity. The purpose of this study was to compare D(b) measured by ADP to D(b) measured by underwater weighing (UWW) in subjects ranging from normal weight to severely obese. RESEARCH METHODS AND PROCEDURES: D(b) was measured with UWW and BOD POD in 123 subjects (89 men and 34 women; age, 46.5 +/- 16.9 years; BMI, 31.5 +/- 7.3 kg/m2); 15, 70, and 10 subjects were overweight (25 < or = BMI < 30 kg/m2), obese (30 < or = BMI < 40 kg/m2), and severely obese (BMI > or = 40 kg/m2), respectively. RESULTS: There was a strong correlation between D(b) (kilograms per liter) measured by UWW and ADP (r = 0.94, standard error of the estimate = 0.0073 kg/L, p < 0.001). Similarly, percent fat estimates from UWW and ADP using the two-compartment Siri equation were highly correlated (r = 0.94, standard error of the estimate = 3.58%, p < 0.001). Bland-Altman analysis showed no significant bias between D(b) measured by UWW and ADP. After controlling for D(b) measured by ADP, no additional between-subject variation in D(b) by UWW was accounted for by subject age, sex, or BMI. DISCUSSION: Body density, an important physical property used in human body composition models, can be accurately measured by ADP in overweight and obese subjects.     

Intake of sweet foods and counts of cariogenic microorganisms in obese and normal-weight women

OBJECTIVE: To study the intake of sweet foods in obese and normal-weight women, while also taking menstrual cycle effects on eating behaviour into consideration. An objective test of the intake of sugar-containing foods was introduced by measuring salivary counts of mutans streptococci and lactobacilli. DESIGN: A cross-sectional comparison of the intake of sweet foods in obese and normal-weight women. The obese women were also studied longitudinally after 10 weeks in a weight reduction programme. SUBJECTS: Obese (n=72, body mass index (BMI) 42.0+/-5.2 kg/m2) and normal-weight women (n=67, BMI 22.2+/-1.6 kg/m2) participated. RESULTS: Mutans streptococci in saliva were higher in obese than in normal-weight women (P<0.0001), although the reported habitual daily intake of sweet foods did not differ. Of the menstruating women, 80% of the obese subjects and 62% of the normal-weight ones (P<0.05) reported periods during the menstrual cycle with an 'extra large' intake of sweet foods; these intakes were higher in obese than in normal-weight women (P<0.01). The obese women reduced their intake of sweet foods after 10 weeks of weight reduction, although these changes were not pronounced enough to significantly affect the counts of cariogenic microorganisms. CONCLUSIONS: In contrast to most previous cross-sectional studies, this study shows that obese women have a higher intake of sweet foods, especially pre-menstrually. This was indicated by higher salivary counts of cariogenic microorganisms. SPONSORSHIP: Karolinska Institute Research Funds.     

Four-week pedometer-determined activity patterns in normal-weight, overweight and obese adults

OBJECTIVE: To assess pedometer-determined ambulatory activity in normal-weight, overweight and obese UK adults. METHODS: Eighty-six normal-weight (BMI <25 kg/m(2)) (age=34+/-12.1 years), 91 overweight (BMI 25-29.9 kg/m(2)) (age=40.6+/-13.6 years) and 75 obese (BMI >or= 30 kg/m(2)) (age=41.2+/-12.4 years) participants, from the East Midlands, provided 4 weeks of continuous pedometer-determined activity data, during the winter in 2006. Activity levels and patterns were assessed for all three groups. RESULTS: The normal-weight group had a significantly higher mean step count (10247 steps/day) than the overweight (9095 steps/day) and obese (8102 steps/day) participants (p<0.05). No differences in step counts were observed between the overweight and obese groups. A consistent reduction in activity was observed on Sundays in all groups, with this reduction being two-fold greater in the overweight and obese groups (approximately 2000 steps/day) when compared with the normal-weight group (approximately 1000 steps/day). CONCLUSIONS: With the increasing prevalence of obesity in the UK, changes in the activity levels of those at risk are needed. The issuing of pedometers to overweight and obese individuals, with the instruction to increase their ambulatory activity on all days of the week, with particular emphasis on Sunday activity, could be a good starting point in tackling the problem of obesity in the UK.     

