Comparison of regional fat distribution and health risk factors in middle-aged white and African American women: The Healthy Transitions Study

Adipose tissue deposition region affects fall risk in people with obesity: A systematic review and meta-analysis

This review sought to meta-analyze previous research observing the effects of fat mass distribution on the fall risk among people with obesity. The literature search yielded five qualified studies enrolling 1218 participants (650 with android vs. 568 with gynoid). The outcome variables included the annual fall prevalence (primary outcome) and the center of pressure (COP) movement measurements during a posturography test (secondary) among people with android or gynoid obesity. Meta-analyses were conducted using the inverse variance weighted random-effects model. The odds ratio (OR) and standardized mean difference (SMD) were used as the effect size for the primary and secondary variables, respectively. The results revealed that more people with android obesity fall annually than their gynoid obesity counterparts (OR = 1.78 [1.34, 2.37], p < 0.0001). People with android obesity also exhibited significantly faster overall COP velocity (SMD = 0.49 [0.11, 0.88], p = 0.01) during standing compared to individuals with gynoid obesity. Our results indicated that people with android obesity could have a greater fall risk than those with gynoid obesity. Given the limited number of studies included, more well-designed and quality work is desired to further clarify how fat mass distribution alters the fall risk among people with obesity. A standardized approach to quantify the fat mass distribution (android vs. gynoid) is imperatively needed for people with obesity.

The Association Between Dietary Inflammatory Index (DII) and Risk of Hypertension: A Case-Control Study

INTRODUCTION

Hypertension (HTN) is a common risk factor for various medical diseases. Recently, there is growing evidence focusing on the potential inflammatory properties of food in the developing HTN risk. However, limited data are indicating the link between the dietary inflammatory index score (DII) and HTN risk.

AIM

This study aimed to investigate the relationship between DII score and HTN risk in middle-aged people.

METHODS

This case-control study was performed on 945 middle-aged participants (376 subjects with HTN and 569 control group). Usual dietary intakes were collected using a validated semi-quantitative food frequency questionnaire. The dietary inflammatory index (DII) for each participant was calculated with a standardized procedure, and the relationship between the risk of HTN and the DII score was investigated.

RESULTS

The multi-adjusted regression analysis showed that subjects with the higher DII score had a 1.61 times greater chance of developing HTN than individuals in the lowest ones (95% CI 1.07-2.65). Interestingly, after conducting a sex-based analysis, there was no significant relationship between DII score and risk of HTN in middle-aged women (95% CI 0.38-1.61). However, middle-aged men in the highest quartile of DII had greater (2.91 times) odds of HTN compared to the lowest quarter of DII (95% CI 1.52-5.23).

CONCLUSION

The findings of this study suggested that adherence to a diet with a high inflammatory index could increase the risk of HTN in middle-aged men by approximately 2.9 times. However, following a diet with a high DII score had no significant relationship with HTN risk in middle-aged women.

Evolutionary forces in diabetes and hypertension pathogenesis in Africans

Rates of type 2 diabetes (T2D) and hypertension are increasing rapidly in urbanizing sub-Saharan Africa (SSA). While lifestyle factors drive the increases in T2D and hypertension prevalence, evidence across populations shows that genetic variation, which is driven by evolutionary forces including a natural selection that shaped the human genome, also plays a role. Here we report the evidence for the effect of selection in African genomes on mechanisms underlying T2D and hypertension, including energy metabolism, adipose tissue biology, insulin action and salt retention. Selection effects found for variants in genes PPARA and TCF7L2 may have enabled Africans to respond to nutritional challenges by altering carbohydrate and lipid metabolism. Likewise, African-ancestry-specific characteristics of adipose tissue biology (low visceral adipose tissue [VAT], high intermuscular adipose tissue and a strong association between VAT and adiponectin) may have been selected for in response to nutritional and infectious disease challenges in the African environment. Evidence for selection effects on insulin action, including insulin resistance and secretion, has been found for several genes including MPHOSPH9, TMEM127, ZRANB3 and MC3R. These effects may have been historically adaptive in critical conditions, such as famine and inflammation. A strong correlation between hypertension susceptibility variants and latitude supports the hypothesis of selection for salt retention mechanisms in warm, humid climates. Nevertheless, adaptive genomics studies in African populations are scarce. More work is needed, particularly genomics studies covering the wide diversity of African populations in SSA and Africans in diaspora, as well as further functional assessment of established risk loci.

The Link between Obesity and Inflammatory Markers in the Development of Type 2 Diabetes in Men of Black African and White European Ethnicity

In this study, we aimed to assess ethnic differences in visceral (VAT), deep subcutaneous (dSAT), and superficial subcutaneous (sSAT) adipose tissue and their relationships with inflammatory markers between white European (WE) and black West African (BWA) men with normal glucose tolerance (NGT) and type 2 diabetes (T2D). Forty-two WE (23 NGT/19 T2D) and 43 BWA (23 NGT/20 T2D) men underwent assessment of plasma inflammatory markers using immunoassays alongside Dixon magnetic resonance imaging to quantify L4-5 VAT, dSAT and sSAT. Despite no ethnic differences in sSAT and dSAT, BWA men exhibited lower VAT (p = 0.002) and dSAT:sSAT (p = 0.047) than WE men. Adiponectin was inversely associated with sSAT in WE (p = 0.041) but positively associated in BWA (p = 0.031) men with T2D. Interleukin-6 (IL-6) was associated with VAT in WE but not in BWA men with NGT (WE: p = 0.009, BWA: p = 0.137) and T2D (WE: p = 0.070, BWA: p = 0.175). IL-6 was associated with dSAT in only WE men with NGT (WE: p = 0.030, BWA: p = 0.833). The only significant ethnicity interaction present was for the relationship between adiponectin and sSAT (P_interaction = 0.003). The favourable adipose tissue distribution and the weaker relationships between adiposity and inflammation in BWA men suggest that adipose tissue inflammation may play a lesser role in T2D in BWA than WE men.

Effect of conjugated estrogens and bazedoxifene on glucose, energy and lipid metabolism in obese postmenopausal women

OBJECTIVE

Combining conjugated estrogens (CE) with the selective estrogen receptor modulator bazedoxifene (BZA) is a novel, orally administered menopausal therapy. We investigated the effect of CE/BZA on insulin sensitivity, energy metabolism, and serum metabolome in postmenopausal women with obesity.

DESIGN

Randomized, double-blind, crossover pilot trial with washout was conducted at Pennington Biomedical Research Center. Eight postmenopausal women (age 50-60 years, BMI 30-40 kg/m2) were randomized to 8 weeks CE/BZA or placebo. Primary outcome was insulin sensitivity (hyperinsulinemic-euglycemic clamp). Secondary outcomes included body composition (DXA); resting metabolic rate (RMR); substrate oxidation (indirect calorimetry); ectopic lipids (1H-MRS); fat cell size, adipose and skeletal muscle gene expression (biopsies); serum inflammatory markers; and serum metabolome (LC/MS).

