The use of anthropometric and dual-energy X-ray absorptiometry (DXA) measures to estimate total abdominal and abdominal visceral fat in men and women

Sex differences in the association of regional fat distribution with the severity of obstructive sleep apnea

STUDY OBJECTIVES

To describe sex differences in the associations between severity of obstructive sleep apnea (OSA) and measures of obesity in body regions defined using both dual-energy absorptiometry and traditional anthropometric measures in a sleep-clinic sample.

DESIGN

A prospective case-series observational study.

SETTING

The Western Australian Sleep Health Study operating out of the Sir Charles Gairdner Hospital Sleep Clinic, Perth, Western Australia.

PARTICIPANTS

Newly referred clinic patients (60 men, 36 women) suspected of having OSA.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Obstructive sleep apnea severity was defined by apnea-hypopnoea index from laboratory-based overnight polysomnography. Body mass index, neck, waist and hip circumference, neck-to-waist ratio, and waist-to-hip ratio were measured. Dual energy absorptiometry measurements included percentage fat and lean tissue. Multivariate regression models for each sex were developed. In women, percentage of fat in the neck region and body mass index together explained 33% of the variance in apnea-hypopnea index. In men, percentage of fat in the abdominal region and neck-to-waist ratio together accounted for 37% of the variance in apnea-hypopnea index.

CONCLUSIONS

Regional obesity is associated with obstructive sleep apnea severity, although differently in men and women. In women, a direct influence of neck fat on the upper airway patency is implicated. In men, abdominal obesity appears to be the predominant influence. The apnea-hypopnea index was best predicted by a combination of Dual Energy Absorptiometry-measured mass and traditional anthropometric measurements.

Estimation of abdominal fat compartments by bioelectrical impedance: the validity of the ViScan measurement system in comparison with MRI

BACKGROUND/OBJECTIVES

Abdominal obesity, more specifically increased intra-abdominal adipose tissue, is strongly associated with increased risk of metabolic disease. Bioelectrical impedance analysis (BIA) has been proposed as a potential method of determining individual abdominal fat compartments in the form of the commercially available ViScan measurement system (Tanita Corporation), but it has yet to be independently validated. The objective of this study was to analyse the validity of the ViScan to assess adult abdominal adiposity across a range of body fatness.

SUBJECTS/METHODS

This was a cross-sectional study with 74 participants (40 females and 34 males with body mass index (BMI) between 18.5 and 39.6 kg/m(2)). Total abdominal adipose tissue, subcutaneous abdominal adipose tissue (SAAT) and intra-abdominal adipose tissue (IAAT) were measured by magnetic resonance imaging (MRI). In addition, intra-hepatocellular lipid was obtained by magnetic resonance spectroscopy. Estimates of abdominal adiposity (total and compartmental) were obtained from BIA and anthropometry.

RESULTS

ViScan-derived percentage trunk fat strongly and significantly related with total abdominal adipose tissue and SAAT in both lean and overweight/obese individuals, and categorized individuals reliably in terms of total abdominal fat. ViScan-derived 'visceral' fat correlated significantly with IAAT but the strength of this relationship was much weaker in overweight/obese individuals, particularly those with higher SAAT, leading to less reliable classification of individuals for IAAT.

CONCLUSIONS

The ViScan may serve as a useful tool for predicting total abdominal fat, but prediction of visceral fat (IAAT) may be limited, especially in abdominally obese individuals.

Overweight and central adiposity in school-age children and links with hypertension

The purpose of this study of school-age children was to estimate prevalence and interrelationships of overweight, central adiposity, and hypertension. It included 1,070 children in kindergarten through sixth grade (67% Hispanic, 26% African American, mean age = 8.9 years). Measures included body mass index (BMI), waist circumference (WC), systolic and/or diastolic hypertension identified by measurements on three separate occasions. Percentage overweight (BMI >or=95th percentile) was 28.7%, 17.9% were at risk of overweight, 28.8% had WC >or=90th percentile, and 9.4% had elevated (>or=90th percentile) systolic and/or diastolic blood pressure (BP). If we had screened only for BMI and examined those with BMI >or=85th percentile or underweight for hypertension, we would have missed 26% of the children with persistently elevated BP. WC explained variance in elevated BP not explained by BMI (p < .001). Measurement of WC is easily incorporated in a school-based screening protocol.

Metabolic risk varies according to waist circumference measurement site in overweight boys and girls

OBJECTIVES

To compare waist circumference (WC) values measured at 4 commonly recommended sites and examine the relationships between WC sites and markers of metabolic risk in a sample of overweight boys and girls referred for weight management.

STUDY DESIGN

Overweight (mean body mass index percentile, 98.7; SD, 1.0) children and adolescents (n = 73; 41 girls, 32 boys; mean age, 12.5 years; SD, 2.6 years) had WC measured at 4 sites: iliac crest (WC1), narrowest waist (WC2), midpoint between the floating rib and iliac crest (WC3), and umbilicus (WC4). Height, weight, fasting insulin level, glucose level, cholesterol level, and systolic and diastolic blood pressure were also measured.

RESULTS

Overall, WC1 (108.5 cm; SD, 16.3 cm) was greater than WC2 (97.4 cm; SD, 13.6 cm; P < .003), and WC2 was smaller than WC3 (104.3 cm; SD, 15.3 cm; P = .02) and WC4 (108.7 cm; SD, 16.2 cm; P < .0003). With logistic regression, WC2 and WC3 were revealed to be more consistently associated with metabolic syndrome by using 3 different definitions.

CONCLUSION

In our sample, we observed differences in 4 commonly recommended WC measurement sites and found that all sites were not equivalently associated with metabolic risk. Our findings provide preliminary support suggesting that WC measured at the narrowest waist and midpoint between the floating rib and iliac crest may represent the measurement sites most closely associated with metabolic risk in overweight boys and girls.

The role of body mass index, insulin, and adiponectin in the relation between fat distribution and bone mineral density

Despite the positive association between body mass index (BMI) and bone mineral density (BMD) and content (BMC), the role of fat distribution in BMD/BMC remains unclear. We examined relationships between BMD/BMC and various measurements of fat distribution and studied the role of BMI, insulin, and adiponectin in these relations. Using a cross-sectional investigation of 2631 participants from the Erasmus Rucphen Family study, we studied associations between BMD (using dual-energy X-ray absorptiometry (DXA]) at the hip, lumbar spine, total body (BMD and BMC), and fat distribution by the waist-to-hip ratio (WHR), waist-to-thigh ratio (WTR), and DXA-based trunk-to-leg fat ratio and android-to-gynoid fat ratio. Analyses were stratified by gender and median age (48.0 years in women and 49.2 years in men) and were performed with and without adjustment for BMI, fasting insulin, and adiponectin. Using linear regression (adjusting for age, height, smoking, and use of alcohol), most relationships between fat distribution and BMD and BMC were positive, except for WTR. After BMI adjustment, most correlations were negative except for trunk-to-leg fat ratio in both genders. No consistent influence of age or menopausal status was found. Insulin and adiponectin levels did not explain either positive or negative associations. In conclusion, positive associations between android fat distribution and BMD/BMC are explained by higher BMI but not by higher insulin and/or lower adiponectin levels. Inverse associations after adjustment for BMI suggest that android fat deposition as measured by the WHR, WTR, and DXA-based android-to-gynoid fat ratio is not beneficial and possibly even deleterious for bone.

Stress, inflammation, and yoga practice

OBJECTIVE

To address the mechanisms underlying hatha yoga's potential stress-reduction benefits, we compared inflammatory and endocrine responses of novice and expert yoga practitioners before, during, and after a restorative hatha yoga session, as well as in two control conditions. Stressors before each of the three conditions provided data on the extent to which yoga speeded an individual's physiological recovery.

METHODS

A total of 50 healthy women (mean age, 41.32 years; range, 30-65 years), 25 novices and 25 experts, were exposed to each of the conditions (yoga, movement control, and passive-video control) during three separate visits.

