Intra-abdominal Fat Volume Research Articles

The role of skeletal muscle insulin resistance in the pathogenesis of the metabolic syndrome

We examined the hypothesis that insulin resistance in skeletal muscle promotes the development of atherogenic dyslipidemia, associated with the metabolic syndrome, by altering the distribution pattern of postprandial energy storage. Following ingestion of two high carbohydrate mixed meals, net muscle glycogen synthesis was reduced by approximately 60% in young, lean, insulin-resistant subjects compared with a similar cohort of age-weight-body mass index-activity-matched, insulin-sensitive, control subjects. In contrast, hepatic de novo lipogenesis and hepatic triglyceride synthesis were both increased by >2-fold in the insulin-resistant subjects. These changes were associated with a 60% increase in plasma triglyceride concentrations and an approximately 20% reduction in plasma high-density lipoprotein concentrations but no differences in plasma concentrations of TNF-alpha, IL-6, adiponectin, resistin, retinol binding protein-4, or intraabdominal fat volume. These data demonstrate that insulin resistance in skeletal muscle, due to decreased muscle glycogen synthesis, can promote atherogenic dyslipidemia by changing the pattern of ingested carbohydrate away from skeletal muscle glycogen synthesis into hepatic de novo lipogenesis, resulting in an increase in plasma triglyceride concentrations and a reduction in plasma high-density lipoprotein concentrations. Furthermore, insulin resistance in these subjects was independent of changes in the plasma concentrations of TNF-alpha, IL-6, high-molecular-weight adiponectin, resistin, retinol binding protein-4, or intraabdominal obesity, suggesting that these factors do not play a primary role in causing insulin resistance in the early stages of the metabolic syndrome.

Abdominal Shape of Gastric Cancer Patients Influences Short-Term Surgical Outcomes

There is a prevailing belief that both obesity and abdominal shape influence abdominal accessibility, and thus affect short-term surgical outcomes of gastric cancer surgery. We measured the thickness of subcutaneous fat (SCF), abdominal anterior-posterior diameter (APD), transverse diameter (TD), and intra-abdominal fat volume (IFV) at the umbilicus level by using the abdominal CT scans of 291 gastric cancer patients who had undergone subtotal gastrectomy and D2 lymph node dissection. Clinicopathological factors including body mass index (BMI), APD, TD, IFV, and SCF and surgical outcomes, i.e., dissected lymph node number, morbidity, and mortality were analyzed. SCF thickness, APD, TD, IFV, and BMI mean values were 20.0 mm (range 2.0-64.0), 188.4 mm (range 128.0-332.0), 301.4 mm (range 160.0-651.0), 198.3 mm(2) (range 123.4-312.1), and 23.9 kg/m(2) (range 16.6-34.6), respectively. In male patients, APD was found to correlate with the number of retrieved lymph nodes (P = 0.045). Whereas in female patients, this was not the case (P = 0.093). Twenty-one patients experienced postoperative complications but no postoperative mortality occurred. Female patients who experienced postoperative complications had higher APD (32.9 +/- 10.0 mm versus 26.1 +/- 7.9 mm, P = 0.044) and BMI (27.3 +/- 4.1 kg/m(2) versus 24.3 +/- 3.5 kg/m(2), P = 0.049) values than those who did not. We conclude that obesity and abdominal shape of gastric cancer patients both influence the short-term surgical outcomes of subtotal gastrectomy with D2 lymph node dissection.

Intra‐abdominal Fat Burden Discriminated In Vivo Using Proton Magnetic Resonance Spectroscopy

