Visceral adipose tissue is an independent correlate of glucose disposal in older obese postmenopausal women

Non-alcoholic fatty liver disease through the female lifespan: the role of sex hormones

The prevalence of non-alcoholic fatty liver disease (NAFLD) differs between various stages of the female lifespan. The aim of this review is to summarize current evidence on the association of NAFLD and circulating sex hormones and to explore the pathogenesis of NAFLD within the context of (1) sex hormone changes during the reproductive, post-reproductive female life and beyond and (2) the in vitro and in vivo evidence on pharmacological modulation in women on menopausal hormone treatment (MHT) or endocrine therapy after breast cancer. The fluctuation in estrogen concentrations, the relative androgen excess, and the age-related reduction in sex hormone-binding globulin are related to increased NAFLD risk. Moreover, the peri-menopausal changes in body composition and insulin resistance might contribute to the increased NAFLD risk. Whether MHT prevents or improves NAFLD in this population remains an open question. Studies in women with breast cancer treated with tamoxifen or non-steroidal aromatase inhibitors point to their adverse effects on NAFLD development, although a more pronounced effect of tamoxifen is reported. Future studies focusing on the underlying pathogenesis should identify subgroups with the highest risk of NAFLD development and progression into more aggressive forms, as well as elucidate the role of hormone therapies, such as MHT.

Associations of Body Composition and Physical Activity Level With Multiple Measures of Epigenetic Age Acceleration

Epigenetic clocks use DNA methylation to estimate biological age. Whether body composition and physical activity are associated with these clocks is not well understood. Using blood samples collected at enrollment (2003-2009) from 2,758 women in the US nationwide Sister Study, we calculated 6 epigenetic age acceleration metrics using 4 epigenetic clocks (Hannum, Horvath, PhenoAge, GrimAge). Recreational physical activity was self-reported, and adiposity measures were assessed by trained medical examiners (body mass index (BMI), waist-to-hip ratio (WtH), waist circumference). In cross-sectional analyses, all adiposity measures were associated with epigenetic age acceleration. The strongest association was for BMI and PhenoAge, a measure of biological age that correlates with chronic disease (BMI of ≥35.0 vs. 18.5-24.9, β = 3.15 years, 95% confidence interval (CI): 2.41, 3.90; P for trend < 0.001). In a mutual-adjustment model, both were associated with PhenoAge age acceleration (BMI of ≥35.0 vs. 18.5-24.9, β = 2.69 years, 95% CI: 1.90, 3.48; P for trend < 0.001; quartile 4 vs.1 WtH, β = 1.00 years, 95% CI: 0.34, 1.65; P for trend < 0.008). After adjustment, physical activity was associated only with GrimAge (quartile 4 vs. 1, β = -0.42 years, 95% CI: -0.70, -0.14; P for trend = 0.001). Physical activity attenuated the waist circumference associations with PhenoAge and GrimAge. Excess adiposity was associated with epigenetic age acceleration; physical activity might attenuate associations with waist circumference.

Investigating the relationship between insulin resistance and adipose tissue in a randomized Tehrani population

OBJECTIVES

Insulin resistance is the most common metabolic change associated with obesity. The present study aimed to investigate the relationship between insulin resistance and body composition especially adipose tissue in a randomized Tehrani population.

METHODS

This study used data of 2,160 individuals registered in a cross-sectional study on were randomly selected from among subjects who were referred to nutrition counseling clinic in Tehran, from April 2016 to September 2017. Insulin resistance was calculated by homeostasis model assessment formula. The odds ratio (95% CI) was calculated using logistic regression models.

RESULTS

The mean age of the men was 39 (±10) and women were 41 (±11) (the age ranged from 20 to 50 years). The risk of increased HOMA-IR was 1.03 (95% CI: 1.01-1.04) for an increase in one percent of Body fat, and 1.03 (95% CI: 1.00-1.05) for an increase in one percent of Trunk fat. Moreover, the odds ratio of FBS for an increase in one unit of Body fat percent and Trunk fat percent increased by 1.05 (adjusted odds ratio [95% CI: 1.03, 1.06]) and 1.05 (95% CI: 1.02, 1.08). Also, the risk of increased Fasting Insulin was 1.05 (95% CI: 1.03-1.07) for an increase in one unit of Body fat percent, and 1.05 (95% CI: 1.02-1.08) for an increase in one unit of Trunk fat percent.

CONCLUSIONS

The findings of the present study showed that there was a significant relationship between HOMA-IR, Fasting blood sugar, Fasting Insulin, and 2 h Insulin with percent of Body fat, percent of Trunk fat.

Is visceral abdominal fat area a better indicator for hyperglycemic risk? Results from the Pinggu Metabolic Disease Study

AIMS/INTRODUCTION

The aim of the present study was to analyze the strength of association between fasting plasma glucose (FPG), 2-h postprandial glucose (2h PPG), hemoglobin A1c (HbA1c), disposition index (DI) and nine anthropometrics measures, to explore the best indicator for hyperglycemia.

MATERIALS AND METHODS

Analyses were based on the cross-sectional data of 3,572 adults from the Pinggu Metabolic Disease Study. Anthropometrics were measured, visceral fat area (VFA) and subcutaneous fat area were calculated using an abdominal computed tomography scan. Linear regression was used to analyze the association between FPG, 2h PPG, HbA1c, DI and nine anthropometrics measures (height, weight, waist circumference [WC], body mass index and waist-to-hip ratio [WHR], waist-to-height ratio, VFA, subcutaneous fat area, and visceral-to-subcutaneous ratio). Logistic regression was further carried out to understand the association between per standard increase and risk for hyperglycemia.

RESULTS

Higher VFA and subcutaneous fat area were associated with higher FPG, 2h PPG, HbA1c and DI after adjusting for other covariates. The strongest association observed after adjustment was WC for FPG, with one standard deviation greater WC being associated with 1.70 increased odds; WHR for 2h PPG, with one standard deviation greater WHR being associated with 1.83 increased odds. The strength of the association between VFA and FPG, 2h PPG, HbA1c, and DI was less than WHR and WC, but slightly stronger than body mass index. Stratified analyses showed that VFA performs better as an anthropometrics indicator in predicting hyperglycemic risk in women than men.

CONCLUSIONS

WHR and WC remain the best indicators for hyperglycemic risk among ahealthy Chinese population.

Association between the Thigh Muscle and Insulin Resistance According to Body Mass Index in Middle-Aged Korean Adults

BACKGROUND

We examined the associations between thigh muscle area (TMA) and insulin resistance (IR) according to body mass index (BMI) in middle-aged Korean general population.