RESULTS

The yoga session boosted participants' positive affect compared with the control conditions, but no overall differences in inflammatory or endocrine responses were unique to the yoga session. Importantly, even though novices and experts did not differ on key dimensions, including age, abdominal adiposity, and cardiorespiratory fitness, novices' serum interleukin (IL)-6 levels were 41% higher than those of experts across sessions, and the odds of a novice having detectable C-reactive protein (CRP) were 4.75 times as high as that of an expert. Differences in stress responses between experts and novices provided one plausible mechanism for their divergent serum IL-6 data; experts produced less lipopolysaccharide-stimulated IL-6 in response to the stressor than novices, and IL-6 promotes CRP production.

CONCLUSION

The ability to minimize inflammatory responses to stressful encounters influences the burden that stressors place on an individual. If yoga dampens or limits stress-related changes, then regular practice could have substantial health benefits.

Sagittal abdominal diameter as a screening tool in clinical research: cutoffs for cardiometabolic risk

Background. Waist girth and BMI are commonly used as markers of cardiometabolic risk. Accumulating data however suggest that sagittal abdominal diameter (SAD) or "abdominal height" may be a better marker of intra-abdominal adiposity and cardiometabolic risk. We aimed to identify cutoffs for SAD using a cardiometabolic risk score. Design. A population-based cross-sectional study. Methods. In 4032 subjects (1936 men and 2096 women) at age 60, different anthropometric variables (SAD, BMI, waist girth, and waist-to-hip ratio) were measured and cardiometabolic risk score calculated. ROC curves were used to assess cutoffs. Results. Among men SAD showed the strongest correlations to the majority of the individual risk factors; whereas in women SAD was equal to that of waist girth. In the whole sample, the area under the ROC curve was highest for SAD. The optimal SAD cutoff for an elevated cardiometabolic risk score in men was approximately 22 cm (95%CI; 21.6 to 22.8) and in women approximately 20 cm (95%CI; 19.4 to 20.8). These cutoffs were similar if the Framingham risk score was used. Conclusions. These cutoffs may be used in research and screening to identify "metabolically obese" men who would benefit from lifestyle and pharmacological interventions. These results need to be verified in younger age groups.

Body mass index is associated with increased creatinine clearance by a mechanism independent of body fat distribution

CONTEXT

Although obesity has been, in general, associated with glomerular hyperfiltration, visceral adiposity has been suggested to be associated with reduced glomerular filtration.

OBJECTIVE

The aim of the study was to evaluate the differential effects of obesity and body fat distribution on glomerular filtration.

DESIGN AND SETTING

We conducted a cross-sectional study of the Japanese-American community in Seattle, Washington.

PARTICIPANTS

We studied a representative sample of second-generation Japanese-American men and women with normal glucose tolerance (n = 124) and impaired glucose metabolism (impaired fasting glucose and/or impaired glucose tolerance) (n = 144) residing in King County, Washington.

MAIN OUTCOME MEASURES

Glomerular filtration rate was estimated by 24-h urinary creatinine clearance, body size by body mass index (BMI), and intra-abdominal fat (IAF), sc fat (SCF), and lean thigh areas by CT scan.

RESULTS

Creatinine clearance was positively correlated with BMI (r = 0.429; P < 0.001), fasting glucose (r = 0.198; P = 0.001), and insulin levels (r = 0.125; P = 0.042), as well as IAF (r = 0.239; P < 0.001), SCF (r = 0.281; P < 0.001), and lean thigh (r = 0.353; P < 0.001) areas. The association between creatinine clearance and BMI remained significant after adjustments for IAF, SCF areas, and fasting insulin levels (r = 0.337; P < 0.001); whereas IAF and SCF areas were not independently associated with creatinine clearance after adjusting for BMI. Creatinine clearance increased with increasing BMI after adjusting for fasting insulin, fasting glucose, IAF and SCF areas in subjects with normal glucose tolerance (r = 0.432; P < 0.001) and impaired glucose metabolism (r = 0.471; P < 0.001).

CONCLUSIONS

BMI rather than body fat distribution is an independent determinant of creatinine clearance in nondiabetic subjects. Lean body mass, rather than adiposity, may explain this association.

Close relationships, inflammation, and health

Different aspects of personal relationships including social integration, social support, and social conflict have been related to inflammation. This article summarizes evidence linking the quality and quantity of relationships with gene expression, intracellular signaling mechanisms, and inflammatory biomarkers, and highlights the biological and psychological pathways through which close relationships impact inflammatory responses. Relationship conflict and lower social support can effectively modulate proinflammatory cytokine secretion both directly (via CNS/neural/endocrine/immune biobehavioral pathways), and indirectly, by promoting depression, emotional stress responses, and detrimental health behaviors. Accordingly, thorough assessments of health behaviors and attention to key methodological issues are necessary to identify the contributions of relationships to inflammation, and thus we highlight procedural issues to be considered in the design of studies. Despite some notable methodological challenges, the evidence suggests that learning more about how close relationships influence inflammation will provide important new insights into the ways that relationships impact health.

DXA-derived abdominal fat mass, waist circumference, and blood lipids in postmenopausal women

The purpose of this study was to determine the utility of dual-energy X-ray absorptiometry (DXA)-derived fat mass indices for predicting blood lipid profile in postmenopausal women. A secondary purpose was to determine whether waist circumference is comparable with DXA-derived measurements in predicting blood lipid profile. Subjects were 423 postmenopausal women (age 58.1 +/- 6.3 years). Fat mass was assessed at abdomen, trunk, and total body using DXA. Anthropometric measurements included BMI and waist circumference. Blood samples were analyzed for total cholesterol (TC), triglyceride (TAG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and cholesterol/HDL ratio. Of the DXA-derived measures, abdominal-fat mass was the best predictor of blood lipid profiles. DXA-derived abdominal fat mass and waist girth explained 20 and 16.5% of variation in TC/HDL ratio, respectively, in univariate analysis, with no difference between the slopes of the regression coefficients. Eighty-four percent of subjects were common to the top quartiles of waist circumference and abdominal fat mass, and blood lipid profiles generally worsened across increasing quartiles. DXA-derived abdominal fat mass and waist circumference are of equivalent utility for predicting alterations in blood lipids. Waist circumference is, therefore, ideal as an inexpensive means in primary health-care services for predicting risk of cardiovascular diseases in postmenopausal women.

Salivary cortisol differs with age and sex and shows inverse associations with WHR in Swedish women: a cross-sectional study

BACKGROUND

Most studies on cortisol have focused on smaller, selected samples. We therefore aimed to sex-specifically study the diurnal cortisol pattern and explore its association with abdominal obesity in a large unselected population.

METHODS

In 2001-2004, 1811 men and women (30-75 years) were randomly selected from the Vara population, south-western Sweden (81% participation rate). Of these, 1671 subjects with full information on basal morning and evening salivary cortisol and anthropometric measurements were included in this cross-sectional study. Differences between groups were examined by general linear model and by logistic and linear regression analyses.

RESULTS

Morning and Delta-cortisol (morning - evening cortisol) were significantly higher in women than men. In both genders older age was significantly associated with higher levels of all cortisol measures, however, most consistently with evening cortisol. In women only, age-adjusted means of WHR were significantly lower in the highest compared to the lowest quartile of morning cortisol (p = 0.036) and Delta-cortisol (p < 0.001), respectively. Furthermore, when comparing WHR above and below the mean, the age-adjusted OR in women for the lowest quartile of cortisol compared to the highest was 1.5 (1.0-2.2, p = 0.058) for morning cortisol and 1.9 (1.3-2.8) for Delta-cortisol. All findings for Delta-cortisol remained after adjustments for multiple covariates and were also seen in a linear regression analysis (p = 0.003).

