Regional fat mass by DXA: high leg fat mass attenuates the relative risk of insulin resistance and dyslipidaemia in obese but not in overweight postmenopausal women

Associations of anthropometric cardiometabolic risk factors and leg fat accumulation in children and adolescents from Poland

OBJECTIVES

To analyze the correlation between anthropometric cardiometabolic risk factors with calf adiposity in 4-16-year-olds from Poland.

METHODS

Three thousand seventy-six persons (1568 girls and 1508 boys) were examined. Analyzed characteristics included body height, waist, hips and neck circumferences, body weight, six skinfolds. The following were calculated: body mass index (BMI), waist-to-hips ratio (WHR), the sum of all skinfolds, and the sum of skinfolds on the waist area.

RESULTS

The relationship between the calf skinfold and the rest of the characteristics was estimated using multiple regression. There was a negative relationship between calf adiposity and fat tissue accumulated around the waist and the BMI (in some groups). This suggests that participants with greater calf adiposity had lower waist adiposity and BMI than those with less fat tissue on the lower limb.

CONCLUSION

Persons with higher calf adiposity may have a lower cardiometabolic risk. This observation is significant because cardiovascular risk factors can persist from childhood into adulthood. Additionally, cardiovascular issues have numerous medical consequences but also socio-economic ones, thus they can affect individuals and be a burden on public health.

Leg and arm adiposity is inversely associated with diastolic hypertension in young and middle-aged United States adults

BACKGROUND

We sought to determine the association between appendicular adiposity and hypertension, with the purpose of better understanding the role of body fat distribution on blood pressure (BP).

METHODS

We included 7411 adults aged 20 to 59 who were not taking antihypertensives and without cardiovascular disease from the 2011 to 2018 National Health and Nutrition Examination Surveys. Leg & arm adiposity, determined via dual-energy X-ray absorptiometry scans, was defined as percent of total body fat present in legs/arms (leg/total%, arm/total%). Measures were categorized into sex-specific tertiles. We estimated change in BP and odds ratios (ORs) of hypertension (BP ≥ 130/80) and hypertension subtypes using multivariable, survey design-adjusted linear & logistic regression, respectively.

RESULTS

Of the participants, 49% were female, the average (standard deviation) age was 37.4 (0.3) years, and 24% had hypertension. Those in the highest tertile (T3) of leg/total% had 30% decreased adjusted ORs (aOR) of hypertension compared to the lowest tertile (T1; aOR, 0.70; 95% confidence interval [95% CI], 0.55-0.89). This association was not significant for arm/total% (0.89, 0.68-1.17). T3 of leg/total% was associated with 49% lower, 41% lower, and unchanged relative odds of isolated diastolic hypertension (IDH), systolic-diastolic hypertension (SDH), and isolated systolic hypertension (ISH) compared to T1 (IDH: 0.51, 0.37-0.70; SDH: 0.59, 0.43-0.80; ISH: 1.06, 0.70-1.59). For every 10% increase in leg/total%, diastolic BP decreased by an adjusted mean 3.5 mmHg (95% CI, - 4.8 to - 2.2) in males and 1.8 mmHg (95% CI, - 2.8 to - 0.8) in females (P < 0.001 for both).

CONCLUSIONS

A greater proportional distribution of fat around the legs is inversely, independently associated with hypertension, and more specifically, diastolic hypertension (IDH and SDH).

Distinct opposing associations of upper and lower body fat depots with metabolic and cardiovascular disease risk markers

BACKGROUND

To examine the associations of total and regional adiposity with metabolic and cardiovascular disease (CVD) risk markers.

METHODS

This cross-sectional study included 1080 (53.8% men, aged 39-44 years) individuals from South India. Anthropometry (height, weight, waist and hip circumference), body composition assessment using dual-energy X-ray absorptiometry (DXA), blood pressure (BP), and plasma glucose, insulin and lipids were measured. Regression analysis was used to examine associations of standardized fat measurements with type 2 diabetes (T2D), insulin resistance (IR), hypertension and hypertriglyceridemia and continuous measurements of BP, glucose, insulin, HOMA-IR and lipids. Contour plots were constructed to visualize the differential effect of upper and lower fat depots.

RESULTS

DXA-measured fat depots were positively associated with metabolic and CVD risk markers. After adjusting for fat mass index, upper body fat remained positively, while lower body fat was negatively associated with risk markers. A one standard deviation (SD) increase in android fat showed higher odds ratios (ORs) for T2D (6.59; 95% CI 3.17, 13.70), IR (4.68; 95% CI 2.31, 9.50), hypertension (2.57; 95% CI 1.56, 4.25) and hypertriglyceridemia (6.39; 95% CI 3.46, 11.90) in men. A 1 SD increase in leg fat showed a protective effect with ORs for T2D (0.42; 95% CI 0.24, 0.74), IR (0.31; 95% CI 0.17, 0.57) and hypertriglyceridemia (0.61; 95% CI 0.38, 0.98). The magnitude of the effect was greater with DXA-measured fat compared with anthropometry.

CONCLUSION

At any level of total body fat, upper and lower body fat depots demonstrate opposite risk associations with metabolic and CVD risk markers in Asian Indians.