RESULTS

CE/BZA treatment produced no detectable effect on insulin sensitivity, body composition, ectopic fat, fat cell size, or substrate oxidation, but resulted in a non-significant increase in RMR (basal: P = 0.06; high-dose clamp: P = 0.08) compared to placebo. CE/BZA increased serum high-density lipoprotein (HDL)-cholesterol. CE/BZA also increased serum diacylglycerol (DAG) and triacylglycerol (TAG) species containing long-chain saturated, mono- and polyunsaturated fatty acids (FAs) and decreased long-chain acylcarnitines, possibly reflecting increased hepatic de novo FA synthesis and esterification into TAGs for export into very low-density lipoproteins, as well as decreased FA oxidation, respectively (P < 0.05). CE/BZA increased serum phosphatidylcholines, phosphatidylethanolamines, ceramides, and sphingomyelins, possibly reflecting the increase in serum lipoproteins (P < 0.05).

CONCLUSIONS

A short treatment of obese postmenopausal women with CE/BZA does not alter insulin action or ectopic fat but increases serum markers of hepatic de novo lipogenesis and TAG production.

Ethnic differences in adiposity and diabetes risk - insights from genetic studies

Type 2 diabetes is more common in non-Europeans and starts at a younger age and at lower BMI cut-offs. This review discusses the insights from genetic studies about pathophysiological mechanisms which determine risk of disease with a focus on the role of adiposity and body fat distribution in ethnic disparity in risk of type 2 diabetes. During the past decade, genome-wide association studies (GWAS) have identified more than 400 genetic variants associated with the risk of type 2 diabetes. The Eurocentric nature of these genetic studies has made them less effective in identifying mechanisms that make non-Europeans more susceptible to higher risk of disease. One possible mechanism suggested by epidemiological studies is the role of ethnic difference in body fat distribution. Using genetic variants associated with an ability to store extra fat in a safe place, which is subcutaneous adipose tissue, we discuss how different ethnic groups could be genetically less susceptible to type 2 diabetes by developing a more favourable fat distribution.

Association of abdominal fat with metabolic syndrome components in overweight women: effect of menopausal status

BACKGROUND

The association between abdominal fat distribution and metabolic syndrome (MetSyn) components by menopausal status has yet to be explicated. The purpose of this study was to examine a cross-sectional association between abdominal fat compartments and MetSyn components in pre- and post-menopausal overweight Japanese women.

METHODS

Of 212 overweight Japanese women, 76 pre-menopausal overweight (BMI ≥ 25) women (PreM age, 42.1 ± 5.9 years) and 87 post-menopausal overweight women (PostM: age, 56.2 ± 4.5 years) were analyzed in this study. Measurements were taken for body mass index (BMI), abdominal compartments [visceral fat (VF), subcutaneous fat (SF), superficial subcutaneous fat (SSF), and deep subcutaneous fat (DSF)], serum high-density lipoprotein cholesterol (HDLC), low-density lipoprotein cholesterol, triglycerides (TG), and fasting plasma glucose (FPG). Abdominal compartments were assessed using computed tomography.

RESULTS

No significant differences were found for BMI, SF, SSF, or DSF between the PreM and PostM. Despite this, the PreM had a significantly smaller VF area than that of the PostM. However, the difference in VF area disappeared when age was adjusted for. VFA significantly correlated with HDLC, TG, and FPG independently of menopause status.

CONCLUSIONS

These results suggest that the effect of menopause status on the association between VF and MetSyn components is negligible. Abdominal subcutaneous fat compartments were not associated with MetSyn components in overweight women regardless of menopausal status.

Decreased Mitochondrial Dynamics Is Associated with Insulin Resistance, Metabolic Rate, and Fitness in African Americans

CONTEXT

African American women (AAW) have a higher incidence of insulin resistance and are at a greater risk for the development of obesity and type 2 diabetes than Caucasian women (CW). Although several factors have been proposed to mediate these racial disparities, the mechanisms remain poorly defined. We previously demonstrated that sedentary lean AAW have lower peripheral insulin sensitivity, reduced maximal aerobic fitness (VO2max), and lower resting metabolic rate (RMR) than CW. We have also demonstrated that skeletal muscle mitochondrial respiration is lower in AAW and appears to play a role in these racial differences.

OBJECTIVE

The goal of this study was to assess mitochondrial pathways and dynamics to examine the potential mechanisms of lower insulin sensitivity, RMR, VO2max, and mitochondrial capacity in AAW.

DESIGN

To achieve this goal, we assessed several mitochondrial pathways in skeletal muscle using gene array technology and semiquantitative protein analysis.

RESULTS

We report alterations in mitochondrial pathways associated with inner membrane small molecule transport genes, fusion-fission, and autophagy in lean AAW. These differences were associated with lower insulin sensitivity, RMR, and VO2max.

CONCLUSIONS

Together these data suggest that the metabolic racial disparity of insulin resistance, RMR, VO2max, and mitochondrial capacity may be mediated by perturbations in mitochondrial pathways associated with membrane transport, fission-fusion, and autophagy. The mechanisms contributing to these differences remain unknown.

Racial differences in body composition and cardiometabolic risk during the menopause transition: a prospective, observational cohort study

BACKGROUND

Obesity disproportionately affects more women than men. The loss of ovarian function during the menopause transition coincides with weight gain, increases in abdominal adiposity, and impaired metabolic health. Racial differences in obesity prevalence that results from the menopause transition are not well understood.

OBJECTIVE

The purpose of the study was to assess longitudinal changes in body composition and cardiometabolic risk among black and white women during the menopausal transition.

STUDY DESIGN

In a secondary analysis of a prospective, observational cohort study (the Healthy Transitions study), 161 women ≥43 years old with a body mass index of 20-40 kg/m² and who had not yet transitioned through menopause were enrolled at Pennington Biomedical Research Center. Women were seen annually for body composition by dual-energy X-ray absorptiometry, for abdominal adipose tissue distribution by computed tomography, for sex steroid hormones, and for cardiometabolic risk factors that include fasting glucose, insulin, and lipids. Surrogate measures of insulin sensitivity were also calculated.