To assess proton magnetic resonance spectroscopy (1H-MRS) as a means to distinguish among mice with disparate intra-abdominal body fat compositions, and to measure changes in intra-abdominal fat burden during weight loss and regain. Intra-abdominal fat burden was analyzed as a ratio of integrated areas under the curves of fat to water (1)H-MRS signals collected from a region of interest standardized across B6.V-Lep(ob), C57BL/6, and A-ZIP/F mice that exhibited various genotypically related body fat compositions, ranging from obese (B6.V-Lep(ob)) to minimal body fat (A-ZIP/F). 1H-MRS analysis of fat burden was compared with intra-abdominal fat volume and with a single cross-sectional intra-abdominal fat area calculated from segmented magnetic resonance images. Similar measurements were made from obese B6.V-Lep(ob) mice before, during, and after they were induced to lose weight by leptin administration. Relative amounts of intra-abdominal fat analyzed by 1H-MRS differed significantly according to body composition and genotype of the three strains of mice (p < 0.05). Intra-abdominal fat assessed by 1H-MRS correlated with both intra-abdominal fat volume (r = 0.88, p < 0.001) and body weight (r = 0.82, p < 0.001) among, but not within, all three genotypes. During weight loss and regain, there was a significant overall pattern of changes in intra-abdominal fat quantity that occurred, which was reflected by 1H-MRS (p = 0.006). Results support the use of localized 1H-MRS for assessing differences in intra-abdominal fat. Refinements in 1H-MRS voxel region of interest size and location as well as instrument precision may result in improved correlations within certain body compositions.

Effects of transdermal testosterone administration on insulin sensitivity, fat mass and distribution, and markers of inflammation and thrombolysis in human immunodeficiency virus–infected women with mild to moderate weight loss

To determine the effects of raising serum T levels into the high normal female range by transdermal T administration on insulin sensitivity, fat volume, and markers of inflammation and thrombolysis in HIV-infected women with recent weight loss. Placebo-controlled, randomized clinical trial. Academic clinical research center. Fifty-two HIV-infected, menstruating women with >5% weight loss over the prior 6 months and current T<33 ng/dL. Placebo or T patches twice weekly for 24 weeks to achieve nominal delivery of 300 microg T daily. Testosterone by liquid chromatography-tandem mass spectrometry, insulin sensitivity by the frequently sampled intravenous glucose tolerance test (FSIVGT), abdominal and thigh fat volumes by magnetic resonance imaging (MRI), and C-reactive protein (CRP) as a measure of inflammation and plasminogen-activated inhibitor-1 (PAI-1) levels as a marker of thrombolysis. Serum and free T levels significantly increased into the high normal female range in T-treated but not placebo-treated women. Insulin sensitivity by FSIVGT, whole body, thigh SC, and intra-abdominal fat volumes, and CRP and PAI-1 levels did not change significantly in either group and were not significantly different between the two groups. Fasting insulin increased in the placebo group and fell slightly in the T group, resulting in significant differences in change between groups. Twenty-four weeks of elevation of serum T levels into the high normal female range in HIV-infected women with mild to moderate weight loss by transdermal T patches did not adversely affect insulin sensitivity, whole-body fat mass or regional fat distribution, or markers of inflammation and thrombolysis. More prolonged and larger studies are needed to determine the effects of higher doses of T on body composition and insulin sensitivity in women.

Overproduction of large VLDL particles is driven by increased liver fat content in man

We determined whether hepatic fat content and plasma adiponectin concentration regulate VLDL(1) production. A multicompartment model was used to simultaneously determine the kinetic parameters of triglycerides (TGs) and apolipoprotein B (ApoB) in VLDL(1) and VLDL(2) after a bolus of [(2)H(3)]leucine and [(2)H(5)]glycerol in ten men with type 2 diabetes and in 18 non-diabetic men. Liver fat content was determined by proton spectroscopy and intra-abdominal fat content by MRI. Univariate regression analysis showed that liver fat content, intra-abdominal fat volume, plasma glucose, insulin and HOMA-IR (homeostasis model assessment of insulin resistance) correlated with VLDL(1) TG and ApoB production. However, only liver fat and plasma glucose were significant in multiple regression models, emphasising the critical role of substrate fluxes and lipid availability in the liver as the driving force for overproduction of VLDL(1) in subjects with type 2 diabetes. Despite negative correlations with fasting TG levels, liver fat content, and VLDL(1) TG and ApoB pool sizes, adiponectin was not linked to VLDL(1) TG or ApoB production and thus was not a predictor of VLDL(1) production. However, adiponectin correlated negatively with the removal rates of VLDL(1) TG and ApoB. We propose that the metabolic effect of insulin resistance, partly mediated by depressed plasma adiponectin levels, increases fatty acid flux from adipose tissue to the liver and induces the accumulation of fat in the liver. Elevated plasma glucose can further increase hepatic fat content through multiple pathways, resulting in overproduction of VLDL(1) particles and leading to the characteristic dyslipidaemia associated with type 2 diabetes.

