Body mass index and waist circumference independently contribute to the prediction of nonabdominal, abdominal subcutaneous, and visceral fat

BACKGROUND: It is unknown whether the ability of waist circumference (WC) to predict health risk beyond that predicted by body mass index (BMI) alone is explained in part by the ability of WC to identify those with elevated concentrations of total or abdominal fat. OBJECTIVE: We sought to determine whether BMI and WC independently contribute to the prediction of non-abdominal (total fat - abdominal fat), abdominal subcutaneous, and visceral fat. DESIGN: Fat distribution was measured by magnetic resonance imaging in 341 white men and women. Multiple regression analysis was performed to measure whether the combination of BMI and WC explained a greater variance in non-abdominal, abdominal subcutaneous, and visceral fat than did BMI or WC alone. These fat depots were also compared after a subdivision of the cohort into 3 BMI (normal, overweight, and class I obese) and 3 WC (low, intermediate, and high) categories according to the classification system used to identify associations between BMI, WC, and health risk. RESULTS: Independent of age and sex, the combination of BMI and WC explained a greater variance in non-abdominal, abdominal subcutaneous, and visceral fat than did either BMI or WC alone (P < 0.05). For non-abdominal and abdominal subcutaneous fat, BMI was the strongest correlate; thus, by adding BMI to WC, the variance accrued was greater than when WC was added to BMI. However, when WC was added to BMI, the added variance explained for visceral fat was greater than when BMI was added to WC. Furthermore, within each of the 3 BMI categories studied, an increase in the WC category was associated with an increase in visceral fat (P < 0.05). CONCLUSIONS: BMI and WC independently contribute to the prediction of non-abdominal, abdominal subcutaneous, and visceral fat in white men and women. These observations reinforce the importance of using both BMI and WC in clinical practice.     

Pleiotropic relationships between cortisol levels and adiposity: The HERITAGE Family Study

OBJECTIVE: To investigate familial basis for the relationship between cortisol adiposity at baseline and their training responses. RESEARCH METHODS AND PROCEDURES: Bivariate correlation and segregation analyses were employed between cortisol and several adiposity measures [body mass index, fat mass (FM), fat-free mass, percentage of body fat (% BF), abdominal visceral fat (AVF), abdominal subcutaneous fat (ASF), and abdominal total fat (ATF)] from 99 white families and 105 black families. RESULTS: In both races, significant inverse phenotypic correlations were generally observed between cortisol and adiposity measures at baseline but not for training responses. Significant cross-trait familial correlations were found for cortisol with abdominal fat (ASF, AVF, ATF) and overall body adiposity (FM, % BF) measures at baseline, which accounted for 14% to 20% of the phenotypic variance in whites. The cross-trait correlations were not significant for baseline phenotypes in blacks, perhaps because of the small sample size. A bivariate segregation analysis showed evidence of polygenic pleiotropy for cortisol with both abdominal fat and overall adiposity measures that accounted for 14% to 17% of the phenotypic covariance, but major gene pleiotropy was not suggested in whites. However, when ASF, AVF, and ATF were additionally adjusted for FM, no familial cross-trait correlations or polygenic pleiotropy between cortisol and the abdominal fat measures remained. DISCUSSION: Evidence was found for polygenic pleiotropy but not for pleiotropic major gene effects between cortisol and overall adiposity in whites. However, the covariation of cortisol with abdominal fat phenotypes is dependent on concomitant polygenic factors for total-body fat.     

Cardiorespiratory fitness and abdominal adiposity in youth

The purpose of this study was to determine whether cardiorespiratory fitness (CRF) is associated with lower abdominal adiposity in youth. Subjects included healthy 61 African-American and 52 white children and adolescents (age: 8-17 years). Body composition was measured by dual-energy X-ray absorptiometry and computed tomography. CRF (VO(2max)) was assessed using a graded maximal treadmill test. CRF was inversely related (P<0.05) to total adiposity, waist circumference, and visceral and abdominal subcutaneous adipose tissue (AT) independent of race. These findings remained significant (P<0.05) after adjusting for age, gender and pubertal status. Multiple regression analyses revealed that CRF is an independent contributor (P<0.05) of waist circumference, and visceral and abdominal subcutaneous AT after accounting for age, pubertal status, gender and body mass index percentile. Our observation suggest that in youth, CRF is associated with lower visceral and abdominal subcutaneous AT, and reinforces the notion that youth should engage in regular physical activity to improve aerobic fitness and reduce abdominal adiposity.     