RESULTS

Ninety-four women (25 black, 69 white) transitioned through menopause and were included within the analyses. At menopause onset, black women weighed more (77.8±3.0 vs 70.8±1.8 kg) and had a higher systolic (125±16 vs 118±14 mm Hg) and diastolic (80±8 vs 74±7 mm Hg) blood pressure compared with white women (all P≤.05). No other differences in body composition, sex steroid hormones, or cardiometabolic risk factors were observed at menopause onset. Before menopause, white women gained significant weight (3 kg), total body adiposity (6% percent body fat, 9% fat mass, 12% trunk fat mass) and abdominal adipose tissue (19% subcutaneous fat, 15% visceral fat, 19% total adipose tissue), which coincided with significant decreases in estradiol, sex hormone-binding globulin, and estrone sulfate and increases in follicle-stimulating hormone, total cholesterol, and low-density lipoprotein cholesterol. Conversely, black women had more abdominal adipose tissue before menopause, which was maintained across the menopause transition. Black women also had significant decreases in estrone sulfate and total testosterone and increases in follicle-stimulating hormone before menopause. In the postmenopausal years, abdominal subcutaneous adipose tissue, total adipose tissue, follicle-stimulating hormone, total cholesterol, and low-density and high-density lipoprotein cholesterol increased only in white women.

CONCLUSION

White women gained more abdominal adiposity during the menopause transition compared with black women, which, in part, may be due to differences in the pattern of sex steroid hormone changes between women of different racial backgrounds. The gains in abdominal adiposity in white women were observed in tandem with increased cardiometabolic risk factors. Future studies should consider comprehensive lifestyle approaches to target these increased gains in abdominal adiposity (ie, nutrition and physical activity coaching), while taking into account the potential interactions of race, body adiposity, sex steroid hormones, and their influence on cardiometabolic risk.

Racial Variations in Appetite-Related Hormones, Appetite, and Laboratory-Based Energy Intake from the E-MECHANIC Randomized Clinical Trial

African Americans (AAs) have a higher obesity risk than Whites; however, it is unclear if appetite-related hormones and food intake are implicated. We examined differences in appetite-related hormones, appetite, and food intake between AAs (n = 53) and Whites (n = 111) with overweight or obesity. Participants were randomized into a control group or into supervised, controlled exercise groups at 8 kcal/kg of body weight/week (KKW) or 20 KKW. Participants consumed lunch and dinner at baseline and follow-up, with appetite and hormones measured before and after meals (except leptin). At baseline, AAs had lower peptide YY (PYY; p < 0.01) and a blunted elevation in PYY after lunch (p = 0.01), as well as lower ghrelin (p = 0.02) and higher leptin (p < 0.01) compared to Whites. Despite desire to eat being lower and satisfaction being higher in AAs relative to Whites (p ≤ 0.03), no racial differences in food intake were observed. Compared to Whites, leptin increased in the 8 KKW group in AAs (p = 0.01), yet no other race-by-group interactions were evident. Differences in appetite-related hormones between AAs and Whites exist; however, their influence on racial disparities in appetite, food intake, and obesity within this trial was limited.

The Prediction of Body Composition in African Americans From Spine and Hip Dual-Energy Absorptiometry

Body composition, the makeup of the body's fat and lean tissue, is associated with important health outcomes and provides useful clinical information. Although body composition can be measured with total body dual-energy X-ray absorptiometry (DXA), this is rarely performed. As an alternative to total body DXA measurement, methods for estimation of body composition have been developed. These methods use soft tissue measures from spine and hip DXA to predict body composition and include prediction equations previously published by Leslie and proprietary equations within General Electric densitometry software. However, these estimates have not been tested in African Americans (AA), an ethnicity with a different distribution of fat than Caucasians (CA). Therefore, we examined the performance of the existing models in 99 CA and 162 AA subjects over the age of 40 who had total body, spine, and hip DXA measurements. We observed that existing models estimated body composition well in CA but underestimated fat mass and overestimated lean mass in AA. AA subjects were then randomly divided into 2 equal-sized subgroups-the first to develop new prediction equations and the second to independently validate them. We found that body composition can be more accurately estimated using either a new model that we derived in AA subjects using backward stepwise elimination or by adding a fixed offset for AA to the previously published model. Our results demonstrate that body composition estimates from spine and hip DXA require consideration of race/ethnicity.

Racial and Ethnic Differences in Anthropometric Measures as Risk Factors for Diabetes

OBJECTIVE

The study objective was to examine the impact of race/ethnicity on associations between anthropometric measures and diabetes risk.

RESEARCH DESIGN AND METHODS

A total of 136,112 postmenopausal women aged 50-79 years participating in the Women's Health Initiative without baseline cancer or diabetes were followed for 14.6 years. BMI, waist circumference (WC), and waist-to-hip ratio (WHR) were measured in all participants, and a subset of 9,695 had assessment of whole-body fat mass, whole-body percent fat, trunk fat mass, and leg fat mass by DXA. Incident diabetes was assessed via self-report. Multivariate Cox proportional hazards regression models were used to assess associations between anthropometrics and diabetes incidence.

RESULTS

During follow-up, 18,706 cases of incident diabetes were identified. BMI, WC, and WHR were all positively associated with diabetes risk in each racial and ethnic group. WC had the strongest association with risk of diabetes across all racial and ethnic groups. Compared with non-Hispanic whites, associations with WC were weaker in black women (P < 0.0001) and stronger in Asian women (P < 0.0001). Among women with DXA determinations, black women had a weaker association with whole-body fat (P = 0.02) but a stronger association with trunk-to-leg fat ratio (P = 0.03) compared with white women.

CONCLUSIONS

In postmenopausal women across all racial/ethnic groups, WC was a better predictor of diabetes risk, especially for Asian women. Better anthropometric measures that reflect trunk-to-leg fat ratio may improve diabetes risk assessment for black women.

The Weight of Things: Understanding African American Women's Perceptions of Health, Body Image, and Attractiveness

Negative attitudes toward being overweight or obese are widespread, and these notions perpetuate into conceptions about one's health. Clinically, being overweight is associated with health problems such as diabetes, hypertension, heart disease, and many other illnesses. African American women, who are generally larger in body size, are a particular target for health interventions. However, these women have resisted the "obesity" label, arguing that dominant measures of health are White norms and oppressive. Through the use of in-depth interviews, this study investigates how African American women understand and experience healthfulness, body image, and barriers to each. Findings show that African American women are ambivalent in their acceptance of dominant markers of health and expressed an almost universal disdain for the thin ideal as a marker of "good" health and a positive body image. Moreover, participants articulated a suspicion of formal medical measurements of obesity.

Visceral and Intrahepatic Fat Are Associated with Cardiometabolic Risk Factors Above Other Ectopic Fat Depots: The Framingham Heart Study

BACKGROUND

We examined the associations among 8 different fat depots accumulated in various anatomic regions and the relationship between these fat depots and multiple cardiometabolic risk factors.