A Technique for the Measurement of Visceral Fat by Ultrasonography: Comparison of Measurements by Ultrasonography and Computed Tomography

This study aims to create a method of calculating intra-abdominal visceral fat volume by using ultrasound (US). The visceral fat volume measured by US was evaluated by comparison with the volume measured by computed tomography (CT). Eighty-seven patients (52 males and 35 females) were enrolled in this study. Both US and CT were performed, and the visceral fat volume was measured. Both the distance and thickness of the parameters in US were measured as follows: 1) the distance between the internal surface of the abdominal muscle and the splenic vein, 2) the distance between the internal surface of the abdominal muscle and the posterior wall of aorta on the umbilicus, and 3) the thickness of the fat layer of the posterior right renal wall. The equation was calculated as follows: [visceral fat volume]=-9.008+1.191x[distance between the internal surface of the abdominal muscle and the splenic vein (mm)]+0.987x[distance between the internal surface of the abdominal muscle and the posterior wall of the aorta on the umbilicus (mm)]+3.644x[thickness of the fat layer of the posterior right renal wall (mm)]. There was a good correlation between the visceral fat volume calculated by the above equation and the volume by CT described (r=0.860, p<0.0001). The measurement of the visceral fat volume using US provided results as effectively as CT, and it was proven to be a useful method.

Correlation Between Anthropometric Parameters and Abdominal Fat Volumes Assessed by a Magnetic Resonance Imaging Method in Patients with Diabetes

Anthropometric measurements such as body mass index (BMI), waist-to-hip ratio, or waist circumference are used in clinical settings as a rough estimation of abdominal fat volumes. In contrast, abdominal magnetic resonance imaging (MRI) allows a precise and noninvasive imaging modality to measure the whole abdominal fat volumes. The main difference between the two methods is that only MRI provides detailed anatomical information about fat distribution in terms of a three-dimensional volumetric model. The aim of this study was to evaluate the relationship between selected anthropometric parameters and MRI-estimated abdominal fat volumes in patients with diabetes. Total fat volume coverage of the abdomen was obtained in a total of 37 patients with diabetes (mean +/- SD age, 48 +/- 13 years) with a BMI of 27.9 +/- 3.6 kg/m2 and a waist-to-hip ratio of 0.94 +/- 0.01 using T1-weighted magnetic resonance images. Quantification of intraabdominal, subcutaneous, and total abdominal fat volumes was performed using a semiautomated computer-assisted analysis of the images. Anthropometric parameters (height, weight, BMI, circumference hip, waist circumference, and waist-to-hip ratio) of all patients and abdominal fat volumes estimated by the MRI method proposed were correlated. The volumes estimated were as follows: intraabdominal fat, 10.5 +/- 5.0 L; subcutaneous fat, 15.2 +/- 7.3 L; and total abdominal fat, 25.7 +/- 11.5 L. The correlation coefficients between BMI and the three different fat volumes were, respectively, r = 0.38, r = 0.31, and r = 0.36. For the waist-to-hip ratio the respective correlation coefficients were r = 0.46, r = 0.14, and r = 0.29. Correlation in patients with diabetes of abdominal fat volumes estimated with a reliable MRI method with conventionally applied anthropometric parameters revealed poor correlation coefficients. In contrast, the fat volume determination by means of the novel MRI analysis method is rapid and reliable. Therefore, this method has the potential to be of high value in studies in patients with diabetes.

Effects of equal weight loss with orlistat and placebo on body fat and serum fatty acid composition and insulin resistance in obese women