Exercise-induced reduction in obesity and insulin resistance in women: a randomized controlled trial

OBJECTIVES: To determine the effects of equivalent diet- or exercise-induced weight loss and exercise without weight loss on subcutaneous fat, visceral fat, and insulin sensitivity in obese women. RESEARCH METHODS AND PROCEDURES: Fifty-four premenopausal women with abdominal obesity [waist circumference 110.1 +/- 5.8 cm (mean +/- SD)] (BMI 31.3 +/- 2.0 kg/m2) were randomly assigned to one of four groups: diet weight loss (n = 15), exercise weight loss (n = 17), exercise without weight loss (n = 12), and a weight-stable control group (n = 10). All groups underwent a 14-week intervention. RESULTS: Body weight decreased by approximately 6.5% within both weight loss groups and was unchanged in the exercise without weight loss and control groups. In comparison with controls, cardiorespiratory fitness improved within the exercise groups only (p < 0.01). Reduction in total, abdominal, and abdominal subcutaneous fat within the exercise weight loss group was greater (p < 0.001) than within all other groups. The reduction in total and abdominal fat within the diet weight loss and exercise without weight loss groups was greater than within controls (p < 0.001) but not different from each other (p > 0.05). Visceral fat decreased within all treatment groups (p < 0.008), and these changes were not different from each other. In comparison with the control group, insulin sensitivity improved within the exercise weight loss group alone (p < 0.001). DISCUSSION: Daily exercise without caloric restriction was associated with substantial reductions in total fat, abdominal fat, visceral fat, and insulin resistance in women. Exercise without weight loss was also associated with a substantial reduction in total and abdominal obesity.     

Effects of beta2-adrenergic receptor gene variants on adiposity: the HERITAGE Family Study

We investigated whether the Arg16Gly and Gln27Glu polymorphisms of the beta2-adrenergic receptor gene were associated with body-fat and fat-distribution phenotypes measured before and in response to a 20-week endurance-training program. BMI, fat mass (FAT), percentage of body fat (%FAT), sum of eight skinfolds (SF8), and abdominal fat areas assessed by computed tomography were measured in adult sedentary white and black participants of the HERITAGE Family Study. Evidence of gene-by-obesity interaction was found in whites for several adiposity phenotypes measured before training. Analyses performed separately in nonobese and obese subjects revealed that obese men carrying the Glu27 allele have lower fat accumulation (BMI, FAT, and %FAT) than noncarriers. Among white obese women, Gly16Gly homozygotes had a lower fat accumulation (BMI, FAT, and SF8) than Arg16Gly and Arg16Arg carriers. In response to endurance training, white women with the Arg16Arg genotype exhibited a greater reduction in BMI, FAT, and %FAT. Results observed in blacks were mostly negative. These results suggest that polymorphisms in the beta2-adrenergic receptor gene influence the amount of body fat in white obese men (Gln27Glu) and women (Arg16Gly), as well as the changes in adiposity in response to endurance training in white women (Arg16Gly).     

简易体脂参数估测腹内型肥胖的可靠性评价

目的：评价体重指数（BMI）、腰围（WC）、腰臀比（WHR）估测腹内型肥胖的最佳临界点及敏感度、特异度。方法：应用核磁共振（MRI）对690名受试者（男305人，女385人）进行腹内脂肪（VA）测量，同时测量BMI、WC、WHR。以受试者工作特性（ROC）曲线评价简易体脂参数对腹内型肥胖的诊断价值。结果：①经MRI诊断，超重／肥胖者中61．7％，正常体重者中14．2％呈腹内型肥胖（VA≥100cm^2）；②BMI、WC、WHR与腹内脂肪面积呈显著正相关，尤以WC的相关性最好;③简易体脂参数估测腹内脂肪积聚的最佳切割点为BMI：26kg/m^2,WC:90cm,WHR:0.93;④BMI≥28kg/m^2、WC≥95cm时，95％的男性及90％左右的女性呈腹内型肥胖。结论：BMI、WC及WHR都可估测腹内型肥胖，但以腰围的准确率稍高。     

Abdominal fat distribution measured by ultrasound and aerobic fitness in young Danish men born with low and normal birth weight

