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

Prediction of future visceral adiposity and application to cancer research: The Multiethnic Cohort Study

BACKGROUND

We previously developed a prediction score for MRI-quantified abdominal visceral adipose tissue (VAT) based on concurrent measurements of height, body mass index (BMI), and nine blood biomarkers, for optimal performance in five racial/ethnic groups. Here we evaluated the VAT score for prediction of future VAT and examined if enhancement with additional biomarkers, lifestyle behavior information, and medical history improves the prediction.

METHODS

We examined 500 participants from the Multiethnic Cohort (MEC) with detailed data (age 50-66) collected 10 years prior to their MRI assessment of VAT. We generated three forecasted VAT prediction models: first by applying the original VAT equation to the past data on the predictors ("original"), second by refitting the past data on anthropometry and biomarkers ("refit"), and third by building a new prediction model based on the past data enhanced with lifestyle and medical history ("enhanced"). We compared the forecasted prediction scores to future VAT using the coefficient of determination (R2). In independent nested case-control data in MEC, we applied the concurrent and forecasted VAT models to assess association of the scores with subsequent incident breast cancer (950 pairs) and colorectal cancer (831 pairs).

RESULTS

Compared to the VAT prediction by the concurrent VAT score (R2 = 0.70 in men, 0.68 in women), the forecasted original VAT score (R2 = 0.54, 0.48) performed better than past anthropometry alone (R2 = 0.47, 0.40) or two published scores (VAI, METS-VF). The forecasted refit (R2 = 0.61, 0.51) and enhanced (R2 = 0.62, 0.55) VAT scores each showed slight improvements. Similar to the concurrent VAT score, the forecasted VAT scores were associated with breast cancer, but not colorectal cancer. Both the refit score (adjusted OR for tertile 3 vs. 1 = 1.27; 95% CI: 1.00-1.62) and enhanced score (1.27; 0.99-1.62) were associated with breast cancer independently of BMI.

CONCLUSIONS

Predicted VAT from midlife data can be used as a surrogate to assess the effect of VAT on incident diseases associated with obesity, as illustrated for postmenopausal breast cancer.

A systematic review of economic evaluations of interventions targeting childhood overweight and obesity

This systematic review critically appraised and synthesized evidence from economic evaluations of interventions targeting childhood excess weight. We conducted systematic searches in 11 databases from inception to April 19, 2023. Studies were eligible if they evaluated interventions targeting children up to 18 years and the study intervention(s) targeted childhood excess weight or sought to improve diet or physical activity, regardless of the type of economic evaluation or the underpinning study design. We synthesized evidence using narrative synthesis methods. One-hundred fifty-one studies met the eligibility criteria and were classified into three groups based on the intervention approach: prevention-only (13 studies), prevention and treatment (100 studies), and treatment-only (38 studies). The predominant setting and study design differed considerably between the three groups of studies. However, compared with usual care, most interventions were deemed cost-effective. The study participants' ages, sex, and socioeconomic status were crucial to intervention cost-effectiveness. Interventions whose effects were projected beyond childhood, such as bariatric surgery, lower protein infant formula, and home-based general practitioner consultations, tended to be cost-effective. However, cost-effectiveness was sensitive to the assumptions underlying the persistence and intensity of such effects. Our findings can inform future recommendations on the conduct of economic evaluations of interventions targeting childhood overweight and obesity, as well as practice and policy recommendations.

Estimation of visceral fat area using criteria for metabolic syndrome: A cross-sectional study

BACKGROUND AND AIMS

The aim of this study was to calculate the visceral fat area (VFA) based on the criteria for metabolic syndrome (MetS).

METHODS

A multiple regression analysis was performed to determine the estimated VFA using data from Japanese participants (2315 men and 1684 women). Receiver operating characteristic curve (ROC) analyses were performed to determine the optimal estimated VFA cutoff for the diagnosis of central obesity. The cutoff was also applied to a second cohort to validate the model.

RESULTS

The estimated VFA was calculated using the MetS criteria, age, and body mass index (adjusted coefficient of determination = 0.682 for men and 0.726 for women). The area under the ROC curve for waist circumference, VFA, and estimated VFA were 0.669, 0.741, and 0.749, respectively, for men and 0.711, 0.787, and 0.803, respectively, for women. The optimal cutoffs for estimated VFA were 128.1 cm² for men and 82.2 cm² for women. Multivariate logistic regression for heart disease revealed that estimated VFA, rather than waist circumference, was associated with a high risk of heart disease.

CONCLUSION

The estimated VFA is a better index of central obesity than waist circumference and VFA for the diagnosis of MetS.

Evaluation of the Value of Waist Circumference and Metabolomics in the Estimation of Visceral Adipose Tissue

Visceral adipose tissue (VAT) is a strong prognostic factor for cardiovascular disease and a potential target for cardiovascular risk stratification. Because VAT is difficult to measure in clinical practice, we estimated prediction models with predictors routinely measured in general practice and VAT as outcome using ridge regression in 2,501 middle-aged participants from the Netherlands Epidemiology of Obesity study, 2008-2012. Adding waist circumference and other anthropometric measurements on top of the routinely measured variables improved the optimism-adjusted R2 from 0.50 to 0.58 with a decrease in the root-mean-square error (RMSE) from 45.6 to 41.5 cm2 and with overall good calibration. Further addition of predominantly lipoprotein-related metabolites from the Nightingale platform did not improve the optimism-corrected R2 and RMSE. The models were externally validated in 370 participants from the Prospective Investigation of Vasculature in Uppsala Seniors (PIVUS, 2006-2009) and 1,901 participants from the Multi-Ethnic Study of Atherosclerosis (MESA, 2000-2007). Performance was comparable to the development setting in PIVUS (R2 = 0.63, RMSE = 42.4 cm2, calibration slope = 0.94) but lower in MESA (R2 = 0.44, RMSE = 60.7 cm2, calibration slope = 0.75). Our findings indicate that the estimation of VAT with routine clinical measurements can be substantially improved by incorporating waist circumference but not by metabolite measurements.

Does Education Close the Black-White Physical Activity and Obesity Gaps?

Objective: The purpose of the study was to investigate physical activity patterns and body mass index (BMI) among black and white women in college to determine if attending college acts as a catalyst for sustaining physical activity and for closing the black-white physical activity and obesity gaps. Participants/Methods: 111 undergraduate women (black N = 42; white N = 69) aged 18-25 volunteered to wear Fitbit Zip^TM activity trackers for 7 days. Height and weight measurements were used to compute BMI. Results: White women had higher levels of physical activity, lower weight status, and lower BMIs than black women. Conclusions: Racial disparities were evident; however, both groups had low to moderate levels of physical activity. Required physical education programing that targets women in college could lead to sustained physical activity.

Sex-and race-specific associations of protein intake with change in muscle mass and physical function in older adults: the Health, Aging, and Body Composition (Health ABC) Study

BACKGROUND

Protein intake recommendations advise ≥0.8 g/kg body weight (BW)/d, whereas experts propose a higher intake for older adults (1.0-1.2 g/kg BW/d). It is unknown whether optimal protein intake differs by sex or race.

OBJECTIVES

We examined the shape of sex- and race-specific associations of dietary protein intake with 3- and 6-y changes in appendicular lean mass (aLM) and gait speed and also 6-y incidence of mobility limitation in community-dwelling older men and women.

METHODS

We used data on men (n = 1163) and women (n = 1237) aged 70-81 y of the Health, Aging, and Body Composition Study. Protein intake was assessed using an FFQ (1998-1999). aLM and gait speed were measured at baseline and at 3 and 6 y. Difficulty walking one-quarter mile or climbing stairs was measured every 6 mo over 6 y. Prospective associations were evaluated with linear and Cox regression models, comparing fit of models with and without spline functions. All analyses were stratified by sex and additionally by race.

RESULTS

Mean ± SD protein intake was 0.94 ± 0.36 g/kg adjusted body weight (aBW)/d in men and 0.95 ± 0.36 g/kg aBW/d in women. There were no strong indications of nonlinear associations. In women, higher protein intake was associated with less aLM loss over 3 y (adjusted B per 0.1 g/kg aBW/d: 39.4; 95% CI: 11.6, 67.2), specifically in black women, but not over 6 y or with gait speed decline. In men, protein intake was not associated with changes in aLM and gait speed. Higher protein intake was associated with a lower risk of mobility limitation in men (adjusted HR per 1.0 g/kg aBW/d: 0.55; 95% CI: 0.34, 0.91) and women (adjusted HR: 0.56; 95% CI: 0.33, 0.94), specifically white women.