The association of glucocorticoid receptor polymorphism with metabolic outcomes in menopausal women with adrenal incidentalomas

OBJECTIVES

To investigate whether BclI polymorphism in the glucocorticoid receptor gene influences hypothalamic-pituitary-adrenal (HPA) axis regulation, body composition and metabolic parameters in women with adrenal incidentalomas (AIs).

STUDY DESIGN

A cross-sectional study.

MAIN OUTCOME MEASURES

We analyzed 106 women with AIs. Insulin resistance was assessed using a homeostasis model while HPA activity was assessed using dexamethasone suppression tests (DST), basal ACTH, urinary free cortisol, and midnight serum cortisol level. Body composition was analyzed using dual-energy X-ray absorptiometry. DNA was obtained from peripheral blood leucocytes and BclI polymorphism was detected using PCR, RFLP and DNA sequencing.

RESULTS

BclI carriers in comparison with those with wild-type BclI had less suppressed cortisol after DST-0.5 mg (126.4 ± 111.4 vs 80.9 ± 75.7 nmol/l, p = 0.026) and had a lower prevalence of impaired glucose tolerance and of type 2 diabetes mellitus (T2DM). BclI carriers had a higher percentage of leg fat mass (FM), lower left-sided limb muscle mass and a decline in total lean body mass. Duration of menopause remained a strong predictor of appendicular lean mass index (ALMI) (β=-0.125, p = 0.034). BclI polymorphism was significantly associated with sum of legs FM percentage (β=0.327, p = 0.048). T2DM was negatively associated with BclI polymorphism, after adjusting for age, truncal FM, ALMI, and sum of legs FM (OR=0.158, 95%CI 0.031-0.806, p = 0.027).

CONCLUSIONS

BclI polymorphism is associated with tissue-specific glucocorticoid sensitivity, relative glucocorticoid resistance of the HPA axis and peripheral adipose tissue, and glucocorticoid hypersensitivity at the muscle level. By modulating glucocorticoid and insulin sensitivity, BclI polymorphism appears to reduce the risk of T2DM in women with AIs.

Sex and body mass index implications on gluteofemoral subcutaneous tissue morphology visualized by ultrasonography - preliminary study

Introduction

Since the protective value of gluteofemoral subcutaneous adipose tissue against cardiovascular risk factors has already been described in scientific reports, it is important to pay more attention to its evaluation.

Aim of the study

The purpose of this study was to evaluate sex and body mass index implications on gluteofemoral subcutaneous tissue morphology visualized by ultrasonography.

Material and method

A population of 40 participants between 20–50 years of age was examined. All individuals underwent the ultrasound examination of subcutaneous adipose tissue in three locations: anterior, posterior and lateral side of a thigh in the 1/3 distal part. All examinations were collected, and the following parameters were evaluated: thickness of subcutaneous adipose tissue in general, thickness of superficial and deep subcutaneous adipose tissue.

Results

The study revealed significant differences in the architecture of subcutaneous adipose tissue between male and female subgroups. In the group of males, a significantly thinner layer of not only subcutaneous adipose tissue in general (0.65 vs. 1.67 cm, p <0.0001), but also in its main compartments was observed. Moreover, we observed strong positive correlation between body mass index and all subcutaneous adipose tissue layers in the female subgroup. Interestingly, there was no relation between the thickness of the subcutaneous adipose tissue layers between subgroups with a decreased and normal body mass index and an increased body mass index.

Conclusions

The presented data indicates that sex is an important factor in the determination of subcutaneous adipose tissue architecture of a thigh. The ultrasound examination of this structure can be a useful prognostic tool in the assessment of cardiovascular risk.

Body adiposity indicators and cardiometabolic risk: Cross-sectional analysis in participants from the PREDIMED-Plus trial

BACKGROUND & AIMS

Excess adiposity is associated with poor cardiometabolic (CM) health. To date, several techniques and indicators have been developed to determine adiposity. We aimed to compare the ability of traditional anthropometric, as well as standard and novel DXA-derived parameters related to overall and regional adiposity, to evaluate CM risk.

METHODS

Using the cross-sectional design in the context of the PREDIMED-Plus trial, 1207 Caucasian senior men and women with overweight/obesity and metabolic syndrome (MetS) were assessed. At baseline, anthropometry- and DXA-measured parameters of central, visceral, peripheral and central-to-peripheral adiposity together with comprehensive set of CM risk factors were obtained. Partial correlations and areas under the ROC curve (AUC) were estimated to compare each adiposity measure with CM risk parameters, separately for men and women, and in the overall sample.

RESULTS

DXA-derived indicators, other than percentage of total body fat, showed stronger correlations (rho -0.172 to 0.206, p < 0.001) with CM risk than anthropometric indicators, after controlling for age, diabetes and medication use. In both sexes, DXA-derived visceral adipose tissue measures (VAT, VAT/Total fat, visceral-to-subcutaneous fat) together with lipodystrophy indicators (Trunk/Legs fat and Android/Gynoid fat) were strongly and positively correlated (p < 0.001) with glycated hemoglobin (HbA1c), the triglyceride and glucose index (TyG), triglycerides (TG), the ratio TG/HDL-cholesterol (TG/HDL-C), and were inversely related to HDL-C levels (p < 0.001). Furthermore, in AUC analyses for both sexes, VAT/Total fat showed the highest predictive ability for abnormal HbA1c levels (AUC = 0.629), VAT for TyG (AUC = 0.626), both lipodystrophy indicators for TG (AUCs = 0.556), and Trunk/Legs fat for HDL-C (AUC = 0.556) and TG/HDL-C (AUC = 0.581).