Abdominal subcutaneous and visceral adipose tissue thickness was examined by ultrasound in 17 men with low birth weight (LBW) and 26 with normal BW control individuals to determine if abdominal obesity in LBW individuals is due to increased visceral or subcutaneous fat mass/thickness, or both. Men born with LBW had an increased waist-to-hip ratio (P = 0.04), greater abdominal fat thickness (P = 0.05) and increased visceral (VAT) and subcutaneous adipose tissue (SAT) thickness compared with controls, however the latter not statistically significant (P = 0.08, P = 0.10). A significant difference between birth weight groups in both SAT (P = 0.04) and VAT (P = 0.03) was found after adjustment for weight, whereas no significant difference in either SAT (P = 0.93) or VAT (P = 0.30) was found after adjustment for BMI. Increased waist-to-hip ratio in LBW individuals is due to increased total abdominal fat including both subcutaneous and visceral fat.     

Adipose tissue in muscle: a novel depot similar in size to visceral adipose tissue

BACKGROUND: The manner in which fat depot volumes and distributions, particularly the adipose tissue (AT) between the muscles, vary by race is unknown. OBJECTIVE: The objective was to quantify a previously unstudied and novel intermuscular AT (IMAT) depot and subcutaneous AT, visceral AT (VAT), and total-body skeletal muscle mass in healthy sedentary African American (AA), Asian, and white adults by whole-body magnetic resonance imaging. IMAT is the AT between muscles and within the boundary of the muscle fascia. DESIGN: Analyses were conducted on 227 women [AA (n = 79): body mass index (BMI; in kg/m(2)), 29.0 +/- 5.5; age, 45.7 +/- 16.9 y; Asian (n = 38): BMI, 21.7 +/- 2.9; age, 47.2 +/- 19.9 y; whites (n = 110): BMI, 24.9 +/- 5.4; age, 43.7 +/- 16.2 y]) and 111 men [AA (n = 39): BMI, 25.6 +/- 3.2; age, 45.5 +/- 18.8 y; Asian (n = 13): BMI, 24.9 +/- 2.5; age, 45.6 +/- 25.0 y; white (n = 59): BMI, 25.8 +/- 3.8; age 44.5 +/- 16.3 y]. RESULTS: IMAT depots were not significantly different in size between race groups at low levels of adiposity; however, with increasing adiposity, AAs had a significantly greater increment in the proportion of total AT (TAT) than did the whites and Asians (58, 46, and 44 g IMAT/kg TAT, respectively; P = 0.001). VAT depots were not significantly different in size at low levels of adiposity but, with increasing adiposity, VAT accumulation was greater than IMAT accumulation in the Asians and whites; no significant differences were observed in AAs. CONCLUSION: Race differences in AT distribution extend to IMAT, a depot that may influence race-ethnicity differences in dysglycemia.     

Waist circumference, dual-energy X-ray absortiometrically measured abdominal adiposity, and computed tomographically derived intra-abdominal fat area on detecting metabolic risk factors in obese women

OBJECTIVES: We investigated which abdominal adiposity measurements, waist circumference (WC), dual-energy X-ray absorptiometry (DXA)-measured abdominal fat, and computed tomography (CT)-derived intra-abdominal fat areas (IAF), were the most predictive in identifying metabolic risk factors. METHODS: Ninety-five Korean women (body mass index 27.5 +/- 3.2 kg/m(2), WC 90.2 +/- 6.8 cm, age 42 +/- 10.6 y) with abdominal obesity (WC > or = 80 cm) were examined in this study. Abdominal adiposity was assessed using DXA (absolute values and percentages of trunk and android fat, trunk-to-leg fat ratio, and android-to-gynoid fat ratio) and CT (IAF and ratio of IAF to subcutaneous abdominal fat [SAF]). Metabolic indicators were blood pressure, high-density lipoprotein cholesterol, triacylglycerol, fasting glucose, insulin, and high-sensitivity C-reactive protein. Metabolic syndrome (MS) was defined as the presence of at least two of the following: triacylglycerol level > or = 150 mg/dL, high-density lipoprotein cholesterol level <50 mg/dL, blood pressure > or = 130/85 mmHg, and/or fasting glucose level > or = 100 mg/dL. RESULTS: The correlations between adiposity measurements and metabolic indicators were stronger in premenopausal compared with postmenopausal women. Areas under the curve for MS and all abdominal adiposity measurements (WC, DXA-measured abdominal fat, and CT-derived IAF) were significant. Areas under the curve were not significantly different among measurements. The sensitivity and specificity at the threshold value of each abdominal adiposity measurement to predict MS were 38-93% and 34-96%, respectively. Women with 1 SD higher abdominal adiposity were 1.6-3.4 times more likely to have MS. CONCLUSION: No single abdominal adiposity measurement, i.e., WC, DXA-measured abdominal fat, and CT-assessed IAF, was a stronger predictor of metabolic risk factors than the other.     