Echocardiographic abnormalities in normotensive obese patients: relationship with visceral fat

OBJECTIVE: To evaluate the relationship of echocardiographic characteristics and visceral adipose tissue (VAT) distribution in normotensive obese patients. RESEARCH METHODS AND PROCEDURES: Echocardiographic parameters were assessed in 28 normotensive obese patients [7 men, 21 women, mean age, 43.2 years; mean body mass index (BMI), 37.2 kg/m(2); 10 with impaired glucose tolerance (IGT); 6 with type 2 diabetes] and 18 sex- and age-matched healthy, normal-weight controls (4 men, 14 women; mean age, 45.8 years; mean BMI, 22.4 kg/m(2)) by an M-mode, color-doppler videofluoroscope. VAT in the obese patients was assessed by computed tomography (at L4 level). RESULTS: The obese patients had a significantly larger internal diastolic left ventricular (LV) diameter (p < 0.05), a thicker end-diastolic septum (p < 0.001) and posterior wall (p < 0.001), a greater indexed (g/m(2.7)) LV mass (p < 0.001), a higher atrial diastolic filling wave velocity (p < 0.001), a lower ratio between early and atrial diastolic filling wave velocities (p < 0.01), and a prolonged isovolumic relaxation time (p < 0.05). End-diastolic septum and posterior wall thickness and the LV mass were significantly greater in patients with a VAT area >130 cm(2) than with <130 cm(2). In the multivariate regression analysis, only VAT (p < 0.0001), waist-to-hip ratio (p < 0.001), and sex (p < 0.001) were associated with the most important echocardiographic alterations. DISCUSSION: The morphological and functional echocardiographic alterations usually found in normotensive obese patients closely correlate with the amount of intra-abdominal fat deposition, even in the presence of diabetes or IGT.     

Lipoprotein oxidation and plasma vitamin E in nondiabetic normotensive obese patients

OBJECTIVE: To correlate the susceptibility of low-(LDL) and very-low-density lipoprotein to oxidation in vitro and the concentrations of serum antibodies against malondialdehyde-modified LDL and plasma vitamin E with the anthropometric and laboratory characteristics of obesity. RESEARCH METHODS AND PROCEDURES: A total of 75 nondiabetic, normotensive obese patients were assigned to one of four groups according to their body mass index (BMI): moderately obese (30 50 kg/m(2), n = 15). RESULTS: The oxidation lag time for LDL from patients with a BMI >or=35 kg/m(2) was shorter than that for LDL from non-obese controls (n = 13), whereas very-low-density lipoprotein oxidation lag times were not significantly different. The serum antibodies against modified LDL were similar in all groups, whereas the plasma vitamin E concentrations of obese patients were decreased (p 相似文献   