Dietary fat has been reported to influence insulin sensitivity. The objective of the study was to determine how identical weight loss (target: loss of 8% of body weight over 3-6 mo) in women taking orlistat or placebo combined with a hypocaloric diet influences body composition and insulin sensitivity. Forty-seven obese women [body mass index (in kg/m(2)): 32.1 +/- 0.4] were randomly assigned to receive either orlistat (120 mg 3 times daily; n = 23) or placebo (n = 24) with a hypocaloric diet. Whole-body insulin sensitivity (insulin clamp technique), serum fatty acids, and body composition (magnetic resonance imaging) were measured before and after weight loss. The groups did not differ significantly at baseline with respect to age, body weight, intraabdominal and subcutaneous fat volumes, or insulin sensitivity. Weight loss did not differ significantly between the orlistat (7.3 +/- 0.2 kg, or 8.3 +/- 0.1%) and placebo (7.4 +/- 0.2 kg, or 8.2 +/- 0.1%) groups. Insulin sensitivity improved significantly (P < 0.001) and similarly after weight loss in the orlistat (from 4.0 +/- 0.3 to 5.1 +/- 0.3 mg x kg fat-free mass(-1) x min(-1)) and placebo (from 4.4 +/- 0.4 to 5.4 +/- 0.4 mg x kg fat-free mass(-1) x min(-1)) groups. Intraabdominal fat and subcutaneous fat decreased significantly in both groups, but the ratio of the 2 decreased significantly only in the orlistat group. The proportion of dihomo-gamma-linolenic acid (20:3n-6) in serum phospholipids was inversely related to insulin sensitivity both before (r = -0.48, P < 0.001) and after (r = -0.46, P < 0.001) weight loss, but it did not change significantly in either group. Weight loss rather than inhibition of fat absorption enhances insulin sensitivity. A decrease in fat absorption by orlistat appears to favorably influence the ratio between intraabdominal and subcutaneous fat, which suggests that exogenous fat or its composition influences fat distribution.

Quantification of Intra-Abdominal Fat During Controlled Weight Reduction: Assessment Using the Water-Suppressed Breath-Hold MRI Technique

A group of 14 healthy female subjects was studied using MRI during 2 months of life-style intervention. A series of 21 water-suppressed images was used to determine the intra-abdominal fat volume before and after the controlled loss of weight. The average weight decrease was 8.2 %, but the average relative loss of visceral fat was 20.3 %, whereas subcutaneous fat decreased by 13.4 %. A small but significant increase of insulin sensitivity (decrease in fasting insulin and blood glucose) was observed, but no changes in lipoprotein parameters were demonstrated. There was a significant negative correlation (r=-0.633, p=0.028) between the relative abdominal fat decrease and the initial amount of subcutaneous fat.

Abdominal volume index. an anthropometry-based index for estimation of obesity is strongly related to impaired glucose tolerance and type 2 diabetes mellitus

Background Our objective was to develop an anthropometric-based index (abdominal volume index, AVI) for estimating overall abdominal volume and to determine its relationship with presence of impaired glucose tolerance (IGT) and type 2 diabetes mellitus (DM). Methods We conducted a cross-sectional, population-based study between November 1998 and June 2001 among 746 men and non-pregnant women randomly recruited from Durango City in northern Mexico. AVI was calculated using volume formulas for cylinder (V = πr 2h) and vertical cone V = (1/3)πr 2h. The formula developed was AVI = [2 cm (waist) 2 + 0.7 cm (waist-hip) 2]/1,000, which estimates overall abdominal volume between symphysis of pubis and xiphoid appendix and theoretically includes intra-abdominal fat and adipose tissue volumes. Results Receiver operating curve (ROC) scatter plot showed as best cut-off value of AVI for estimation of obesity, corresponding to 24.5 liters (L). Logistic regression analysis adjusted by age and sex showed higher odds ratio between AVI and IGT 1.6 (95% confidence interval [95% CI] 1.1–9.1, p = 0.01) as well as between AVI and DM 2.1 (95% CI 1.3–7.9, p = 0.001) than odds ratio (OR) estimated by other anthropometric obesity criteria such as waist-to-hip ratio, body mass index, truncated cone, and waist circumference. Conclusions AVI is a reliable and easy-to-calculate anthropometric tool for estimation of overall abdominal volume that is shown to be strongly related to IGT and DM.