CONCLUSIONS

Associations between protein intake and physical outcomes may vary by sex and race. Therefore, it is important to consider sex and race in future studies regarding protein needs in older adults.

Do the Same Central Anthropometric Variables that Best Predict Blood Pressure in European Americans also Best Predict Blood Pressure in African Americans?

Objective

The purpose of this study was to determine if central anthropometric variables that best estimate blood pressure risks in European Americans also best estimate blood pressure risks in African Americans.

Design

The participants were 357 normotensive African and European American volunteers with a mean age of 32.6 ± 12.4 years. Participants were evaluated for central adiposity with dual energy X-ray absorptiometry, abdomen and thigh skinfolds, waist and hip circumferences, waist/hip ratio, waist/height ratio, body mass index, and systolic and diastolic blood pressures. Descriptive statistics, partial correlations, ANOVA and stepwise regressions were used to analyze the data.

Results

Central adiposity anthropometric indices made different contributions to blood pressure in African and European American men and women. When weight was held constant, waist circumference shared stronger partial relationships with blood pressure in African Americans (r = .30 to .47) than in European Americans (r = .11 to .32). Waist circumference in combination with other indices was a predictor of systolic and diastolic blood pressures in European American men (P<.05) but only a predictor for diastolic blood pressure in African American men and women (P<.01). Hip circumference was the only predictor for systolic blood pressure (P<.01) in African American men and women.

Conclusions

Further research on the relative contributions of central anthropometric indices to blood pressure in African and European Americans is warranted. A better understanding of this relationship may help reduce hypertensive morbidity and mortality disparities between African and European Americans.

Trunk Muscle Composition 2 Months After Hip Fracture: Findings From the Baltimore Hip Studies

OBJECTIVE

To determine if hip fracture patients would have smaller cross-sectional area (CSA) and lower radiological attenuation (suggesting greater fat infiltration) in all trunk muscles as compared to older adults without hip fractures.

DESIGN

Cross-sectional analysis of computed tomography (CT) scans.

SETTING

Clinical imaging facility.

PARTICIPANTS

Forty-one white participants (19 men, 22 women) from the Baltimore Hip Studies seventh cohort at 2 months postfracture were compared to 693 white participants (424 men, 269 women) from the Health, Aging and Body Composition (Health ABC) study at the year 6 visit (N=734).

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Trunk muscle CSA and attenuation values were obtained from a single 10-mm, axial CT scan completed at the L4-L5 disc space in each participant.

RESULTS

The hip fracture cohort had significantly smaller CSA for all trunk muscles (range: 12.1%-38% smaller) compared to the Health ABC cohort (P<.01), with the exception of the rectus abdominus muscle in men (P=.12). But, hip fracture patients, particularly female patients, had higher attenuation levels (lower intramuscular fat) in all trunk muscles (P<.0001).

CONCLUSIONS

Findings are consistent with atrophy of the trunk muscles in the hip fracture population without a high level of intramuscular fat. Future work should evaluate the role of trunk muscle composition in the functional recovery of older adults after hip fracture.

Equation to estimate visceral adipose tissue volume based on anthropometry for workplace health checkup in Japanese abdominally obese men

The purpose of this study was to develop a new equation model for predicting abdominal visceral adipose tissue (VAT) volume using anthropometric values for workplace health checkup and to clarify the association between metabolic risk factors and measured and predicted VAT volumes. Two hundred sixty male workers (200 for derivation group and 60 for validation group) participated in the cross-sectional study. The anthropometric variables and VAT volume were measured with 24 consecutive magnetic resonance images. Measurements in the validation group also included metabolic risk factors, i.e. blood pressure, HDL cholesterol, triglyceride, fasting glucose and HbA1c. Using multiple regression analyses for the derivation group, we determined the best prediction equation for abdominal VAT volume with a variance of 47% as follows: 47.03 age+117.79 BMI+74.18 waist circumference -8,792.7. In our validation group, the correlation coefficient between the measured and predicted VAT volumes was 0.74 (p<0.01). Furthermore, blood pressure, fasting glucose and HbA1c correlated with both measured and predicted VAT volumes. This study suggests that the equation model has potential to assess VAT accumulation levels in workers health checkup where CT and MRI are not available.

Associations between dietary patterns, socio-demographic factors and anthropometric measurements in adult New Zealanders: an analysis of data from the 2008/09 New Zealand Adult Nutrition Survey

PURPOSE

To investigate associations between dietary patterns, socio-demographic factors and anthropometric measurements in adult New Zealanders.

METHODS

Dietary patterns were identified using factor analysis in adults 15 years plus (n = 4657) using 24-h diet recall data from the 2008/09 New Zealand Adult Nutrition Survey. Multivariate regression was used to investigate associations between dietary patterns and age, gender and ethnicity. After controlling for demographic factors, associations between dietary patterns and food insecurity, deprivation, education, and smoking were investigated. Associations between dietary patterns and body mass index and waist circumference were examined adjusting for demographic factors, smoking and energy intake.

RESULTS

Two dietary patterns were identified. 'Healthy' was characterised by breakfast cereal, low fat milk, soy and rice milk, soup and stock, yoghurt, bananas, apples, other fruit and tea, and low intakes of pies and pastries, potato chips, white bread, takeaway foods, soft drinks, beer and wine. 'Traditional' was characterised by beef, starchy vegetables, green vegetables, carrots, tomatoes, savoury sauces, regular milk, cream, sugar, tea and coffee, and was low in takeaway foods. The 'healthy' pattern was positively associated with age, female gender, New Zealand European or other ethnicity, and a secondary school qualification, and inversely associated with smoking, food insecurity, area deprivation, BMI and waist circumference. The 'traditional' pattern was positively associated with age, male gender, smoking, food insecurity and inversely associated with a secondary school qualification.

CONCLUSIONS

A 'Healthy' dietary pattern was associated with higher socio-economic status and reduced adiposity, while the 'traditional' pattern was associated with lower socio-economic status.

TM6SF2 rs58542926 variant affects postprandial lipoprotein metabolism and glucose homeostasis in NAFLD

Mechanisms underlying the opposite effects of transmembrane 6 superfamily member 2 (TM6SF2) rs58542926 C>T polymorphism on liver injury and cardiometabolic risk in nonalcoholic fatty liver disease (NAFLD) are unclear. We assessed the impact of this polymorphism on postprandial lipoprotein metabolism, glucose homeostasis, and nutrient oxidation in NAFLD. Sixty nonobese nondiabetic normolipidemic biopsy-proven NAFLD patients and 60 matched controls genotyped for TM6SF2 C>T polymorphism underwent: indirect calorimetry; an oral fat tolerance test with measurement of plasma lipoprotein subfractions, adipokines, and incretin glucose-dependent insulinotropic polypeptide (GIP); and an oral glucose tolerance test with minimal model analysis of glucose homeostasis. The TM6SF2 T-allele was associated with higher hepatic and adipose insulin resistance, impaired pancreatic β-cell function and incretin effect, and higher muscle insulin sensitivity and whole-body fat oxidation rate. Compared with the TM6SF2 C-allele, the T-allele entailed lower postprandial lipemia and nefaemia, a less atherogenic lipoprotein profile, and a postprandial cholesterol (Chol) redistribution from smaller atherogenic lipoprotein subfractions to larger intestinal and hepatic VLDL1 subfractions. Postprandial plasma VLDL1-Chol response independently predicted the severity of liver histology. In conclusion, the TM6SF2 C>T polymorphism affects nutrient oxidation, glucose homeostasis, and postprandial lipoprotein, adipokine, and GIP responses to fat ingestion independently of fasting values. These differences may contribute to the dual and opposite effect of this polymorphism on liver injury and cardiometabolic risk in NAFLD.

Predictors of Treatment Response to Tesamorelin, a Growth Hormone-Releasing Factor Analog, in HIV-Infected Patients with Excess Abdominal Fat

BACKGROUND

Tesamorelin, a synthetic analog of human growth hormone-releasing factor, decreases visceral adipose tissue (VAT) in human immunodeficiency virus (HIV)-infected patients with lipodystrophy.