METHODS

TMA was measured using quantitative computed tomography and corrected by body weight (TMA/Wt) in 1,263 men, 788 premenopausal women, and 1,476 postmenopausal women all aged 30 to 64 years. The tertiles of TMA/Wt were calculated separately for men and for premenopausal and postmenopausal women. Homeostatic model assessment for insulin resistance (HOMA-IR) was performed using fasting blood glucose and insulin levels, and increased IR was defined according to sex-specific, top quartiles of HOMA-IR. Associations between the TMA/Wt tertiles and increased IR according to the BMI categories (<25 and ≥25 kg/m²) were assessed using multivariable logistic regression analysis.

RESULTS

In men with higher BMIs, but not in those with lower BMIs, the presence of an increased IR had significantly higher odds ratios in the lower TMA/Wt tertiles, even after adjustment for visceral fat area. However, in premenopausal and postmenopausal women, there was no significant inverse association between TMA/Wt tertiles and increased IR, regardless of BMI category.

CONCLUSION

Our findings suggest that the thigh muscle is inversely associated with IR in men, particularly in those with higher BMIs.

Cut-Off Values for Visceral Fat Area Identifying Korean Adults at Risk for Metabolic Syndrome

Background

Cut-off values for visceral fat area (VFA) measured by computed tomography (CT) for identifying individuals at risk of metabolic syndrome (MetS) have not been clearly established in Korean adults, particularly for large populations. We aimed to identify optimal VFA and waist circumference (WC) cut-off values and compare the ability of VFA and WC to predict the presence of ≥2 metabolic risk factors.

Methods

We included 36,783 subjects aged 19–79 years undergoing abdominal fat CT during regular health checkups between January 2007 and February 2015 in Seoul. The risk factors for MetS except WC were based on the International Diabetes Federation criteria. Receiver operating characteristic curve analyses were used to determine the appropriate VFA and WC cut-off values for MetS.

Results

VFA was a more significant predictor of metabolic risk factors than WC and body mass index (BMI). The optimal cut-off values for VFA and WC were 134.6 cm² and 88 cm for men and 91.1 cm² and 81 cm for women, respectively. We estimated age-specific cut-off values for VFA, WC, and BMI. VFA cut-off values increased with age, particularly among women.

Conclusion

This large population study proposed the cut-off values for VFA and WC for identifying subjects at risk of MetS among Korean adults. For more accurate diagnosis, different age-specific cut-off values for VFA and WC may be considered.

The effects of aerobic, resistance, and combination training on insulin sensitivity and secretion in overweight adults from STRRIDE AT/RT: a randomized trial

Most health organizations recommend a combination of aerobic training (AT) and resistance training (RT), yet few studies have compared their acute (within 24 h of the last exercise bout) and sustained (after 14 days of no exercise training) effects alone and in combination on glucose metabolism. The present study (Studies Targeting Risk Reduction Interventions through Defined Exercise-Aerobic Training and/or Resistance Training) compared the effects of AT, RT, and the combination (AT/RT) on insulin action at both acute and sustained phases. Subjects (N = 196) were 18-70 yr old (mean age = 50 yr), overweight (mean body mass index = 30 kg/m2), sedentary with moderate dyslipidemia, and were randomized into one of three 8-mo exercise groups: 1) RT: 3 days/wk, 8 exercises, 3 sets/exercise, 8-12 repetitions/set; 2) AT: equivalent to ∼19.2 km/wk (12 miles/wk) at 75% peak O2 consumption; 3) AT/RT: the combination of AT and RT. One hundred forty-four subjects completed the intervention. Eighty-eight subjects completed all pre- and postintervention testing visits. Insulin sensitivity, glucose effectiveness, and disposition index were measured via a frequently sampled intravenous glucose tolerance test with subsequent minimal model analyses. AT/RT resulted in greater improvements in insulin sensitivity, β-cell function (disposition index), and glucose effectiveness than either AT or RT alone (all P < 0.05). Approximately 52% of the improvement in insulin sensitivity by AT/RT was retained 14 days after the last exercise training bout. Neither AT or RT led to acute or chronic improvement in sensitivity index. In summary, only AT/RT (which required twice as much time as either alone) led to significant acute and sustained benefits in insulin sensitivity

Inverse Relationship between Serum Lipoxin A4 Level and the Risk of Metabolic Syndrome in a Middle-Aged Chinese Population

Metabolic syndrome (MetS) has been identified to be associated with a state of chronic, low-grade inflammation in adipose tissue. Lipoxins are endogenously generated from arachidonic acid, and exhibit anti-inflammatory actions. Currently, there is no available cohort study identifying the association between serum lipoxins level and MetS. Here we investigate the relationship between serum lipoxin A4 (LXA4) level and the risk of incident MetS in a middle-aged Chinese population. A total 624 participants aged 40–65 years were enrolled at baseline, with 417 (including 333 MetS absence) of them were followed up at 2.5 years. Abdominal visceral fat area (VFA) and abdominal subcutaneous fat area (SFA) were determined using MRI. Serum lipoxin A4 levels were measured by ELISA. At baseline, serum LXA4 levels were significantly correlated with a cluster of traditional MetS risk factors related to obesity (P≤0.05). A higher incidence of new Mets was found in the participants of the lowest tertile of LXA4 levels as compared with that in participants of the highest tertile (P = 0.025). Low serum LXA4 levels [OR 2.607(1.151–5.909), P = 0.022] and high VFA [OR 2.571(1.176–5.620), P = 0.018] were associated with an increased incident Mets, respectively, which remained statistically significant after adjustment for age, gender, current smoking, and alcohol drinking status. Logistic regression analysis suggested a combination of low serum LXA4 levels and high WC/VFA might optimize the prediction of incident Mets in middle-aged Chinese population [OR 4.897/4.967, P = 0.009/0.003]. Decrease in serum LXA4 level and increase in VFA are independent predictors of incident Mets in a population-based cohort, and a combination of them enhances the prognostic value of incident Mets. Taken together, our data suggest that serum LXA4 levels might be useful for early detection and prevention of Mets.

Best single-slice location to measure visceral adipose tissue on paediatric CT scans and the relationship between anthropometric measurements, gender and VAT volume in children

OBJECTIVE

Visceral adipose tissue (VAT) is a significant risk factor for obesity-related metabolic diseases. This study investigates (1) the best single CT slice location for predicting total abdominal VAT volume in paediatrics and (2) the relationship between waist circumference (WC), sagittal diameter (SD), gender and VAT volume.