METHODS

Participants were from the Framingham Heart Study Offspring and Third Generation who also participated in the multidetector computed tomography substudy in 2002-2005. Exposures were multidetector computed tomography-derived fat depots, including abdominal subcutaneous adipose tissue, abdominal visceral adipose tissue, intramuscular fat, intrathoracic fat, pericardial fat, thoracic periaortic fat, intrahepatic fat, and renal sinus fat. Multivariable-adjusted regression analyses with a forward selection procedure were performed to identify the most predictive fat depots.

RESULTS

Of 2529 participants, 51.9% were women (mean age, 51.1 years). Visceral adipose tissue had the strongest correlations with each of the other fat measures (range, 0.26-0.77) and with various cardiometabolic risk factors (range, -0.34 to 0.39). As determined by the selection models, visceral adipose tissue was the only fat depot that was associated with all cardiometabolic risk factors evaluated in this study (all P<.05). Selection models also showed that subcutaneous adipose tissue and intrahepatic fat were associated with cardiometabolic risk factors related to the traits of dysglycemia, dyslipidemia, and hypertension (all P<.05). However, only associations with visceral adipose tissue and intrahepatic fat persisted after further adjustment for body mass index and waist circumference.

CONCLUSIONS

Visceral adipose tissue and intrahepatic fat were consistent correlates of cardiometabolic risk factors, above and beyond standard anthropometric indices. Our data provide important insights for understanding the associations between variations in fat distribution and cardiometabolic abnormalities.

Associations of stunting in early childhood with cardiometabolic risk factors in adulthood

Early life stunting may have long-term effects on body composition, resulting in obesity-related comorbidities. We tested the hypothesis that individuals stunted in early childhood may be at higher cardiometabolic risk later in adulthood. 1753 men and 1781 women participating in the 1982 Pelotas (Brazil) birth cohort study had measurements of anthropometry, body composition, lipids, glucose, blood pressure, and other cardiometabolic traits at age 30 years. Early stunting was defined as height-for-age Z-score at age 2 years below -2 against the World Health Organization growth standards. Linear regression models were performed controlling for sex, maternal race/ethnicity, family income at birth, and birthweight. Analyses were stratified by sex when p-interaction<0.05. Stunted individuals were shorter (β = -0.71 s.d.; 95% CI: -0.78 to -0.64), had lower BMI (β = -0.14 s.d.; 95%CI: -0.25 to -0.03), fat mass (β = -0.28 s.d.; 95%CI: -0.38 to -0.17), SAFT (β = -0.16 s.d.; 95%CI: -0.26 to -0.06), systolic (β = -0.12 s.d.; 95%CI: -0.21 to -0.02) and diastolic blood pressure (β = -0.11 s.d.; 95%CI: -0.22 to -0.01), and higher VFT/SAFT ratio (β = 0.15 s.d.; 95%CI: 0.06 to 0.24), in comparison with non-stunted individuals. In addition, early stunting was associated with lower fat free mass in both men (β = -0.39 s.d.; 95%CI: -0.47 to -0.31) and women (β = -0.37 s.d.; 95%CI: -0.46 to -0.29) after adjustment for potential confounders. Our results suggest that early stunting has implications on attained height, body composition and blood pressure. The apparent tendency of stunted individuals to accumulate less fat-free mass and subcutaneous fat might predispose them towards increased metabolic risks in later life.

Visceral and subcutaneous abdominal adiposity and pulmonary function in 30-year-old adults: a cross-sectional analysis nested in a birth cohort

BACKGROUND

Several studies have verified body fat distribution in association with pulmonary function (PF), mainly waist circumference, but few have used measures able to distinguish abdominal fat compartments. The present study aims to verify the association of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) with PF measures.

METHODS

In 1982, all hospital births occurring in Pelotas, Brazil, were identified and those livebirths have been followed. In 2012-13, the cohort participants were evaluated and VAT and SAT measured using ultrasound; forced expiratory volume in the first second (FEV₁) or forced vital capacity (FVC) were patronized in z-scores stratified by sex. The associations were verified using crude and adjusted linear regressions.

RESULTS

The present analyses comprised 3438 individuals (1721 women). VAT was inversely associated with spirometric parameters, in both crude and adjusted models. SAT showed inverse associations in the crude analyzes in males and a positive trend after adjustment, except for SAT and FVC in males. To each centimeter of VAT, mean adjusted FEV₁ z-scores decreased 0.072 (95% CI -0.107; -0.036) in men and 0.127 (95% CI -0.164; -0.090) in women, and FVC z-scores decreased -0.075 (95% CI -0.111; -0.039) and 0.121 (95% CI -0.158; -0.083), in men and women, respectively.

CONCLUSIONS

VAT has a consistent inverse association with FEV₁ and FVC in both sexes. On the other hand, SAT showed inconsistent results with PF parameters.

Association of adiposity, measures of metabolic dysregulation, and elevated alanine aminotransferase in subjects with normal body mass index

Background: Differences in body fat (BF) distribution in patients with normal body mass index (BMI) with elevated alanine aminotransferase (ALT) remains poorly described.

Objective: To determine the relationship between total BF, waist circumference (WC), insulin resistance (IR), and cardiometabolic risk profile in subjects with elevated ALT and normal BMI.

Methods: We analyzed cross-sectional data from 4,914 US participants in the third National Health and Nutrition Examination Survey database, who were ≥20 years of age, had normal BMI, and had body composition assessed by bioimpedance.

Results: Mean ± SD age was 41.4 ± 0.3 years, and 58% participants were women. BF was 20 ± 0.1% in men and 29.9 ± 0.1% in women. As total BF increased by tertiles, there was a tendency towards a higher prevalence of nonalcoholic fatty liver disease in men (6.1%, 6.5%, 9.5%, P = 0.13), but not in women (8.7%, 8.2%, 10.7%, P = 0.71). As WC increased by tertiles, there was a higher prevalence of elevated ALT in men (2.6%, 8.6%, 6.6%, P < 0.0001), but not in women. As ALT increased, men had significantly higher levels of nonhigh density lipoprotein cholesterol (HDL-C), increased apolipoprotein B, increased IR, and lower levels of C-reactive protein, whereas, women had higher levels of non-HDL-C and increased IR.

Conclusion: In subjects with normal BMI, increased WC is associated with a higher prevalence of elevated ALT in men, but not in women. Higher levels of ALT correlated with a poor cardiometabolic risk profile.

Associations between body fat distribution, insulin resistance and dyslipidaemia in black and white South African women

Aim

The aim was to examine differences in body fat distribution between premenopausal black and white South African (SA) women and explore the ethnic-specific associations with cardiometabolic risk.

Methods

Body composition, using dual-energy X-ray absorptiometry (DXA) and computerised tomography, insulin resistance (HOMA-IR) and lipid levels were assessed in 288 black and 197 white premenopausal SA women.