CONCLUSIONS

DXA regional adiposity measures offer advantages beyond traditional anthropometric and DXA overall adiposity indicators for CM risk assessment in senior overweight/obese subjects with MetS. In particular, in both sexes, visceral adiposity better stratifies individuals at risk for glucose abnormalities, and indicators of lipodystrophy better predict markers of dyslipidemia.

Comparison of regional fat measurements by dual-energy X-ray absorptiometry and conventional anthropometry and their association with markers of diabetes and cardiovascular disease risk

Background/Objectives:

Fat distribution is a strong and independent predictor of type 2 diabetes (T2D) and cardiovascular disease (CVD) and is usually determined using conventional anthropometry in epidemiological studies. Dual-energy X-ray absorptiometry (DXA) can measure total and regional adiposity more accurately. Nonetheless, whether DXA provides more precise estimates of cardiovascular risk in relation to total and regional adiposity is not known. We determined the strength of the associations between DXA- and conventional anthropometry determined fat distribution and T2D and CVD risk markers.

Subjects/Methods:

Waist (WC) and hip circumference (HC) and DXA was used to measure total and regional adiposity in 4950 (2119 men) participants aged 29–55 years from the Oxford Biobank without pre-existing T2D or CVD. Cross-sectional associations were compared between WC and HC vs. DXA-determined regional adiposity (all z-score normalised) with impaired fasting glucose, hypertriglyceridemia, hypertension and insulin resistance (IR).

Results:

Following adjustment for total adiposity, upper body adiposity measurements showed consistently increased risk of T2D and CVD risk markers except for abdominal subcutaneous fat in both sexes, and arm fat in men, which showed protective associations. Among upper adiposity depots, visceral fat mass showed stronger odds ratios (OR) ranging from 1.69 to 3.64 compared with WC 1.07–1.83. Among lower adiposity depots, HC showed modest protection for IR in both sexes (men: OR 0.80 (95% confidence interval 0.67, 0.96); women: 0.69 (0.56, 0.86)), whereas gynoid fat and in particular leg fat showed consistent and strong protective effects for all outcomes in both men and women. The differential effect of body fat distribution on CVD and T2D were more pronounced at higher levels of total adiposity.

Conclusions:

Compared with DXA, conventional anthropometry underestimates the associations of regional adiposity with T2D and CVD risk markers. After correcting for overall adiposity, greater subcutaneous fat mass in particular in the lower body is protective relative to greater android or visceral adipose tissue mass.

Circulating SIRT1 Increases After Intragastric Balloon Fat Loss in Obese Patients

BACKGROUND

Sirtuins (SIRTs), ubiquitous deacetylases, are main regulators of energy homeostasis and metabolism. SIRT1 has a positive impact on obesity, diabetes mellitus, liver steatosis, and other metabolic disorders. Lean subjects have higher expression of SIRT1 in the adipose tissue compared to obese. However, it is not known whether weight loss associates with changes in blood SIRT1. We evaluated the effect of weight loss on circulating SIRT1, metabolic parameters, and body composition.

METHODS

Thirty-two obese subjects were studied before and 6 months after BioEnterics® Intragastric Balloon (BIB®) [22 patients, BMI 41.82 ± 6.28 kg/m(2)] or hypocaloric diet [10 patients, BMI 38.95 ± 6.90 kg/m(2)]. Plasma SIRT1, body composition, measures of metabolic syndrome (waist circumference, fasting plasma glucose, blood pressure, HDL cholesterol, triglycerides), and inflammation markers (ESR, CRP, fibrinogen) were recorded.

RESULTS

SIRT1 levels showed a significant increase, together with a significant reduction of BMI, excess body weight, and total fat mass either after BIB or diet intervention. The percent excess body weight loss was 33.73 ± 19.06 and 22.08 ± 11.62 % after BIB and diet, respectively, a trend toward a metabolic and inflammatory amelioration was observed with both treatments. Negative correlation between SIRT1 and % fat mass (BIB, ρ = -0.537, p = 0.017; diet, ρ = -0.638, p = 0.047) was also seen.

CONCLUSIONS

The reduction of fat mass associates with increased plasma SIRT1 indicating that, besides tissue levels, circulating SIRT1 is stimulated by a negative caloric balance. The rise of plasma SIRT1 may represent a parameter associating with fat loss rather than weight lowering regardless of the weight reduction system method used.

Mesenchymal stromal cells for the delivery of oncolytic viruses in gliomas

Mesenchymal stromal cells (MSCs) are a type of adult stem cell that has been exploited for the treatment of a variety of diseases, including cancer. In particular, MSCs have been studied extensively for their ability to treat glioblastoma (GBM), the most common and deadly form of brain cancer in adults. MSCs are attractive therapeutics because they can be obtained relatively easily from patients, are capable of being expanded numerically in vitro, can be easily engineered and are inherently capable of homing to tumors, making them ideal vehicles for delivering biological antitumoral agents. Oncolytic viruses are promising biological therapeutic agents that have been used in the treatment of GBMs, and MSCs are currently being explored as a means of delivering these viruses. Here we review the role of MSCs in the treatment of GBMs, focusing on the intersection of MSCs and oncolytic viruses.