QT dispersion in uncomplicated human obesity

OBJECTIVE: Because obese patients generally may be prone to ventricular arrhythmias, this study was designed to measure the interval between Q- and T-waves of the electrocardiogram (QT) interval dispersion (QTD) in uncomplicated overweight and obese patients. QTD is an electrocardiographic parameter whose prolongation is thought to be predictive of the possibility of sudden death caused by ventricular arrhythmias. To better evaluate the association between obesity per se and QTD, the study population was intentionally selected because they were free of complications. RESEARCH METHODS AND PROCEDURES: QTD (defined as the difference between the maximum and the minimum QT corrected interval [QTc] across the 12-lead electrocardiogram) was measured manually in 54 obese patients (Group A: mean body mass index [BMI] of 38.1 +/- 0.9 kg/m2 [SEM], 15 males and 39 females), 35 overweight patients (Group B: mean BMI of 27.3 +/- 0.2 kg/m2, 10 males and 25 females), and 57 normal weight healthy control subjects (Group C: mean BMI of 21.9 +/- 0.2 kg/m2, 17 males and 40 females). The obese and overweight patients had no heart disease, hypertension, diabetes, or impaired glucose tolerance and did not have any hormonal, hepatic, renal or electrolyte disorders. The study subjects were matched in terms of age (mean age 38.4 +/- 1.2 years) and sex. RESULTS: The QTDs were comparable among the three groups: Group A, 56.4 +/- 2.6 ms; Group B, 56.7 +/- 2.1 ms; and Group C, 59.4 +/- 2.1 ms; not significant. The QTc intervals of Group A and Group B were similar to that of Group C (411.8 +/- 3.3, 407.2 +/- 3.9, and 410.3 +/- 3.9 ms, respectively [not significant]) and did not correlate with BMI. An association was found between QTD and QTc (r = 0.24, p < 0.005). Using multivariate stepwise regression analysis of the study population, QTD did not correlate with age, BMI, waist circumference, or abdominal sagittal diameter. DISCUSSION: These data suggest that QTD in uncomplicated obese or overweight subjects is comparable with that in age- and sex-matched normal weight healthy controls. In this study population, no association was found between QTD and anthropometric parameters reflecting body fat distribution.     

Validation of a three-frequency bioimpedance spectroscopic method for body composition analysis

OBJECTIVE: We assessed whether whole-body multiple frequency impedance (MFBIA) data obtained at a few discrete frequencies could be used to estimate accurately resistance at 0 (R(0)) and infinite (R(infinity)) frequencies required for prediction of body composition by mixture theory. METHODS: Fat-free mass (FFM) was measured in 157 subjects (77 males, 80 females; body mass index [BMI] 17.8-41.7 kg/m(2)) by dual X-ray absorptiometry (DXA). Whole-body impedance was measured and R(0) and R(infinity) were calculated by three different methods. FFM predicted using the different values of R(0) and R(infinity) were compared with each other and with the reference DXA values for all subjects stratified according to BMI band (BMI <24.9 kg/m(2), normal weight; BMI 25-29.9 kg/m(2), overweight; BMI >30 kg/m(2), obese). RESULTS: All BIA procedures predicted an FFM that was slightly but significantly different from DXA-derived values, underestimating by 0.24 to 1.4 kg in the normal-weight subjects and overestimating by 5.3 to 7.1 kg in the obese subjects. Although statistically significant, the different impedance procedures were highly correlated (r > 0.98), with small limits of agreement (approximately +/-2%) when used to predict FFM. Predictive power was associated with BMI, worsening as BMI increased. CONCLUSION: MFBIA can be used to estimate impedance parameters required for mixture theory prediction of body composition, but this approach requires adjustment for BMI to be accurate.     

Sensory-specific satiety in obese and normal-weight women

BACKGROUND: Sensory-specific satiety has been found to play an important role in food choice and meal termination, and it might be a factor contributing to obesity. OBJECTIVE: We hypothesized that obese and normal-weight people have different sensitivities to sensory-specific satiety for high-fat foods. DESIGN: Sensory-specific satiety was measured in 21 obese [x body mass index (BMI; in kg/m(2)): 33.1] and 23 normal-weight (BMI: 22.8) women who were matched for restrained eating behavior, physical activity, age, and smoking behavior. Food intake, appetite ratings, and liking scores before and after an ad libitum lunch were measured. Products differed in fat content and taste (ie, low-fat sweet, low-fat savory, high-fat sweet, and high-fat savory), and the subjects tested all 4 products. In the first study, sandwiches were tested; in the second study, snacks were tested. RESULTS: Sensory-specific satiety for all products was observed in both subject groups. No significant differences were observed between the obese and normal-weight subjects in either sensory-specific satiety or food intake for any of the products or product categories tested. Taste (sweet or savory) had a significantly (P < 0.05) stronger effect on sensory-specific satiety than did fat content. Appetite ratings strongly decreased after lunch, and appetite for a meal or snack after lunch was significantly higher in obese than in normal-weight subjects, whereas scores before lunch did not differ significantly. CONCLUSIONS: Obese and normal-weight people do not differ in their sensitivity to sensory-specific satiety, and factors other than fat content have the greatest effect on sensory-specific satiety.     

