Effect of Changes in Fat Distribution on the Rates of Change of Insulin Response in Children

Objective: To develop mixed models for examining longitudinal associations between rates of change in visceral, subcutaneous abdominal, and total body fat with rates of change in fasting insulin (FI) and insulin sensitivity (SI) over 3 years in children. Research Methods and Procedures: Seventy-seven children (mean age, 8.3 years at baseline) from Birmingham, Alabama, with three or more annual measures of FI and SI were included. Abdominal fat was measured by computed tomography, and total body fat and lean tissue mass were measured by DXA. Mixed models examined the longitudinal associations between the baseline level/rate of change of different fat compartments and the rate of change in FI or SI. Results: An annual increase of ∼5% in FI was associated with 1 cm²/yr of visceral fat gain per year (p < 0.05), independent of subcutaneous abdominal fat. A 1-cm² difference in initial subcutaneous abdominal fat was associated with an ∼0.2% increase per year in FI (p < 0.02), independent of visceral fat. None of the rates of change in any of the fat measures was associated with the rate of change of SI. Discussion: The rate of change in visceral fat was positively associated with the rate of change in FI, independent of increasing subcutaneous abdominal fat; however, subcutaneous abdominal fat may be more predictive of the rate of change of FI than visceral or total fat. Therefore, growth-related increases in abdominal fat, particularly subcutaneous abdominal fat, may contribute to accelerating increases in FI, but have no effect on SI.     

Higher Free Fatty Acid Uptake in Visceral Than in Abdominal Subcutaneous Fat Tissue in Men

Visceral adipose tissue has been shown to have high lipolytic activity. The aim of this study was to examine whether free fatty acid (FFA) uptake into visceral adipose tissue is enhanced compared to abdominal subcutaneous tissue in vivo. Abdominal adipose tissue FFA uptake was measured using positron emission tomography (PET) and [¹⁸F]‐labeled 6‐thia‐hepta‐decanoic acid ([¹⁸F]FTHA) and fat masses using magnetic resonance imaging (MRI) in 18 healthy young adult males. We found that FFA uptake was 30% higher in visceral compared to subcutaneous adipose tissue (0.0025 ± 0.0018 vs. 0.0020 ± 0.0016 µmol/g/min, P = 0.005). Visceral and subcutaneous adipose tissue FFA uptakes were strongly associated with each other (P < 0.001). When tissue FFA uptake per gram of fat was multiplied by the total tissue mass, total FFA uptake was almost 1.5 times higher in abdominal subcutaneous than in visceral adipose tissue. In conclusion, we observed enhanced FFA uptake in visceral compared to abdominal subcutaneous adipose tissue and, simultaneously, these metabolic rates were strongly associated with each other. The higher total tissue FFA uptake in subcutaneous than in visceral adipose tissue indicates that although visceral fat is active in extracting FFA, its overall contribution to systemic metabolism is limited in healthy lean males. Our results indicate that subcutaneous, rather than visceral fat storage plays a more direct role in systemic FFA availability. The recognized relationship between abdominal visceral fat mass and metabolic complications may be explained by direct effects of visceral fat on the liver.     

Relationships between Dietary Fat,Body Fat,and Serum Lipid Profile in Prepubertal Children

KU, CHING YI, BARBARA A. GOWER, TIM R. NAGY, MICHAEL I. GORAN. Relationships between dietary fat, body fat, and serum lipid profile in prepubertal children. Obes Res. 1998;6:400–407. Objective : The purpose of the study was to test the hypothesis that dietary fat components were associated with the serum lipid profile independent of ethnicity, body fat, and fat distribution in prepubertal children. Research Methods and Procedures : Sixty-six children (45 African American and 21 Caucasian), aged from 4 to 10 years, were recruited into the study. Dietary total fat, saturated fat, monounsaturated fat, and polyunsaturated fat were estimated by averaging two 24-hour diet recalls. Fasting serum triacylglycerol, total cholesterol, and high-density lipoprotein cholesterol were analyzed, and low-density lipoprotein cholesterol (LDL-C) was calculated by the method of Friedewald. Body composition and fat distribution were measured by dual energy X-ray absorptiometry and computed tomography. Results : Children in both ethnic groups tended to overreport their dietary intake relative to total energy expenditure by 18%. African American children consumed more energy from total fat (35.3% vs. 31.5%, p<0.05), saturated fat (13.7% vs 12.2%, p<0.05), protein (16.4% vs. 13.2%, p = 0.02), and less from carbohydrate (48% vs. 57.1%, p<0.01) than Caucasian children. There was no significant correlation between dietary fat and either serum lipids or body fat indices after adjusting for nonfat energy intake and total lean tissue mass. Total body fat (r = 0.32), subcutaneous abdominal adipose tissue (r = 0.39), and intraabdominal adipose tissue (r = 0.42) were positively related to serum triacylglycerol; these associations remained significant in a multiple linear regression model in which body fat indices were adjusted for ethnicity, total lean tissue, dietary total fat, and nonfat intake. Discussion : Our results do not support a link between dietary fat and serum lipids; instead, our data suggest that body fat may play a more important role than dietary fat in the course of cardiovascular disease development in prepubertal children.     