Total and regional adiposity measured by dual-energy X-ray absorptiometry and mortality in NHANES 1999-2006

OBJECTIVE

Associations of overall and regional body fat measured by dual-energy X-ray absorptiometry with total and cause-specific mortality in the National Health and Nutrition Examination Survey (NHANES) 1999-2006 were investigated.

METHODS

This study included 9,471 participants (≥20 years) free of major chronic diseases at baseline. Death information was obtained from the National Death Index (mean follow-up duration: 8.8 years).

RESULTS

A total of 682 participants died after 12 months since baseline, with 206 and 170 deaths attributed to cardiovascular diseases (CVD) and cancer, respectively. The second quartile of fat mass percentages (FM%) was used as the reference to account for potential nonlinearity. In the multivariate-adjusted model, participants in the highest quartile of total FM% had increased total mortality; hazard ratio (HR; 95% confidence interval, 95% CI) was 1.48 (1.07-2.04; P < 0.05). Higher total and trunk FM%, but not leg FM%, were significantly associated with an increased CVD mortality; HRs (95% CIs) in the highest quartiles of total, trunk, and leg FM% were 2.24 (1.17-4.31), 1.93 (1.02-3.66), and 1.50 (0.77-2.94), respectively.

CONCLUSIONS

Higher total body fat was associated with increased total mortality in U.S. adults. Higher total and trunk fat contents were also associated with increased CVD mortality, although fat accumulation in the lower body was not an independent predictor of mortality.

Associations of Different Adipose Tissue Depots with Insulin Resistance: A Systematic Review and Meta-analysis of Observational Studies

Fat distribution is strongly associated with insulin resistance, a risk factor for type 2 diabetes and cardiovascular diseases. However, associations of different adipose tissue depots or/and obesity indices with insulin resistance have not been systematically evaluated. In this study we examined associations of different adipose tissue depots/obesity indices with insulin resistance, as measured by homeostatic model assessment of insulin resistance (HOMA-IR) in observational studies. A total of 40 studies with 56 populations and 29 adipose tissue depots/obesity indices were included in the meta-analysis. There were strong correlation between HOMA-IR and visceral fat mass (r = 0.570, 95% confidence interval(CI): 0.424~0.687), total fat mass (r = 0.492, 95%CI: 0.407~0.570), body mass index (r = 0.482, 95%CI: 0.445~0.518) and waist circumference (r = 0.466, 95%CI: 0.432~0.500), except lower extremity fat (r = 0.088, 95%CI: -0.116~0.285). Sample size, diabetic status, gender, mean of body mass index, and race contributed to heterogeneity of these associations. This study showed a positive correlation between insulin resistance and most adipose tissue depots/obesity indices, and the strongest association is for visceral fat mass.

Correlation between waist and mid-thigh circumference and cardiovascular fitness in Korean college students: a case study

[Purpose] We investigated whether waist and mid-thigh circumference correlated with cardiovascular fitness (VO₂max) in a selected sample of Korean college students. [Subjects and Methods] The subjects were 41 college students (25 males, 16 females; age, > 19 years) who visited the sports medicine laboratory at the Korea National University of Transportation in Chungju-si, Republic of Korea, to undergo measurements of body composition, cardiovascular fitness, and waist and mid-thigh circumference. [Results] VO₂max did not correlate with waist circumference or mid-thigh circumference in males, whereas VO₂max was negatively correlated with mid-thigh circumference, but not waist circumference, in females. [Conclusion] Mid-thigh circumference was not associated with cardiovascular fitness or waist in male college students. However, it was associated with cardiovascular fitness in female college students. Well-designed studies are needed to investigate this further.

Impact of body composition during weight change on resting energy expenditure and homeostasis model assessment index in overweight nonsmoking adults

BACKGROUND

Weight change affects resting energy expenditure (REE) and metabolic risk factors. The impact of changes in individual body components on metabolism is unclear.

OBJECTIVE

We investigated changes in detailed body composition to assess their impacts on REE and insulin resistance.

DESIGN

Eighty-three healthy subjects [body mass index (BMI; in kg/m²) range: 20.2-46.8; 50% obese] were investigated at 2 occasions with weight changes between -11.2 and +6.5 kg (follow-up periods between 23.5 and 43.5 mo). Detailed body composition was measured by using the 4-component model and whole-body magnetic resonance imaging. REE, plasma thyroid hormone concentrations, and insulin resistance were measured by using standard methods.

RESULTS

Weight loss was associated with decreases in fat mass (FM) and fat-free mass (FFM) by 72.0% and 28.0%, respectively. A total of 87.9% of weight gain was attributed to FM. With weight loss, sizes of skeletal muscle, kidneys, heart, and all fat depots decreased. With weight gain, skeletal muscle, liver, kidney masses, and several adipose tissue depots increased except for visceral adipose tissue (VAT). After adjustments for FM and FFM, REE decreased with weight loss (by 0.22 MJ/d) and increased with weight gain (by 0.11 MJ/d). In a multiple stepwise regression analysis, changes in skeletal muscle, plasma triiodothyronine, and kidney masses explained 34.9%, 5.3%, and 4.5%, respectively, of the variance in changes in REE. A reduction in subcutaneous adipose tissue rather than VAT was associated with the improvement of insulin sensitivity with weight loss. Weight gain had no effect on insulin resistance.