OBJECTIVES

1) To evaluate the utility of patient characteristics and validated disease-risk scores, namely indicator variables for the metabolic syndrome defined by the International Diabetes Federation (MetS-IDF) or the National Cholesterol Education Program (MetS-NCEP) and the Framingham Risk Score (FRS), as predictors of VAT reduction during tesamorelin therapy at 3 and 6 months, and 2) To explore the characteristics of patients who reached a threshold of VAT <140 cm2, a level associated with lower risk of adverse health outcomes, after 6 months of treatment with tesamorelin.

METHODS

Data were analyzed from two Phase 3 studies in which HIV-infected patients with excess abdominal fat were randomized in a 2:1 ratio to receive tesamorelin 2 mg (n = 543) or placebo (n = 263) subcutaneously daily for 6 months, using ANOVA and ANCOVA models.

RESULTS

Metabolic syndrome (MetS-IDF or MetS-NCEP) and FRS were significantly associated with VAT at baseline. Presence of metabolic syndrome ([MetS-NCEP), triglyceride levels >1.7 mmol/L, and white race had a significant impact on likelihood of response to tesamorelin after 6 months of therapy (interaction p-values 0.054, 0.063, and 0.025, respectively). No predictive factors were identified at 3 months. The odds of a VAT reduction to <140 cm2 for subjects treated with tesamorelin was 3.9 times greater than that of subjects randomized to placebo after controlling for study, gender, baseline body mass index (BMI) and baseline VAT (95% confidence interval [CI] 2.03; 7.44).

CONCLUSIONS

Individuals with baseline MetS-NCEP, elevated triglyceride levels, or white race were most likely to experience reductions in VAT after 6 months of tesamorelin treatment. The odds of response of VAT <140 cm2 was 3.9 times greater for tesamorelin-treated patients than that of patients receiving placebo.

The Interplay Between Sex, Ethnicity, and Adipose Tissue Characteristics

The obesity epidemic in the USA affects disproportionately women and the ethnic minorities. On the other hand, female sex is traditionally associated with a favorable fat distribution preferentially in the subcutaneous depots of the lower body and with improved endocrine and metabolic function of the adipose tissue. However, these data are derived from predominantly non-Hispanic white populations. This review discusses fat distribution patterns in women of diverse ethnic backgrounds, together with data on the release of adipokines from adipose tissue in these populations. Very little information is available on how the metabolic function of the adipocyte differs depending on ethnicity. Thus, it becomes clear that future clinical and translational research should explicitly discuss and take into account the sex and ethnic background of the populations studied.

Ectopic cardiovascular fat in middle-aged men: effects of race/ethnicity, overall and central adiposity. The ERA JUMP study

BACKGROUND/OBJECTIVES

Higher volumes of ectopic cardiovascular fat (ECF) are associated with greater risk of coronary heart disease (CHD). Identifying factors that are associated with ECF volumes may lead to new preventive efforts to reduce risk of CHD. Significant racial/ethnic differences exist for overall and central adiposity measures, which are known to be associated with ECF volumes. Whether racial/ethnic differences also exist for ECF volumes and their associations with these adiposity measures remain unclear.

SUBJECTS/METHODS

Body mass index (BMI), computerized tomography-measured ECF volumes (epicardial, pericardial and their summation) and visceral adipose tissue (VAT) were examined in a community-based sample of 1199 middle-aged men (24.2% Caucasians, 7.0% African-Americans, 23.6% Japanese-Americans, 22.0% Japanese, 23.2% Koreans).

RESULTS

Significant racial/ethnic differences existed in ECF volumes and their relationships with BMI and VAT. ECF volumes were the highest among Japanese-Americans and the lowest among African-Americans. The associations of BMI and VAT with ECF differed by racial/ethnic groups. Compared with Caucasians, for each 1-unit increase in BMI, African-Americans had lower, whereas Koreans had higher increases in ECF volumes (P-values<0.05 for both). Meanwhile, compared with Caucasians, for each 1-unit increase in log-transformed VAT, African-Americans, Japanese-Americans and Japanese had similar increases, whereas Koreans had a lower increase in ECF volumes (P-value<0.05).

CONCLUSIONS

Racial/ethnic groups differed in their propensity to accumulate ECF at increasing level of overall and central adiposity. Future studies should evaluate whether reducing central adiposity or overall weight will decrease ECF volumes more in certain racial/ethnic groups. Evaluating these questions might help in designing race-specific prevention strategy of CHD risk associated with higher ECF.

Differential associations of abdominal visceral, subcutaneous adipose tissue with cardiometabolic risk factors between African and European Americans

OBJECTIVE

To examine the relative association of abdominal visceral adipose tissue (VAT) with cardiometabolic risk factors between African and European Americans.

METHODS

A cross-sectional study of 2,035 African Americans from the Jackson Heart Study (JHS) and 3,170 European Americans from the Framingham Heart Study (FHS) who underwent computed tomography assessment of VAT and subcutaneous adipose tissue (SAT) was conducted. The FHS participants were weighted to match the age distribution of the JHS participants, and the metabolic risk factors were examined by study groups in relation to VAT.

RESULTS

JHS participants had higher rates of obesity, hypertension, diabetes, and metabolic syndrome than FHS participants (all P = 0.001). The associations were weaker in JHS women for VAT with blood pressure, triglycerides, HDL-C, and total cholesterol (Pinteraction = 0.03-0.001) than FHS women. In contrast, JHS men had stronger associations for VAT with high triglycerides, low HDL, and metabolic syndrome (all Pinteraction = 0.001) compared to FHS men. Similar associations and gender patterns existed for SAT with most metabolic risk factors.

CONCLUSIONS

The relative association between VAT and cardiometabolic risk factors is weaker in JHS women compared to FHS women, whereas stronger associations with triglycerides and HDL were observed in JHS men.

Predictive equations for central obesity via anthropometrics, stereovision imaging and MRI in adults

OBJECTIVE

Abdominal visceral adiposity is related to risks for insulin resistance and metabolic perturbations. Magnetic resonance imaging (MRI) and computed tomography are advanced instruments that quantify abdominal adiposity; yet field use is constrained by their bulkiness and costliness. The purpose of this study is to develop prediction equations for total abdominal, subcutaneous, and visceral adiposity via anthropometrics, stereovision body imaging (SBI), and MRI.

METHODS

Participants (67 men and 55 women) were measured for anthropometrics and abdominal adiposity volumes evaluated by MRI umbilicus scans. Body circumferences and central obesity were obtained via SBI. Prediction models were developed via multiple linear regression analysis, utilizing body measurements and demographics as independent predictors, and abdominal adiposity as a dependent variable. Cross-validation was performed by the data-splitting method.

RESULTS

The final total abdominal adiposity prediction equation was -470.28 + 7.10 waist circumference - 91.01 gender + 5.74 sagittal diameter (R2 = 89.9%), subcutaneous adiposity was -172.37 + 8.57 waist circumference - 62.65 gender - 450.16 stereovision waist-to-hip ratio (R2 =90.4%), and visceral adiposity was -96.76 + 11.48 central obesity depth - 5.09 central obesity width + 204.74 stereovision waist-to-hip ratio - 18.59 gender (R2 = 71.7%). R2 significantly improved for predicting visceral fat when SBI variables were included, but not for total abdominal or subcutaneous adiposity.

CONCLUSIONS

SBI is effective for predicting visceral adiposity and the prediction equations derived from SBI measurements can assess obesity.

Barrett's oesophagus: epidemiology, cancer risk and implications for management

Although endoscopic surveillance of patients with Barrett's oesophagus has been widely implemented, its effectiveness is debateable. The recently reported low annual oesophageal adenocarcinoma risk in population studies, the failure to identify most Barrett's patients at risk of disease progression, the poor adherence to surveillance and biopsy protocols, and the significant risk of misclassification of dysplasia all tend to undermine the effectiveness of current management, in particular, endoscopic surveillance programmes, to prevent or improve the outcomes of patients with oesophageal adenocarcinoma. The ongoing increase in incidence of Barrett's oesophagus and consequent growth of the surveillance population, together with the associated discomfort and costs of endoscopic surveillance, demand improved techniques for accurately determining individual risk of oesophageal adenocarcinoma. More accurate techniques are needed to run efficient surveillance programmes in the coming decades. In this review, we will discuss the current knowledge on the epidemiology of Barrett's oesophagus, and the challenging epidemiological dilemmas that need to be addressed when assessing the current screening and surveillance strategies.