Serum leptin concentrations and body adipose measures in older black and white adults

BACKGROUND: Among US adults, serum leptin concentrations are higher in women than in men and are higher in blacks than in whites independent of anthropometric measures of body fatness. OBJECTIVE: Using radiographic measures of body fat, we determined the best correlates of leptin and whether adiposity can explain sex and race differences in leptin concentrations in older adults. DESIGN: This was a cross-sectional analysis of fasting serum leptin concentrations and body fat measured by dual-energy X-ray absorptiometry (DXA), abdominal computed tomography, and standard anthropometry in 3026 well-functioning 70-79-y-old participants (42% black, 51% women) of the Health, Aging, and Body Composition Study. RESULTS: Geometric mean (+/-SE) leptin concentrations (ng/mL) were higher in the women than in the men (16.5 +/- 0.3 and 5.7 +/- 0.1, respectively) and in the black women than in the white women (20.2 +/- 0.6 and 13.9 +/- 0.4, respectively), but did not differ significantly between the white and black men (5.8 +/- 0.2 and 5.5 +/- 0.2, respectively). Percentage fat estimated from DXA showed the highest correlation with leptin (R(2) = 0.56 for both sexes). Addition of abdominal visceral fat minimally increased the correlation. In the multivariate analysis, the association with sex was eliminated after adjustment for percentage fat and visceral fat in both whites (P = 0.051) and blacks (P = 0.34). Among women, higher leptin concentrations in blacks remained after adjustment for percentage fat and visceral fat (mean race difference = 4.95 ng/mL; P < 0.001). Among men, an association with black race emerged after adjustment for these factors (mean race difference = 1.42 ng/mL; P < 0.001). CONCLUSIONS: Among older adults, higher serum leptin concentrations in women are explained by a greater percentage of body fat. Higher leptin concentrations in blacks are not explained by percentage of body fat.     

Relationship between waist circumference,body mass index,and medical care costs

OBJECTIVE: Excessive visceral adiposity as measured by anthropomorphic measures may be more closely associated with adverse health consequences than body weight or body mass index (BMI), the more commonly obtained clinical measures. Waist circumference (WC) provides information about regional adiposity and may correlate with health care costs better than body weight or BMI. RESEARCH METHODS AND PROCEDURES: A total of 424 men (37%) and women (63%) were identified as they were seen in outpatient medical clinics at Denver Health, an integrated health care system serving a largely indigent population. Height, weight, and WC were measured by one examiner. Information on outpatient, laboratory, pharmacy, inpatient, and total charges attributable to each subject for the preceding year were obtained from computerized databases. Data on health care charges were divided into quartiles based on WC and BMI. RESULTS: Total annual health care charges were significantly greater in the highest WC quartile (WC < 83.3 cm: $6062 +/- $784; 83.3 to 93.5 cm: $5968 +/- $812; 93.7 to 103.5 cm: $6369 +/- $1015; >103.5 cm: $8699 +/- $1092; p = 0.047). Those with a WC >103.5 cm generated 85% more inpatient charges than the group with a WC <83.3 cm. Although there was a positive trend, BMI was not found to significantly correlate with total health care charges in this population sample. DISCUSSION: These results suggest that abdominal adiposity as assessed by WC is associated with increased total health care charges and may be a better predictor of health care charges than the more widely used BMI.     