METHODS

A random sample of 130 paediatric abdomen CT scans, stratified according to age and gender, was collected. Three readers measured VAT area at each intervertebral level between T12 and S1 using ImageJ analysis (National Institute of Health, Bethesda, MD) software by thresholding -190 to -30 HU and manually segmenting VAT. Single-slice VAT measurements were correlated with total VAT volume to identify the most representative slice. WC and SD were measured at L3-L4 and L4-L5 slices, respectively. Regression analysis was used to evaluate WC, SD and gender as VAT volume predictors.

RESULTS

Interviewer and intraviewer reliability were excellent (intraclass correlation coefficient = 0.99). Although VAT measured at multiple slices correlated strongly with abdominal VAT, only one slice in females at L2-L3 and two slices in males at L1-L2 and L5-S1 were strongly correlated across all age groups. Linear regression analysis showed that WC was strongly correlated with VAT volume (beta = 0.970, p < 0.001).

CONCLUSION

Single-slice VAT measurements are highly reproducible. Measurements performed at L2-L3 in females and L1-L2 or L5-S1 in males were most representative of VAT. WC is indicative of VAT.

ADVANCES IN KNOWLEDGE

VAT should be measured at L2-L3 in female children and at either L1-L2 or L5-S1 in males. WC is a strong indicator of VAT in children.

Effects of a weight loss program on body composition and the metabolic profile in obese postmenopausal women displaying various obesity phenotypes: a MONET group study

Obesity is a heterogeneous condition, since the metabolic profile may differ greatly from one individual to another. The objective of this study was to compare the effect of a 6-month diet-induced weight loss program on body composition and the metabolic profile in obese individuals displaying different obesity phenotypes. Secondary analyses were done on 129 obese (% body fat: 46% ± 4%) postmenopausal women (age: 57 ± 4 years). Outcome measures included body composition, body fat distribution, glucose homeostasis, fasting lipids, and blood pressure. Obesity phenotypes were determined based on lean body mass (LBM) index (LBMI = LBM/height2) and visceral fat (VF) accumulation, as follows: 1, lower VF and lower LBMI (n = 35); 2, lower VF and higher LBMI (n = 19); 3, higher VF and lower LBMI (n = 14); and 4, higher VF and higher LBMI (n = 61). All groups had significantly improved measures of body composition after the intervention (P < 0.0001). Greater decreases in LBM and LBMI were observed in the higher LBMI groups than in the lower LBMI groups (P < 0.0001). Similarly, decreases in VF were greater in the higher VF groups than in the lower VF groups (P < 0.05). Overall, fasting insulin levels and glucose disposal improved following the intervention, with higher LBMI groups showing a trend for greater improvements (P = 0.06 and 0.07, respectively). Overall, no difference was observed among the different obesity phenotypes regarding improvements in the metabolic profile in response to weight loss. Individuals displaying higher VF or higher LBMI at baseline experienced significantly greater decreases for these variables after the intervention.

Measurement of skeletal muscle radiation attenuation and basis of its biological variation

Skeletal muscle contains intramyocellular lipid droplets within the cytoplasm of myocytes as well as intermuscular adipocytes. These depots exhibit physiological and pathological variation which has been revealed with the advent of diagnostic imaging approaches: magnetic resonance (MR) imaging, MR spectroscopy and computed tomography (CT). CT uses computer-processed X-rays and is now being applied in muscle physiology research. The purpose of this review is to present CT methodologies and summarize factors that influence muscle radiation attenuation, a parameter which is inversely related to muscle fat content. Pre-defined radiation attenuation ranges are used to demarcate intermuscular adipose tissue [from −190 to −30 Hounsfield units (HU)] and muscle (−29 HU to +150 HU). Within the latter range, the mean muscle radiation attenuation [muscle (radio) density] is reported. Inconsistent criteria for the upper and lower HU cut-offs used to characterize muscle attenuation limit comparisons between investigations. This area of research would benefit from standardized criteria for reporting muscle attenuation. Available evidence suggests that muscle attenuation is plastic with physiological variation induced by the process of ageing, as well as by aerobic training, which probably reflects accumulation of lipids to fuel aerobic work. Pathological variation in muscle attenuation reflects excess fat deposition in the tissue and is observed in people with obesity, diabetes type II, myositis, osteoarthritis, spinal stenosis and cancer. A poor prognosis and different types of morbidity are predicted by the presence of reduced mean muscle attenuation values in patients with these conditions; however, the biological features of muscle with these characteristics require further investigation.

Insulin resistance and impaired mitochondrial function in obese adolescent girls

BACKGROUND

Mitochondrial dysfunction plays a role in the development of muscle insulin resistance (IR) and the accumulation of intramyocellular lipid (IMCL) in skeletal muscle that can, in turn, interfere with insulin signaling. The purpose of this study was to assess mitochondrial function (MF) and IMCL in obese adolescent girls with and without IR to determine whether: (1) Girls with IR have impaired MF, and (2) impaired MF in girls with IR is related to higher IMCL.

METHODS

We examined 22 obese girls aged 13-21 years old for IR [defined as a homeostasis model assessment of insulin resistance (HOMA-IR) value >4. Phosphorus magnetic resonance spectroscopy (31P-MRS) and proton magnetic resonance spectroscopy (1H-MRS), respectively, were used to determine MF and IMCL of the soleus muscle along with magnetic resonance imaging (MRI) measures of visceral, subcutaneous, and total adipose tissue (VAT, SAT, and TAT) in girls with HOMA-IR >4 (insulin-resistant group) versus HOMA-IR ≤ 4 (insulin-sensitive group). Serum lipids and waist-to-hip ratio (W/H) were also measured.

RESULTS

Girls with IR (n=8) did not differ from the insulin-sensitive group (n=14) for age, bone age, weight, VAT, SAT, TAT, or IMCL. However, the insulin-resistant group had higher W/H. Additionally the insulin-resistance group had a lower log rate of postexercise phosphocreatine (PCr) recovery (ViPCr) and a higher log PCr recovery constant (tau), indicative of impaired MF.

CONCLUSIONS

Obese girls with increased IR have impaired mitochondrial function. This association is not mediated by alterations in IMCL or adipose tissue. Further studies are necessary to determine whether there is a causal relation between impaired mitochondrial function and IR in obesity and mediators of such a relationship.