CONCLUSION

Beyond a 2-compartment model, detailed changes in organ and tissue masses further add to explain changes in REE and insulin resistance.

Abdominal adiposity distribution in diabetic/prediabetic and nondiabetic populations: a meta-analysis

Excess fat in the abdomen can be classified generally as visceral and subcutaneous adiposity. Evidence suggests that visceral adiposity has greater implications for diabetes than other fat depots. The purpose of this study is to explore the disparities in the distribution of abdominal adiposity in diabetic/prediabetic and nondiabetic populations and to identify moderators that influence the pattern of central obesity via a meta-analysis technique. The Hedges' g was used as a measure of effect size and 95% confidence interval was computed. A total of 41 relevant studies with 101 effect sizes were retrieved. Pooled effect sizes for visceral and subcutaneous adiposity were 0.69 and 0.42, respectively. Diabetic/prediabetic populations exhibited greater visceral and subcutaneous adiposity compared to nondiabetic populations (Z = 10.35, P < 0.05). Significant moderator effects of gender (Z = -2.90) and assessment method of abdominal adiposity (Z = -2.17) were found for visceral fat (P < 0.05), but not for subcutaneous fat. Type of health condition influenced both visceral (Z = -5.10) and subcutaneous (Z = -7.09) abdominal adiposity volumes (P < 0.05). Abdominal adiposity distributions were significantly altered in the diabetic/prediabetic population compared to the nondiabetic population. Gender, assessment method of abdominal adiposity, and type of health conditions (diabetic/prediabetics) were identified as crucial moderators that influence the degree of abdominal adiposity.

Associations of leg fat accumulation with adiposity-related biological factors and risk of metabolic syndrome

OBJECTIVE

To examine associations between regional fat mass (FM) distribution and cardiometabolic risk factors among ethnic minority groups, such as non-Hispanic blacks and Hispanics.

DESIGN AND METHODS

The associations among 8,802 US residents who participated in the 1999-2004 US National Health and Nutrition Examination Survey were examined. Body composition was measured using dual-energy X-ray absorptiometry. Leg fat indices included leg FM, leg FM percent (FM%), leg to whole body FM ratio (leg/whole), and leg to trunk FM ratio (leg/trunk). The correlation between leg fat indices and adiposity-related risk factors, as well as the association of these indices with metabolic syndrome (MetS) was evaluated.

RESULTS

After adjusting for covariates including age, gender, and trunk FM or trunk FM%, higher leg FM and leg FM% were, in general, correlated favorably with adiposity-related risk factors and associated with lower odds of MetS in all ethnicities, including non-Hispanic whites and blacks and Hispanic groups. In addition, in all multivariate-adjusted models, leg/whole and leg/trunk ratios were strongly associated with lower levels of most risk factors and decreased odds of MetS in these ethnicities (all odds ratios comparing extreme quintiles < 0.1).

CONCLUSIONS

Results show that leg fat accumulation is inversely associated with adiposity-related biological factors and risk of MetS in both whites and ethnic groups, suggesting that regional fat distribution plays an important role in the etiology of adiposity-related diseases in these populations.

Intrauterine protein restriction combined with early postnatal overfeeding was not associated with adult-onset obesity but produced glucose intolerance by pancreatic dysfunction

We investigated if whether intrauterine protein restriction in combination with overfeeding during lactation would cause adult-onset obesity and metabolic disorders. After birth, litters from dams fed with control (17% protein) and low protein (6% protein) diets were adjusted to a size of four (CO and LO groups, respectively) or eight (CC and LC groups, respectively) pups. All of the offspring were fed a diet containing 12% protein from the time of weaning until they were 90 d old. Compared to the CC and LC groups, the CO and LO groups had higher relative and absolute food intakes, oxygen consumption and carbon dioxide production; lower brown adipose tissue weight and lipid content and greater weight gain and absolute and relative white adipose tissue weight and absolute lipid content. Compared with the CO and CC rats, the LC and LO rats exhibited higher relative food intake, brown adipose tissue weight and lipid content, reduced oxygen consumption, carbon dioxide production and spontaneous activity, increased relative retroperitoneal adipose tissue weight and unaltered absolute white adipose tissue weight and lipid content. The fasting serum glucose was similar among the groups. The area under the glucose curve was higher in the LO and CO rats than in the LC and CC rats. The basal insulinemia and homeostasis model assessment of insulin resistance (HOMA-IR) were lower in the LO group than in the other groups. The total area under the insulin curve for the LO rats was similar to the CC rats, and both were lower than the CO and LC rats. K_itt was higher in the LO, LC and CO groups than in the CC group. Thus, intrauterine protein restriction followed by overfeeding during lactation did not induce obesity, but produced glucose intolerance by impairing pancreatic function in adulthood.

Relation of absolute or relative adiposity to insulin resistance, retinol binding protein-4, leptin, and adiponectin in type 2 diabetes

BACKGROUND

Central fat mass (CFM) correlates with insulin resistance and increases the risk of type 2 diabetes and cardiovascular complications; however, peripheral fat mass (PFM) is associated with insulin sensitivity. The aim of this study was to investigate the relation of absolute and relative regional adiposity to insulin resistance index and adipokines in type 2 diabetes.