Results:

Compared to the white women, black women had less central and more peripheral (lower-body) fat, and lower serum lipid and glucose concentrations, but similar homeostasis models for insulin resistance (HOMA-IR) values. The associations between body fat distribution and HOMA-IR, triglyceride and high-density lipoprotein cholesterol concentrations were similar, while the associations with fasting glucose, total and low-density lipoprotein cholesterol levels differed between black and white women.

Conclusion:

Ethnic differences in body fat distribution are associated, in part, with differences in cardiometabolic risk between black and white SA women.

Determinants of change in body weight and body fat distribution over 5.5 years in a sample of free-living black South African women

Objective

To identify socio-demographic and lifestyle determinants of weight gain in a sample of premenopasual black South African (SA) women.

Methods

Changes in body composition (dual-energy X-ray absorptiometry, computerised tomography), socio-economic status (SES) and behavioural/lifestyle factors were measured in 64 black SA women at baseline (27 ± 8 years) and after 5.5 years.

Results

A lower body mass index (BMI) and nulliparity, together with access to sanitation, were significant determinants of weight gain and change in body fat distribution over 5.5 years. In addition, younger women increased their body weight more than their older counterparts, but this association was not independent of other determinants.

Conclusion

Further research is required to examine the effect of changing SES, as well as the full impact of childbearing on weight gain over time in younger women with lower BMIs. This information will suggest areas for possible intervention to prevent long-term weight gain in these women.

Abdominal fat depots associated with insulin resistance and metabolic syndrome risk factors in black African young adults

Background

Individuals of black African ethnicity tend to have less visceral adipose tissue (VAT) but more subcutaneous-abdominal adipose tissue (SCAT) than white Caucasians. However, it is unclear whether such distribution of abdominal fat is beneficial for metabolic disease risk in black individuals. Here we compared the associations between these specific abdominal fat depots, insulin sensitivity and metabolic syndrome risk.

Methods

A cross-sectional analysis of 76 black South African young adults (36 men; 40 women) aged 18–19 years participating in the Birth to Twenty Cohort Study had VAT and SCAT measured by MRI. The metabolic syndrome traits (blood pressure, lipid profile, fasting glucose and insulin) were measured and the values were combined into a metabolic syndrome risk score. Fasting glucose and insulin were used to derive the HOMA-index of insulin resistance (HOMA-IR).

Results

Compared to men, women had greater VAT (mean: 16.6 vs. 12.5 cm²) and SCAT (median 164.0 vs. 59.9 cm²). In men, SCAT (r = 0.50) was more strongly correlated to the metabolic syndrome score (MetS) than was VAT (r = 0.23), and was associated with both MetS (P = 0.001) and HOMA-IR (P = 0.001) after adjustment for VAT and total fat mass. In women, both abdominal fat compartments showed comparable positive correlations with MetS (r = 0.26 to 0.31), although these trends were weaker than in men.

Conclusions

In young black South African adults, SCAT appears to be more relevant than VAT to metabolic syndrome traits.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-2147-x) contains supplementary material, which is available to authorized users.

Longitudinal Changes in Body Fat and Its Distribution in Relation to Cardiometabolic Risk in Black South African Women

BACKGROUND

Ethnic differences in body composition and cardiometabolic risk have been reported in cross-sectional studies. This study aimed to investigate changes in body composition over 5.5 years, and its association with cardiometabolic risk in premenopausal black South African (SA) women.

METHODS

Changes in body composition and body fat distribution (dual-energy x-ray absorptiometry and computerized tomography), fasting glucose, insulin, and lipid concentrations, were measured in 63 black SA women at baseline (age: 27 ± 8 years), and 5.5 years later.

RESULTS

Body weight and fat mass (FM) increased by 6.9 ± 9.9 kg and 4.3 ± 6.9 kg, respectively, over the 5.5 years with a relative (%FM) increase in central and decrease in peripheral FM (all P < 0.05). Fasting glucose and lipid concentrations (except HDL-cholesterol) increased over the follow-up period (all P < 0.05). Both baseline and changes in body fat distribution were associated with cardiometabolic risk. Independent of baseline age, FM and insulin sensitivity, baseline trunk:leg was associated with reduced insulin sensitivity at follow-up (Matsuda index; β = -0.41, P = 0.002). Increasing trunk:gynoid ratio was associated with higher plasma insulin levels (β = 0.31, P = 0.023) and reduced insulin sensitivity (Matsuda index; β = -0.52, P < 0.001) at follow-up.

CONCLUSIONS

Weight gain in free-living black SA women over 5.5 years was associated with a centralization of fat mass, which predicted an increase in cardiometabolic risk.

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.

Intermuscular and intramuscular adipose tissues: Bad vs. good adipose tissues

Human studies of the influence of aging and other factors on intermuscular fat (INTMF) were reviewed. Intermuscular fat increased with weight loss, weight gain, or with no weight change with age in humans. An increase in INTMF represents a similar threat to type 2 diabetes and insulin resistance as does visceral adipose tissue (VAT). Studies of INTMF in animals covered topics such as quantitative deposition and genetic relationships with other fat depots. The relationship between leanness and higher proportions of INTMF fat in pigs was not observed in human studies and was not corroborated by other pig studies. In humans, changes in muscle mass, strength and quality are associated with INTMF accretion with aging. Gene expression profiling and intrinsic methylation differences in pigs demonstrated that INTMF and VAT are primarily associated with inflammatory and immune processes. It seems that in the pig and humans, INTMF and VAT share a similar pattern of distribution and a similar association of components dictating insulin sensitivity. Studies on intramuscular (IM) adipocyte development in meat animals were reviewed. Gene expression analysis and genetic analysis have identified candidate genes involved in IM adipocyte development. Intramuscular (IM) adipocyte development in human muscle is only seen during aging and some pathological circumstance. Several genetic links between human and meat animal adipogenesis have been identified. In pigs, the Lipin1 and Lipin 2 gene have strong genetic effects on IM accumulation. Lipin1 deficiency results in immature adipocyte development in human lipodystrophy. In humans, overexpression of Perilipin 2 (PLIN2) facilitates intramyocellular lipid accretion whereas in pigs PLIN2 gene expression is associated with IM deposition. Lipins and perilipins may influence intramuscular lipid regardless of species.