Visceral Fat Accumulation as a Risk Factor for Prostate Cancer

Objective: No clear association between obesity or body fat distribution and prostate cancer has been shown. We investigated the relation between visceral fat accumulation as measured by computed tomography (CT) and the occurrence of prostate cancer. Research Methods and Procedures: We compared body fat distribution assessed by a direct method (CT) in 63 prostate cancer cases with 63 age‐matched healthy community controls. A CT scan at the level of the fourth lumbar vertebra was performed in all participants. Results: Patients presented a significantly higher mean total abdominal fat area (509.2 ± 226.1 vs. 334.3 ± 132.9 cm², p < 0.001), mostly because of a higher mean visceral fat area (VF; 324.7 ± 145.6 vs. 177.4 ± 88.4 cm², p < 0.001) and a significantly higher mean ratio between visceral and subcutaneous fat areas (V/S ratio; 1.8 ± 0.4 vs. 1.2 ± 0.4, p < 0.001). A significantly higher risk of prostate cancer was found for participants with higher VF (odds ratio = 4.6; 95% confidence interval = 2.6 to 8.2 per SD increase) and V/S ratio (odds ratio = 6.0; 95% confidence interval = 2.3 to 11.0 per SD increase). Discussion: These results suggest a role for visceral obesity, quantified by CT, as a risk factor for prostate cancer. The action of the adipocytokines secreted by visceral fat cells, steroid hormone disturbances, and increased levels of insulin or other hormones noted in visceral obesity may explain this association.     

A 12‐Week Aerobic Exercise Program Reduces Hepatic Fat Accumulation and Insulin Resistance in Obese,Hispanic Adolescents

The rise in obesity‐related morbidity in children and adolescents requires urgent prevention and treatment strategies. Currently, only limited data are available on the effects of exercise programs on insulin resistance, and visceral, hepatic, and intramyocellular fat accumulation. We hypothesized that a 12‐week controlled aerobic exercise program without weight loss reduces visceral, hepatic, and intramyocellular fat content and decreases insulin resistance in sedentary Hispanic adolescents. Twenty‐nine postpubertal (Tanner stage IV and V), Hispanic adolescents, 15 obese (7 boys, 8 girls; 15.6 ± 0.4 years; 33.7 ± 1.1 kg/m²; 38.3 ± 1.5% body fat) and 14 lean (10 boys, 4 girls; 15.1 ± 0.3 years; 20.6 ± 0.8 kg/m²; 18.9 ± 1.5% body fat), completed a 12‐week aerobic exercise program (4 × 30 min/week at ≥70% of peak oxygen consumption (VO₂peak)). Measurements of cardiovascular fitness, visceral, hepatic, and intramyocellular fat content (magnetic resonance imaging (MRI)/magnetic resonance spectroscopy (MRS)), and insulin resistance were obtained at baseline and postexercise. In both groups, fitness increased (obese: 13 ± 2%, lean: 16 ± 4%; both P < 0.01). In obese participants, intramyocellular fat remained unchanged, whereas hepatic fat content decreased from 8.9 ± 3.2 to 5.6 ± 1.8%; P < 0.05 and visceral fat content from 54.7 ± 6.0 to 49.6 ± 5.5 cm²; P < 0.05. Insulin resistance decreased indicated by decreased fasting insulin (21.8 ± 2.7 to 18.2 ± 2.4 µU/ml; P < 0.01) and homeostasis model assessment of insulin resistance (HOMA_IR) (4.9 ± 0.7 to 4.1 ± 0.6; P < 0.01). The decrease in visceral fat correlated with the decrease in fasting insulin (R² = 0.40; P < 0.05). No significant changes were observed in any parameter in lean participants except a small increase in lean body mass (LBM). Thus, a controlled aerobic exercise program, without weight loss, reduced hepatic and visceral fat accumulation, and decreased insulin resistance in obese adolescents.     