CONCLUSION

In summary, our findings of generally higher cortisol levels in women than men of all ages are novel and the stronger results seen for Delta-cortisol as opposed to morning cortisol in the association with WHR emphasise the need of studying cortisol variation intra-individually. To our knowledge, the associations in this study have never before been investigated in such a large population sample of both men and women. Our results therefore offer important knowledge on the descriptive characteristics of cortisol in relation to age and gender, and on the impact that associations previously seen between cortisol and abdominal obesity in smaller, selected samples have on a population level.

Predicting abdominal adipose tissue among women with familial partial lipodystrophy

The objective of the study was to determine correlations between magnetic resonance imaging (MRI) measures of truncal adiposity (trunk fat percentage [TrF %(MRI)], visceral adipose tissue [VAT], and subcutaneous abdominal adipose tissue [SAT]), simple clinical measures (body mass index [BMI], waist circumference [WC], and waist-to-hip ratio [WHR]), and bioelectrical impedance analysis (BIA)-derived measures (total fat percentage [TF %] and TrF %(BIA)) in female patients with familial partial lipodystrophy (FPLD). Our secondary aim was to generate and cross-validate predictive equations for VAT and SAT using these simple clinical and BIA-derived variables. Measures of truncal adiposity were measured using 1.5-T MRI (VAT, SAT, and TrF %(MRI)) and Tanita (Tokyo, Japan) 8-electrode body composition analyzer BC-418 (TrF %(BIA)) in 13 female FPLD patients. Pearson correlation coefficients were determined among the various adiposity parameters (BMI, WC, WHR, SAT, VAT, TrF %(MRI), TrF %(BIA), and TF %). Equations to estimate VAT and SAT were determined among 6 of the 13 FPLD subjects using multilinear regression analysis, and the best equations were then cross-validated in the remaining 7 subjects. Variables entered into the model included age, BMI, WC, WHR, TrF %(BIA), and TF %. The TrF %(MRI) showed moderate correlation (r = 0.647, P = .02) with the TrF %(BIA), but the discrepancy between the 2 variables increased with increasing truncal adiposity. The strongest correlate for TrF %(MRI) was BMI (r = 0.886, P < .0001). Visceral adipose tissue was poorly associated with simple clinical measures of BMI, WC, and WHR, but was inversely correlated with TF %, TrF %(BIA), and SAT. The TF % was the strongest correlate for both SAT and VAT. Thus, the best regression equation for VAT included age, BMI, WC, and TF % (R(2) = 1.0), whereas that for SAT only included TF % (R(2) = 0.75). The corresponding standard error of the estimate for the predictive equations was approximately 0.03 % and 18.5 % of the mean value of VAT and SAT, respectively. In the cross-validation study, differences between predicted and observed values of SAT were larger than those of VAT. We conclude that, among female FPLD patients, (1) no simple clinical anthropometric measure correlates well with VAT, whereas BMI correlates well with SAT; (2) BIA measure of TF % most strongly correlated with both VAT and SAT; and (3) based on the cross-validation study, VAT but not SAT could be more reliably estimated using the regression equations derived.

Sagittal abdominal diameter is more predictive of cardiovascular risk than abdominal fat compartments in severe obesity

OBJECTIVE

To compare the predictive role of abdominal fat distribution by computed tomography (CT) with that of total abdominal fat by sagittal abdominal diameter (SAD) on cardiovascular risk in severe obesity.

DESIGN

A cross-sectional, clinical study.

SUBJECTS

64 males and 64 females, aged 42+/-15 years (mean+/-s.d.; range 18-75 years), BMI (kg/m(2)) 41.7+/-5.3 (30.2-57.6).

MEASUREMENTS

Blood glucose, total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides (TGLs), insulin (IRI), insulin resistance (HOMA-IR), slice areas (cm(2)) of total (tSAT), superficial (sSAT) and deep subcutaneous adipose tissue (dSAT), visceral adipose tissue (VAT) and SAD (mm) by CT.

RESULTS

The sSAT depot was negatively associated with blood glucose, HOMA-IR, LDL cholesterol and TGLs, whereas dSAT was negatively associated with HDL cholesterol. VAT was associated with blood glucose and HOMA-IR, whereas SAD was associated with all variables evaluated. In males, VAT was associated with blood glucose (r(2)=0.12, P<0.01), SAD was associated with blood glucose (r(2)=0.67, P<0.01), IRI (r(2)=0.65, P<0.05), and HOMA-IR (r(2)=0.67, P<0.01). In females, sSAT was negatively associated with blood glucose (r(2)=0.63, P<0.05), whereas VAT was associated positively with blood glucose (r(2)=0.21, P< 0.001), total cholesterol (r(2)=0.16, P<0.01), LDL cholesterol (r(2)=0.20, P<0.001) and TGLs (r(2)=0.12, P<0.01). SAD was associated positively with IRI (r(2)=0.52, P<0.05), HOMA-IR (r(2)=0.53, P<0.05), total cholesterol (r(2)=0.52, P<0.05), LDL cholesterol (r(2)=0.54, P<0.01), TGLs (r(2)=0.52, P<0.05) and negatively to HDL cholesterol (r(2)=0.51, P<0.001).

CONCLUSION

When compared with CT-based measures of abdominal fat compartments, SAD is a more predictive indicator of cardiovascular risk in severe obesity.

Prevalência de sobrepeso e obesidade em militares do exército brasileiro: associação com a hipertensão arterial

Este estudo teve por objetivo determinar a associação entre o índice de massa corporal (IMC), a relação cintura/quadril (RCQ) e a circunferência de cintura (CC) com a prevalência de hipertensão arterial sistêmica (HAS) em militares do Exército Brasileiro, do sexo masculino. A amostra foi constituída por 426 militares, com idade entre 27 e 37 anos, todos alunos da Escola de Aperfeiçoamento de Oficiais do Exército em 2006. Foram considerados hipertensos os sujeitos que apresentaram valores de pressão arterial igual ou acima de 140 / 90mmHg e também aqueles que faziam uso de anti-hipetertensivos. Os resultados apontam as seguintes percentagens de sujeitos obesos ou com excesso de gordura: 12,91%, 7,98%, e 17,84%, considerando o IMC a RCQ e a CC, respectivamente. O indicador antropométrico que melhor se associou à hipertensão arterial sistêmica foi a relação cintura/quadril (Odds Ratio = 4,45). Encontrou-se uma prevalência de hipertensão arterial sistêmica (5,63%) bem abaixo das encontradas em outros estudos nacionais e fortes associações entre os indicadores antropométricos utilizados e a hipertensão.

Changes in bone mineral density, body composition and adiponectin levels in morbidly obese patients after bariatric surgery

BACKGROUND

Gastric bypass surgery (GBP) is increasingly used as a treatment option in morbid obesity. Little is known about the effects of this surgery on bone mineral density (BMD) and the underlying mechanisms. To evaluate changes on BMD after GBP and its relation with changes in body composition and serum adiponectin, a longitudinal study in morbid obese subjects was conducted.

METHODS

Forty-two women (BMI 45.0 +/- 4.3 kg/m(2); 37.7 +/- 9.6 years) were studied before surgery and 6 and 12 months after GBP. Percentage of body fat (%BF), fat-free mass (FFM), and BMD were measured by dual-energy X-ray absorptiometry and serum adiponectin levels by RIA.

RESULTS

Twelve months after, GBP weight was decreased by 34.4 +/- 6.5% and excess weight loss was 68.2 +/- 12.8%. Significant reduction (p < 0.001) in total BMD (-3.0 +/- 2.1%), spine BMD (-7.4 +/- 6.8%) and hip BMD (-10.5 +/- 5.6%) were observed. Adiponectin concentration increased from 11.4 +/- 0.7 mg/L before surgery to 15.7 +/- 0.7 and 19.8 +/- 1.0 at the sixth and twelfth month after GBP, respectively (p < 0.001). Thirty-seven percent of the variation in total BMD could be explained by baseline weight, initial BMD, BF reduction, and adiponectin at the twelfth month (r (2) = 0.373; p < 0.001). Adiponectin at the twelfth month had a significant and positive correlation with the reduction of BMD, unrelated to baseline and variation in body composition parameters (adjusted correlation coefficient: r = 0.36).