Characteristics, changes and influence of body composition during a 4486 km transcontinental ultramarathon: results from the TransEurope FootRace mobile whole body MRI-project

BACKGROUND

Almost nothing is known about the medical aspects of runners doing a transcontinental ultramarathon over several weeks. The results of differentiated measurements of changes in body composition during the Transeurope Footrace 2009 using a mobile whole body magnetic resonance (MR) imager are presented and the proposed influence of visceral and somatic adipose and lean tissue distribution on performance tested.

METHODS

22 participants were randomly selected for the repeated MR measurements (intervals: 800 km) with a 1.5 Tesla MR scanner mounted on a mobile unit during the 64-stage 4,486 km ultramarathon. A standardized and validated MRI protocol was used: T1 weighted turbo spin echo sequence, echo time 12 ms, repetition time 490 ms, slice thickness 10 mm, slice distance 10 mm (breath holding examinations). For topographic tissue segmentation and mapping a modified fuzzy c-means algorithm was used. A semi-automatic post-processing of whole body MRI data sets allows reliable analysis of the following body tissue compartments: Total body volume (TV), total somatic (TSV) and total visceral volume (TVV), total adipose (TAT) and total lean tissue (TLT), somatic (SLT) and visceral lean tissue (VLT), somatic (SAT) and visceral adipose tissue (VAT) and somatic adipose soft tissue (SAST). Specific volume changes were tested on significance. Tests on difference and relationship regarding prerace and race performance and non-finishing were done using statistical software SPSS.

RESULTS

Total, somatic and visceral volumes showed a significant decrease throughout the race. Adipose tissue showed a significant decrease compared to the start at all measurement times for TAT, SAST and VAT. Lean adipose tissues decreased until the end of the race, but not significantly. The mean relative volume changes of the different tissue compartments at the last measurement compared to the start were: TV -9.5% (SE 1.5%), TSV -9.4% (SE 1.5%), TVV -10.0% (SE 1.4%), TAT -41.3% (SE 2.3%), SAST -48.7% (SE 2.8%), VAT -64.5% (SE 4.6%), intraabdominal adipose tissue (IAAT) -67.3% (SE 4.3%), mediastinal adopose tissue (MAT) -41.5% (SE 7.1%), TLT -1.2% (SE 1.0%), SLT -1.4% (SE 1.1%). Before the start and during the early phase of the Transeurope Footrace 2009, the non-finisher group had a significantly higher percentage volume of TVV, TAT, SAST and VAT compared to the finisher group. VAT correlates significantly with prerace training volume and intensity one year before the race and with 50 km- and 24 hour-race records. Neither prerace body composition nor specific tissue compartment volume changes showed a significant relationship to performance in the last two thirds of the Transeurope Footrace 2009.

CONCLUSIONS

With this mobile MRI field study the complex changes in body composition during a multistage ultramarathon could be demonstrated in detail in a new and differentiated way. Participants lost more than half of their adipose tissue. Even lean tissue volume (mainly skeletal muscle tissue) decreased due to the unpreventable chronic negative energy balance during the race. VAT has the fastest and highest decrease compared to SAST and lean tissue compartments during the race. It seems to be the most sensitive morphometric parameter regarding the risk of non-finishing a transcontinental footrace and shows a direct relationship to prerace-performance. However, body volume or body mass and, therefore, fat volume has no correlation with total race performances of ultra-athletes finishing a 4,500 km multistage race.

Metabolic heterogeneity of obesity: role of adipose tissue

Obesity is not synonymous with insulin resistance. Why some but not all individuals develop insulin resistance with weight excess is not clear, but a number of plausible hypotheses with ample support now exist. This article reviews regional fat distribution, inflammation, lipotoxicity/ectopic fat and impaired adipogenesis as leading theories as to why excess body weight has the potential to promote insulin resistance.

Genome-wide association for abdominal subcutaneous and visceral adipose reveals a novel locus for visceral fat in women

Body fat distribution, particularly centralized obesity, is associated with metabolic risk above and beyond total adiposity. We performed genome-wide association of abdominal adipose depots quantified using computed tomography (CT) to uncover novel loci for body fat distribution among participants of European ancestry. Subcutaneous and visceral fat were quantified in 5,560 women and 4,997 men from 4 population-based studies. Genome-wide genotyping was performed using standard arrays and imputed to ~2.5 million Hapmap SNPs. Each study performed a genome-wide association analysis of subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), VAT adjusted for body mass index, and VAT/SAT ratio (a metric of the propensity to store fat viscerally as compared to subcutaneously) in the overall sample and in women and men separately. A weighted z-score meta-analysis was conducted. For the VAT/SAT ratio, our most significant p-value was rs11118316 at LYPLAL1 gene (p = 3.1 × 10E-09), previously identified in association with waist-hip ratio. For SAT, the most significant SNP was in the FTO gene (p = 5.9 × 10E-08). Given the known gender differences in body fat distribution, we performed sex-specific analyses. Our most significant finding was for VAT in women, rs1659258 near THNSL2 (p = 1.6 × 10-08), but not men (p = 0.75). Validation of this SNP in the GIANT consortium data demonstrated a similar sex-specific pattern, with observed significance in women (p = 0.006) but not men (p = 0.24) for BMI and waist circumference (p = 0.04 [women], p = 0.49 [men]). Finally, we interrogated our data for the 14 recently published loci for body fat distribution (measured by waist-hip ratio adjusted for BMI); associations were observed at 7 of these loci. In contrast, we observed associations at only 7/32 loci previously identified in association with BMI; the majority of overlap was observed with SAT. Genome-wide association for visceral and subcutaneous fat revealed a SNP for VAT in women. More refined phenotypes for body composition and fat distribution can detect new loci not previously uncovered in large-scale GWAS of anthropometric traits.

Preferential fat deposition in subcutaneous versus visceral depots is associated with insulin sensitivity

BACKGROUND

Studies on the relationship between regional fat and insulin resistance yield mixed results. Our objective was to determine whether regional fat distribution, independent of obesity, is associated with insulin resistance.

DESIGN

Subjects included 115 healthy, overweight/moderately obese adults with body mass index (BMI) 25-36.9 kg/m(2) who met predetermined criteria for being insulin resistant (IR) or insulin sensitive (IS) based on the modified insulin suppression test. Computerized tomography was used to quantify visceral adipose tissue (VAT), sc adipose tissue (SAT), and thigh adipose tissue. Fat mass in each depot was compared according to IR/IS group, adjusting for BMI and sex.