METHODS

Total of 83 overweighted-Korean women with type 2 diabetes were enrolled, and rate constants for plasma glucose disappearance (K(ITT)) and serum adipokines, such as retinol binding protein-4 (RBP4), leptin, and adiponectin, were measured. Using dual X-ray absorptiometry, trunk fat mass (in kilograms) was defined as CFM, sum of fat mass on the lower extremities (in kilograms) as PFM, and sum of CFM and PFM as total fat mass (TFM). PFM/TFM ratio, CFM/TFM ratio, and PFM/CFM ratio were defined as relative adiposity.

RESULTS

Median age was 55.9 years, mean body mass index 27.2 kg/m(2), and mean HbA1c level 7.12±0.84%. K(ITT) was positively associated with PMF/TFM ratio, PMF/CFM ratio, and negatively with CFM/TFM ratio, but was not associated with TFM, PFM, or CFM. RBP4 levels also had a significant relationship with PMF/TFM ratio and PMF/CFM ratio. Adiponectin, leptin, and apolipoprotein A levels were related to absolute adiposity, while only adiponectin to relative adiposity. In correlation analysis, K(ITT) in type 2 diabetes was positively related with HbA1c, fasting glucose, RBP4, and free fatty acid.

CONCLUSION

These results suggest that increased relative amount of peripheral fat mass may aggravate insulin resistance in type 2 diabetes.

Body composition at 6 months of life: comparison of air displacement plethysmography and dual-energy X-ray absorptiometry

Body composition assessment during infancy is important because it is a critical period for obesity risk development, thus valid tools are needed to accurately, precisely, and quickly determine both fat and fat-free mass. The purpose of this study was to compare body composition estimates using dual-energy x-ray absorptiometry (DXA) and air displacement plethysmography (ADP) at 6 months old. We assessed the agreement between whole body composition using DXA and ADP in 84 full-term average-for-gestational-age boys and girls using DXA (Lunar iDXA v11-30.062; Infant whole body analysis enCore 2007 software, GE, Fairfield, CT) and ADP (Infant Body Composition System v3.1.0, COSMED USA, Concord, CA). Although the correlations between DXA and ADP for %fat (r = 0.925), absolute fat mass (r = 0.969), and absolute fat-free mass (r = 0.945) were all significant, body composition estimates by DXA were greater for both %fat (31.1 ± 3.6% vs. 26.7 ± 4.7%; P < 0.001) and absolute fat mass (2,284 ± 449 vs. 1,921 ± 492 g; P < 0.001), and lower for fat-free mass (5,022 ± 532 vs. 5,188 ± 508 g; P < 0.001) vs. ADP. Inter-method differences in %fat decreased with increasing adiposity and differences in fat-free mass decreased with increasing infant age. Estimates of body composition determined by DXA and ADP at 6 months of age were highly correlated, but did differ significantly. Additional work is required to identify the technical basis for these rather large inter-method differences in infant body composition.

Association of epicardial fat thickness with the severity of obstructive sleep apnea in obese patients

BACKGROUND

The correlation between obesity and severity of obstructive sleep apnea (OSA) is controversial. Although fat excess is a predisposing factor for the development of OSA, it has not been determined whether fat distribution rather than obesity per se is associated with OSA severity. Epicardial fat thickness (EFT) is an independent index of visceral adiposity and cardiometabolic risk. We investigated the relation between fat distribution and cardiometabolic risk factors, including EFT and common carotid intima-media thickness (cIMT), with the severity of OSA in obese patients.

METHODS

One hundred and fifteen obese patients (56 males, 59 females) with polysomnographic evidence of OSA (≥ 5 apnea/hypopnea events per hour) of various degrees, without significant differences in grade of obesity as defined by body mass index (BMI), were evaluated. The following parameters were measured: BMI, body composition by dual energy X-ray absorptiometry, EFT, right ventricular end-diastolic diameter (RVEDD) and cIMT by ultrasound, and parameters of metabolic syndrome (waist circumference, arterial blood pressure, fasting glucose, HDL-cholesterol and triglycerides).

RESULTS

EFT, RVEDD, cIMT and trunk/leg fat mass ratio showed a positive correlation with OSA severity in univariate analysis (r=0.536, p<0.001; r=0.480, p<0.001; r=0.345, p<0.001; r=0.330, p<0.001, respectively). However, multiple linear regression analysis showed that EFT was the most significant independent correlate of the severity of OSA (R(2)=0.376, p=0.022).

CONCLUSIONS

The present study suggests that, in obese patients, EFT may be included among the clinical parameters associating with OSA severity. The association of EFT with OSA, both cardiovascular risk factors, is independent of obesity as defined by classical measures.