Use of anthropometry for the prediction of regional body tissue distribution in adults: benefits and limitations in clinical practice

Regional body composition changes with aging. Some of the changes in composition are considered major risk factors for developing obesity related chronic diseases which in turn may lead to increased mortality in adults. The role of anthropometry is well recognized in the screening, diagnosis and follow-up of adults for risk classification, regardless of age. Regional body composition is influenced by a number of intrinsic and extrinsic factors. Therapeutic measures recommended to lower cardiovascular disease risk include lifestyle changes. The aim of this review is to systematically summarize studies that assessed the relationships between anthropometry and regional body composition. The potential benefits and limitations of anthropometry for use in clinical practice are presented and suggestions for future research given.

Estimation of CT-derived abdominal visceral and subcutaneous adipose tissue depots from anthropometry in Europeans, South Asians and African Caribbeans

BACKGROUND

South Asians and African Caribbeans experience more cardiometabolic disease than Europeans. Risk factors include visceral (VAT) and subcutaneous abdominal (SAT) adipose tissue, which vary with ethnicity and are difficult to quantify using anthropometry.

OBJECTIVE

We developed and cross-validated ethnicity and gender-specific equations using anthropometrics to predict VAT and SAT.

DESIGN

669 Europeans, 514 South Asians and 227 African Caribbeans (70 ± 7 years) underwent anthropometric measurement and abdominal CT scanning. South Asian and African Caribbean participants were first-generation migrants living in London. Prediction equations were derived for CT-measured VAT and SAT using stepwise regression, then cross-validated by comparing actual and predicted means.

RESULTS

South Asians had more and African Caribbeans less VAT than Europeans. For basic VAT prediction equations (age and waist circumference), model fit was better in men (R(2) range 0.59-0.71) than women (range 0.35-0.59). Expanded equations (+ weight, height, hip and thigh circumference) improved fit for South Asian and African Caribbean women (R(2) 0.35 to 0.55, and 0.43 to 0.56 respectively). For basic SAT equations, R(2) was 0.69-0.77, and for expanded equations it was 0.72-0.86. Cross-validation showed differences between actual and estimated VAT of <7%, and SAT of <8% in all groups, apart from VAT in South Asian women which disagreed by 16%.

CONCLUSION

We provide ethnicity- and gender-specific VAT and SAT prediction equations, derived from a large tri-ethnic sample. Model fit was reasonable for SAT and VAT in men, while basic VAT models should be used cautiously in South Asian and African Caribbean women. These equations will aid studies of mechanisms of cardiometabolic disease in later life, where imaging data are not available.

DXA estimates of fat in abdominal, trunk and hip regions varies by ethnicity in men

Objective:

The aim of this study was to determine whether the quantity of fat is different across the central (that is, android, trunk) and peripheral (that is, arm, leg and gynoid) regions among young African-American (AA), Asian (AS), Hispanic (HI) and non-Hispanic White (NHW) men.

Subjects and Methods:

A cohort of 852 men (18–30 years; mean total body fat percent (TBF%)=18.8±7.9, range=3.7–45.4) were assessed for body composition in five body regions via dual-emission X-ray absorptiometry (DXA).

Results:

HI men (21.8±8.3) had higher TBF% than AA (17.0±10.0), NHW (17.9±7.2) and AS (18.9±8.0) groups (P-values <0.0001). AS had a lower BMI (23.9±3.4) than all other groups, and NHW (24.7±3.2) had a lower BMI than HI (25.7±3.9) and AA (26.5±4.7; P-values<0.0001). A linear mixed model (LMM) revealed a significant ethnicity by region fat% interaction (P<0.0001). HI men had a greater fat% than NHW for every region (adjusted means (%); android: 29.6 vs 23.3; arm: 13.3 vs 10.6; gynoid: 27.2 vs 23.8; leg: 21.2 vs 18.3; trunk: 25.5 vs 20.6) and a greater fat% than AA for every region except the arm. In addition, in the android and trunk regions, HI had a greater fat% than AS, and AS had a higher fat% than AA. Finally, the android fat% for AS was higher than that of NHW. When comparing the region fat% within ethnicities, the android region was greater than the gynoid region for AS and HI, but did not differ for AA and NHW, and the arm region had the least fat% in all ethnicities.

Conclusions:

Fat deposition and body fat patterning varies by ethnicity.

Body adipose distribution among patients with type 2 diabetes mellitus

SUMMARY

Both diabetes mellitus (DM) and obesity are prevalent in adults. The relationship between DM and body adipose tissue (AT) distribution is complex and although it has been investigated extensively, the subject remains controversial. Although a causal association between DM and obesity and AT distribution cannot be established on the basis of existing data, it is possible to conclude from many studies that gene, serum sex steroids level, daily physical activity and food supply can be the risk of obesity and AT redistribution factor among type 2 DM patients (T2DM). Obesity and AT redistribution of T2DM patients can increase the risk of insulin resistant (IR), cardiovascular disease and many other disorders. Even though obesity and AT redistribution screening or prophylactic treatment in all patients with T2DM is not being recommended at present, such patient populations should be given general guidelines regarding exercise, food intake control, and even medicinal treatment. The extent of diagnostic and therapeutic interventions should be based on the individual's risk profile.:

Nonalcoholic steatohepatitis versus steatosis: adipose tissue insulin resistance and dysfunctional response to fat ingestion predict liver injury and altered glucose and lipoprotein metabolism

Nonalcoholic fatty liver disease (NAFLD) ranges from simple steatosis (SS) to nonalcoholic steatohepatitis (NASH). Though liver-related risk seems confined to NASH, it is currently unclear whether NASH has a higher risk of cardiovascular disease (CVD) and diabetes than SS as a result of the coexistence of obesity and other cardiometabolic confounders. Adipose tissue is an emerging modulator of liver disease in NAFLD and of cardiometabolic disease in the general population. We evaluated in SS and NASH (1) glucose homeostasis and cardiovascular risk profile and (2) the effect of adipose tissue dysfunction, assessed in fasting conditions and postprandially, on liver injury, glucose and lipoprotein metabolism, and markers of early atherosclerosis. Forty nonobese, nondiabetic, normolipidemic biopsy-proven NAFLD patients (20 with SS and 20 with NASH) and 40 healthy subjects, matched for overall/abdominal adiposity and metabolic syndrome, underwent an oral fat load test, with measurement of plasma triglyceride-rich lipoproteins, oxidized low-density lipoproteins, adipokines, and cytokeratin-18 fragments, and an oral glucose tolerance test with minimal model analysis to yield glucose homeostasis parameters. Circulating endothelial adhesion molecules were measured, and adipose tissue insulin resistance (adipose IR) index and visceral adiposity index were calculated. Despite similar fasting values, compared to SS, NASH showed a more atherogenic postprandial lipoprotein profile, an altered adipokine response (i.e., higher resistin increase and an adiponectin fall), and hepatocyte apoptosis activation after fat ingestion. Adipose IR index, endothelial adhesion molecules, and hepatic insulin resistance progressively increased across NAFLD stages. NASH, but not SS, showed an impaired pancreatic β-cell function. On multiple regression analysis, adipose IR index and postprandial adiponectin independently predicted liver histology and altered cardiometabolic parameters.

CONCLUSION

Adipose tissue dysfunction, including a maladaptive adipokine response to fat ingestion, modulates liver injury and cardiometabolic risk in NAFLD.

Fat in android, trunk, and peripheral regions varies by ethnicity and race in college aged women

The aim of this study was to determine whether quantity of fat is different across the central (i.e., android, trunk) and peripheral (i.e., arm, leg, and gynoid) regions among young African-American (AA), Asian (AS), Hispanic (HI), and non-Hispanic white (NHW) women. A cohort of 1,161 women (18-30 years) from university physical activity classes were assessed for body composition via dual-emission X-ray absorptiometry (DXA). The mean total body fat percent (TBF%, x = 31.0 ± 7.36%, range = 11.4-54.4%) indicates sufficient variability for the aims. A linear mixed model (LMM) revealed an ethnicity by region fat% interaction (P < 0.0001). Differences existed between ethnicities for each region fat% (all P's < 0.0001) except between HI and AA for the arm region (P = 0.0086) and between AS and NHW for all peripheral regions (P > 0.05). AAs had the highest fat% and HI had the second highest fat% for each region. AS had the third highest fat% for the trunk and android regions. For each ethnicity, the gynoid region had the greatest fat%, followed by the android region, whereas the arm region had the lowest fat%. Future research needs to determine if ethnic differences in central body fat in young women are associated with health outcomes such as cardiovascular disease and insulin resistance.