CONCLUSION

GBP induces a significant BMD loss related with changes in body composition, although some metabolic mediators, such as adiponectin increase, may have an independent action on BMD which deserves further study.

Visceral adipose tissue and the ratio of visceral to subcutaneous adipose tissue are greater in adults with than in those without spinal cord injury, despite matching waist circumferences

BACKGROUND

Abdominal obesity, particularly visceral adipose tissue (VAT), is associated with an increased risk of coronary heart disease (CHD). Despite an elevated risk of CHD mortality in persons with spinal cord injury (SCI), neither abdominal adipose tissue accumulation nor the validity of waist circumference (WC) has been determined in persons with SCI.

OBJECTIVES

The objectives of this study were to compare total adipose tissue (TAT), visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and the ratio of VAT to SAT (VAT:SAT) between adults with SCI and age-, sex-, and WC-matched able-bodied (AB) controls and to determine the relation between WC and VAT in both groups.

DESIGN

Thirty-one men and women (n = 15 SCI and 16 AB) with a mean (+/-SD) age of 38.9 +/- 7.9 y participated in this cross-sectional study. Abdominal adipose tissue was quantified by computed tomography at L4-L5. WC was measured at 3 sites: lowest rib, iliac crest, and the midpoint between the lowest rib and iliac crest.

RESULTS

Persons with SCI had a 58% greater mean VAT (P = 0.003), 48% greater mean VAT:SAT (P = 0.034), and 26% greater mean TAT (P = 0.055) than did matched AB controls after differences in weight were accounted for. Mean SAT was not significantly different between groups. WC at all sites was correlated with VAT in both groups (SCI: 0.905 < or = r < or = 0.925; AB: 0.838 < or = r < or = 0.877; both P < 0.001).

CONCLUSIONS

High levels of VAT exist in young people with SCI who classify themselves as active and healthy. WC may be a valid surrogate measure of VAT in this population and serve as a tool for clinicians to identify those at risk of CHD.

Metabolic aspects of the extreme longevity

Starting from young to very old subjects, aging is associated with a progressive remodeling. Such an age-dependent remodeling process mainly affects anthropometrics, endocrine and thus, also metabolic factors. Interestingly, it occurs in some individuals successfully, while in others unsuccessfully. Centenarians in good health conditions are a very selected group of subjects representing an exceptional condition. Why the centenarians reach the extreme human life span is still unknown. Thus, in this article we will review the best known causes of age-related insulin resistance, outline the main metabolic differences between aged subjects and healthy centenarians, underline the clinical relevance of insulin resistance in the elderly and finally, we will try to propose a unifying hypothesis for explaining the development of insulin resistance with aging.

Relationship of abdominal obesity measured by DXA and waist circumference with insulin sensitivity in Hispanic and non-Hispanic white individuals: the San Luis Valley Diabetes Study

BACKGROUND

To determine if dual-energy X-ray absorptiometry (DXA) measures of trunk fat, a user-defined abdominal region of interest (ROI) and waist circumference (WC) differ in their association with insulin sensitivity among Hispanics and non-Hispanic whites (NHW) or explain any ethnic differences in insulin sensitivity.

METHODS

A cross-sectional study of data collected (1997-98) as part of the longitudinal San Luis Valley Diabetes Study was utilized. There were 664 non-diabetic participants including 349 women (220 NHW, 139 Hispanic) and 305 men (197 NHW, 108 Hispanic), average age 63 years. Measurements included body mass index, WC and DXA measures of total and abdominal fat. Fasting glucose and insulin were used to estimate insulin sensitivity using the QUICKI index. A 2-h oral glucose tolerance test was used to classify participants with normal glucose tolerance (NGT) or impaired glucose tolerance (IGT).

RESULTS

Among women with NGT, Hispanics had lower insulin sensitivity, with DXA trunk fat explaining the most variance in QUICKI and 54% of the ethnic difference in QUICKI after adjusting for total body fat and lean mass. Among men with NGT, there were no differences between Hispanics and NHW in insulin sensitivity or any differences in the association of the abdominal fat measures with insulin sensitivity. Among men and women with IGT, the fat distribution variables explained little variance in QUICKI.

CONCLUSIONS

DXA measures of trunk fat provide additional information over WC and the DXA abdominal ROI measure about ethnic differences in insulin sensitivity between older Hispanic and NHW women with NGT.

Whole-body three-dimensional photonic scanning: a new technique for obesity research and clinical practice

Information on body shape has long been used in categorizing and monitoring obesity. Alongside abdominal circumferences, recent studies further emphasize the value of indices such as sagittal diameter adjusted for thigh girth in categorizing cardiovascular risk. Whole-body three-dimensional photonic scanning has rapidly emerged as a new technology for digital anthropometric measurement. Photonic scanners capture sophisticated raw data on body surface topography in a few seconds, from which extensive body shape information can be extracted using computer algorithms. Photonic scanning now has the potential to play a key role in (1) categorizing obesity (including childhood screening), (2) ranking abdominal size and shape in large-scale epidemiological studies, (3) monitoring individual patients to evaluate treatment efficacy and (4) estimating surface area for drug dosage calculations. New statistical modeling techniques offer the opportunity to develop novel parameters of body shape for linking with biological health outcomes. The low cost, accuracy, ease of use and high acceptability of the technique make it highly suitable for both research and clinical applications.

No difference in insulin sensitivity between healthy postmenopausal women with or without sarcopenia: a pilot study

Insulin plays a pivotal role in skeletal muscle protein metabolism and its action decreases with age. A loss of muscle mass, termed sarcopenia, also occurs with age. The age-associated decline in insulin sensitivity (IS) may negatively alter muscle protein metabolism and, therefore, be implicated in the aetiology of sarcopenia. However, no studies have yet compared the level of IS between older individuals with or without sarcopenia. Thus, in this study, we compared the IS of 20 class I sarcopenics (CIS), 8 class II sarcopeniscs (CIIS), and 16 non-sarcopenics (NS), among a group of otherwise healthy, non-obese, postmenopausal women. IS was estimated with the quantitative IS check index (QUICKI). Muscle mass index (MMI), which was used to determine sarcopenia, was calculated as follows: (appendicular muscle massx1.19)-1.01/h2, where h=height. Fat-free mass (FFM), fat mass (FM), and trunk FM (TFM) were measured by dual-energy X-ray absorptiometry. Accelerometry and indirect calorimetry were used to estimate resting (REE), daily (DEE), and physical activity (PAEE) energy expenditure. A 3 d food record was used to determine total energy, protein (animal and vegetal), and carbohydrate intakes. As expected, MMI and FFM differed significantly among groups. However, no significant differences were found among groups for IS, FM, TFM, REE, DEE, PAEE, or total energy, protein (both animal and vegetable), and carbohydrate intakes. Using QUICKI, a surrogate measure of IS, the present results suggest that the action of insulin does not play an important role in the development and maintenance of sarcopenia in healthy, non-obese, postmenopausal women.

Prediction of visceral fat area at the umbilicus level using fat mass of the trunk: The validity of bioelectrical impedance analysis

The aims of this study were to determine the validity of fat mass of the trunk as a predictor for visceral fat area at the umbilicus level and to develop equations to predict visceral fat mass at the umbilicus level using fat mass of the trunk measured by dual-energy X-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA). The participants were 121 normal Japanese adults (69 males, 52 females). Another 60 volunteer adults (34 males, 26 females) were recruited for examination of cross-validity. Altogether, 41 adults (15 males, 26 females) in the original group and 19 adults (7 males, 12 females) in the cross-validity group received BIA measurement. We measured fat mass by DXA and the BIA system, which was a single-frequency BIA with 8-point contact electrodes, and visceral fat area by computed tomography. We observed significant correlations for visceral fat area in waist circumference (0.56) and fat mass of the trunk measured by DXA (0.64). There was no significant difference in fat mass of the trunk between the DXA and BIA systems, but the BIA system tended to provide an underestimate compared with DXA. With combined fat mass of the trunk measured by DXA and waist circumference as predictors, visceral fat area was estimated by equation (1) (R = 0.87, R(2) = 0.76, standard error of the estimate = 20.9 cm(2)). When substituting fat mass of the trunk measured by BIA into equation (1), there was no significant difference in visceral fat area between the reference and predicted values. An equation using fat mass of the trunk measured by BIA (equation 2) was obtained (R = 0.89, R(2) = 0.78, standard error of the estimate = 20.7 cm(2)), but a systematic error was found for the males. There was cross-validity in both equations. In conclusion, fat mass of the trunk is an effective predictor for the visceral fat area at the umbilicus level. Fat mass of the trunk measured by BIA might be a valid method to predict visceral fat, although further studies with larger samples taking into account the extent and type of obesity are required.