Body mass index and hip and thigh circumferences are negatively associated with visceral adipose tissue after control for waist circumference

BACKGROUND: Waist circumference (WC) is positively associated with morbidity and mortality with or without control for hip circumference (HC) or body mass index (BMI; in kg/m(2)). This association is thought to be explained by an expanded visceral adipose tissue (VAT) depot. Conversely, HC and BMI are negatively associated with morbidity and mortality after control for WC. Whether this inverse association is explained in part by the ability of HC and BMI to identify subjects with increased subcutaneous adipose tissue (SAT), increased skeletal muscle (SM) mass, or decreased VAT after control for WC is unclear. OBJECTIVE: We examined the independent associations between WC, HC, thigh circumference (ThC), and BMI with VAT and total, lower-body, and abdominal SAT and SM. DESIGN: Total and regional body composition were measured in 256 white men and women with magnetic resonance imaging. RESULTS: WC, HC, ThC, and BMI were all positively correlated with total, lower-body, and abdominal SAT and SM and with VAT. After statistical control for WC, HC, ThC, and BMI remained positively associated with total, lower-body, and abdominal SAT and SM (men only) but were negatively associated with VAT (P < 0.05). HC (P < 0.05) but not BMI (P > 0.10) or ThC (P = 0.06) remained negatively associated with VAT after further control for age. CONCLUSIONS: HC, ThC, and BMI are positively associated with total, lower-body, and abdominal SAT and SM but negatively associated with VAT after control for WC. However, only HC remained negatively associated with VAT after control for age and WC.     

非肥胖型PCOS不孕患者超声测量肥胖指标的临床研究

目的:探讨体重指数(BMI)正常的不孕症患者中,多囊卵巢综合征(Polycystic Ovary Syndrome,PCOS)即非肥胖型PCOS(NOB-PCOS)与非PCOS(对照组)患者之间内脏脂肪厚度(visceral fat thicknes,VFT)及判断肥胖相关的人体测量值的差异,为更好地治疗NOB-PCOS不孕症提供依据。方法:检测不孕症患者中BMI正常的140例PCOS及81例非P-COS患者的基础性激素,用超声检测腹部皮下脂肪、内脏脂肪、肝前脂肪、肝前皮下脂肪厚度,测量身高、体重、腹围、腰围、臀围等,对两组间上述指标进行分析。结果:NOB-PCOS组血清促黄体生成素(LH)、睾酮(T)明显高于非PCOS组(P<0.05);NOB-PCOS组腹围、腹部皮下脂肪厚度及内脏脂肪厚度明显高于非PCOS组(P<0.05)。结论:NOB-PCOS不孕症患者腹围、腹部皮下脂肪及内脏脂肪厚度等判断肥胖的指标大于非PCOS患者,治疗时应引起重视。     

Association of Binge Eating Behavior with Total and Abdominal Adipose Tissue in a Large Sample of Participants Starting a Weight Loss or Maintenance Program

ABSTRACT

Objective: It is not clear whether binge eating (BE) behavior is associated with body composition independently of body mass index (BMI). Our aim has been to evaluate the BMI-independent contribution of BE severity and BE status on the total amount of fat mass and abdominal fat distribution in a large sample of participants.

Method: We performed a cross-sectional study among 8524 participants followed at a nutritional center. BMI and waist circumference (WC) were measured, body fat (BF) was estimated by skinfold measurement, and abdominal visceral (VAT) and subcutaneous (SAT) adipose tissues were measured by ultrasonography. BE was assessed using the Binge Eating Scale (BES). The association between the continuous BES score (BE severity) and adiposity was assessed in the whole sample after adjustment for BMI and other confounders. The effect of BE status on adiposity was also assessed by matching binge eaters (BES ≥ 18), for sex, age, and BMI, with non-binge eaters (BES < 18).

Results: We found that 17.7% of the participants were binge eaters. Continuous BES score was associated with increasing WC (0.03 cm, 95% confidence interval [CI], 0.02 to 0.05 every 1 BES unit, p < 0.001) and decreasing BF (0.01%, 95% CI, ?0.02 to ?0.00 every 1 BES unit, p = 0.003). No association was found between BE severity and VAT and SAT. After matching, the BF of binge eaters was 0.29% (95% CI, ?0.50 to ?0.07, p = 0.01) lower than that of non-binge eaters.

Conclusions: Given the very small effect size, BE severity and status are not associated in a biologically meaningful manner with BF content and distribution.     

Cut-off values of body mass index, waist circumference, and waist-to-height ratio to identify excess abdominal fat: population-based screening of Japanese school children

Background

School-based screening and prevention programs for adiposity generally target school children in grades 4 and 6 (age 9–11 years). The aims of this study were to evaluate the validity of body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) in identifying abdominal adiposity in fifth-grade Japanese school children and to determine optimal cut-off values for anthropometric measures.