ADIPOQ, ADIPOR1, and ADIPOR2 polymorphisms in relation to serum adiponectin levels and BMI in black and white women

Adiponectin is an adipose-secreted protein with influence on several physiologic pathways including those related to insulin sensitivity, inflammation, and atherogenesis. Adiponectin levels are highly heritable and several single-nucleotide polymorphisms (SNPs) in adiponectin-related genes (ADIPOQ, ADIPOR1, ADIPOR2) have been examined in relation to circulating adiponectin levels and obesity phenotypes, but despite differences in adiponectin levels and obesity prevalence by race, few studies have included black participants. Using cross-sectional interview data and blood samples collected from 990 black and 977 white women enrolled in the Southern Community Cohort Study (SCCS) from 2002 to 2006, we examined 25 SNPs in ADIPOQ, 19 in ADIPOR1, and 27 in ADIPOR2 in relation to serum adiponectin levels and BMI using race-stratified linear regression models adjusted for age and percentage African ancestry. SNP rs17366568 in ADIPOQ was significantly associated with serum adiponectin levels in white women only (adjusted mean adiponectin levels = 15.9 for G/G genotype, 13.7 for A/G, and 9.3 for A/A, P = 0.00036). No other SNPs were associated with adiponectin or BMI among blacks or whites. Because adiponectin levels as well as obesity are highly heritable and vary by race but associations with polymorphisms in the ADIPOQ, ADIPOR1, and ADIPOR2 genes have been few in this and other studies, future work including large populations from diverse racial groups is needed to detect additional genetic variants that influence adiponectin and BMI.

Validation of ultrasound estimates of visceral fat in black South African adolescents

Accurate quantification of visceral adipose tissue (VAT) is needed to understand ethnic variations and their implications for metabolic disease risk. The use of reference methods such as computed tomography (CT) and magnetic resonance imaging (MRI) is limited in large epidemiological studies. Surrogate measures such as anthropometry and dual-energy X-ray absorptiometry (DXA) do not differentiate between VAT and subcutaneous abdominal adipose tissue (SCAT). Ultrasound provides a validated estimate of VAT and SCAT in white populations. This study aimed to validate the use of ultrasound-based assessment of VAT in black South African adolescents. One hundred healthy adolescents (boys = 48, girls = 52) aged 18-19 years participating in the birth to twenty cohort study had VAT and SCAT measured by single slice MRI at L4. These MRI "criterion measures" were related to ultrasound VAT and SCAT thickness, anthropometry (BMI, waist and hip circumferences), and DXA android region fat. Ultrasound VAT thickness showed the strongest correlations with MRI VAT (Spearman's correlation coefficients: r = 0.72 and r = 0.64; in boys and girls, respectively), and substantially improved the estimation of MRI VAT compared to anthropometry and DXA alone; in regression models the addition of ultrasound VAT thickness to models containing BMI, waist, and DXA android fat improved the explained variance in VAT from 39% to 60% in boys, and from 31% to 52% in girls. In conclusion, ultrasound substantially increased the precision of estimating VAT beyond anthropometry and DXA alone. Black South African adolescents have relatively little VAT compared to elderly whites, and we therefore provide new ultrasound-based prediction equations for VAT specific to this group.

Ethnic bias in anthropometric estimates of DXA abdominal fat: the TIGER study

BACKGROUND/INTRODUCTION

The purpose of this study was to examine the race/ethnicity bias of using waist circumference (WC) to estimate abdominal fat.

METHODS

A total of 771 females and 484 males (17-35 yr) were tested one to three times during a prescribed 30-wk aerobic exercise program. The race/ethnicity distribution for women was non-Hispanic white, 29%; Hispanic, 25%; African American (AA), 35%; Asian Indian, 3%; and Asian, 8%. The distribution for men was non-Hispanic white, 37%; Hispanic, 26%; AA, 22%; Asian Indian, 5%; and Asian, 10%. Abdominal fat (L1-L5) was estimated from whole-body scanning using dual-energy x-ray absorptiometry (DXA Abd-Fat).

RESULTS

DXA Abd-Fat varied by race/ethnicity after accounting for WC and height in both women and men. The increase in DXA Abd-Fat per increase in WC was lower in the Asian and Asian-Indian women than that in the other women. The increase in DXA Abd-Fat per increase in WC was higher in the AA men and lower in the Asian-Indian men than that in the other men. These differential race/ethnicity effects were most notable when WC exceeded ≍90 cm in the women and ≍100 cm in the men, values which are consistent with current definitions of abdominal obesity in the United States.

CONCLUSIONS

Prediction equations for abdominal fat using WC that do not account for race/ethnicity group provide biased estimates. These results may affect assessment of disease risk from abdominal obesity among racial/ethnic groups.

Pleiotropy of type 2 diabetes with obesity

The risk of type 2 diabetes (T2D) increases with obesity. One possible explanation is that pleiotropic genes affect risk of both T2D and obesity. To identify pleiotropic genes, we performed bivariate analysis of T2D with waist-hip ratio (WHR) and with body mass index (BMI) in the African-American subset of the Genetics of NIDDM (GENNID) sample. Of 12 T2D loci identified through suggestive or higher univariate logarithm of the odds ratio (lod) scores, we inferred pleiotropy with obesity for six (chromosomes 1 at 17-19 Mb, 2 at 237-240 Mb, 7 at 54-73 Mb, 13 at 26-30 Mb, 16 at 26-47 Mb and 20 at 56-59 Mb). These findings provide evidence that at least some of the co-occurrence of obesity with T2D is because of pleiotropic genes. We also inferred four obesity loci through suggestive or higher lod scores for WHR (chromosomes 1 at 24-32 Mb, 2 at 79-88 Mb, 2 at 234-238 Mb and 3 at 148-159 Mb).

Caloric restriction in humans: impact on physiological, psychological, and behavioral outcomes

The current societal environment is marked by overabundant accessibility of food coupled with a strong trend of reduced physical activity, both leading to the development of a constellation of disorders, including central obesity, insulin resistance, dyslipidemia, and hypertension (metabolic syndrome). Prolonged calorie restriction (CR) has been shown to extend both the median and maximal lifespan in a variety of lower species such as yeast, worms, fish, rats, and mice. Mechanisms of this CR-mediated lifespan extension are not fully elucidated, but possibly involve significant alterations in energy metabolism, oxidative damage, insulin sensitivity, inflammation, and functional changes in both the neuroendocrine and sympathetic nervous systems. Here we review some of the major physiological, psychological, and behavioral changes after 6 months of CR in overweight otherwise healthy volunteers. Special emphasis is given to the first completed clinical studies that have investigated the effects of controlled, high-quality energy-restricted diets on both biomarkers of longevity and on the development of chronic diseases related to age in humans. With the incremental expansion of research endeavors in the area of energy or caloric restriction, data on the effects of CR in animal models and human subjects are becoming more accessible.

Physical activity and reduced intra-abdominal fat in midlife African-American and white women

The purpose of our study was to determine whether self-reported physical activity (PA), including recreational, household, and exercise activities, is associated with intra-abdominal fat (IAF) in community-dwelling white and black midlife women. We performed a cross-sectional study of 369 women from the Chicago site of the Study of Women's Health Across the Nation (SWAN) ancillary study, the SWAN Fat Patterning Study. PA level was the independent variable, and IAF, assessed by computerized tomography (CT) scan, was the dependent variable. Measures were obtained at SWAN Fat Patterning Baseline visit between August 2002 and December 2005. Linear regression models explored the association between PA and IAF. The first model included IAF as the outcome and total score PA as the main predictor, adjusting for total percent fat mass, age, and ethnicity. The second model included education, parity, sex hormone-binding globulin (SHBG) level, and depressive symptoms, measured by Center for Epidemiological Studies-Depression (CES-D) scale. Each 1-point higher total PA score was associated with a 4.0 cm(2) lower amount of IAF (P = 0.004), independent of total percent fat mass, age, ethnicity, SHBG level, educational level, CES-D, and parity. Associations did not differ between white and black women. This study demonstrates a significant negative association between PA and IAF independent of multiple covariates in midlife women. Our findings suggest that motivating white and black women to increase PA during midlife may lessen IAF, which may have a positive impact on subsequent development of diabetes and cardiovascular disease.