Influence of Total vs. Visceral Fat on Insulin Action and Secretion in African American and White Children

Objective: To examine whether total body fat (FAT) in general or visceral fat (VFAT) in particular is associated with greater metabolic risk in white and African American children. Research Methods and Procedures: A total of 68 white and 51 African American children had measures of insulin sensitivity (Si) and acute insulin response (AIR) by a frequently sampled intravenous glucose tolerance test, total body fat by DXA and abdominal fat distribution (visceral vs. subcutaneous) by computed tomography. The influence of FAT and VFAT on insulin parameters were examined by comparing subgroups of children with high or low FAT vs. high or low VFAT and by multiple regression analysis. Results: In whites, fasting insulin, Si, and AIR were significantly influenced by FAT, but not VFAT (e.g., for Si, 9.8 ± 0.8 in low FAT vs. 4.6 ± 0.7 × 10^?4/min/[μIU/mL] in high FAT, p < 0.05; 6.8 ± 0.7 in low VFAT vs. 7.5 ± 0.8 × 10^?4/min/[μIU/mL] in high VFAT, p > 0.1). In African Americans, fasting insulin and Si were also primarily influenced by FAT (e.g., for Si, 4.9 ± 0.4 in low FAT vs. 2.8 ± 0.5 × 10^?4/min/[μIU/mL] in high FAT, p < 0.05) but not by VFAT, and there were no significant effects of either fat compartment on AIR. In multiple regression analysis, Si was significantly influenced by FAT (negative effect), ethnicity (lower in African Americans), and gender (lower in females), whereas fasting insulin was significantly influenced by VFAT (positive effect), ethnicity (higher in African Americans), and fat free mass (positive effect). Discussion: Body fat in general is the predominant factor influencing Si, but VFAT may have additional effects on fasting insulin. The lack of major effects of VFAT on Si in children may be explained by lower levels of VFAT or because VFAT affects aspects of whole body insulin action that are not measured by the minimal model.     

Fat Depot‐specific Impact of Visceral Obesity on Adipocyte Adiponectin Release in Women

Our objective was to examine omental and subcutaneous adipocyte adiponectin release in women. We tested the hypothesis that adiponectin release would be reduced to a greater extent in omental than in subcutaneous adipocytes of women with visceral obesity. Omental and subcutaneous adipose tissue samples were obtained from 52 women undergoing abdominal hysterectomies (age: 47.1 ± 4.8 years; BMI: 26.7 ± 4.7 kg/m²). Adipocytes were isolated and their adiponectin release in the medium was measured over 2 h. Measures of body fat accumulation and distribution were obtained using dual‐energy X‐ray absorptiometry and computed tomography, respectively. Adiponectin release by omental and subcutaneous adipocytes was similar in lean individuals; however, in subsamples of obese or visceral obese women, adiponectin release by omental adipocytes was significantly reduced while that of subcutaneous adipocytes was not affected. Omental adipocyte adiponectin release was significantly and negatively correlated with total body fat mass (r = ?0.47, P < 0.01), visceral adipose tissue area (r = ?0.50, P < 0.01), omental adipocyte diameter (r = ?0.43, P < 0.01), triglyceride levels (r = ?0.32, P ≤ 0.05), cholesterol/high‐density lipoprotein (HDL)‐cholesterol (r = ?0.31, P ≤ 0.05), fasting glucose (r = ?0.39, P ≤ 0.01), fasting insulin (r = ?0.36, P ≤ 0.05), homeostasis model assessment index (r = ?0.39, P ≤ 0.01), and positively associated with HDL‐cholesterol concentrations (r = 0.33, P ≤ 0.05). Adiponectin release from subcutaneous cells was not associated with any measure of adiposity, lipid profile, or glucose homeostasis. In conclusion, compared to subcutaneous adipocyte adiponectin release, omental adipocyte adiponectin release is reduced to a greater extent in visceral obese women and better predicts obesity‐associated metabolic abnormalities.     