RESULTS

Despite nearly identical mean BMI in the IR vs. IS groups, VAT and %VAT were significantly higher in the IR group, whereas SAT, %SAT, and thigh sc fat were significantly lower. In logistic regression analysis, each sd increase in VAT increased the odds of being IR by 80%, whereas each increase in SAT decreased the odds by 48%; each increase in thigh fat decreased the odds by 59% and retained significance after adjusting for other depots. When grouped by VAT tertile, IS vs. IR individuals had significantly more SAT. There was no statistically significant interaction between sex and these relationships.

CONCLUSION

These data demonstrate that after adjustment for BMI and VAT mass, sc abdominal and thigh fat are protective for insulin resistance, whereas VAT, after adjustment for SAT and BMI, has the opposite effect. Whether causal in nature or a marker of underlying pathology, these results clarify that regional distribution of fat-favoring sc depots is associated with lower risk for insulin resistance.

Gender differences in diagnostic values of visceral fat area and waist circumference for predicting metabolic syndrome in Koreans

Abdominal fat accumulation is known to be strongly implicated in development of metabolic syndrome (MetS). We examined diagnostic values of obesity-related parameters in 95 men and 185 women, and we determined optimal cutoff values of visceral fat area (VFA) and waist circumference (WC) for predicting the presence of multiple non-adipose components of MetS. Receiver operating characteristic (ROC) curve analysis revealed that VFA was the best indicator of MetS. WC and VFA exhibited similar diagnostic values for men and postmenopausal women, whereas WC was inferior to VFA for premenopausal women (area under ROC curve of VFA and WC was 0.76 and 0.52, respectively; P < 0.001). Optimal cutoff points of VFA and WC for predicting MetS were 136 cm(2) and 89 cm in men and 95 cm(2) and 82 cm in women, respectively. Subjects with VFA and WC above these cutoff values exhibited increased insulin resistance and increased carotid intima-media thickness. In conclusion, WC has a diagnostic value similar to VFA for predicting MetS in men and postmenopausal women, but not in premenopausal women. Further studies are necessary to develop a simple clinical parameter that reflects visceral fat in premenopausal women.

Visceral adiposity, insulin resistance and cancer risk

BACKGROUND

There is a well established link between obesity and cancer. Emerging research is characterising this relationship further and delineating the specific role of excess visceral adiposity, as opposed to simple obesity, in promoting tumorigenesis. This review summarises the evidence from an epidemiological and pathophysiological perspective.

METHODS

Relevant medical literature was identified from searches of PubMed and references cited in appropriate articles identified. Selection of articles was based on peer review, journal and relevance.

RESULTS

Numerous epidemiological studies consistently identify increased risk of developing carcinoma in the obese. Adipose tissue, particularly viscerally located fat, is metabolically active and exerts systemic endocrine effects. Putative pathophysiological mechanisms linking obesity and carcinogenesis include the paracrine effects of adipose tissue and systemic alterations associated with obesity. Systemic changes in the obese state include chronic inflammation and alterations in adipokines and sex steroids. Insulin and the insulin-like growth factor axis influence tumorigenesis and also have a complex relationship with adiposity. There is evidence to suggest that insulin and the IGF axis play an important role in mediating obesity associated malignancy.

CONCLUSIONS

There is much evidence to support a role for obesity in cancer progression, however further research is warranted to determine the specific effect of excess visceral adipose tissue on tumorigenesis. Investigation of the potential mechanisms underpinning the association, including the role of insulin and the IGF axis, will improve understanding of the obesity and cancer link and may uncover targets for intervention.

ADRB2 haplotype is associated with glucose tolerance and insulin sensitivity in obese postmenopausal women

The β(2)-adrenergic receptor (ADRB2) mediates obesity, cardiorespiratory fitness, and insulin resistance. We examined the hypothesis that ADRB2 Arg16Gly-Gln27Glu haplotype is associated with body composition, glucose tolerance, and insulin sensitivity in obese, postmenopausal women. Obese (>35% body fat), postmenopausal (age 45-75 years) women (n = 123) underwent genotyping, dual-energy X-ray absorptiometry, and computed tomography scans, exercise testing (VO(2(max))), 2-h oral glucose tolerance tests (OGTTs), and hyperinsulinemic-euglycemic clamps (80 mU/m(2)/min). Analysis of covariance (ANCOVA) tested for differences among haplotypes, with race, % body fat, and VO(2(max)) as covariates. We found that ADRB2 haplotype was independently associated with % body fat, abdominal fat distribution, VO(2(max)), insulin sensitivity (M/ΔInsulin), and glucose tolerance (ANOVA, P < 0.05 for all). Women homozygous for Gly16-Gln27 haplotype had the highest % body fat (52.7 ± 1.9%), high abdominal fat, low M/ΔInsulin (0.49 ± 0.08 mg/kg/min/pmol/l/10(2)), and impaired glucose tolerance (IGT) during an OGTT (G(120) = 10.2 ± 0.9 mmol/l). Women homozygous for Gly16-Glu27 haplotype also had low M/ΔInsulin (0.51 ± 0.05 mg/kg/min/pmol/l/10(2)) and IGT (G(120) = 8.2 ± 0.7 mmol/l). Subjects with Arg16-Gln27/Gly16-Gln27 haplotype combination had the highest VO(2(max)) (1.84 ± 0.07 l/min) and M/ΔInsulin (0.7 ± 0.04 mg/kg/min/pmol/l/10(2)), and normal glucose tolerance (G(120) = 6.4 ± 0.4 mmol/l), despite being obese. These data show associations of the ADRB2 Arg16Gly-Gln27Glu haplotype with VO(2(max)) and body composition, and an independent association with glucose metabolism, which persists after controlling for body composition and fitness. This suggests that ADRB2 haplotypes may mediate insulin action, glucose tolerance, and potentially risk for type 2 diabetes mellitus (T2DM) in obese, postmenopausal women.

Association between Abdominal Fat (DXA) and Its Subcomponents (CT Scan) before and after Weight Loss in Obese Postmenopausal Women: A MONET Study

Introduction. Subcutaneous fat (ScF) and visceral fat (VF) measurements using CT scan are expensive and may imply significant radiation doses. Cross-sectional studies using CT scan showed that ScF and VF are significantly correlated with abdominal fat measured by DXA (AF-DXA). The association has not been studied after a weight loss. Objective. To determine (1) the associations between AF-DXA and ScF and VF before and after weight loss and (2) the associations between their changes. Methods. 137 overweight/obese postmenopausal women were divided in two groups (1-caloric restriction or 2-caloric restriction + resistance training). AF was assessed using DXA and CT scan. Results. Correlations between AF-DXA and ScF (before: r = 0.87, after; r = 0.87; P < .01) and, AF-DXA and VF (before: r = 0.61, after; r = 0.69; P < .01) are not different before and after the weight loss. Correlations between delta AF-DXA and delta ScF (r = 0.72; P < .01) or delta VF (r = 0.51; P < .01) were found. Conclusion. The use of AF-DXA as a surrogate for VF after weight loss is questionable, but may be interesting for ScF.