Comparação entre a adiposidade subcutânea dos hemicorpos direito e esquerdo

O objetivo deste estudo foi comparar os níveis de adiposidade subcutânea dos hemicorpos direito e esquerdo e, posteriormente, analisar o impacto dessas informações para o estudo da composição corporal. Setenta e seis indivíduos fisicamente ativos, 47 homens (21,6 ± 4,3 anos) e 29 mulheres (21,0 ± 2,6 anos), fizeram parte da amostra. As espessuras das dobras cutâneas abdominal, suprailíaca, subescapular, tricipital, bicipital, axilar média e perna medial foram mensuradas com um compasso Lange. Em valores médios absolutos, as maiores diferenças verificadas foram de 0,9mm (6,9%) e 0,8mm (6,8%), na dobra cutânea suprailíaca de homens e mulheres, respectivamente. Entretanto, nenhuma diferença estatisticamente significante foi encontrada na comparação entre os lados, em ambos os sexos, nas sete dobras cutâneas analisadas (P > 0,05). Similarmente, quando os valores medidos foram aplicados em equações preditivas para a determinação da gordura corporal relativa, de acordo com o sexo, nenhuma diferença significante foi encontrada (P > 0,05). Os resultados sugerem que fatores como o erro técnico de medida do avaliador, o tipo de compasso e a escolha da equação preditiva a ser utilizada, provavelmente tenham maior impacto para a estimativa da composição corporal pelo método de espessura de dobras cutâneas do que o lado a ser adotado como referência para a obtenção das medidas.

Relationships of obesity and fat distribution with atherothrombotic risk factors: baseline results from the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial

The impact of obesity on cardiovascular disease (CVD) outcomes in patients with type 2 diabetes mellitus (T2DM) and established coronary artery disease (CAD) is controversial; whether BMI and/or waist circumference correlate with atherothrombotic risk factors in such patients is uncertain. We sought to evaluate whether higher BMI or waist circumference are associated with specific risk factors among 2,273 Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) study participants with T2DM and documented CAD (baseline data, mean age 62 years, 66% non-Hispanic white, 71% men). Multiple linear regression models were constructed after adjusting for sex, age, race/ethnicity, US vs. non-US site, diabetes duration, exercise, smoking, alcohol, and relevant medication use. First-order partial correlations of BMI with risk factors after controlling for waist circumference and of waist circumference with risk factors after controlling for BMI were also evaluated. Ninety percent of the patients were overweight (BMI > or =25 kg/m(2)); 68% of men and 89% of women had high-risk waist circumference measures (> or =102 and > or =88 cm, respectively). BMI and waist circumference, in separate models, explained significant variation in metabolic (insulin, lipids, blood pressure (BP)) and inflammatory/procoagulation (C-reactive protein, PAI-1 activity and antigen, and fibrinogen) risk factors. In partial correlation analyses BMI was independently associated with BP and inflammatory/procoagulation factors, waist circumference with lipids, and both BMI and waist circumference with insulin. We conclude that, in cross-sectional analyses, both BMI and waist circumference, independently, are associated with increased atherothrombotic risk in centrally obese cohorts such as the BARI 2D patients with T2DM and CAD.

Age-related changes in total and regional fat distribution

Aging is associated with progressive changes in total and regional fat distribution that have negative health consequences. Indeed, a preferential increase in abdominal fat, in particular visceral fat, combined with a decrease in lower body subcutaneous fat are commonly cited in the literature. These age-related changes in body composition can occur independent of changes in total adiposity, body weight or waist circumference, and represent a phenotype closely associated with increased morbidity and mortality risk. Tissues such as the heart, liver and skeletal muscle in the elderly have increased fat deposition, which increases risk for insulin resistance and cardiovascular disease. Furthermore, aging is associated with increased fat content within bone marrow, which exposes the elderly to fracture risk beyond that associated with low bone mineral density alone. Many of the age-associated body compositional changes cannot be detected by simple anthropometric measures alone, and the influence of gender, race or ethnicity, and physical activity patterns on these changes is unclear. This review will explore some of these age-related changes in total and regional fat distribution. Consideration will also be given to the strengths and limitations associated with some of the anthropometric methodologies employed for assessing these changes.

Trends in esophageal cancer and body mass index by race and gender in the state of Michigan

BACKGROUND

Adenocarcinoma of the esophagus has been increasing in incidence in the U.S. over the past several decades, particularly among white males. The factors driving the racial disparity in adenocarcinomas rates are not well understood.

METHODS

Here we examine trends in both esophageal cancer incidence and body mass index (BMI) in a geographically defined cohort by gender and race. Age-adjusted esophageal cancer incidence rates from 1985 to 2005 were calculated from data collected by the Michigan state cancer registry. Trends were analyzed along with trends in BMI data obtained from the Behavioral Risk Factor Survey administered by the Centers for Disease Control.

RESULTS

Overall, age adjusted incidence rates in esophageal carcinoma increased from 4.49 to 4.72 cases/100,000 persons per year in Michigan from 1985 to 2005. Among white males, the rate of adenocarcinomas increased by 0.21 cases/100,000 per year to a maximum of 6.40 cases/100,000 in 1999, after which these rates remained constant. There was a slight but non-significant increase in the rate of adenocarcinomas among African American males, for whom the average incidence rate was 8 times lower than that for white males (0.58 vs 4.72 cases/100,000 person years). While average BMI is rising in Michigan (from 26.68 in 1988 to 30.33 in 2005), average BMI was slightly higher among African Americans on average, and the rates of increase in BMI were not different between African American males and white males.

CONCLUSION

The disparity between African American males and white males is not explained by ecological-level trends in BMI. Further research to identify the factors responsible for this disparity, possibly including anatomic fat distribution, are required.

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.

Inflammation and race and gender differences in computerized tomography-measured adipose depots

A growing body of evidence has consistently shown a correlation between obesity and chronic subclinical inflammation. It is unclear whether the size of specific adipose depots is more closely associated with concentrations of inflammatory markers than overall adiposity. This study investigated the relationship between inflammatory markers and computerized tomography-derived abdominal visceral and subcutaneous fat and thigh intermuscular and subcutaneous fat in older white and black adults. Data were from 2,651 black and white men and women aged 70-79 years participating in the Health, Aging, and Body Composition (Health ABC) study. Inflammatory markers, interleukin-6 (IL-6), C-reactive protein (CRP), and tumor necrosis factor-alpha (TNF-alpha) were obtained from serum samples. Abdominal visceral and subcutaneous fat and thigh intermuscular and subcutaneous fat were quantified on computerized tomography images. Linear regression analysis was used to evaluate the cross-sectional relationship between specific adipose depots and inflammatory markers in four race/gender groups. As expected, blacks have less visceral fat than whites and women less visceral fat than men. However, abdominal visceral adiposity was most consistently associated with significantly higher IL-6 and CRP concentrations in all race/gender groups (P < 0.05), even after controlling for general adiposity. Thigh intermuscular fat had an inconsistent but significant association with inflammation, and there was a trend toward lower inflammatory marker concentration with increasing thigh subcutaneous fat in white and black women. Despite the previously established differences in abdominal fat distribution across gender and race, visceral fat remained a significant predictor of inflammatory marker concentration across all four subgroups examined.

Depressive symptoms and increased visceral fat in middle-aged women

OBJECTIVE

To examine whether depressive symptoms are differentially associated with visceral adipose tissue (VAT), which is more metabolically active and confers greater cardiovascular risk than subcutaneous fat (SAT). Prior research has shown an association between depression and central adiposity. Mechanisms underlying the association between depression and increased cardiovascular risk remain poorly understood. Central adiposity is one potential pathway.

METHODS

We investigated the cross-sectional association between depressive symptoms, assessed by the Center for Epidemiological Studies Depression Scale (CES-D), and VAT and SAT, assessed by computed tomography, in a sample of 409 middle-aged women (44.7% African-Americans, 55.3% Whites; mean age = 50.4 years) participating in the Chicago site of the Study of Women's Health Across the Nation (SWAN).