Practical approach for estimation of subcutaneous and visceral adipose tissue

OBJECTIVES

The first objective was to investigate the correlations between anthropometrical measurements and visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) in two cohorts differing in age using magnetic resonance imaging (MRI) as reference. A second objective was to investigate the potential usage of abdominal diameters in practical estimation of adipose tissue compartments using these cohorts.

METHODS

Measurements of body mass index, waist circumference, sagittal abdominal diameter (sagittal AD) and transverse abdominal diameter (transverse AD) were obtained from 336 volunteers of age 14-70 years. Manual measurements of VAT and SAT from single slice MRI at the L4-L5 level were used as reference. The abdominal diameters were measured from the MR images. Linear correlations between the anthropometrical measurements and the reference were studied.

RESULTS

Sagittal AD showed the strongest correlation to VAT (r >or= 0 x 780, P<0 x 0001) and transverse AD was found to give information about the amount of SAT (r >or= 0 x 866, P<0 x 0001). The ellipse spanned by the sagittal AD and the transverse AD was strongly correlated to the total amount of adipose tissue (r >or= 0 x 962, P<0 x 0001).

CONCLUSION

Strong correlations were found between sagittal and transverse abdominal diameters, assessed using MRI, and VAT and SAT, respectively. These results suggest the use of abdominal diameters in practical estimations of VAT and SAT depots.

Cortisol clearance and associations with insulin sensitivity, body fat and fatty liver in middle-aged men

AIMS/HYPOTHESIS

The regulation of cortisol metabolism in vivo is not well understood. We evaluated the relationship between cortisol metabolism and insulin sensitivity, adjusting for total and regional fat content and for non-alcoholic fatty liver disease.

MATERIALS AND METHODS

Twenty-nine middle-aged healthy men with a wide range of BMI were recruited. We measured fat content by dual-energy X-ray absorptiometry and magnetic resonance imaging (MRI), liver fat by ultrasound and MRI, the hypothalamic-pituitary-adrenal axis by adrenal response to ACTH(1-24), unconjugated urinary cortisol excretion, corticosteroid-binding globulin, and cortisol clearance by MS. We assessed insulin sensitivity by hyperinsulinaemic-euglycaemic clamp and by OGTT.

RESULTS

Cortisol clearance was strongly inversely correlated with insulin sensitivity (M value) (r = -0.61, p = 0.002). Cortisol clearance was increased in people with fatty liver compared with those without (mean+/-SD: 243 +/- 10 vs 158 +/- 36 ml/min; p = 0.014). Multiple regression modelling showed that the relationship between cortisol clearance and insulin sensitivity was independent of body fat. The relationship between fatty liver and insulin sensitivity was significantly influenced by body fat and cortisol clearance.

CONCLUSIONS/INTERPRETATION

Cortisol clearance is strongly associated with insulin sensitivity, independently of the amount of body fat. The relationship between fatty liver and insulin sensitivity is mediated in part by both fatness and cortisol clearance.

Body composition and functional limitation in COPD

Background

Low body mass index has been associated with increased mortality in severe COPD. The impact of body composition earlier in the disease remains unclear. We studied the impact of body composition on the risk of functional limitation in COPD.

Methods

We used bioelectrical impedance to estimate body composition in a cohort of 355 younger adults with COPD who had a broad spectrum of severity.

Results

Among women, a higher lean-to-fat ratio was associated with a lower risk of self-reported functional limitation after controlling for age, height, pulmonary function impairment, race, education, and smoking history (OR 0.45 per 0.50 increment in lean-to-fat ratio; 95% CI 0.28 to 0.74). Among men, a higher lean-to-fat ratio was associated with a greater distance walked in 6 minutes (mean difference 40 meters per 0.50 ratio increment; 95% CI 9 to 71 meters). In women, the lean-to-fat ratio was associated with an even greater distance walked (mean difference 162 meters per 0.50 increment; 95% CI 97 to 228 meters). In women, higher lean-to-fat ratio was also associated with better Short Physical Performance Battery Scores. In further analysis, the accumulation of greater fat mass, and not the loss of lean mass, was most strongly associated with functional limitation among both sexes.

Conclusion

Body composition is an important non-pulmonary impairment that modulates the risk of functional limitation in COPD, even after taking pulmonary function into account. Body composition abnormalities may represent an important area for screening and preventive intervention in COPD.

Prediction of visceral fat area in Japanese adults: proposal of prediction method applicable in a field setting

OBJECTIVE

This study aimed to develop a prediction equation for the visceral fat area at the umbilical level (VFA(L4-5)) in Japanese adults, using internal fat mass (IFM) estimated from a few anthropometric variables.

METHODS

Subjects were 112 adults aged from 25 to 82 years (body mass index (BMI)=24.2+/-3.1 kg/m(2), ranged from 15.7 to 31.2 kg/m(2)). Another 60 adults aged from 21 to 71 years were recruited for the crossvalidation group (BMI=24.5+/-4.0 kg/m(2), ranged from 17.1 to 34.6 kg/m(2)). We examined (1) the prediction of IFM based on a small number of skinfold thicknesses; (2) the prediction of VFA(L4-5) using IFM and (3) the application of bioelectrical impedance analysis (BIA) measurement. VFA(L4-5) was measured by computed tomography (reference value). Total fat mass was measured by dual-energy X-ray absorptiometry (DXA) and single-frequency BIA with 8-point tactile electrodes.

RESULTS

Three skinfolds at the abdomen, side chest and suprailiac were selected to estimate IFM. From IFM estimated using these three skinfolds, waist-to-hip ratio (WHR), sex and age, about 75% of the variance of VFA(L4-5) could be explained (Eq(VFA)1: R=863, R(2)=0.745, standard error of estimate (s.e.e.)=20.483 cm(2)). When substituting IFM based on BIA measurement (IFM(BIA)) into Eq(VFA)1, there were no significant mean differences from the reference in both equations, and high correlations were found (r=0.860, s.e.e.=20.902 cm(2)), although a significant mean difference in total fat mass was found between DXA and BIA measurements. The prediction equation using IFM(BIA) (Eq(VFA)2) could have prediction accuracy comparable with that of Eq(VFA)1 (Eq(VFA)2: R=879, R(2)=0.773, s.e.e.=20.324 cm(2)). Furthermore, when applying these equations to the crossvalidation group, there were cross-validity in both equations.

CONCLUSION

This study proposed a prediction equation for VFA(L4-5) from WHR and IFM based on three skinfolds, and the validity of BIA measurement in Japanese adults. We can propose the procedure for a field setting.

Sagittal abdominal diameter: no advantage compared with other anthropometric measures as a correlate of components of the metabolic syndrome in elderly from the Hoorn Study

BACKGROUND

The sagittal abdominal diameter has been proposed as a useful measure by which to estimate abdominal obesity and as being more strongly related to components of the metabolic syndrome than are other anthropometric measures.

OBJECTIVE

The objective was to study which anthropometric measure (ie, sagittal abdominal diameter, waist circumference, waist-to-hip ratio, waist-to-height ratio, or body mass index) is the strongest correlate of components of the metabolic syndrome (ie, glucose and lipid concentrations and blood pressure) in the elderly.