Methods

The target population was fifth-grade school children enrolled in 2 schools in Shizuoka, Japan between 2008 and 2010; 422 of the 466 children participated in the present study. Abdominal adiposity was defined as percent trunk fat in the 95th percentile or higher, as determined by dual-energy x-ray absorptiometry (DXA). We analyzed the validity of BMI, WC, and WHtR using receiver operating characteristic (ROC) curve analysis. The Youden index was used to determine cut-off values of BMI, WC, and WHtR that identify excess abdominal fat.

Results

Optimal cut-off values to identify abdominal adiposity were 20.8 kg/m² (BMI), 76.5 cm (WC), and 0.519 (WHtR) for boys, and 19.6 kg/m² (BMI), 73.0 cm (WC), and 0.499 (WHtR) for girls. Areas under the ROC curve were 0.983 (BMI), 0.987 (WC), and 0.981 (WHtR) for boys, and 0.981 (BMI), 0986 (WC), and 0.992 (WHtR) for girls.

Conclusions

BMI, WC, and WHtR successfully identified a high proportion of children with excess abdominal fat as measured by DXA, demonstrating that these measures are useful indices for school screening.Key words: child, screening, obesity, statistics as topic, reference values     

Visceral adipose tissue accumulation differs according to ethnic background: results of the Multicultural Community Health Assessment Trial (M-CHAT)

BACKGROUND: It was suggested that body fat distribution differs across ethnic groups, and this may be important when considering risk of disease. Previous studies have not adequately investigated differences in discrete regions of abdominal adiposity across ethnic groups. OBJECTIVE: We compared the relation between abdominal adipose tissue and total body fat between persons living in Canada of Aboriginal, Chinese, and South Asian origin with persons of European origin. DESIGN: Healthy Aboriginal, Chinese, European, and South Asian participants (n = 822) aged between 30 and 65 y were matched by sex, ethnicity, and body mass index (BMI; in kg/m(2)) range. Total abdominal adipose tissue (TAT), subcutaneous abdominal adipose tissue (SAT), visceral adipose tissue (VAT), total body fat mass, lifestyle, and demographics were assessed. Relations between BMI and total body fat, TAT, SAT, and VAT and between total body fat and TAT, SAT, and VAT were investigated. RESULTS: BMI significantly underestimated VAT in all non-European groups. Throughout a range of total body fat mass, VAT was not significantly different between the Aboriginals and the Europeans. With total body fat >9.1 kg, Chinese participants had increasingly greater amounts of VAT than did the Europeans (P for interaction = 0.008). South Asians had less VAT with total body fat >37.4 kg but more VAT below that amount than did Europeans (P for interaction < 0.001). CONCLUSION: Compared with Europeans, the Chinese and South Asian cohorts had a relatively greater amount of abdominal adipose tissue, and this difference was more pronounced with VAT. No significant differences were observed between the Aboriginals and the Europeans.     

Perinatal and early adulthood factors associated with adiposity

We used body mass index (BMI) and waist circumference (WC) as fat indicators to assess whether perinatal and early adulthood factors are associated with adiposity in early adulthood. We hypothesized that risk factors differ between men and women and are also different when WC is used for measuring adiposity as opposed to BMI. We conducted a longitudinal study based on a sample of 2,063 adults from the 1978/1979 Ribeir?o Preto birth cohort. Adjustment was performed using four sequential multiple linear regression models stratified by sex. Both perinatal and early adulthood variables influenced adulthood BMI and WC. The associations differed between men and women and depending on the measure of abdominal adiposity (BMI or WC). Living with a partner, for both men and women, and high fat and alcohol intake in men were factors that were consistently associated with higher adulthood BMI and WC levels. The differences observed between sexes may point to different lifestyles of men and women, suggesting that prevention policies should consider gender specific strategies.     