RESULTS

With adjustments for age, race, total percent fat, and sex hormone binding globulin (SHBG), each 1-point higher score on the CES-D was associated with 1.03-cm(2) greater VAT (p < .001). Women with a CES-D score of >or=16, indicative of clinically relevant depressive symptomatology, had 24.5% more VAT than women with lower CES-D scores (p < .001). Further adjustment for Framingham Risk Score and physical activity did not alter the findings, and associations did not vary by race. Associations were strongest in obese and overweight women. Depressive symptoms were unrelated to SAT.

CONCLUSIONS

Increased visceral fat may be one pathway by which depression contributes to excess risk for cardiovascular disease and diabetes. Further research is needed to examine whether depressive symptoms influence accumulation of VAT over time.

Body mass index bias in defining obesity of diverse young adults: the Training Intervention and Genetics of Exercise Response (TIGER) study

The BMI cut-score used to define overweight and obesity was derived primarily using data from Caucasian men and women. The present study evaluated the racial/ethnic bias of BMI to estimate the adiposity of young men and women (aged 17-35 years) using dual-energy X-ray absorptiometry (DXA) determination of percentage body fat (DXA-BF%) as the referent standard. The samples were 806 women and 509 men who were tested from one to three times over 9 months providing 1300 observations for women and 820 observations for men. Linear mixed models (LMM) regression showed that with age and BMI controlled, DXA-BF% of African-American (AA) men and women, Asian-Indian men and women, Hispanic women and Asian women significantly differed from non-Hispanic white (NHW) men and women. For the same BMI of NHW women, the DXA-BF% of AA women was 1.76 % lower, but higher for Hispanic (1.65 %), Asian (2.65 %) and Asian-Indian (5.98 %) women. For the same BMI of NHW men, DXA-BF% of AA men was 4.59 % lower and 4.29 % higher for Asian-Indian men. Using the recommended BMI cut-scores to define overweight and obesity systematically overestimated overweight and obesity prevalence for AA men and women, and underestimated prevalence for Asian-Indian men and women, Asian women and Hispanic women. The present study extends the generalisability of research documenting the racial/ethnic bias of the universal overweight and obesity BMI cut-scores.

The ageing male heart: myocardial triglyceride content as independent predictor of diastolic function

AIMS

In animal models of obesity and diabetes mellitus, myocardial TG accumulation is associated with decreased myocardial function. In the physiologically ageing heart, myocardial triglyceride (TG) accumulation may also occur due to reduced myocardial fatty acid oxidation. The role of myocardial TG in the ageing human heart is unknown. Therefore, the purpose of our study was to evaluate the effects of ageing on myocardial TG content, and to determine the association between myocardial TG content and heart function.

METHODS AND RESULTS

1H-magnetic resonance spectroscopy and magnetic resonance imaging of the heart were performed in 43 healthy male subjects. Mean age (range) of the subjects was 44 (20-66) years. Body mass index (BMI), blood pressure, and biochemical markers were determined. Age correlated significantly to myocardial TG content (r = 0.57, P < 0.05) independently of BMI. Furthermore, myocardial TG content correlated negatively with left ventricular diastolic function (represented by E/A ratio, r = -0.68, P < 0.05). Multivariable analysis indicated myocardial TG content as independent predictor (P < 0.05) of the age related decrease in diastolic heart function.

CONCLUSION

Myocardial TG content increases in the physiologically ageing male heart and is associated with the age-related decline in diastolic function, independent of BMI, blood pressure, and biochemical blood markers.

IAAT, catecholamines, and parity in African-American and European-American women

OBJECTIVE

We have recently reported that parous European-American (EA) women have disproportionately more intra-abdominal adipose tissue (IAAT) than their nulliparous counterparts. Mediating mechanisms for IAAT accumulation remain unknown; however, some evidence suggests a possible catecholamine link. The objective of this study was to determine whether the IAAT-parity relationship found in EA women exists in African-American (AA) women and to determine whether catecholamines play a mediating role.

METHODS AND PROCEDURES

Subjects included 44 EA and 47 AA premenopausal women. Free-living physical activity by doubly labeled water (activity-related time equivalent (ARTE)), body composition (air plethysmography, computed tomography), and 24-h fractionated urinary catecholamines were measured.

RESULTS

Repeated measures ANOVA revealed parous EA and AA women had significantly higher IAAT than their nulliparous counterparts (100.1 +/- 28.5 and 76.2 +/- 34.8 cm(2) vs. 75.9 +/- 29.1 and 59.6 +/- 15.0 cm(2)). In AA women and nulliparous women, 24-h urinary dopamine was significantly higher (AA parous 260.8 +/- 88; EA parous 197.2 +/- 78.8; AA nulliparous 376.5 +/- 81; EA nulliparous 289.6 +/- 62). Multiple regression analysis for modeling IAAT indicated that race, parity, dopamine, ARTE, and VO(2max) were all significant and independent contributors to the model (Unstandardized betas: race -32.6 +/- 7.4; parity (number of births) 10.0 +/- 3.4; 24-h urinary dopamine 0.08 +/- 0.04; ARTE (min/day) -0.09 +/- 0.04; VO(2max) (ml/kg/min) -2.8 +/- 1.0).

DISCUSSION

Independent of the potential confounders: age, race, percent body fat, IAAT, 24-h fractionated urinary catecholamines, physical activity, and VO(2max), parous EA and AA women had more IAAT than their nulliparous counterparts. Of the catecholamines, dopamine was found to be significantly lower in parous women and higher in AA's. Dopamine, however, did not explain racial or parity differences in IAAT.

A comparative study of methods for diagnosis of obesity in an urban mixed-race population in Minas Gerais, Brazil

Background

Obesity is defined as an excess of total body fat and may be assessed by different methods. The objective of the present study was to establish the discriminatory power of anthropometric data in determining obesity.

Methods

The subjects comprised 685 individuals, aged 20–79 years, sampled from a population-based survey. The following indicators were used: body mass index (BMI), waist circumference (WC) and total body fat percentage estimated with both Siri's equation (%BF Siri) and foot-to-foot bioelectrical impedance analysis (%BF BIA). Sensitivity and specificity of different cut-off points for each method were determined using %BF BIA as reference.

Results

Of 685 participants, 57.6% were aged ≥ 40 years, 69.9% were women and 72.6% self-referred themselves as non-white. To classify obesity based on sex and age among women aged < 40 years, the cut-off points were BMI of 26.0 kg m− 2, WC of 84.0 cm and %BF Siri of 34.0%; in those aged ≥ 40 years, the cut-off points were 28.0 kg m− 2, 90.0 cm and 37.4%, respectively. The cut-off points among men aged < 40 years were BMI of 26.3 kg m− 2, WC of 86.0 cm and %BF Siri of 22.5%, and in those aged ≥ 40 years, 26.3 kg m− 2, 89.0 cm and 24.5%, respectively. BMI was the method with the largest area under the curve (AUC) independent of sex and sex/age, yet no differences were observed in AUC between BMI and WC (P>0.05). Classifying according to skin colour did not change cut-off points in any indicator.

Conclusion

BMI and WC better discriminate obesity among women and men aged ≥ 40 years from a mixed-race population.

Visceral and subcutaneous adiposity measurements in adults: influence of measurement site

OBJECTIVE

Excess abdominal adiposity is a known risk factor for cardiovascular diseases. Computed tomography can be used to examine the visceral (VAT) and subcutaneous (SAT) components of abdominal adiposity, but it is unresolved whether single-slice or multi-slice protocols are needed.

RESEARCH METHOD AND PROCEDURES

Nine computed tomography scans were obtained in the lumbar spine region of 24 adults. The nine slices were obtained at three intervertebral positions (L2-L3, L3-L4, and L4-L5) and at 7 mm above and below these locations. Intra-site and inter-site differences in SAT, VAT, total adipose tissue, and the VAT/SAT ratio were examined using ANOVA and confidence intervals for pairwise differences between means.

RESULTS

Intervertebral SAT values increased from 103.1 +/- 50.9 (standard deviation) cm(2) at L2-L3 to 153.3 +/- 68.8 cm(2) at L4-L5, whereas the corresponding VAT values decreased from 164.3 +/- 125.4 to 126.0 +/- 82.7 cm(2). The VAT/SAT ratio was not constant, decreasing from 1.8 +/- 1.4 to 0.9 +/- 0.7. Repeated-measures ANOVA indicated significant inter- and intra-site differences (p </= 0.02) for SAT, VAT, and the VAT/SAT ratio at L3-L4 and L4-L5 (p < 0.001).