DESIGN

The Hoorn Study is a population-based cohort study in older Dutch men and women. Cross-sectional data were analyzed. Age-adjusted Pearson correlations of anthropometric measures with components of the metabolic syndrome were calculated in 826 subjects (389 men, 437 women) aged 56-83 y. Analyses were performed with adjustment for age and stratification for sex and age (<65 or >/=65 y).

RESULTS

No single anthropometric measure was consistently correlated more strongly with components of the metabolic syndrome than were the other measures in either men or women. The associations were generally stronger in younger subjects than in older subjects and in women than in men. For example, the correlation between sagittal abdominal diameter and postload glucose was 0.35 (P < 0.001) in younger and 0.14 (P = 0.051) in older men, and the correlation between waist circumference and postload glucose was 0.33 (P < 0.001) in older women and 0.14 (P = 0.062) in older men.

CONCLUSION

The use of sagittal abdominal diameter has no advantages over simpler and more commonly used anthropometric measures such as the waist circumference in older men and women.

GH peak response to GHRH-arginine: relationship to insulin resistance and other cardiovascular risk factors in a population of adults aged 50-90

OBJECTIVE

To assess the GH response to GHRH-arginine in apparently healthy adults in relation to cardiovascular risk factors.

DESIGN

Cross-sectional.

PATIENTS

Eighty-six male and female volunteers aged 50-90.

MEASUREMENTS

GH peak response to GHRH-arginine and cardiovascular risk factors, including obesity, insulin resistance, low levels of high density lipoprotein (HDL) cholesterol, elevated triglycerides, and hypertension. The primary outcome measurement was GH response to GHRH-arginine. The relationship between GH peak responses and cardiovascular risk factors was determined after data collection.

RESULTS

GH peaks were highly variable, ranging from 2.3 to 185 microg/l (14% with GH peaks < 9 microg/l). An increasing number of cardiovascular risk factors were associated with a lower mean GH peak (P < 0.0001). By univariate analysis, fasting glucose, insulin, body mass index (BMI), HDL cholesterol and triglycerides were significantly associated with GH peak (all P < 0.0001). Multiple regression analysis revealed that fasting glucose, fasting insulin, BMI, triglycerides and sex accounted for 54% of GH peak variability. The role of abdominal fat as it relates to GH peak was explored in a subset of 45 subjects. Trunk fat and abdominal subregion fat measured by dual energy X-ray absorptiometry (DXA) were inversely related to GH peak (P < 0.008 and 0.001, respectively). Analysis of this subgroup by multiple regression revealed that subregion abdominal fat became the significant obesity-related determinant of GH peak, but still lagged behind fasting insulin and glucose.

CONCLUSIONS

GH response to secretagogues was highly variable in apparently healthy adults aged 50-90 years. Peak GH was significantly related to fasting glucose, insulin, BMI, HDL cholesterol, triglycerides, trunk fat and abdominal subregion fat, with fasting glucose ranking first by multiple regression analysis. There was a strong relationship between cardiovascular risk factors and low GH, with individual risk factors being additive. Although these data do not differentiate between low GH being a cause or an effect of these cardiovascular risk factors, they indicate that the relationship between low GH and increased cardiovascular risk may be physiologically important in the absence of pituitary disease.

Níveis de intervenção para obesidade abdominal: prevalência e fatores associados

Estudo transversal de base populacional na Cidade de Pelotas, Sul do Brasil, entre 1999 e 2000, para descrever a distribuição de adiposidade abdominal na população de acordo com os níveis de intervenção e identificar fatores de risco. O estudo incluiu uma amostra de 1.935 adultos (20-69 anos) residentes na zona urbana do município. Obesidade abdominal foi classificada como nível I para circunferência da cintura (CCnI) de 80-88cm em mulheres e de 94-102cm em homens; e nível II (CCnII) > 88cm para mulheres e > 102cm para homens. Apresentavam obesidade abdominal 62% das mulheres e 37% dos homens. Os valores de CCnI foram 23% e 19% e de CCnII 39% e 19%, para mulheres e homens, respectivamente. Após ajuste para fatores de confusão, o aumento da idade e estar casado ou vivendo em união, em homens e mulheres, mantiveram-se fortemente associadas com CCnII. Escolaridade manteve-se como fator de risco apenas para homens e renda familiar apenas para mulheres, nas quais, o efeito da renda manteve-se inversamente associado com a obesidade abdominal. A utilização da medida da CC deveria ser incorporada às ações de promoção à saúde, principalmente, no acompanhamento e monitoramento da população.

Validity of body mass index and waist circumference in the classification of obesity as compared to percent body fat in Chinese middle-aged women

OBJECTIVE

To evaluate the validity of currently recommended obesity cutoffs of body mass index (BMI, in kg/m(2)) and waist circumference (WC, in cm) for Asians by the WHO/IASO/IOTF and for Chinese by the Working Group on Obesity in China (WGOC) using the percentage body fat (%BF)-obesity criteria.

DESIGN

A cross-sectional study.

SUBJECTS

A total of 1122 community-based Hong Kong Chinese women aged between 41 and 63 years.

MEASUREMENTS

Total %BF and percent truncal fat (%TF) were measured using dual-energy X-ray absorptiometry. Anthropometric indices were measured using standard methods.

RESULTS

Regression analyses showed that the BMI cutoffs of 23, 24, 25, and 28 kg/m(2) corresponded to the %BF of 34.8, 35.9, 36.9 and 39.5%, and the 80 cm WC corresponded to 34% TF, respectively. Compared with the %BF obesity cutoff (>/=40%), the WHO/IASO/IOTF BMI-obesity criterion (>/=25) shows a good sensitivity (75%) and specificity (71%); and the WGOC criterion (BMI>/=28) had a low sensitivity (41%) but an excellent specificity (93%), respectively. Corresponding to the BMI cutoffs of 23, 24, 25 and 28 kg/m(2), the %BF cutoffs associated with peak kappa statistic were 33, 34, 35 and 40%, and the relevant %TF linked with 80 cm WC was 33%, respectively.

CONCLUSION

BMI and WC have a good accuracy in the prediction of obesity. Our findings suggest that the WGOC BMI cutoffs are appropriate, but 80 cm of WC is a very rigorous cutoff for this population when using the criteria of 34 and 40% of body fat or truncal fat for overweight and obesity.

Favourable association of leg fat with cardiovascular risk factors

OBJECTIVES

To assess the association of trunk and leg fat mass (FM) and leg lean tissue mass (LTM) with conventional cardiovascular risk factors.

DESIGN

Cross-sectional study.

SETTING AND SUBJECTS

We studied 1249 men and 3007 women (age 20-79 years) who attended a research institute for a health checkup between October 1995 and February 2004.

MAIN OUTCOME MEASURES

Body mass index, waist circumference (WC), hip circumference (HC), systolic and diastolic blood pressure, total cholesterol, HDL cholesterol, triglycerides, glucose and haemoglobin A(1C) were measured. Trunk FM, leg FM and leg LTM were obtained by dual-energy X-ray absorptiometry. We evaluated the associations between the indices for regional body composition and cardiovascular risk factors, which included hypertension, hypercholesterolaemia, hypo-HDL cholesterolaemia, hypertriglyceridaemia, dyslipidaemia and diabetes mellitus.

RESULTS

Increase in WC and HC respectively showed increase and decrease in odds ratios of cardiovascular risk factors. Increase in trunk FM by 1 kg significantly increased the risk of the cardiovascular risk factors with the odds ratios ranging between 1.11 and 1.45. Increase in leg FM by 1 kg significantly decreased the risk with the odds ratios ranging between 0.52 and 0.90, except for the nonsignificant results for hypercholesterolaemia and hypo-HDL cholesterolaemia in men. Odds ratios of 1 kg increase in leg LTM were only significant for dyslipidaemia in men and hypercholesterolaemia in women (both 0.93).