Subcutaneous adipocyte size and body fat distribution

BACKGROUND: Both body fat distribution and adipocyte size are associated with metabolic abnormalities. OBJECTIVE: We defined the extent to which subcutaneous adipocyte size is related to regional fat mass and to the sizes of adipocytes in other subcutaneous depots independent of adiposity, age, and sex. DESIGN: Data collected from 188 women and 133 men who were 18-50 y old and who had a body mass index (in kg/m2) of 18 to 50 were analyzed. The mean size of isolated subcutaneous abdominal, femoral, and gluteal adipocytes was measured by direct microscopy or by automated analysis of digital images. Visceral fat area was measured with computed tomography. Dual-energy X-ray absorptiometry was used to calculate adiposity. RESULTS: Stepwise multiple regression analyses showed that abdominal adipocyte size was associated positively with visceral and subcutaneous abdominal fat areas and negatively with lower-body fat mass as a percentage of total-body fat, after control for sex and percentage body fat. Femoral adipocyte size was related to percentage body fat (P<0.0001), whereas gluteal adipocyte size was related to visceral fat area (P=0.002), which suggests that these 2 lower-body fat depots are distinct. Analyses of data from a subset of volunteers (n=99) for whom we had adipocyte size from all 3 depots showed that adipocyte size from 1 depot could be better predicted if adipocyte size from other depots were known. CONCLUSIONS: Abdominal adipocyte size is related to body fat distribution. Adipocyte size in a person seems to be globally regulated by factors independent of variations in body fat distribution.     

Growth of visceral fat, subcutaneous abdominal fat, and total body fat in children

OBJECTIVE: To examine the patterns of growth of visceral fat, subcutaneous abdominal fat, and total body fat over a 3- to 5-year period in white and African American children. RESEARCH METHODS AND PROCEDURES: Children (mean age: 8.1 +/- 1.6 years at baseline) were recruited from Birmingham, Alabama, and those with three or more repeated annual measurements were included in the analysis (N = 138 children and 601 observations). Abdominal adipose tissue (visceral and subcutaneous) was measured using computed tomography. Total body fat and lean tissue mass were measured by DXA. Random growth curve modeling was performed to estimate growth rates of the different body fat compartments. RESULTS: Visceral fat and total body fat both exhibited significant growth effects before and after adjusting for subcutaneous abdominal fat and lean tissue mass, respectively, and for gender, race, and baseline age (5.2 +/- 2.2 cm(2)/yr and 1.9 +/- 0.8 kg/yr, respectively). After adjusting for total body fat, the growth of subcutaneous abdominal fat was not significant. Whites showed a higher visceral fat growth than did African Americans (difference: 1.9 +/- 0.8 cm(2)/yr), but there was no ethnic difference for growth of subcutaneous abdominal fat or total body fat. There were no gender differences found for any of the growth rates. DISCUSSION: Growth of visceral fat remained significant after adjusting for growth of subcutaneous abdominal fat, implying that the acquisition of the two abdominal fat compartments may involve different physiologic mechanisms. In contrast, growth of subcutaneous abdominal fat was explained by growth in total body fat, suggesting that subcutaneous fat may not be preferentially deposited in the abdominal area during this phase of growth. Finally, significantly higher growth of visceral fat in white compared with African American children is consistent with cross-sectional findings.     

Which obesity index is the most useful marker for predicting hepatic steatosis in children and adolescents with obesity? A cross-sectional study using quantitative magnetic resonance imaging

IntroductionWe aimed to evaluate the relationships between hepatic steatosis and various indices of obesity, and to identify the most useful index for the prediction of hepatic steatosis in children and adolescents with obesity.MethodsA total of 226 children and adolescents with a mean body mass index (BMI) z-score of 2.65 and a mean age of 11.4 years were subjected to anthropometric and body composition measurements, laboratory testing, abdominal fat mass assessment, and hepatic fat accumulation by magnetic resonance imaging-derived proton density fat fraction (MRI-PDFF). The participants were divided into quartiles according to the severity of their hepatic steatosis, and the presence of hepatic steatosis was defined using an MRI-PDFF ≥ 5%.ResultsThe multivariate ordinal regression analysis showed that the severity of hepatic steatosis was positively associated with BMI, waist circumference, waist-to-hip ratio, waist-to-height ratio, fat mass, fat-free mass, visceral adiposity, and abdominal subcutaneous adiposity. Higher activities of liver enzymes and higher concentrations of triglyceride, C-reactive protein, fasting insulin, and leptin were associated with more severe hepatic steatosis, whereas high-density lipoprotein-cholesterol and adiponectin were negatively associated with hepatic steatosis. The indices of obesity with areas under the receiver operating characteristic curves (AUCs) > 0.8 for the prediction of hepatic steatosis were liver enzymes, visceral adipose tissue area, waist-to-hip ratio, and waist-to-height ratio.ConclusionThe severity of hepatic steatosis significantly correlated with various indices of obesity and cardiometabolic markers in children and adolescents with obesity. The indices of abdominal obesity would be the most useful for the prediction of hepatic steatosis.