Impact of abdominal visceral and subcutaneous adipose tissue on cardiometabolic risk factors: the Jackson Heart Study

OBJECTIVE

Obesity is a major driver of cardiometabolic risk. Abdominal visceral adipose tissue (VAT) and sc adipose tissue (SAT) may confer differential metabolic risk profiles. We investigated the relations of VAT and SAT with cardiometabolic risk factors in the Jackson Heart Study cohort.

METHODS

Participants from the Jackson Heart Study (n=2477; 64% women; mean age, 58 yr) underwent multidetector computed tomography, and the volumetric amounts of VAT and SAT were assessed between 2007 and 2009. Cardiometabolic risk factors were examined by sex in relation to VAT and SAT.

RESULTS

Men had a higher mean volume of VAT (873 vs. 793 cm3) and a lower mean volume of SAT (1730 vs. 2659 cm3) than women (P=0.0001). Per 1-sd increment in either VAT or SAT, we observed elevated levels of fasting plasma glucose and triglyceride, lower levels of high-density lipoprotein-cholesterol, and increased odds ratios for hypertension, diabetes, and metabolic syndrome. The effect size of VAT in women was larger than that of SAT [fasting plasma glucose, 5.51±1.0 vs. 3.36±0.9; triglyceride, 0.17±0.01 vs. 0.05±0.01; high-density lipoprotein-cholesterol, -5.36±0.4 vs. -2.85±0.4; and odds ratio for hypertension, 1.62 (1.4-1.9) vs. 1.40 (1.2-1.6); diabetes, 1.82 (1.6-2.1) vs. 1.58 (1.4-1.8); and metabolic syndrome, 3.34 (2.8-4.0) vs. 2.06 (1.8-2.4), respectively; P<0.0001 for difference between VAT and SAT]. Similar patterns were also observed in men. Furthermore, VAT remained associated with most risk factors even after accounting for body mass index (P ranging from 0.006-0.0001). The relationship of VAT to most risk factors was significantly different between women and men.

CONCLUSIONS

Abdominal VAT and SAT are both associated with adverse cardiometabolic risk factors, but VAT remains more strongly associated with these risk factors. The results from this study suggest that relations with cardiometabolic risk factors are consistent with a pathogenic role of abdominal adiposity in participants of African ancestry.

Abdominal subcutaneous and visceral adipose tissue and insulin resistance in the Framingham heart study

Insulin resistance is associated with central obesity and an increased risk of cardiovascular disease. Our objective is to examine the association between abdominal subcutaneous (SAT) and visceral adipose tissue (VAT) and insulin resistance, to determine which fat depot is a stronger correlate of insulin resistance, and to assess whether there was an interaction between SAT, VAT, and age, sex, or BMI. Participants without diabetes from the Framingham Heart Study (FHS), who underwent multidetector computed tomography to assess SAT and VAT (n = 3,093; 48% women; mean age 50.4 years; mean BMI 27.6 kg/m(2)), were evaluated. Insulin resistance was measured using the homeostasis model and defined as HOMA(IR) ≥75th percentile. Logistic regression models, adjusted for age, sex, smoking, alcohol, menopausal status, and hormone replacement therapy use, were used to assess the association between fat measures and insulin resistance. The odds ratio (OR) for insulin resistance per standard deviation increase in SAT was 2.5 (95% confidence interval (CI): 2.2-2.7; P < 0.0001), whereas the OR for insulin resistance per standard deviation increase in VAT was 3.5 (95% CI: 3.1-3.9; P < 0.0001). Overall, VAT was a stronger correlate of insulin resistance than SAT (P < 0.0001 for SAT vs. VAT comparison). After adjustment for BMI, the OR of insulin resistance for VAT was 2.2 (95% CI: 1.9-2.5; P < 0.0001). We observed an interaction between VAT and BMI for insulin (P interaction = 0.0004), proinsulin (P interaction = 0.003), and HOMA(IR) (P interaction = 0.003), where VAT had a stronger association in obese individuals. In conclusion, SAT and VAT are both correlates of insulin resistance; however, VAT is a stronger correlate of insulin resistance than SAT.

Metabolic syndrome and cardiovascular risk

The constellation of dyslipidemia (hypertriglyceridemia and low levels of high-density lipoprotein cholesterol), elevated blood pressure, impaired glucose tolerance, and central obesity is now classified as metabolic syndrome, also called syndrome X. In the past few years, several expert groups have attempted to set forth simple diagnostic criteria for use in clinical practice to identify patients who manifest the multiple components of the metabolic syndrome. These criteria have varied somewhat in specific elements, but in general, they include a combination of multiple and metabolic risk factors. The most widely recognized of the metabolic risk factors are atherogenic dyslipidemia, elevated blood pressure, and elevated plasma glucose. Individuals with these characteristics, commonly manifest a prothrombotic state as well as and a proinflammatory state. Atherogenic dyslipidemia consists of an aggregation of lipoprotein abnormalities including elevated serum triglyceride and apolipoprotein B (apoB), increased small LDL particles, and a reduced level of HDL cholesterol (HDL-C). The metabolic syndrome is often referred to as if it were a discrete entity with a single cause. Available data suggest that it truly is a syndrome, ie, a grouping of atherosclerotic cardiovascular disease (ASCVD) risk factors, that probably has more than one cause. Regardless of cause, the syndrome identifies individuals at an elevated risk for ASCVD. The magnitude of the increased risk can vary according to the components of the syndrome present as well as the other, non-metabolic syndrome risk factors in a particular person.

Visceral fat dominant distribution in male type 2 diabetic patients is closely related to hepatic insulin resistance, irrespective of body type

Background

All previous studies that investigated the association between abdominal fat distribution and insulin resistance evaluated subcutaneous and visceral fat area and/or volume, but these values were not related to the body type of each subject. In the present study we have examined the association between abdominal fat distribution and peripheral (muscle)/hepatic sensitivity to insulin using the visceral to abdominal subcutaneous fat area ratio (VF/SF ratio) in male patients with type 2 diabetes mellitus. This ratio defines the predominancy of visceral or subcutaneous abdominal adiposity, independent of the body type of each individual.