Fat Distribution and Insulin Sensitivity in Postmenopausal Women: Influence of Hormone Replacement

Objective: To examine cross‐sectionally the influence of hormone replacement therapy (HRT) on the relationship between body composition and insulin sensitivity (Si). Research Methods and Procedures: Subjects were 57 early postmenopausal white women, 33 receiving HRT and 24 controls. Body composition was estimated using DXA and computed tomography scans at the abdomen and mid‐thigh. Si was assessed by a frequently sampled intravenous glucose tolerance test with minimal model analysis. Results: Compared with nonusers, HRT users had lower visceral adipose tissue, fasting serum glucose, and fasting insulin. Total body fat and unadjusted Si did not differ between groups. Visceral adipose tissue mass (VATM) was the only body‐fat compartment significantly associated with Si (r² = 0.43, p < 0.0001) in a model including total‐body fat, upper‐trunk fat, subcutaneous abdominal fat mass, leg fat, and mid‐thigh low‐density lean tissue. Lean body mass was positively correlated with Si among HRT users and tended to be negatively correlated among nonusers. HRT status also affected the relationship between VATM and Si such that, relative to nonusers, HRT users had lower Si across lower VATM levels, but higher Si across higher VATM. Discussion: These results suggest that in postmenopausal women, VATM is uniquely related to Si. HRT affects the relationship between VATM and Si and between lean body mass and Si. These interactions should be considered in future studies.     

Sagittal Diameter Minus Subcutaneous Thickness. An Easy-to-Obtain Parameter That Improves Visceral Fat Prediction

ARMELLINI FABIO, MAURO ZAMBONI, TAMARA HARRIS, ROCCO MICCIOLO, OTTAVIO BOSELLO. Sagittal diameter minus subcutaneous thickness. An easy-to-obtain parameter that improves visceral fat prediction. Two groups of 99 and 98 women were studied to test if correcting sagittal diameter by subtracting the thickness of subcutaneous abdominal adipose tissue improves its degree of association with visceral adipose tissue. The first group (age, 40 ± 14 years; body mass index [BMI], 36 ± 6 kg/m²) was used to calculate the predictive equations for visceral adipose tissue. The second group (age, 43 ± 14 years; BMI, 37 ± 6 kg/m²) was used for cross-validation. Various anthropometric parameters were measured by ultrasound and computed tomography. Correlation coefficients with single-slice visceral adipose tissue area, after sagittal diameter was corrected by subtracting subcutaneous thickness, rose from 0.63 to 0.72 in the first group and from 0.64 to 0.71 in the second group. The standard error of residuals of the regression formula for visceral adipose tissue area was 10% lower with modified sagittal diameter than with sagittal diameter alone. During cross-validation, the standard error of differences was 5% lower with modified sagittal diameter. The visceral adipose tissue estimate was also less biased by the size of the area when sagittal diameter minus subcutaneous thickness was used. Results show that subtracting the thickness of abdominal subcutaneous adipose tissue from sagittal diameter significantly improves the predictive power of sagittal diameter for visceral adipose tissue and could be a useful tool for epidemiological studies.     

Methods of Estimation of Visceral Fat: Advantages of Ultrasonography

Objective: To compare methods for the assessment of visceral fat with computed tomography (CT) and establish cutoffs to define visceral obesity based on such alternative methods. Research Methods and Procedures: One hundred women (50.4 ± 7.7 years; BMI 39.2 ± 5.4 kg/m²) underwent anthropometric evaluation, bioelectrical impedance, DXA, abdominal ultrasonography (US), and CT scan. Results: Waist circumference, waist‐to‐hip ratio (WHR), and US‐determined visceral fat values showed the best correlation coefficients with visceral fat determined by CT (r = 0.55, 0.54, and 0.71, respectively; p < 0.01). Fat mass determined by DXA was inversely correlated with visceral‐to‐subcutaneous‐fat ratio (r = ?0.47, p < 0.01). Bioimpedance‐determined fat mass and skinfolds were correlated with only subcutaneous abdominal fat quantified by CT. Linear regression indicated US visceral‐fat distance and WHR as the main predictors of CT‐determined visceral fat (adjusted r² = 0.51, p < 0.01). A waist measurement of 107 cm (82.7% specificity, 60.6% sensitivity) and WHR of 0.97 (78.8% specificity, 63.8% sensitivity) were chosen as discriminator values corresponding with visceral obesity diagnosed by CT. A value of 6.90 cm for visceral fat US‐determined diagnosed visceral obesity with a specificity of 82.8%, a sensitivity of 69.2%, and a diagnostic concordance of 74% with CT. Discussion: US seemed to be the best alternative method for the assessment of intra‐abdominal fat in obese women. Its diagnostic value could be optimized by an anthropometric measurement. Prospective studies are needed to establish CT and US cutoffs for defining visceral‐fat levels related to elevated cardiovascular risk.     