DISCUSSION

These differences show the limitation of using a single-slice assessment of abdominal fat distribution, both for a subject and between subjects. Furthermore, the sizeable differences in the intra-site scans indicate that precise repositioning is needed for longitudinal studies. In summary, our findings suggest that a multi-site imaging protocol may provide a more complete assessment of abdominal fat stores and distribution than use of a single site.

Development of a Physiology-Based Whole-Body Population Model for Assessing the Influence of Individual Variability on the Pharmacokinetics of Drugs

In clinical development stages, an a priori assessment of the sensitivity of the pharmacokinetic behavior with respect to physiological and anthropometric properties of human (sub-) populations is desirable. A physiology-based pharmacokinetic (PBPK) population model was developed that makes use of known distributions of physiological and anthropometric properties obtained from the literature for realistic populations. As input parameters, the simulation model requires race, gender, age, and two parameters out of body weight, height and body mass index. From this data, the parameters relevant for PBPK modeling such as organ volumes and blood flows are determined for each virtual individual. The resulting parameters were compared to those derived using a previously published model (P(3)M). Mean organ weights and blood flows were highly correlated between the two models, despite the different methods used to generate these parameters. The inter-individual variability differed greatly especially for organs with a log-normal weight distribution (such as fat and spleen). Two exemplary population pharmacokinetic simulations using ciprofloxacin and paclitaxel as model drugs showed good correlation to observed variability. A sensitivity analysis demonstrated that the physiological differences in the virtual individuals and intrinsic clearance variability were equally influential to the pharmacokinetic variability but were not additive. In conclusion, the new population model is well suited to assess the influence of individual physiological variability on the pharmacokinetics of drugs. It is expected that this new tool can be beneficially applied in the planning of clinical studies.

Ethnic differences in body composition and other markers of cardiovascular disease risk: study in matched Haitian and White subjects from Quebec

OBJECTIVES

People of African descent may be at greater risk of metabolic syndrome (MS) compared with whites. We examined the associations among MS markers, body composition, and resting metabolic rate (RMR) in black Haitians and in white subjects living in Quebec, Canada.

RESEARCH METHODS AND PROCEDURES

Forty randomly selected Haitians were matched with 40 white subjects for age, sex, and BMI. Glycemic status and insulin resistance were assessed based on a 3-hour glucose tolerance test. Blood lipids, blood pressure, abdominal fat (computed tomography), and waist circumference (WC) were measured. RMR was estimated by indirect calorimetry.

RESULTS

Triglycerides were significantly correlated with blood pressure only in Haitians and with the area under the curve for insulin only in whites. Haitians had significantly (p < 0.05) lower triglycerides and higher high-density lipoprotein-cholesterol concentrations but higher blood pressure than whites at any given WC value. General linear models showed that Haitians had less visceral adipose tissue than whites for the same WC. RMR was lower among Haitians for any given value of BMI or WC than in whites. Also, WC was more strongly associated with glucose area under the curve and to log-homeostasis model assessment in white than in Haitian subjects.

DISCUSSION

The MS may be ethnospecific in its features and etiology. The standard anthropometric indices of obesity may not be as effective in populations of African descent compared with whites, unless appropriate cut-off values are defined.

Heart Rate Variability in Adolescents: Relations to Physical Activity, Fitness, and Adiposity

PURPOSE

We determined the degree to which variation in cardiac autonomic modulation was explained by race, sex, moderate-vigorous physical activity (MVPA), cardiovascular fitness (CVF), percent body fat (%BF), waist girth, subcutaneous abdominal adipose tissue (SAAT), and visceral adipose tissue (VAT).

METHODS

Subjects were 304 adolescents; SAAT and VAT values were available for 168 youths. Cardiac parasympathetic modulation (PM) was the root mean square of successive differences (RMSSD). Sympathetic-parasympathetic balance was the ratio of low- to high-frequency power (LFnu:HFnu). MVPA was measured with accelerometry, CVF with a treadmill, %BF with dual-energy x-ray absorptiometry (DXA), and SAAT and VAT with magnetic resonance imaging (MRI).

RESULTS

Root mean square of successive differences was higher, and LFnu:HFnu was lower, in blacks than in whites. The final regression model revealed positive relations with CVF and MVPA, and a %BF by race by sex interaction, such that higher %BF was associated with lower RMSSD in black females and higher RMSSD in white females. Higher RMSSD was associated with lower VAT; for SAAT, the relationship was negative for blacks and positive for whites. For LFnu:Hfnu, a negative relationship was seen with MVPA and higher waist girth was associated with a higher ratio in blacks, but not in whites. Both higher VAT and SAAT were related to higher LFnu:HFnu.

CONCLUSIONS

Black youths had a more favorable HRV profile than white youths. After controlling for age, race, and sex, more favorable HRV profiles were associated with more MVPA, better CVF, and less visceral and subcutaneous adiposity. The deleterious impact of higher adiposity was greater in blacks, especially females, than in whites. Enhancement of cardiac autonomic modulation may be a pathway through which physical activity, fitness, and leanness contribute to cardiovascular health early in life.

Adipokines in NASH: postprandial lipid metabolism as a link between adiponectin and liver disease

Circulating levels of four adipokines (adiponectin, TNF-alpha, leptin, and resistin) and the postprandial lipid and adiponectin responses to an oral fat load were assessed in 25 non-obese, non-diabetic patients with biopsy-proven nonalcoholic steatohepatitis (NASH) and correlated with metabolic indices and liver histology. Circulating adiponectin was lower in NASH compared with controls (5,476 +/- 344 vs. 11,548 +/- 836 ng/mL; P = .00001) and on multiple regression analysis correlated negatively with liver steatosis, necroinflammation (OR = 5.0; P = .009), and fibrosis (OR = 8.0; P = .003). The magnitude of postprandial lipemia was significantly higher in NASH than in controls and was related to fasting adiponectin (beta = -0.78; P = .00003). Controls showed a significant increase in serum adiponectin in response to the fat load, whereas patients with NASH showed a slight decrease. Postprandial free fatty acids response correlated inversely with adiponectin response in both groups and independently predicted the severity of liver steatosis in NASH (beta = 0.51; P = .031). In conclusion, hypoadiponectinemia is present before overt diabetes and obesity appear and correlates with the severity of liver histology in NASH. Impaired postprandial lipid metabolism may be an additional mechanism linking hypoadiponectinemia and NASH and posing a higher cardiovascular risk to these subjects. The mechanism(s) underlying these differences are unknown, but the type of dietary fat seems to play a role. These findings may have important pathogenetic and therapeutic implications in both liver and metabolic disease.

Predictive performance of anthropometric indexes of central obesity for the risk of type 2 diabetes

BACKGROUND

In spite of several available anthropometric indexes, the relative merit of these indexes for the prediction of type 2 diabetes remains unknown. Considering that obesity and diabetes commonly coexist as co-morbidities, our objective was to directly compare the performance of measures of central and general obesity to predict the risk of type 2 diabetes.

METHODS

We conducted a case-control study of type 2 diabetes on 150 cases and 150 age- and gender-matched controls. We directly compared the predictive performance of five anthropometric indexes: four related to central obesity--waist circumference (WC), waist/hip ratio (WHR), abdominal volume index (AVI) and conicity index (CI); and one related to general obesity--body mass index (BMI). We used various statistical approaches like area under (AUC) receiver-operating characteristic (ROC) curves, likelihood ratios, logistic regression and Shannon's entropy to compare the performance of the indexes in the study sample as well as bootstrapped samples.

RESULTS

WC had the highest overall predictive accuracy that was gender insensitive (AUC=0.77 in males and 0.74 in females); a comparable information content as that of AVI (Shannon's entropy=1.81 for WC and 1.84 for AVI) and was a better predictor of the risk of type 2 diabetes than all the remaining indexes. WC also correlated strongly with the biochemical markers of diabetes like blood sugar and lipid profile.

CONCLUSIONS

WC is a simple, non-invasive and accurate predictor of the risk of type 2 diabetes that can potentially be used in screening programs in developing countries.