Methods

Thirty-six type 2 diabetic male patients underwent a euglycemic insulin clamp (insulin infusion rate = 40 mU/m²·min) with 3-³H-glucose to measure insulin-mediated total body (primarily reflects muscle) glucose disposal (TGD) and suppression of endogenous (primarily reflects liver) glucose production (EGP) in response to a physiologic increase in plasma insulin concentration. Abdominal subcutaneous (SF) and intraabdominal visceral fat (VF) areas were quantitated with magnetic resonance imaging (MRI) at the level of L_4–5.

Results

TGD and TGD divided by steady state plasma insulin concentration during the insulin clamp (TGD/SSPI) correlated inversely with body mass index (BMI), total fat mass (FM) measured by ³H₂O, SF and VF areas, while VF/SF ratio displayed no significant relationship with TGD or TGD/SSPI. In contrast, EGP and the product of EGP and SSPI during the insulin clamp (an index hepatic insulin resistance) correlated positively with VF/SF ratio, but not with BMI, FM, VF or SF.

Conclusion

We conclude that, independent of the individual's body type, visceral fat dominant accumulation as opposed to subcutaneous fat accumulation is associated with hepatic insulin resistance, whereas peripheral (muscle) insulin resistance is more closely related to general obesity (i.e. higher BMI and total FM, and increased abdominal SF and VF) in male patients with type 2 diabetes.

Loss of total and visceral adipose tissue mass predicts decreases in oxidative stress after weight-loss surgery

It is not known whether there are mechanisms linking adipose tissue mass and increased oxidative stress in obesity. This study investigated associations between decreasing general and abdominal fat depots and oxidative stress during weight loss. Subjects were severely obese women who were measured serially at baseline and at 1, 6 (n = 30), and 24 months (n = 18) after bariatric surgery. Total fat mass (FAT) and volumes of visceral (VAT) and subcutaneous abdominal adipose tissue (SAT) were related to plasma concentrations of derivatives of reactive oxidative metabolites (dROMS), a measure of lipid peroxides and oxidative stress. After intervention, BMI significantly decreased, from 47.7 +/- 0.8 kg/m(2) to 43.3 +/- 0.8 kg/m(2) (1 month), 35.2 +/- 0.8 kg/m(2) (6 months), and 30.2 +/- 1.2 kg/m(2) (24 months). Plasma dROMS also significantly deceased over time. At baseline, VAT (r = 0.46), FAT (r = 0.42), and BMI (r = 0.37) correlated with 6-month decreases in dROMS. Similarly, at 1 month, VAT (r = 0.43) and FAT (r = 0.41) correlated with 6-month decreases in dROMS. Multiple regression analysis showed that relationships between VAT and dROMS were significant after adjusting for FAT mass. Increased plasma dROMS at baseline were correlated with decreased concentrations of high-density lipoprotein (HDL) at 1 and 6 months after surgery (r = -0.38 and -0.42). This study found longitudinal associations between general, and more specifically intra-abdominal adiposity, and systemic lipid peroxides, suggesting that adipose tissue mass contributes to oxidative stress.

Abdominal obesity and the metabolic syndrome: a surgeon's perspective

Over the past decade, a major shift in the clinical risk factors in the population undergoing a cardiac surgery has been observed. In the general population, an increasing prevalence of obesity has largely contributed to the development of cardiovascular disorders. Obesity is a heterogeneous condition in which body fat distribution largely determines metabolic perturbations. Consequently, individuals characterized by increased abdominal fat deposition and the so-called metabolic syndrome (MetS) have a higher risk of developing coronary artery disease. Recent studies have also emphasized that visceral obesity is a strong risk factor for the development of heart valve diseases. In fact, individuals characterized by visceral obesity and its metabolic consequences, such as the small dense low-density lipoprotein phenotype, have a faster progression rate of aortic stenosis, which is related to increased valvular inflammation. Furthermore, the degenerative process of implanted bioprostheses is increased in subjects with the MetS and/or diabetes, suggesting that a process akin to atherosclerosis could be involved in the failure of bioprostheses. In addition to being an important risk factor for the development of cardiovascular disorders, the MetS is increasing the operative mortality risk following coronary artery bypass graft surgery. Thus, recent evidence supports visceral obesity as a global risk factor that is affecting the development of many heart disorders, and that is also impacting negatively on the results of patients undergoing surgical treatment for cardiovascular diseases. In the present paper, recent concepts surrounding the MetS and its implications in various cardiovascular disorders are reviewed along with the clinical implications.

Is weight loss the optimal target for obesity-related cardiovascular disease risk reduction?

In the present review, it is argued that while weight loss is associated with substantial reduction in obesity-related cardiovascular disease risk and remains a desired outcome of relevant treatment strategies, increasing physical activity is associated with marked reduction in waist circumference, visceral fat and cardiometabolic risk factors, concurrent with an increase in cardiorespiratory fitness despite minimal or no change in body weight. Failure to recognize the benefits of exercise independent of weight loss masks opportunities to counsel and educate patients whose sole criteria for gauging obesity reduction success is the bathroom scale.

Abdominal obesity in older women: potential role for disrupted fatty acid reesterification in insulin resistance

CONTEXT

Excess abdominal adiposity is a primary factor for insulin resistance in older age.

OBJECTIVES

Our objectives were to examine the role of abdominal obesity on adipose tissue, hepatic, and peripheral insulin resistance in aging, and to examine impaired free fatty acid metabolism as a mechanism in these relations.

DESIGN

This was a cross-sectional study.

SETTING

The study was performed at a General Clinical Research Center.

PARTICIPANTS

Healthy, inactive older (>60 yr) women (n = 25) who were not on hormone replacement therapy or glucose-lowering medication were included in the study. Women with abdominal circumference values above the median (>97.5 cm) were considered abdominally obese.

MAIN OUTCOME MEASURES

Whole-body peripheral glucose utilization, adipose tissue lipolysis, and hepatic glucose production were measured using in vivo techniques according to a priori hypotheses.