Multiaxial mechanical properties and constitutive modeling of human adipose tissue: a basis for preoperative simulations in plastic and reconstructive surgery

A preoperative simulation of soft tissue deformations during plastic and reconstructive surgery is desirable to support the surgeon's planning and to improve surgical outcomes. The current development of constitutive adipose tissue models, for the implementation in multilayer computational frameworks for the simulation of human soft tissue deformations, has proved difficult because knowledge of the required mechanical parameters of fat tissue is limited. Therefore, for the first time, human abdominal adipose tissues were mechanically investigated by biaxial tensile and triaxial shear tests. The results of this study suggest that human abdominal adipose tissues under quasi-static and dynamic multiaxial loadings can be characterized as a nonlinear, anisotropic and viscoelastic soft biological material. The nonlinear and anisotropic features are consequences of the material's collagenous microstructure. The aligned collagenous septa observed in histological investigations causes the anisotropy of the tissue. A hyperelastic model used in this study was appropriate to represent the quasi-static multiaxial mechanical behavior of fat tissue. The constitutive parameters are intended to serve as a basis for soft tissue simulations using the finite element method, which is an apparent method for obtaining promising results in the field of plastic and reconstructive surgery.

Estrogen receptor protein content is different in abdominal than gluteal subcutaneous adipose tissue of overweight-to-obese premenopausal women

OBJECTIVE

Premenopausal women demonstrate a distinctive gynoid body fat distribution and circulating estrogen status is associated with the maintenance of this adiposity patterning. Estrogen's role in modulation of regional adiposity may occur through estrogen receptors (ERs), which are present in human adipose tissue. The purpose of this study was to determine regional differences in the protein content of ERα, ERβ, and the G protein-coupled estrogen receptor (GPER) between the abdominal (AB) and gluteal (GL) subcutaneous adipose tissue of overweight-to-obese premenopausal women.

MATERIALS/METHODS

Biopsies of the subcutaneous AB and GL adipose tissue were performed in 15 premenopausal women (7 Caucasian/8 African American, 25.1 ± 1.8 years, BMI 29.5 ± 0.5kg/m(2)). Adipose tissue protein content was measured by western blot analysis and correlation analyses were conducted to assess the relationship between ER protein content and anthropometric indices/body composition measurements.

RESULTS

We found that ERα protein was higher in AB than GL (AB 1.0 ± 0.2 vs GL 0.67 ± 0.1 arbitrary units [AU], P=0.02), ERβ protein was higher in GL than AB (AB 0.78 ± 0.12 vs GL 1.3 ± 0.2 AU, P=0.002), ERα/ERβ ratio was higher in AB than GL (AB 1.9 ± 0.4 vs GL 0.58 ± 0.08 AU, P=0.007), and GPER protein content was similar in AB and GL (P=0.80) subcutaneous adipose tissue. Waist-to-hip ratio was inversely related to gluteal ERβ (r(2)=0.315, P=0.03) and positively related to gluteal ERα/ERβ ratio (r(2)=0.406, P=0.01).

CONCLUSIONS

These results indicate that depot specific ER content may be an important underlying determinant of regional effects of estrogen in upper and lower body adipose tissue of overweight-to-obese premenopausal women.

Gestational diabetes, pre-pregnancy obesity and pregnancy weight gain in relation to excess fetal growth: variations by race/ethnicity

AIMS/HYPOTHESIS

The escalating rate of childhood obesity is a public health concern worldwide, with children in certain ethnic groups being disproportionately affected. Our objective was to examine the joint effects of pre-pregnancy adiposity, pregnancy weight gain and gestational diabetes (GDM) in relation to excess fetal growth and to identify susceptible races or ethnic populations.

METHODS

The risk for delivery of a large-for-gestational-age (LGA) infant, specific to race and fetal sex, was evaluated in 105,985 pregnancies in the Consortium on Safe Labor from 2002-2008. Generalised estimating equations were used to estimate the risk for delivery of LGA infants. Joint effects were employed to evaluate the interplay of three risk factors. Models were stratified by racial group considering one, two or three factors (i.e. pre-pregnancy adiposity, pregnancy weight gain and GDM, with 0 factors as the reference group).

RESULTS

Greater pre-pregnancy adiposity, pregnancy weight gain and GDM were independently associated with increased risk of giving birth to an LGA infant across all races (except GDM among non-Hispanic whites), in both underweight and normal-weight women. Among non-Hispanic white, non-Hispanic black and Hispanic women, the three-factor joint effect was associated with substantially increased odds of LGA (OR [95% CI] 11.27 [8.40, 15.11], 7.09 [4.81, 10.45] and 10.19 [6.84, 15.19], respectively). However, for Asian women the joint effect of all three factors (OR [95% CI] 5.14 [2.11, 12.50]) was approximately the same as any of the two factors.

CONCLUSIONS/INTERPRETATION

GDM, pre-pregnancy obesity and excessive pregnancy weight gain were jointly associated with elevated risk of giving birth to an LGA infant and the effects varied by race. This suggests that those involved in public health efforts aimed at preventing LGA deliveries should consider variations in racial groups when devising effective strategies.

The role of adipose tissue in insulin resistance in women of African ancestry

Women of African ancestry, particularly those living in industrialized countries, experience a disproportionately higher prevalence of type 2 diabetes (T2D) compared to their white counterparts. Similarly, obesity and insulin resistance, which are major risk factors for T2D, are greater in black compared to white women. The exact mechanisms underlying these phenomena are not known. This paper will focus on the role of adipose tissue biology. Firstly, the characteristic body fat distribution of women of African ancestry will be discussed, followed by the depot-specific associations with insulin resistance. Factors involved in adipose tissue biology and their relation to insulin sensitivity will then be explored, including the role of sex hormones, glucocorticoid metabolism, lipolysis and adipogenesis, and their consequent effects on adipose tissue hypoxia, oxidative stress, and inflammation. Finally the role of ectopic fat deposition will be discussed. The paper proposes directions for future research, in particular highlighting the need for longitudinal and/or intervention studies to better understand the mechanisms underlying the high prevalence of insulin resistance and T2D in women of African ancestry.

FTO genotype and 2-year change in body composition and fat distribution in response to weight-loss diets: the POUNDS LOST Trial

Recent evidence suggests that the fat mass and obesity-associated gene (FTO) genotype may interact with dietary intakes in relation to adiposity. We tested the effect of FTO variant on weight loss in response to 2-year diet interventions. FTO rs1558902 was genotyped in 742 obese adults who were randomly assigned to one of four diets differing in the proportions of fat, protein, and carbohydrate. Body composition and fat distribution were measured by dual-energy x-ray absorptiometry and computed tomography. We found significant modification effects for intervention varying in dietary protein on 2-year changes in fat-free mass, whole body total percentage of fat mass, total adipose tissue mass, visceral adipose tissue mass, and superficial adipose tissue mass (for all interactions, P < 0.05). Carriers of the risk allele had a greater reduction in weight, body composition, and fat distribution in response to a high-protein diet, whereas an opposite genetic effect was observed on changes in fat distribution in response to a low-protein diet. Likewise, significant interaction patterns also were observed at 6 months. Our data suggest that a high-protein diet may be beneficial for weight loss and improvement of body composition and fat distribution in individuals with the risk allele of the FTO variant rs1558902.