Effect of different macronutrients in excess on gastric sensory and motor functions and appetite in normal-weight, overweight, and obese humans

BACKGROUND: The effects of supplementation with different macronutrients on gastric sensory and motor functions are unclear. OBJECTIVE: We aimed to compare the effects of 2 wk of supplementation with different classes of macronutrients on gastric function, satiation, and appetite in healthy and overweight subjects. DESIGN: In a parallel-group, double-blind study, 52 (14 men, 38 women) healthy normal-weight, overweight, and obese participants [body mass index (BMI; in kg/m(2)): 19.4-47.0] aged 18-64 y were randomly assigned to consume different isocaloric diets (n = 13 per diet group) adjusted for BMI and activity level. The standard diet provided 20% of energy as protein, 30% as fat, and 50% as carbohydrate. The high-protein, high-fat, and high-carbohydrate diets contained 500 additional kcal in each nutrient class. On 3 separate days, we measured gastric emptying of solids, gastric volumes, postprandial symptoms, appetite, and food choice with validated methods. Age, sex, BMI, and baseline satiation were covariates in the analysis of covariance. RESULTS: Fat supplementation was associated with increased maximum tolerated volume (MTV) in subjects with a high baseline MTV (P < 0.05), irrespective of BMI. Gastric emptying and volumes, postprandial symptoms, total calories, and food choices at an ad libitum meal were not significantly different after each dietary preload. Fasting gastric volumes tended to be higher with the high-fat than with the high-carbohydrate or high-protein diets (P 30). CONCLUSION: Supplementation with 500 kcal fat in excess of required calories for 2 wk increased food tolerance in healthy normal-weight and obese subjects with a high baseline MTV without significantly changing gastric motor functions.     

Dietary medium-chain triacylglycerols suppress accumulation of body fat in a double-blind, controlled trial in healthy men and women.

We investigated the effect of long-term ingestion of dietary medium-chain triacylglycerols (MCT) on body weight and fat in humans. Using a double-blind, controlled protocol, we assessed the potential health benefits of MCT compared with long-chain triacylglycerols (LCT) in 78 healthy men and women [body mass index (BMI) > or = 23 kg/m(2): n = 26 (MCT), n = 30 (LCT); BMI < 23 kg/m(2): n = 15 (MCT), n = 7 (LCT)]. Changes in anthropometric variables, body weight and body fat during the 12-wk MCT treatment period were compared with those in subjects consuming the LCT diet. The subjects were asked to consume 9218 kJ/d and 60 g/d of total fat. The energy, fat, protein and carbohydrate intakes did not differ significantly between the groups. Body weight and body fat in both groups had decreased by wk 4, 8 and 12 of the study. However, in the subjects with BMI > or = 23 kg/m(2), the extent of the decrease in body weight was significantly greater in the MCT group than in the LCT group. In subjects with BMI > or = 23 kg/m(2), the loss of body fat in the MCT group (-3.86 +/- 0.3 kg) was significantly greater than that in the LCT group (-2.75 +/- 0.2 kg) at 8 wk. In addition, in subjects with BMI > or = 23 kg/m(2), the decrease in the area of subcutaneous fat in the MCT group was significantly greater than that in the LCT group at wk 4, 8 and 12. These results suggest that the MCT diet may reduce body weight and fat in individuals (BMI > or = 23 kg/m(2)) more than the LCT diet.     