A rapid and reliable semiautomated method for measurement of total abdominal fat volumes using magnetic resonance imaging

The aim of this study was the development of a reliable and fast method to estimate total abdominal fat volumes (TAF) in diabetic subjects on the basis of T1-weighted MR images. Thirty-seven patients with diabetes were examined (age 48 ± 13 y mean ± SD). A semiautomated computer assisted software program was developed to quantify intraabdominal (IAF), subcutaneous (SCF), and total abdominal fat volumes (TAF). The variability of image analysis for fat measurements between two observers and within observers was assessed. Mean volumes (± SD) for IAF, SCF and TAF were 10.5 1 (± 5.0 1), 15.1 1 (±7.3 1) and 25.7 1 (±11.5 1), respectively. Inter- and intraobserver reliability was excellent (r = 0.999 to r = 1.0). Per patient, the analysis required nine minutes in addition to a scan duration of seven minutes. As this analytic method using T1-weighted MR images allows a fast and reliable quantification of TAF, IAF and SCF, it may serve as a valuable tool for respective studies in diabetic subjects.

A novel method of measuring intra-abdominal fat volume using helical computed tomography.

:We present a novel method of scanning for intra-abdominal fat volume by helical computed tomography (CT), and describe the clinical significance of measuring the volumes of intra-abdominal visceral fat (V(vol)) and subcutaneous fat (S(vol)) vs these respective areas determined by conventional slice-by-slice CT at the umbilical level. Subjects with obesity or hyperlipidemia (79 men, 74 women) were recruited for this study. We obtained helical CT scans with a tube current of 150 mA, voltage of 120 kV and 2:1 pitch (table speed in relation to slice thickness), starting at the upper edge of the liver and continuing until the pelvis. The intra-abdominal visceral fat volume was measured by drawing a line within the muscle wall surrounding the abdominal cavity. The abdominal subcutaneous fat volume was calculated by subtracting the visceral fat volume from the total abdominal fat volume. By comparison, the intra-abdominal visceral and subcutaneous fat areas were determined at the umbilical level by the established slice-by-slice CT scanning technique. V(vol) was correlated positively with visceral fat area (V(area)) measured by conventional CT in both genders (in men (n=79) V(vol) vs V(area), r=0.81 P<0.0001; in women (n=74) V(vol) vs V(area), r=0.85, P<0.0001). S(vol) also showed a positive correlation with subcutaneous fat area (S(area)) in both genders (in men (n=78) S(vol) vs S(area), r=0.95, P<0.0001; in women (n=74) S(vol) vs S(area), r=0.92, P<0.0001). We have reported a novel method for measuring intra-abdominal fat volume by the use of helical CT.

Correlation of anthropometry with CT in Mexican‐American women

Measurement of regional fat has commonly been accomplished by extrapolation from anthropometric measures. Recent studies of White and Black women have demonstrated differences in intra-abdominal fat, using computerized tomographic (CT) techniques. These same estimates were computed for 48 Mexican American women who were undergoing CT for diagnostic purposes. Waist-hip ratios, waist-thigh ratios, and sagittal diameter index were also calculated. Four (7mm) CT slices between L—4 and L - 5 were analyzed with imaging software. The volume of both subcutaneous and visceral fat was estimated. Like other minority women, Mexican American women had less intra-abdominal fat than subcutaneous fat, which is important because of the association of excess intra-abdominal fat with cardiovascular risk. Intra-abdominal fat volume was significantly predicted by only one variable, sagittal abdominal diameter, while subcutaneous fat volume was predicted by hip and thigh circumferences. © 1999 John Wiley & Sons, Inc. Res Nurs Health 22:145–153, 1999

Correlation of anthropometry with CT in Mexican-American women.

Measurement of regional fat has commonly been accomplished by extrapolation from anthropometric measures. Recent studies of White and Black women have demonstrated differences in intra-abdominal fat, using computerized tomographic (CT) techniques. These same estimates were computed for 48 Mexican American women who were undergoing CT for diagnostic purposes. Waist-hip ratios, waist-thigh ratios, and sagittal diameter index were also calculated. Four (7mm) CT slices between L-4 and L - 5 were analyzed with imaging software. The volume of both subcutaneous and visceral fat was estimated. Like other minority women, Mexican American women had less intra-abdominal fat than subcutaneous fat, which is important because of the association of excess intra-abdominal fat with cardiovascular risk. Intra-abdominal fat volume was significantly predicted by only one variable, sagittal abdominal diameter, while subcutaneous fat volume was predicted by hip and thigh circumferences.

Relationship between volumes and areas from single transverse scans of intra-abdominal fat measured by magnetic resonance imaging.