CONCLUSIONS

WC and HC showed opposite and independent associations with cardiovascular risk factors. The favourable association of HC was mainly attributable to that of leg FM.

Endocrine control of body composition in infancy, childhood, and puberty

Body composition exhibits marked variations across the early human lifetime. The precise physiological mechanisms that drive such developmental adaptations are difficult to establish. This clinical challenge reflects an array of potentially confounding factors, such as marked intersubject differences in tissue compartments; the incremental nature of longitudinal intrasubject variations in body composition; technical limitations in quantitating the unobserved mass of mineral, fat, water, and muscle ad seriatim; and the multifold contributions of genetic, dietary, environmental, hormonal, nutritional, and behavioral signals to physical and sexual maturation. From an endocrine perspective (reviewed here), gonadal sex steroids and GH/IGF-I constitute prime determinants of evolving body composition. The present critical review examines hormonal regulation of body composition in infancy, childhood, and puberty.

Physical activity minimizes the association of body fatness with abdominal obesity in white, premenopausal women: Results from the Third National Health and Nutrition Examination Survey

This study explored the association of physical activity with body fatness and abdominal obesity in 1,004 premenopausal white women who participated in the Third National Health and Nutrition Examination Survey. Physical activity was classified into four levels based on fitness criteria from the American College of Sports Medicine. Standard protocols were used for measuring body mass index (BMI), percent body fat, and waist-to-hip ratio (WHR). Means for BMI, percent body fat, and WHR were calculated for each physical activity level. Analysis of variance procedures were performed, followed by pair-wise comparisons, to determine differences among means and for trends. Mean BMI, percent body fat, and WHR were significantly less ( P < .001) at each higher physical activity level except between Levels 0 and 1. The ability of increased daily physical activity to minimize age-related increases in abdominal obesity could be a strong incentive for women approaching menopause to become more physically active.

Novel associations between bioavailable estradiol and adipokines in elderly women with different phenotypes of obesity: implications for atherogenesis

BACKGROUND

Peripheral adiposity confers protection against diabetes and atherosclerosis in elderly women. The underlying mechanisms, however, remain to be elucidated.

METHODS AND RESULTS

On the basis on dual-energy X-ray absorptiometry measurements of central fat mass (CFM) and peripheral fat mass (PFM), we identified 290 elderly women with distinct forms of body fat distribution (lean, peripheral obesity, central obesity, or general obesity). Study parameters were plasma tumor necrosis factor-alpha, interleukin (IL)-6, adiponectin, estradiol, sex hormone-binding globulin, insulin resistance, and aortic calcification, graded on lateral radiography. In peripherally and generally obese women, plasma estradiol and insulin resistance were significantly lower, whereas sex hormone-binding globulin and adiponectin were significantly higher compared with centrally obese women independent of age, body mass index, total fat mass, and smoking habits (all P<0.05). After adjustment for these confounders, IL-6 in centrally obese women was comparable with that seen in generally obese (similar high CFM%) but significantly higher than in peripherally obese women and lean women (low CFM%). Atherosclerosis was less severe in generally obese (2.5+/-0.3) compared with centrally obese women (5.0+/-0.7, P=0.001). In multiple regression analysis, total fat mass, body fat distribution, insulin resistance, estradiol, current smoking, treated hyperlipidemia, and treated hypertension contributed independently to the variation of aortic calcification (R=0.55, SEE=3.60, P<0.001).

CONCLUSIONS

Abundant presence of PFM in generally obese women is associated with increased plasma adiponectin and higher insulin sensitivity, which could explain the apparent protection against the atherogenic effects of IL-6 derived from CFM. Low peripheral exposure to estradiol appears to be a sine qua non of maintained adiponectin secretion from PFM.

Hip girth as a predictor of abdominal adiposity in postmenopausal women

OBJECTIVES

Our primary objective was to determine whether hip girth could accurately predict abdominal fat and total body fat in postmenopausal women. A secondary objective was to investigate the relation between body mass index (BMI) and hip girth in postmenopausal women.

METHODS

Body weight, height, girths, skinfolds, and whole-body dual-energy x-ray absorptiometric scans were obtained in 75 postmenopausal women ages 45 to 76 y. Total body fat, abdominal fat, and the ratio of abdominal fat to lean mass (F:L) were calculated from the dual-energy x-ray absorptiometric scans. Equations predicting total and abdominal fat were developed for 50 subjects by using stepwise multiple regression analysis. These equations were then cross-validated in the remaining 25 subjects.

RESULTS

Hip girth was a strong predictor of total fat (r = 0.86, P < 0.0001, standard error of the estimate = 4.9 kg) and abdominal fat (r = 0.92, P < 0.0001, standard error of estimate = 0.84 kg); with age added, the standard errors of the estimate were 3.8 and 0.8 kg, respectively. Hip girth correlated with BMI (r = 0.89, P < 0.0001). The "healthy" BMI cutoff value lower than 25 kg/m2 equated to a hip girth smaller than 100 cm and an abdominal F:L lower than 1.0. Waist girth (r = 0.83, P < 0.0001) and hip girth (r = 0.76, P < 0.0001) were good predictors of abdominal F:L.

CONCLUSIONS

Hip girth is a practical and useful predictor of abdominal and total adiposity in postmenopausal women. A hip girth of 100 cm or an abdominal F:L of 1.0 can be used as an equivalent cutoff value for the "healthy" BMI value of 25 kg/m2 in this group of women.

Sagittal abdominal diameter is a strong anthropometric marker of insulin resistance and hyperproinsulinemia in obese men

OBJECTIVE

It is clinically important to find noninvasive markers of insulin resistance and hyperproinsulinemia because they both predict cardiovascular and diabetes risk. Sagittal abdominal diameter (SAD) or "supine abdominal height" is a simple anthropometric measure previously shown to predict mortality in men, but its association with insulin resistance and hyperproinsulinemia is unknown.

RESEARCH DESIGN AND METHODS

In a common high-risk group of 59 moderately obese men (aged 35-65 years, BMI 32.6 +/- 2.3 kg/m(2)), we determined anthropometry (SAD, BMI, waist girth, and waist-to-hip ratio [WHR]); insulin sensitivity (euglycemic-hyperinsulinemic clamp); and plasma concentrations of intact proinsulin, specific insulin, C-peptide, glucose, and serum IGF binding protein-1 (IGFBP-1). To compare SAD with other anthropometric measures, univariate and multiple regression analyses were used to determine correlations between anthropometric and metabolic variables.

RESULTS

SAD showed stronger correlations to all measured metabolic variables, including insulin sensitivity, than BMI, waist girth, and WHR. SAD explained the largest degree of variation in insulin sensitivity (R(2) = 0.38, P < 0.0001) compared with other anthropometric measures. In multiple regression analyses, including all anthropometric measures, SAD was the only independent anthropometric predictor of insulin resistance (P < 0.001) and hyperproinsulinemia (P < 0.001).

CONCLUSIONS

In obese men, SAD seems to be a better correlate of insulin resistance and hyperproinsulinemia (i.e., cardiovascular risk) than other anthropometric measures. In overweight and obese individuals, SAD could represent a simple, cheap, and noninvasive tool that could identify the most insulin resistant in both the clinic and clinical trials evaluating insulin sensitizers. These results need confirmation in larger studies that also include women and lean subjects.

Generalized abdominal visceral fat prediction models for black and white adults aged 17–65 y: the HERITAGE Family Study

OBJECTIVE

To determine if the relationship between abdominal visceral fat (AVF) and measures of adiposity are different between Black and White subjects and to develop valid field prediction models that accurately identify those individuals with AVF levels associated with high risk for chronic disease.

DESIGN

Cross-sectional measurements obtained from 91 Black men, 137 Black women, 227 White men, and 237 White women subjects, ages 17-65 y, who were participants in the HERITAGE Family Study, both at baseline and following 20 weeks of endurance training.