The effect of pioglitazone and resistance training on body composition in older men and women undergoing hypocaloric weight loss

Age‐related increases in ectopic fat accumulation are associated with greater risk for metabolic and cardiovascular diseases, and physical disability. Reducing skeletal muscle fat and preserving lean tissue are associated with improved physical function in older adults. PPARγ‐agonist treatment decreases abdominal visceral adipose tissue (VAT) and resistance training preserves lean tissue, but their effect on ectopic fat depots in nondiabetic overweight adults is unclear. We examined the influence of pioglitazone and resistance training on body composition in older (65–79 years) nondiabetic overweight/obese men (n = 48, BMI = 32.3 ± 3.8 kg/m²) and women (n = 40, BMI = 33.3 ± 4.9 kg/m²) during weight loss. All participants underwent a 16‐week hypocaloric weight‐loss program and were randomized to receive pioglitazone (30 mg/day) or no pioglitazone with or without resistance training, following a 2 × 2 factorial design. Regional body composition was measured at baseline and follow‐up using computed tomography (CT). Lean mass was measured using dual X‐ray absorptiometry. Men lost 6.6% and women lost 6.5% of initial body mass. The percent of fat loss varied across individual compartments. Men who were given pioglitazone lost more visceral abdominal fat than men who were not given pioglitazone (?1,160 vs. ?647 cm³, P = 0.007). Women who were given pioglitazone lost less thigh subcutaneous fat (?104 vs. ?298 cm³, P = 0.002). Pioglitazone did not affect any other outcomes. Resistance training diminished thigh muscle loss in men and women (resistance training vs. no resistance training men: ?43 vs. ?88 cm³, P = 0.005; women: ?34 vs. ?59 cm³, P = 0.04). In overweight/obese older men undergoing weight loss, pioglitazone increased visceral fat loss and resistance training reduced skeletal muscle loss. Additional studies are needed to clarify the observed gender differences and evaluate how these changes in body composition influence functional status.     

Comparison of Regional Fat Distribution and Health Risk Factors in Middle‐Aged White and African American Women: The Healthy Transitions Study

Objective: Both ethnicity and menopause appear to influence intra‐abdominal fat distribution. This study evaluated intra‐abdominal fat distribution and obesity‐related health risks in perimenopausal white and African American women. Research Methods and Procedures: Baseline data from a longitudinal study of changes in body composition and energy balance during menopause are reported. Healthy women (55 African Americans and 103 whites) who were on no medication and had at least five menstrual cycles in the previous 6 months were recruited. Body composition was assessed by DXA, and visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were assessed by computed tomography scan. SAT was divided into deep and superficial layers demarcated by the fascia superficialis. Results: African American women were slightly younger (46.7 ± 0.2 vs. 47.7 ± 0.2 years, p = 0.002) and fatter (42.4% ± 1.0% vs. 39.4% ± 0.8% body fat, p = 0.02) than white women. In unadjusted data, African Americans had significantly more total abdominal fat and total, deep, and superficial SAT than whites. After adjustment for percent body fat and age, only total and superficial SAT remained significantly higher in African Americans. VAT although slightly less in African American women, did not differ significantly by race. In multiple regression analysis, VAT was the strongest predictor of serum lipids, glucose, and insulin in women of both races, although superficial SAT was significantly associated with fasting glucose in whites. Conclusions: Middle‐aged African American women have larger SAT depots, adjusted for total body fatness, but do not differ from white women with regard to VAT. The complexity of the relationship between abdominal fat and metabolic risk is increased by ethnic differences in such associations.     