Lower extremity fat mass is associated with insulin resistance in overweight and obese individuals: the CARDIA study

Lower extremity fat mass (LEFM) has been shown to be favorably associated with glucose metabolism. However, it is not clear whether this relationship is similar across varying levels of obesity. We hypothesized that lower amounts of LEFM is associated with higher insulin resistance (IR) and this association may vary according to weight status. Participants with available measures were examined from the Coronary Artery Risk Development in Young Adults study (CARDIA), a multi-center longitudinal study of the etiology of atherosclerosis in black and white men and women aged 38-50 years old in 2005-2006 (n = 1,579). The homeostasis model assessment of IR (HOMA(IR)) was calculated to estimate IR, regional adiposity was measured using dual energy X-ray absorptiometry (DXA), and weight status was defined according to BMI categories. Obese and overweight participants exhibited higher IR, total fat mass (FM), trunk FM (TFM), and LEFM compared to normal weight participants. After controlling for age, height, race, study center, education, smoking, and cardiorespiratory fitness (CRF), greater LEFM was significantly associated with higher IR only in normal weight men and women. Further adjustment for TFM revealed that lower LEFM was significantly associated with higher IR in overweight and obese men and women and the positive association in normal weight individuals was attenuated. These results suggest that excess adiposity in the lower extremities may attenuate the metabolic risk observed at a given level of abdominal adiposity in overweight and obese individuals. Weight status presents additional complexity since the metabolic influence of adipose tissue may not be homogenous across anatomic regions or level of obesity.

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.

Subcutaneous thigh fat area is unrelated to risk of type 2 diabetes in a prospective study of Japanese Americans

AIMS/HYPOTHESIS

Cross-sectional research has reported a negative association between subcutaneous thigh fat (STF) and type 2 diabetes prevalence but no prospective research on this association exists using direct measurements of STF obtained from imaging studies while adjusting for other fat depots. We studied the independent associations of intra-abdominal fat (IAF), subcutaneous abdominal fat (SAF) and STF with future risk of diabetes.

METHODS

We prospectively followed 489 non-diabetic Japanese Americans (BMI 25.0-29.9 kg/m(2) 32.7%, ≥30.0 kg/m(2) 5.4%) over 10 years for the development of diabetes defined by use of hypoglycaemic medication or a fasting plasma glucose ≥7.0 mmol/l or 2 h ≥11.1 mmol/l during an OGTT. STF, SAF and IAF area were measured by computed tomography scan and mid-thigh circumference (TC) by tape measure at baseline.

RESULTS

Over 10 years, 103 people developed diabetes. STF area was not independently associated with the odds of developing diabetes in a univariate or multiple logistic regression model (OR for a 1 SD increase 0.8 [95% CI 0.5, 1.2]) adjusted for age, sex, BMI, IAF and SAF. The only fat depot associated with diabetes odds in this model was IAF. TC was borderline significantly associated with a lower odds of developing diabetes (0.7 [95% CI 0.5, 1.0], p = 0.052).

CONCLUSIONS/INTERPRETATION

Similar to other research, TC was negatively associated with diabetes risk, whereas STF was not, arguing that the negative association between TC and diabetes observed in other research is not due to STF mass. IAF area emerged as the only measured fat depot that was independently associated with type 2 diabetes risk.

Regional adiposity distribution and insulin resistance in young Chinese and European Australian women

OBJECTIVE

Lower than normal leg fat mass and excessive trunk fat mass are predictive of insulin resistance (IR) in obese women of European descent. Whether this regional adiposity relationship applies to moderately overweight women of Chinese descent is undetermined. Thus, the relationship between leg and trunk fat mass and IR of young (22.3 ± 0.3 years) sedentary Australian women of either Chinese (CW; n = 22) or European (EW; n = 36) descent was examined.

MATERIAL AND METHODS

Subjects underwent a maximal oxygen uptake test, blood draw, and dual energy x-ray absorptiometry to measure body composition. Fasting insulin levels and C-reactive protein (CRP) were assessed by ELISA and IR was calculated by HOMA-IR. Blood lipids and glucose were quantified by an automated enzymatic method (Cholestech LDX, USA).

RESULTS

Total, arm, trunk, and leg fat was significantly greater (p < 0.05) for the EW group, whereas IR was significantly higher for CW. Fasting lipids and glucose were within normal levels for both groups, whereas CRP levels were significantly higher in EW. For EW trunk fat mass was the only variable significantly correlated with IR (r = 0.40, p < 0.05). In contrast, for CW leg fat mass was significantly correlated with IR (r = − 0.49, p < 0.05).

CONCLUSIONS

Greater trunk fat mass was associated with higher IR of Australian women of European descent, whereas smaller leg fat mass was associated with higher IR of women of Chinese descent.

Effect of loss of regional fat assessed by DXA on insulin resistance and dyslipidaemia in obese men

OBJECTIVE

To investigate the impact of reduction in total fat mass (FM) and regional FMs on indices of insulin resistance and dyslipidaemia in obese men (BMI > 30 kg/m²) after a 1-year weight loss (WL), and secondly, to examine the potential predictive effect of baseline insulin resistance on reduction in total and regional FMs.

MATERIAL AND METHODS

In nine men with WL > 4 kg, body composition by DXA (dual X-ray absorptiometry) and indices of insulin resistance were assessed: fasting insulin, C-Peptide and HOMA-IR. Insulin sensitivity (QUICKI) and serum lipids were also assessed.

RESULTS

Mean WL was 10.8%; Δ trunk and Δ leg FM were reduced by 30.1% and 21.3%, respectively, increasing leg/trunk FM ratio by 13.2%. Improvement in HOMA-IR was 63.1%, insulin 59.1%, and in QUICKI 17.4%. Loss of total FM, trunk FM, and increase in leg/trunk FM ratio were correlated with improvement in HOMA-IR (p < 0.001-0.05). Linear regression analysis of ln-transformed improvements in HOMA-IR was non-significantly related with losses of trunk FM and increases in leg/trunk FM ratio (p = 0.06). Multivariate analysis suggested improvements in fasting insulin and C-Peptide could be explained by leg/trunk FM ratio (R² = 0.60, p = 0.013, R² = 0.37, p = 0.012, respectively) and in HOMA-IR by trunk FM (R² = 0.42, p = 0.06). The loss of FM and change in FM distribution had no effect on serum lipids.