Ethnic influences on the relations between abdominal subcutaneous and visceral adiposity, liver fat, and cardiometabolic risk profile: the International Study of Prediction of Intra-Abdominal Adiposity and Its Relationship With Cardiometabolic Risk/Intra-Abdominal Adiposity

BACKGROUND

Ethnic differences in cardiometabolic risk (CMR) may be related to patterns of ethnic-specific body fat distribution.

OBJECTIVE

We aimed to identify differences across ethnic groups in interrelations between BMI, abdominal adiposity, liver fat, and CMR profile.

DESIGN

In the International Study of Prediction of Intra-Abdominal Adiposity and Its Relationship With Cardiometabolic Risk/Intra-Abdominal Adiposity, 297 physicians recruited 4504 patients (from 29 countries). In the current cross-sectional analyses, 2011 whites, 166 African Caribbean blacks, 381 Hispanics, 1192 East Asians, and 347 Southeast Asians were included. Computed tomography was used to assess abdominal fat distribution and to estimate liver fat content. Anthropometric variables and CMR profile were measured.

RESULTS

Higher ranges of BMI were associated with higher levels of visceral [visceral adipose tissue (VAT)] and deep subcutaneous [deep subcutaneous adipose tissue (DSAT)] adiposity, with significant ethnic differences regarding the slope of these relations. Despite lower absolute BMI values, East Asians presented the largest accumulation of VAT but the lowest accumulation of DSAT with increasing adiposity. The association of BMI with liver fat did not differ between ethnic groups. Liver fat and DSAT were positively correlated with VAT with no ethnic variation. All ethnic groups had a similar association between a 1-SD increase in VAT, DSAT, or liver fat with hypertension, type 2 diabetes, hypertriglyceridemia, low HDL-cholesterol concentration, or high C-reactive protein concentration.

CONCLUSIONS

Ethnicity significantly affects abdominal adiposity and liver fat partitioning, and East Asians have the most deleterious abdominal fat distribution. Irrespective of ethnicity, abdominal and hepatic fat depots are strongly interrelated and increased with obesity. Higher amounts of VAT or liver fat are associated with a more deteriorated CMR profile in all ethnic groups.

Increase in android fat mass with age in healthy women with normal body mass index

Body fat distribution is gender specific: men tend to accumulate adipose tissue in the android region, whereas women tend to do so in the gynoid region. The aim of the study was to assess total fat mass (TFM), android fat (AF), and gynoid fat (GF) mass in a selected group of healthy adult women with normal body mass index (BMI) to evaluate variations in fat distribution. Seventy-seven women (20--69yr of age) with BMI values between ≥18.5 and ≤24.9kg/m(2) were included. TMF, AF, GF, and the AF to GF ratio (A:G) were assessed using dual-energy X-ray absorptiometry. Results showed an increase in AF after the fifth decade of life (D), which reached statistical significance in the sixth and seventh decades (p<0.05--0.008), a 33% increase in kg of AF between the fourth and seventh and a 20% increase in A:G between the third and the seventh, with no significant changes in TFM and GF. In normal BMI women, age appears to be associated with changes in fat mass distribution with an increase in AF, which might have potential deleterious health consequences, after the fifth D.

Self-reported experiences of discrimination and visceral fat in middle-aged African-American and Caucasian women

The authors examined the association between self-reported experiences of discrimination and subtypes of abdominal fat (visceral, subcutaneous) in a population-based cohort of African-American and Caucasian women. Prior studies examining associations between discrimination and abdominal fat have yielded mixed results. A major limitation of this research has been the reliance on waist circumference, which may be a poor marker of visceral fat, particularly for African-American women. Participants were 402 (45% African-American, 55% Caucasian) middle-aged women from the Chicago, Illinois, site of the Study of Women's Health Across the Nation. Visceral and subcutaneous fat were assessed via computed tomography scans between 2002 and 2005. Linear regression models were conducted to test associations among discrimination and visceral and subcutaneous fat. After adjustment for age and race, every one-point increase on the discrimination scale was associated with a 13.03-cm(2) higher amount of visceral fat (P = 0.04). This association remained significant after further adjustments for total body fat and relevant risk factors, including depressive symptoms. Discrimination was not associated with subcutaneous fat in minimally (P = 0.95) or fully adjusted models. Associations did not differ by race. Findings suggest that visceral fat may be one potential pathway through which experiences of discrimination increase cardiovascular risk.

Body composition phenotypes in pathways to obesity and the metabolic syndrome

Dynamic changes in body weight have long been recognized as important indicators of risk for debilitating diseases. While weight loss or impaired growth can lead to muscle wastage, as well as to susceptibility to infections and organ dysfunctions, the development of excess fat predisposes to type 2 diabetes and cardiovascular diseases, with insulin resistance as a central feature of the disease entities of the metabolic syndrome. Although widely used as the phenotypic expression of adiposity in population and gene-search studies, body mass index (BMI), that is, weight/height(2) (H(2)), which was developed as an operational definition for classifying both obesity and malnutrition, has considerable limitations in delineating fat mass (FM) from fat-free mass (FFM), in particular at the individual level. After an examination of these limitations within the constraints of the BMI-FM% relationship, this paper reviews recent advances in concepts about health risks related to body composition phenotypes, which center upon (i) the partitioning of BMI into an FM index (FM/H(2)) and an FFM index (FFM/H(2)), (ii) the partitioning of FFM into organ mass and skeletal muscle mass, (iii) the anatomical partitioning of FM into hazardous fat and protective fat and (iv) the interplay between adipose tissue expandability and ectopic fat deposition within or around organs/tissues that constitute the lean body mass. These concepts about body composition phenotypes and health risks are reviewed in the light of race/ethnic variability in metabolic susceptibility to obesity and the metabolic syndrome.

Subcutaneous adipose tissue in relation to subclinical atherosclerosis and cardiometabolic risk factors in midlife women

BACKGROUND

Limited data suggest that the effects of abdominal subcutaneous adipose tissue (SAT) on cardiovascular disease risk may depend on accompanying amounts of abdominal visceral adipose tissue (VAT).

OBJECTIVE

The objective was to examine whether abdominal VAT area modifies the effects of abdominal SAT area on subclinical atherosclerosis and cardiometabolic risk factors in both whites and African Americans.

DESIGN

Computed tomographic measures of abdominal SAT and VAT were examined in relation to carotid intima-media thickness (cIMT) and cardiometabolic risk factor levels in 500 African American and white women in midlife. A VAT × SAT interaction term was evaluated.