Serum levels of interleukin-6 and C-reactive protein correlate with body mass index across the broad range of obesity

BACKGROUND: It has been noted that elevated inflammatory markers, such as tumor necrosis factor-alpha (TNF), soluble TNF receptor II (sTNF-RII), interleukin 6 (IL-6) and C-reactive protein (CRP), are characteristically found in the serum in obese patients. In this study, we examined the correlation of these markers with BMI in nonobese, obese, and morbidly obese individuals to explore this relationship across the broad range of obesity. METHODS: A total of 9 nonobese, including normal and overweight (body mass index [BMI] <30 kg/m2) and 41 obese (BMI > or =30 kg/m2) adults were included in this study. Among obese subjects, 11 subjects were grade I or II obese (BMI > or =30 and <40 kg/m2), and 30 subjects were morbidly obese (grade III obese, BMI > or =40 kg/m2). Serum levels of glucose, insulin, TNF, sTNF-RII, IL-6, and CRP were measured. RESULTS: Obese subjects (BMI > or =30 kg/m2) had significantly higher serum levels of TNF, sTNF-RII, IL-6, and CRP compared with nonobese subjects. Serum levels of sTNF-RII, IL-6, and CRP, but not TNF, were positively correlated with BMI in obese subjects. However, in morbidly obese subjects, only the serum concentrations of IL-6 and CRP remained correlated with BMI, primarily because of this relationship in men. CONCLUSIONS: The present results support evidence that obesity represents an inflammatory state. In morbid obesity, the correlation of only IL-6 and CRP with BMI, particularly in males, suggests that IL-6 may be secreted in an endocrine manner in proportion to the expansion of fat mass particularly in the abdominal region, with a corresponding increase in hepatic production of CRP.     

Blunted lipolytic response to fasting in abdominally obese women: evidence for involvement of hyposomatotropism

BACKGROUND: Abdominal obesity is associated with a blunted lipolytic response to fasting that may contribute to the preservation of adipose tissue mass. OBJECTIVE: To further explore the pathophysiology of blunted lipolysis during fasting in obesity, we simultaneously measured lipolysis and distinct neuroendocrine regulatory hormones in abdominally obese and normal-weight (NW) women. DESIGN: Eight abdominally obese [x +/- SD body mass index (BMI; in kg/m(2)): 32.1 +/- 2.6] and 6 NW (BMI: 22.7 +/- 1.5) women were studied during the last 8 h of a 20-h fast. The glycerol appearance rate and the serum and plasma concentrations of insulin, leptin, cortisol, and growth hormone were measured regularly. RESULTS: At 13 h of fasting, the mean (+/-SD) glycerol appearance rate corrected for fat mass was greater in NW women than in obese women (7.2 +/- 1.0 and 5.1 +/- 0.6 micro mol.kg(-1).min(-1), respectively; P = 0.001). After a 20-h fast, lipolysis increased to 8.9 +/- 1.5 mmol.kg(-1).min(-1) in NW women (23%), whereas it did not change significantly in obese women (-2%). Fasting decreased insulin concentrations by approximately 30% in both groups, but it did not induce significant changes in leptin concentrations. Mean cortisol concentrations and urinary catecholamine excretion were comparable in both groups. However, mean plasma growth hormone concentrations were higher in NW women than in obese women (1.81 +/- 0.98 compared with 0.74 +/- 0.52 mU/L; P = 0.046). The relative change in lipolysis tended to correlate with mean plasma growth hormone concentrations (r = 0.515, P = 0.059). CONCLUSION: Abdominal obesity-associated hyposomatotropism may be involved in the blunted increase in lipolysis during fasting.     

Cut-off points for anthropometric indices of adiposity: differential classification in a large population of young women

Anthropometric indices of adiposity include BMI, waist circumference and waist:height ratio. In the recruitment phase of a prospective cohort study carried out between 1998 and 2002 we studied a population sample of 11 786 white Caucasian non-pregnant women in Southampton, UK aged 20-34 years, and explored the extent to which proposed cut-off points for the three indices identified the same or different women and how these indices related to adiposity. Height, weight and waist circumference were measured and fat mass was estimated from skinfold thicknesses; fat mass index was calculated as fat mass/height1.65. Of the subjects, 4869 (42 %) women were overweight (BMI > or = 25 kg/m2) and 1849 (16 %) were obese (BMI > or = 30 kg/m2). A total of 890 (8 %) subjects were not overweight but had a waist circumference > or = 80 cm and 748 (6 %) subjects were overweight but had a waist circumference < 80 cm (6 %). Of the women, 50 % had a BMI > or = 25 kg/m2 or a waist circumference > or = 80 cm or a waist:height ratio > or = 0.5. Of the variation in fat mass index, 85 % was explained by BMI, 76 % by waist circumference and 75 % by waist:height ratio. Our findings demonstrate that many women are differentially classified depending on which index of adiposity is used. As each index captures different aspects of size in terms of adiposity, there is the need to determine how the three indices relate to function and how they can be of use in defining risk of ill health in women.     