To determine the level of a single transverse scan of intra-abdominal fat between L1 and L5 vertebrae that best predicts intra-abdominal fat volumes. Sixteen male and seven female patients with non-insulin-dependent diabetes mellitus, aged 44-74 y. Volumes and areas from single scans of intra-abdominal fat measured by magnetic resonance imaging with a 1.5 Tesla magnetic field strength. Intra-abdominal fat volumes and were calculated from fat areas from eight cross-sectional transverse single scans (nine scans in eight men) of 20 mm thickness. Men and women, respectively, had mean body mass index (BMI) of 27.9 (s.d. 3.0) and 31.6 (s.d. 4.7) kg/m2, and intra-abdominal fat of 2.3 (s.d. 0.5) and 2.5 (s.d. 0.6) kg. Intra-abdominal fat area of the fourth scan (in the direction of L1 to L5) gave the highest prediction of total intra-abdominal fat both in men (r = 0.959, P < 0.001) and in women (r = 0.973, P < 0.001). The intra-abdominal fat area of the third scan gave almost as good a prediction. These third and fourth scans corresponded to L2 and L3 vertebrae. The intra-abdominal fat areas from the sixth and seventh scans, corresponded to the frequently used L4-L5 and had lower correlations with intra-abdominal fat. There were no gender differences in the prediction of volumes from areas of intra-abdominal fat. Intra-abdominal fat areas of the fourth scan explained 93% of variance (SEE = 0.14 kg) of total of intra-abdominal fat for both genders: intra-abdominal fat (kg) = 0.0108 x intra-abdominal fat area of the fourth scan (cm2) + 0.244. In large studies of intra-abdominal fat, using magnetic resonance imaging (MRI) or computerised tomography scanning, a single intra-abdominal fat area at the intervertebral disc between L-2 and L-3 vertebrae offers a cheaper, faster and safer method, with high prediction of total intra-abdominal fat volumes and masses.

The computed tomographic determination of intra-abdominal fat volume by single-layer measurement

Several studies emphasised the importance of the relationship between intra-abdominal and total body adipose tissue as a risk factor for the development of metabolic or cardiovascular diseases. Therefore, the aim of the present study was to examine whether a single-scan computed tomography is able to determine the whole intra-abdominal fat volume with high accuracy and reproducibility. Regions of interests (ROIs) were drawn manually for measuring intra-abdominal fat in 51 unsuspicious abdominal CT. The sexual differentiation of adipose tissue already described in a lot of studies could be confirmed in this study. Fat still predominates in females in lower half of the body (gynecoid obesity). In men it predominates in the upper half (android obesity). Significant correlation concerning measuring the whole intra-abdominal fat volume could be found in L1-level in women (r = 0.992) and in L2-level in men (r = 0.992). Measurement of a single scan enables us to assess whole intra-abdominal fat volume due to a special formula. The determination of intra-abdominal fat measured by a single-scan computed tomography is a procedure associated with high accuracy and reproducibility.

Quantification of body fat distribution in the abdomen using computed tomography

A computed tomographic method was used to assess the pattern of abdominal fat distribution in normal males and females at different abdominal levels. The method permitted site specific calculations of total body volume (TA), total fat volume (TF), subcutaneous fat volume (SF), and intraabdominal fat volume (IF) in each computed tomography scan. The ratio of TF/TA, SF/TF and IF/TF were calculated for the LI, L3, and L5 vertebral levels. Regression analysis of IF versus SF, SF versus TF, IF versus TF, TF versus TA, and TF versus body mass index and age were calculated. A significant linear correlation between the measured variables TA, SF, IF, and TF and between TF and body mass index was found for virtually all correlations attempted at all scanned levels. Females had a higher total fat volume and greater percentage of subcutaneous fat at all levels. Males accumulated more fat intraabdominally than subcutaneously at the L1 and L3 levels. The male-female differences were greatest at L1 and the ratio SF/IF statistically significant at the L1 and L5 levels. Our results demonstrate that computed tomography can noninvasively quantify abdominal fat distribution at various sites. There is an inherent difference in abdominal fat distribution between males and females that is not related to weight. The distribution of body fat in males and females varies markedly from level to level.