Predicting Total Body Fat from Anthropometry in Latino Children

Objective: To develop prediction equations for total body fat specific to Latino children, using demographic and anthropometric measures. Research Methods and Procedures: Ninety‐six Latino children (7 to 13 years old) were studied. Two‐thirds of the sample was randomized into the equation development group; the remainder served as the cross‐validation group. Total body fat was measured by DXA. Measures included weight, height, waist and hip circumferences, and skinfolds (suprailiac, triceps, abdomen, subscapula, thigh, and calf). Results: The previously published equation from Dezenberg et al. did not accurately predict total body fat in Latino children. However, newly developed equations with either body weight alone (intercept ± SE = 1.78 ± 1.53 kg, p > 0.05; slope ± SE = 0.90 ± 0.07, p > 0.05 against slope = 1.0; R² = 0.86), weight plus age and gender (intercept ± SE = 2.28 ± 1.20 kg, p > 0.05; slope ± SE = 0.91 ± 0.05, p > 0.05; against slope = 1.0; R² = 0.92), or weight plus height, gender, Tanner stage, and abdominal skinfold (intercept ± SE = 1.47 ± 1.01 kg, p > 0.05; slope ± SE = 0.93 ± 0.04, p > 0.05; against slope = 1.0, R² = 0.97) predicted total body fat without bias. Discussion: Unique prediction equations of total body fat may be needed for Latino children. Weight, as the single most significant predictor, can be used easily to estimate total body fat in the absence of any additional measures. Including age and gender with weight produces an equally stable prediction equation with increasing precision. Using a combination of demographic and anthropometric measures, we were able to capture 97% of the variance in measured total body fat.     

Insulin Action,Regional Fat,and Myocyte Lipid: Altered Relationships with Increased Adiposity

Objective: Abdominal fat and myocyte triglyceride levels relate negatively to insulin sensitivity, but their interrelationships are inadequately characterized in the overweight. Using recent methods for measuring intramyocyte triglyceride, these relationships were studied in men with a broad range of adiposity. Research Methods and Procedures: Myocyte triglyceride content (¹H‐magnetic resonance spectroscopy of soleus and tibialis anterior muscles and biochemical assessment of vastus lateralis biopsies), regional fat distribution (DXA and abdominal magnetic resonance imaging), serum lipids, insulin action (euglycemic hyperinsulinemic clamp), and substrate oxidation rates (indirect calorimetry) were measured in 39 nondiabetic men (35.1 ± 7.8 years) with a broad range of adiposity (BMI 28.6 ± 4.1 kg/m², range 20.1 to 37.6 kg/m²). Results: Relationships between insulin‐stimulated glucose disposal and regional body fat depots appeared more appropriately described by nonlinear than linear models. When the group was subdivided using median total body fat as the cut‐point, insulin‐stimulated glucose disposal correlated negatively to all regional body fat measures (all p ≤ 0.004), serum triglycerides and free fatty acids (p < 0.02), and both soleus intramyocellular lipid (p = 0.003) and vastus lateralis triglyceride (p = 0.04) in the normal/less overweight group. In contrast, only visceral abdominal fat showed significant negative correlation with insulin‐stimulated glucose disposal in more overweight men (r = ?0.576, p = 0.01), some of whom surprisingly had lower than expected myocyte lipid levels. These findings persisted when the group was subdivided using different cut‐points or measures of adiposity. Discussion: Interrelationships among body fat depots, myocyte triglyceride, serum lipids, and insulin action are generally absent with increased adiposity. However, visceral abdominal fat, which corresponds less closely to total adiposity, remains an important predictor of insulin resistance in men with both normal and increased adiposity.     

Abdominal Visceral Fat is Associated with a BclI Restriction Fragment Length Polymorphism at the Glucocorticoid Receptor Gene Locus

Several investigations have suggested that body fat distribution is influenced by nonpathologic variations in the responsiveness to Cortisol. Genetic variations in the glucocorticoid receptor (GRL) could therefore potentially have an impact on the level of abdominal fat. A restriction fragment length polymorphism (RFLP) has previously been detected with the BelI restriction enzyme in the GRL gene identifying two alleles with fragment lengths of 4.5 and 2.3 kb. This study investigates whether abdominal fat areas measured by computerized tomography (CT) are associated with this polymorphism in 152 middle-aged men and women. The less frequent 4.5-kb allele was found to be associated with a higher abdominal visceral fat (A VF) area independently of total body fat mass (4.5/4.5 vs. 2.3/2.3 kb genotype; men: 190.7 ± 30.1 vs. 150.7 ± 33.3 cm², p=0.04; women: 132.7 ± 37.3 vs. 101.3 ± 34.5 cm², p=0.06). However, the association with AVF was seen only in subjects of the lower tertile of the percent body fat level. In these subjects, the polymorphism was found to account for 41% (p=0.003) and 35% (p=0.007), in men and women, respectively, of the total variance in AVF area. The consistent association between the GRL polymorphism detected with BelI and AVF area suggests that this gene or a locus in linkage disequilibrium with the BelI restriction site may contribute to the accumulation of AVF.     