Skeletal muscle lipid concentration quantified by magnetic resonance imaging

BACKGROUND: Skeletal muscle lipid is associated with obesity and type 2 diabetes and may be altered by diet, physical activity, and weight loss. OBJECTIVE: We explored the utility of magnetic resonance imaging (MRI) for quantifying the lipid concentration of muscle tissue in vivo. DESIGN: Fat-selective MR images of the lower leg were taken in 8 normal-weight [body mass index (in kg/m(2)) < or = 24.9] and 8 obese (body mass index > 29.9) subjects to obtain spatial maps of lipid signal intensity within muscle tissue. Fast-spiral-sequence (echo time = 5.6-13.8 ms, repetition time = 1 s, 8 interleaves) MRI scans were conducted at 3.0 T by using an extremity transmit-receive coil. Lipid concentrations within muscle were determined from manually drawn regions of interest in the tibialis anterior (TA), soleus, and medial head of the gastrocnemius (MHG) muscle groups. RESULTS: There was extremely good agreement (mean R(2) = 0.985) between the fat signal intensity and the actual lipid concentration of standards containing 2.5, 5.0, and 10.0 g lipid/dL, which were placed on the subject's leg during each scan. The lipid content of both the soleus (2.99 +/- 0.37 g/dL) and the MHG (3.80 +/- 0.68 g/dL) was higher (P < 0.05) than that of the TA (1.83 +/- 0.28 g/dL). Lipid content was more than two-fold higher (P < 0.05) in the MHG of obese subjects (5.48 +/- 1.18 g/dL) than in the MHG of normal-weight subjects (2.54 +/- 0.47 g/dL), but did not differ significantly in the TA or soleus. CONCLUSIONS: MRI can be used to quantify lipid within human muscle tissue. MRI can also be used to detect differences in muscle lipid content among various muscle groups and between normal-weight and obese subjects.     

Glucagon-like peptide-1 release and satiety after a nutrient challenge in normal-weight and obese subjects

The present study was conducted to assess whether glucagon-like peptide-1 (GLP-1) release and appetite after a breakfast with or without an additional galactose/guar gum stimulation is different in normal-weight compared with overweight/obese subjects. Twenty-eight overweight/obese (BMI 30.3 (sd 2.7) kg/m2; age 44.3 (sd 9.7) years) and thirty normal-weight subjects (BMI 22.8 (sd 1.4), age 31.5 (sd12.8) years) participated in a crossover study. Fasting and postprandial plasma GLP-1, insulin, glucose and free fatty acid concentrations were measured in response to either a galactose (50 g)/guar gum (2.5 g) load (836 kJ) and a standard breakfast (1.9 MJ; GG), or water (250 ml) and the standard breakfast (W) every 30 min relative to the ingestion for 120 min. Appetite was assessed using 100 mm visual analogue scales. GLP-1 concentrations were significantly increased after GG at 30 and 60 min compared with W in both groups. Plasma GLP-1 concentrations in the W condition were higher in normal-weight than overweight/obese subjects (P=0.03). No difference was observed in the GG condition between groups. Satiety was increased in normal-weight compared with overweight/obese subjects in the GG condition at 30 (P=0.02) and 60 (P=0.04) min. We conclude that after a standard breakfast with water, GLP-1 release was lower in the overweight/obese than the normal-weight subjects. However, postprandial GLP-1 release in overweight/obese subjects was no different from that of normal-weight subjects when galactose/guar gum was added to the breakfast. The latter was not mirrored by subjective feelings of satiety. Disturbed perception of the physiological feedback of a satiety hormone rather than disturbed feedback itself might contribute to obesity.