RESULTS

In the simple analysis, glucose utilization at the 40 mU insulin dose (6.3 +/- 2.8 vs. 9.1 +/- 3.4; P < 0.05), the index of the insulin resistance of basal hepatic glucose production (23.6 +/- 13.0 vs. 15.1 +/- 6.0; P < 0.05), and insulin-stimulated suppression of lipolysis (35 vs. 54%; P < 0.05) were significantly different between women with and without abdominal obesity, respectively. Using the glycerol appearance rate to free fatty acid ratio as an index of fatty acid reesterification revealed markedly blunted reesterification in the women with abdominal adiposity under all conditions: basal (0.95 +/- 0.29 vs. 1.35 +/- 0.47; P < 0.02); low- (2.58 +/- 2.76 vs. 6.95 +/- 5.56; P < 0.02); and high-dose (4.46 +/- 3.70 vs. 12.22 +/- 7.13; P < 0.01) hyperinsulinemia. Importantly, fatty acid reesterification was significantly (P < 0.01) associated with abdominal circumference and hepatic and peripheral insulin resistance, regardless of total body fat.

CONCLUSION

These findings support the premise of dysregulated fatty acid reesterification with abdominal obesity as a pathophysiological link to perturbed glucose metabolism across multiple tissues in aging.

Effects of growth hormone and pioglitazone in viscerally obese adults with impaired glucose tolerance: a factorial clinical trial

OBJECTIVE

Recombinant human growth hormone (GH) and pioglitazone (PIO) in abdominally obese adults with impaired glucose tolerance were evaluated under the hypothesis that the combination attenuates GH-induced increases in glucose concentrations, reduces visceral adipose tissue (VAT), and improves insulin sensitivity over time.

DESIGN

Randomized, double-blind, placebo-controlled, 2 x 2 factorial design.

SETTING

Veterans Affairs Palo Alto Health Care System, Palo Alto, California, United States.

PARTICIPANTS

62 abdominally obese adults aged 40-75 with impaired glucose tolerance.

INTERVENTIONS

GH (8 microg/kg/d, or placebo) and pioglitazone (30 mg/d, or placebo) for 40 wk.

OUTCOME MEASURES

Baseline and after 40 wk of treatment, VAT content was quantified by CT scan, glucose tolerance was assessed using a 75-g oral glucose tolerance test, and insulin sensitivity was measured using steady-state plasma glucose levels obtained during insulin suppression test.

RESULTS

BASELINE: body mass index (BMI), plasma glucose, and visceral fat content were similar. 40 wk: visceral fat area declined 23.9 +/- 7.4 cm(2) in GH group, mean difference from placebo: -28.1 cm(2) (95% CI -49.9 to -6.3 cm(2); p = 0.02). Insulin resistance declined 52 +/- 11.8 mg/dl with PIO, mean difference from placebo of -58.8 mg/dl (95% CI -99.7 to -18.0 mg/dl; p = 0.01). VAT and SSPG declined with GH and PIO combined, mean differences from placebo of -31.4 cm(2) (95% CI -56.5 cm(2) to -6.3 cm(2); p = 0.02) and -55.3 mg/dl (95% CI -103.9 to -6.7 mg/dl; p = 0.02), respectively. Fasting plasma glucose increased transiently in GH group. No significant changes in BMI were observed.

CONCLUSIONS

Addition of PIO to GH attenuated the short-term diabetogenic effect of GH; the drug combination reduced VAT and insulin resistance over time. GH plus PIO may have added benefit on body composition and insulin sensitivity in the metabolic syndrome.

Exercise-induced reversal of insulin resistance in obese elderly is associated with reduced visceral fat

Exercise improves glucose metabolism and delays the onset and/or reverses insulin resistance in the elderly by an unknown mechanism. In the present study, we examined the effects of exercise training on glucose metabolism, abdominal adiposity, and adipocytokines in obese elderly. Sixteen obese men and women (age = 63 +/- 1 yr, body mass index = 33.2 +/- 1.4 kg/m2) participated in a 12-wk supervised exercise program (5 days/wk, 60 min/day, treadmill/cycle ergometry at 85% of heart rate maximum). Visceral fat (VF), subcutaneous fat, and total abdominal fat were measured by computed tomography. Fat mass and fat-free mass were assessed by hydrostatic weighing. An oral glucose tolerance test was used to determine changes in insulin resistance. Exercise training increased maximal oxygen consumption (21.3 +/- 0.8 vs. 24.3 +/- 1.0 ml.kg(-1).min(-1), P < 0.0001), decreased body weight (P < 0.0001) and fat mass (P < 0.001), while fat-free mass was not altered (P > 0.05). VF (176 +/- 20 vs. 136 +/- 17 cm2, P < 0.0001), subcutaneous fat (351 +/- 34 vs. 305 +/- 28 cm2, P < 0.03), and total abdominal fat (525 +/- 40 vs. 443 +/- 34 cm2, P < 0.003) were reduced through training. Circulating leptin was lower (P < 0.003) after training, but total adiponectin and tumor necrosis factor-alpha remained unchanged. Insulin resistance was reversed by exercise (40.1 +/- 7.7 vs. 27.6 +/- 5.6 units, P < 0.01) and correlated with changes in VF (r = 0.66, P < 0.01) and maximal oxygen consumption (r = -0.48, P < 0.05) but not adipocytokines. VF loss after aerobic exercise training improves glucose metabolism and is associated with the reversal of insulin resistance in older obese men and women.

Changes in C-reactive protein predict insulin sensitivity in severely obese individuals after weight loss surgery

The production of inflammatory mediators by abdominal adipose tissue may link obesity and insulin resistance. We determined the influence of systemic levels of interleukin-6 and C-reactive protein on insulin sensitivity after weight loss via Roux-en-Y gastric bypass surgery. Severely obese individuals (n = 15) were evaluated at baseline and at 6 months after surgery. Insulin sensitivity was determined by frequently sampled intravenous glucose tolerance testing at the same time points. Visceral and subcutaneous adipose tissue volumes were quantified by computed tomography. Interleukin-6 and C-reactive protein were measured by enzyme-linked immunoassay in plasma and in adipose tissue biopsies. Correlation analysis was used to determine associations between insulin sensitivity and other outcome variables. Significance was set at P < 0.05. Plasma interleukin-6 concentrations were significantly correlated to the IL-6 content of subcutaneous adipose tissue (r = 0.71). At 6 months postsurgery, subcutaneous and visceral adipose tissue volumes were significantly reduced (34.7% and 44.1%, respectively) and insulin sensitivity had improved by 160.9%. Significant longitudinal correlations were found between insulin sensitivity and plasma C-reactive protein (r = -0.61), but not plasma interleukin-6 at 6 months. These findings offer insights that link obesity and insulin resistance via the activity of inflammatory mediators.