CONCLUSION

Both loss of trunk FM and increase in leg/trunk FM ratio assessed by DXA contribute to the improvement in insulin resistance.

Regional adiposity and risk for coronary artery disease in type 1 diabetes: does having greater amounts of gluteal-femoral adiposity lower the risk?

AIMS

Evidence suggests that the degree of gluteal-femoral adiposity may be inversely associated with coronary artery disease (CAD) risk; however, this association has not been evaluated in type 1 diabetes (T1D).

METHODS

The relationship between regional adiposity, cardiovascular risk factors, and presence of CAD was examined in participants from the Pittsburgh Epidemiology of Diabetes Complications (EDC) study using data collected from the 18-year exam (n=163). Total and regional adiposity was assessed by dual X-ray absorptiometry (DEXA).

RESULTS

Participants with CAD exhibited lower % leg fat mass (FM) (33.42 vs. 36.96, p=0.006) and higher % trunk FM (48.33 vs. 45.18, p=0.02), respectively, after adjusting for age, sex, height, and total adiposity compared to those without CAD. Multivariate logistic regression analyses revealed that in females, every 1 SD increase in % leg FM was associated with an approximate 60% reduction in CAD risk (OR=0.40, 95% CI 0.16-0.99). Higher % trunk FM was also associated with greater risk of CAD prevalence in females (OR=2.79, 95% CI 1.08-7.20 per SD change). These associations were not observed in males.

CONCLUSIONS

This is novel evidence that DEXA-assessed lower body adiposity is inversely associated with CAD in T1D, however, this association seems to only exist in females.

Effect of regional fat loss assessed by DXA on insulin resistance and dyslipidaemia in obese women

OBJECTIVE

To investigate the impact of reduction in total fat mass (FM) and regional FMs on indices of insulin resistance and dyslipidaemia in obese women (BMI > 30 kg/m(2)) after a 1-year weight loss (WL) program; and, secondly, to investigate the potential predictive effect of baseline insulin resistance on reduction in total and regional FMs.

MATERIAL AND METHODS

In 35 women with > 4 kg weight loss, body composition by DXA (dual X-ray absorptiometry), fasting insulin, C-Peptide, insulin resistance (HOMA-IR), insulin sensitivity (QUICKI), metabolic clearance rate (MCRestOGTT) and serum lipids were assessed.

RESULTS

Mean WL was 9.6%; trunk and leg FM were reduced proportionally (14.9-14.7%). Improvement in HOMA-IR was 34.7%, insulin 30.7%, QUICKI 8.6% and MCRest OGTT 74%. The reduction in total, trunk and leg FM were similarly correlated with improvement in indices of insulin resistance (p < 0.001-0.05) and also with initial HOMA-IR (p = 0.000-0.02). In linear regressions improvement in HOMA-IR was similarly related with these FMs (p = 0.008), and initial HOMA predicted loss of trunk FM (p = 0.01). In multivariate analysis improvement in HOMA-IR was explained by loss of total FM (R(2) = 0.20, p = 0.004); improvement of QUICKI by loss of leg FM (R(2) = 0.33, p < 0.001).

CONCLUSION

Loss of leg FM and trunk FM had similar importance for the improvement in insulin resistance. Baseline HOMA-IR predicted the potential for reduction in trunk FM.

Leg fat mass as measured by dual X-ray absorptiometry (DXA) impacts insulin resistance differently in obese women versus men

OBJECTIVE

To investigate the association between regional fat mass (FM) and insulin resistance and dyslipidaemia in obese women and men.

MATERIAL AND METHODS

Body composition was measured by dual-energy X-ray absorptiometry (DXA) in 109 obese women and 113 obese men. Insulin resistance was measured by (HOMA-IR); insulin sensitivity was estimated by metabolic clearance rate (MCRestOGTT) and insulin secretion by HOMAsecr. Serum lipids were assessed.

RESULTS

In women, leg FM was negatively (favourably) associated with HOMA-IR and cholesterol/HDL-cholesterol ratio (p<0.05). Trunk FM was positively (unfavourably) associated with HOMA-IR. Leg/trunk FM ratio was negatively associated with HOMA-IR (p<0.001), cholesterol/HDL-cholesterol ratio (p<0.001) and triglycerides (p<0.01); positively (favourably) with MCRestOGTT (p<0.01) and HDL-cholesterol (p<0.05). No associations were found in men. In women, multiple regression analysis demonstrated that leg/trunk FM ratio was the only explanatory FM for HOMA-IR and MCRestOGTT (R(2) = 0.23 and R(2) = 0.13, respectively; p<0.001), but postmenopausal status was also of importance (R(2) = 0.23, p = 0.019 and R(2) = 0.29, p = 0.015, respectively).

CONCLUSIONS

Leg FM has a favourable influence on insulin resistance and dyslipidaemia in obese women, but not demonstrated in this cohort of obese men.