Assessment of Abdominal Fat Compartments Using DXA in Premenopausal Women From Anorexia Nervosa to Morbid Obesity

Objective: To test a newly developed dual energy X‐ray absorptiometry (DXA) method for abdominal fat depot quantification in subjects with anorexia nervosa (AN), normal weight, and obesity using CT as a gold standard. Design and Methods: 135 premenopausal women (overweight/obese: n = 89, normal‐weight: n = 27, AN: n = 19); abdominal visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and total adipose tissue (TAT) areas determined on CT and DXA. Results: There were strong correlations between DXA and CT measurements of abdominal fat compartments in all groups with the strongest correlation coefficients in the normal‐weight and overweight/obese groups. Correlations of DXA and CT VAT measurements were strongest in the obese group and weakest in the AN group. DXA abdominal fat depots were higher in all groups compared to CT, with the largest % mean difference in the AN group and smallest in the obese group. Conclusion: A new DXA technique is able to assess abdominal fat compartments including VAT in premenopausal women across a large weight spectrum. However, DXA measurements of abdominal fat were higher than CT, and this percent bias was most pronounced in the AN subjects and decreased with increasing weight, suggesting that this technique may be more useful in obese individuals.     

Cardiorespiratory fitness influences the blood pressure response to experimental weight gain

Objective: We tested the hypothesis that with similar weight gain the increase in blood pressure (BP) would be smaller in men with higher cardiorespiratory fitness (HCRF) than in men with lower cardiorespiratory fitness (LCRF). Research Methods and Procedures: Thirteen men (age = 23 ± 1, BMI = 24 ± 1) were overfed by ～1000 kcal/d over ～8 weeks to achieve a 5‐kg weight gain. Resting BP and 24‐hour ambulatory BP, body composition, and fat distribution were measured. Results: Cardiorespiratory fitness (CRF) was higher in the HCRF group compared with the LCRF group (49.9 ± 1.2 vs. 38.1 ± 1.4 mL/kg per minute, p < 0.001). At baseline, body weight was similar in the HCRF and LCRF groups, whereas the HCRF group displayed lower levels of total body fat (13.0 ± 1.7 vs. 16.9 ± 1.3 kg, p = 0.049) and abdominal visceral fat (49 ± 6 vs. 80 ± 14 cm², p = 0.032). Resting BP and 24‐hour ambulatory BP were similar in the two groups at baseline. After weight gain, body weight increased ～5 kg (p < 0.05) in both groups; the changes in body composition and regional fat distribution were similar. As hypothesized, the increases in resting systolic (1 ± 2 vs. 7 ± 2 mm Hg; p = 0.008) and diastolic (?1 ± 4 vs. 5 ± 1 mm Hg; p = 0.005) BP were smaller in the HCRF group. CRF was correlated with the increases in resting systolic (r = ?0.64; p = 0.009) and diastolic BP (r = ?0.80; p < 0.001). Furthermore, the relationship between CRF and BP remained significant after adjusting for the changes in the proportion of total abdominal fat gained as visceral fat. Discussion: These findings suggest that higher levels of CRF are associated with a smaller increase in BP with weight gain, independently of changes in abdominal visceral fat.     