MEASUREMENTS

AVF, abdominal subcutaneous fat (ASF), abdominal total fat (ATF), and sagittal diameter (SagD) were measured by computed tomography (CT). Body density was determined by hydrostatic weighing and was used to estimate relative body fat. Arm, waist (WC), and hip circumferences and skinfold thickness measures were taken, and BMI was calculated from weight (kg) and height (m(2)). Since CT abdominal fat variables were skewed, a natural log transformation (Ln) was used to produce a normal distribution. The General Linear Model (GLM) procedure was used to test the relationship between AVF and two different groups of variables-CT and anthropometric.

RESULTS

The AVF of White men and women was significantly higher than that of Black men and women, independent of BMI, WHR, WC, and age, and was greater for men than for women. The CT model showed that the combination of SagD, Ln (ASF), age, and race accounted for 84 and 75% of the variance in AVF in men and women, respectively. The anthropometric model provided two valid generalized field AVF prediction equations. The Field-I equation, which included BMI, WHR, age and race, had an r(2) of 0.78 and 0.73 for men and women, respectively. The Field-II equation, which included BMI (women only), WC, age, and race, had an r(2) of 0.78 and 0.72 for men and women, respectively. The field model equations became less accurate as the estimated AVF increased.

CONCLUSIONS

(1) At the same age and level of adiposity, Black men and women have less AVF than White men and women. These differences are greater in men than in women. (2) The field regression equations can be generalized to the diverse group of adults studied, both in an untrained and trained state. However, their accuracy decreases with increasing levels of AVF.

Effect of a one-year combined exercise training program on body composition in men with coronary artery disease

Increased fat mass, particularly abdominal fat mass, is associated with poor metabolic profiles and an increase in cardiovascular risk factors. The purpose of this study was to evaluate the effect of a 1-year combined aerobic and strength training regimen, compared to aerobic training only, on body composition in patients with coronary artery disease (CAD). Thirty-six males with CAD were assigned to 3 groups: 13 to weight training plus aerobic training (combined training group [CT]), 13 to aerobic training only (aerobic training group [AT]), and 10 to a control group (no exercise [CG]). Body composition was determined by dual-energy x-ray absorptiometry (DEXA). Differences were observed between groups at the end of the study, controlling for prevalues. The total and trunk percent fat mass (%FM) were lower in CT compared with AT and CG (P<.05). The total %FM in AT was significantly (P<.05) lower than in CG, but the %FM of the trunk did not differ between the 2 groups. Fat-free mass (FFM) was significantly higher in CT than in AT and CG (P<.05). The results suggest that a long-term CT program is more effective than an AT program alone in producing changes in body composition. The percentage changes in total and trunk fat mass were higher in CT (-11% and -12%, respectively) than in AT (-2.4% and -0.7%, respectively). Future studies need to investigate the specific health effects of trunkal fat mass loss in patients with CAD.

Determination of height, weight, body mass index, and body surface area with a single abdominal CT image

Techniques for estimation of an individual's height, weight, body mass index (BMI), and body surface area (BSA) with a single abdominal computed tomographic (CT) image were developed. Eighty-seven abdominal CT examinations performed in adult humans were analyzed. Anatomic structures were outlined on the CT section that included L1. Multiple linear regression analysis was used to derive sex-specific predictive equations. Correlation for height was good (r > 0.65). Relationship between predicted weight and actual weight was good (r > 0.93). For BMI and BSA, r was greater than 0.893 and greater than 0.895, respectively. In this study, predictive equations for height, weight, BMI, and BSA were generated.

Isoflavone-rich soy protein prevents loss of hip lean mass but does not prevent the shift in regional fat distribution in perimenopausal women

OBJECTIVE

Menopause-induced estrogen deficiency increases the risk of cardiovascular disease, which is related to a shift in regional fat distribution. We tested the hypothesis that estrogen-like isoflavones in soy protein isolate (SPI+) would lessen both regional fat gain and lean loss compared with isoflavone-poor soy (SPI-).

DESIGN

Perimenopausal participants (N = 69) were randomly assigned (double-blind) to 24 weeks of treatment (40 g soy or whey protein per day): SPI+ (n = 24), SPI- (n = 24), or whey control (n = 21); each participant had blood drawn in the fasted (12 hours) state, had physical activity assessed, and kept a 5-day food diary. Dual-energy x-ray absorptiometry was used to examine the effects of SPI+ on regional fat and lean tissue distribution changes in the waist, hip, and thigh regions.

RESULTS

Mean body mass increased (P < 0.01) in each group, but treatment had no effect on gain in overall body mass, fat mass, or lean mass using analysis of variance. In all treatment groups combined, lean mass increased in each region; fat mass increased only in the waist region. Treatment had an effect (P = 0.039) on hip lean mass and a marginal effect (P = 0.077) on thigh fat. Regression analyses revealed that SPI+ diminished the increase in thigh fat (P = 0.018) and heightened the increase in hip lean (P = 0.035) mass. Carbohydrate intake (P = 0.006) and cohort (reflective of season; P = 0.011) contributed to the gain in thigh fat. Total protein intake (P = 0.0012), plasma insulin (P = 0.0034), and physical activity (P = 0.047) contributed to the gain in hip lean mass.

CONCLUSIONS

Gain in hip lean mass was greater (P = 0.014) in SPI+ than other groups, but SPI+ did not reduce the disease-promoting menopausal shift in regional fat mass.

Detection of segmental internal fat by bioelectrical impedance analysis in a biological phantom

OBJECTIVE

Quantification of internal adipose tissue such as visceral adipose tissue currently relies on expensive, cross-sectional imaging modalities. The purpose of this study was to test the hypothesis that surface impedance, determined by bioimpedance analysis, might be used to predict regional internal fat content change in a phantom model.

METHODS

Fresh hollowed-out cucumbers were used as cylindrical biological phantoms to test this hypothesis. After removal of the seeds, the cucumbers were filled with normal saline, mixture of saline and corn oil, or porcine adipose tissue bathed in saline. Surface resistance and reactance were measured with a bioimpedance analyzer accurate to 0.1 Omega (Quantum 10X, RJL Systems), and impedance was calculated. A linear regression model was used to interpret the association between composition and impedance.

RESULTS

Surface impedance varied linearly with changes in the relative internal corn oil portions (r- = 0.98). A similar relation was noted with porcine adipose tissue bathed in saline (r(2) = 0.95) regardless of the specific position of adipose tissue within the cucumber.

CONCLUSION

Surface impedance measured by bioimpedance analysis can detect variations in fat content in the interior of a cylindrical phantom.

Comparisons of waist circumferences measured at 4 sites

BACKGROUND

Waist circumference (WC) is now accepted as a practical measure of adipose tissue distribution. Four body sites for WC measurements are commonly used, as follows: immediately below the lowest ribs (WC1), the narrowest waist (WC2), the midpoint between the lowest rib and the iliac crest (WC3), and immediately above the iliac crest (WC4).

OBJECTIVE

We sought to compare the magnitude and reliability of WC measured at these 4 sites in males and females.

DESIGN

WC was measured at each site 1 time in all subjects [49 males and 62 females, aged 7-83 y, with a body mass index (in kg/m(2)) of 9-43] and 3 times in a subgroup (n = 93) by one experienced observer using a heavy-duty inelastic tape. Body fat was measured in a subgroup (n = 74) with the use of dual-energy X-ray absorptiometry.

RESULTS

The mean values of WC were WC2 < WC1 < WC3 < WC4 (P < 0.01) in females and WC2 < WC1, WC3, and WC4 (P < 0.01) in males. For all 4 sites, measurement reproducibility was high, with intraclass correlation (r) values > 0.99. WC values were significantly correlated with fatness; correlations with trunk fat were higher than correlations with total body fat in both sexes.

CONCLUSIONS

WC values at the 4 commonly used anatomic sites differ in magnitude depending on sex, are highly reproducible, and are correlated with total body and trunk adiposity in a sex-dependent manner. These observations have implications for the use of WC measurements in clinical practice and patient-oriented research.