Relationship of Anterior and Posterior Subcutaneous Abdominal Fat to Insulin Sensitivity in Nondiabetic Men

Recent studies from our group reveal that adipose tissue (AT) in the subcutaneous abdominal region is the most important determinant of peripheral and hepatic insulin sensitivity. Because of different anatomic and physiologic characteristics of anterior and posterior subcutaneous abdominal AT, we investigated the relationship of the masses of each compartment, as determined by magnetic resonance imaging, to insulin sensitivity (using euglycemic hyperinsulinemic glucose clamp technique), and other anthropometric variables. Thirty-four healthy men with varying ranges of obesity were recruited for the study. The mass of posterior subcutaneous abdominal AT was ～1.6 times more than that of the anterior compartment, and these masses accounted for 12.9% and 8.2% of the total body fat mass, respectively. All anthropometric variables, including body mass index (BMI), waist-to-hip circumference ratio (WHR), skinfold thicknesses, and intraperitoneal AT mass were more significantly related to the posterior than the anterior subcutaneous abdominal AT mass. Compared to the anterior compartment mass, the posterior compartment mass displayed stronger relationship with insulin-mediated glucose disposal (Rd) (r=-0.44, p=0.009, and r=-0.76, p=0.0001, respectively) as well as with residual hepatic glucose output during the 40 mU.^?2.min-¹ insulin infusion (r=0.39, p=0.02, and r=0.53, p=0.001, respectively). After adjusting for total body fat, the Rd values showed a significant partial correlation with the posterior subcutaneous abdominal AT mass (r=-0.52, p=0.002). To conclude, posterior subcutaneous abdominal AT mass is a more important determinant of peripheral and hepatic insulin sensitivity than the anterior subcutaneous abdominal AT.     

Dietary Calcium Intake Is Associated With Less Gain in Intra‐Abdominal Adipose Tissue Over 1 Year

Calcium intake is reported to enhance weight loss with a preferential loss in trunk fat. Discrepant findings exist as to the effects of calcium intake on longitudinal changes in total fat mass and central fat deposition. Therefore, the purpose of this study was to determine associations between dietary calcium intake and 1‐year change in body composition and fat distribution, specifically intra‐abdominal adipose tissue (IAAT). A total of 119 healthy, premenopausal women were evaluated at baseline and 1 year later. Average dietary calcium was determined via 4‐day food records. Total fat was determined by dual‐energy X‐ray absorptiometry (DXA) and subcutaneous abdominal adipose tissue (SAAT) and IAAT by computed tomography. Over the study period, participants' reported daily calcium and energy intakes were 610.0 ± 229.9 mg and 1,623.1 ± 348.5 kcal, respectively. The mean change in weight, total fat, IAAT, and SAAT was 4.9 ± 4.4 kg, 5.3 ± 4.0 kg, 7.7 ± 19.5 cm², and 49.3 ± 81.1 cm², respectively. Average calcium intake was significantly, inversely associated with 1‐year change in IAAT (standardized β: ?0.23, P < 0.05) after adjusting for confounding variables. For every 100 mg/day of calcium consumed, gain in IAAT was reduced by 2.7 cm². No significant associations were observed for average calcium intake with change in weight, total fat, or SAAT. In conclusion, dietary calcium intake was significantly associated with less gain in IAAT over 1 year in premenopausal women. Further investigation is needed to verify these findings and determine the calcium intake needed to exert beneficial effects on fat distribution.     

Abdominal visceral adiposity influences CD4+ T cell cytokine production in pregnancy

Women with pre-gravid obesity are at risk for pregnancy complications. While the macrophage response of obese pregnant women categorized by body mass index (BMI) has been documented, the relationship between the peripheral CD4⁺ T cell cytokine profile and body fat compartments during pregnancy is unknown. In this study, third trimester peripheral CD4⁺ T cell cytokine profiles were measured in healthy pregnant women [n = 35; pre-pregnancy BMI: 18.5–40]. CD4⁺ T cells were isolated from peripheral blood mononuclear cells and stimulated to examine their capacity to generate cytokines. Between 1 and 3 weeks postpartum, total body fat was determined by dual-energy X-ray absorptiometry and abdominal subcutaneous and visceral fat masses were determined by magnetic resonance imaging. Pearson’s correlation was performed to assess relationships between cytokines and fat mass. Results showed that greater abdominal visceral fat mass was associated with a decrease in stimulated CD4⁺ T cell cytokine expression. IFN-gamma, TNF-alpha, IL-12p70, IL-10 and IL-17A were inversely related to visceral fat mass. Chemokines CCL3 and IL-8 and growth factors G-CSF and FLT-3L were also inversely correlated. Additionally, total body fat mass was inversely correlated with FGF-2 while abdominal subcutaneous fat mass and BMI were unrelated to any CD4⁺ T cell cytokine. In conclusion, lower responsiveness of CD4⁺ T cell cytokines associated with abdominal visceral fat mass is a novel finding late in gestation.