RESULTS

The mean (±SD) age of the sample was 51.0 ± 2.9 y, and 37% were African American. Higher amounts of SAT and VAT were associated with higher cIMT, blood pressure, homeostasis model assessment insulin resistance index (HOMA-IR), and concentrations of glucose, triglycerides, and insulin and with lower concentrations of HDL cholesterol. However, in African Americans, but not in whites, higher amounts of VAT significantly attenuated associations between higher amounts of SAT and higher insulin concentrations (P for interaction = 0.032) and HOMA-IR (P for interaction = 0.011) and reversed associations with cIMT (P for interaction = 0.005) and glucose (P for interaction = 0.044).

CONCLUSIONS

These results suggest that in midlife African American but not white women, adverse associations between abdominal SAT and cardiometabolic risk factors are attenuated and, in the case of subclinical atherosclerosis, are reversed as VAT amounts increase. Given that African American women suffer disproportionately from obesity and cardiovascular disease, further research into the role of this effect modification on obesity-associated vascular disease in African American women is warranted.

Abdominal adiposity depots are correlates of adverse cardiometabolic risk factors in Caucasian and African-American adults

OBJECTIVE

Accumulation of adipose tissue is associated with cardiometabolic risks. Although visceral adipose tissue (VAT) has been strongly implicated in this relationship, there is still some debate regarding the contribution of abdominal subcutaneous adipose tissue (SAT). The purpose of this study was to determine the contribution of abdominal SAT to cardiometabolic risk factors, independent of total and visceral adiposity. These relationships were assessed in Caucasian and African Americans.

DESIGN

It is a cross-sectional analysis of the Pennington Center Longitudinal Study.

SUBJECTS

Data were extracted from 1246 participants. Total body fat mass (FM) was measured by dual-energy X-ray absorptiometry, whereas abdominal VAT and SAT areas (cm(2)) were measured with computed tomography. The cardiometabolic risk factors included resting blood pressure (BP), fasting blood glucose and triglyceride concentrations and high-density lipoprotein cholesterol (HDL-C).

RESULTS

Positive relationships across tertiles of VAT were seen for the participants with high glucose, high BP and low HDL-C (P<0.043). There was also a significant increase in the percentage of participants with two or more cardiometabolic risk factors across most tertiles of abdominal SAT (P<0.042). Logistic regression analysis showed that in univariate models, all adiposity measures were significantly associated with increased odds of having all risk factors in men and women. In multivariate models, VAT was significantly associated with most risk factors across gender. Abdominal SAT and FM (odds ratios (ORs) 1.3-2.1; all P<0.05) were associated with fewer risk factors after accounting for VAT. VAT (OR=5.9 and 5.3) and SAT (OR=2.0 and 1.8) were both associated with higher odds of the presence of two or more cardiometabolic risk factors in both males and females (P<0.001).

CONCLUSION

The data suggest that abdominal SAT is not protective against unfavorable cardiometabolic risk profiles. These conclusions were consistent across ethnic groups.

Significant associations of age, menopausal status and lifestyle factors with visceral adiposity in African-American and European-American women

BACKGROUND

Elevated visceral adiposity is strongly predictive of cardiometabolic disease, but, due to the high cost of biomedical imaging, assessment of factors contributing to normal variation in visceral (VAT) and subcutaneous (SAT) adipose tissue partitioning in large cohorts of healthy individuals are few, particularly in ethnic and racial minority populations.

OBJECTIVE

To describe age, menopausal status, smoking and physical activity differences in VAT and abdominal subcutaneous adipose tissue (ASAT) mass in African-American (AA) and European-American (EA) women.

METHODS

Magnetic resonance imaging measures of VAT and ASAT mass and VAT% (VAT/VAT+ASAT, %) were obtained from a cross-sectional sample of 617 EA and 111 AA non-diabetic women aged 18-80 years. Multivariate linear regression was used to test independent effects of the covariates.

RESULTS

VAT and VAT% were higher in EA than AA women (p < 0.01). Differences in VAT, ASAT and VAT% across age groups began in early adulthood in both ethnic groups, but the association of age with VAT% was stronger in EA women (p for interaction = 0.03). Current smokers had higher VAT and VAT% (p < 0.01) and lower TBF than non-smokers. Frequent participation in sports activities was associated with ∼30% lower VAT in older (>55 years) as well as younger ( < 40 years) women (p < 0.0001).

CONCLUSION

Greater allocation of abdominal adipose tissue into the visceral compartment occurs in EA than AA women and in older than younger women. Avoidance of cigarette smoking and frequent participation in sports activities may partially counteract this deleterious phenomenon of ageing.

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.

Sleep duration and five-year abdominal fat accumulation in a minority cohort: the IRAS family study

STUDY OBJECTIVES

To study 5-year change in computed tomography (CT)-derived visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) associated with sleep duration in 2 minority groups.

DESIGN

Longitudinal epidemiologic study.

SETTING

Three US communities.

PARTICIPANTS

African Americans (N = 332) and Hispanic Americans (N = 775), aged 18-81 years, participating in the IRAS Family Study.

INTERVENTIONS

none

MEASUREMENTS AND RESULTS

Abdominal CT scans and BMI obtained at a 5-year interval. Sleep duration was assessed by questionnaire at baseline and categorized as < or = 5 h, 6-7 h, and > or = 8 h. Generalized estimating equations assessed the association between sleep duration and 5-year fat accumulation with adjustment for age, race, gender, study site, baseline fat measure, physical activity, total calories, smoking status, and education. Age interacted with sleep duration to predict change in fat measures (P < 0.01). In those younger than 40 years, < or = 5 h of sleep was related to a greater accumulation of BMI (1.8 kg/m2, P < 0.001), SAT (42 cm2, P < 0.0001), and VAT (13 cm2, P > 0.01), compared to sleep duration between 6 and 7 h. Eight hours or more of sleep was also significantly related to a greater accumulation of BMI (0.8 kg/m2, P < 0.001), SAT (20 cm2, P < 0.01) and VAT (6 cm2, P < 0.05) compared to sleep duration between 6 and 7 h. No significant relationship existed between sleep duration and fat depot change in participants older than 40 years old.

CONCLUSIONS

In this minority cohort, extremes of sleep duration are related to increases in BMI, SAT, and VAT in persons younger than 40 years old.

[Nutritional status and fat tissue distribution in health adults from some places in Central Banat]

INTRODUCTION

The aim of this study was to determine, relying on anthropological parameters, nutritional status, fat tissue distribution and possible health risk in adult population of Central Banat.

MATERIAL AND METHODS

730 subjects of both genders (average age 40.19 +/- 11.36(y) underwent following measurements: height, weight, waist and hip circumference.

RESULTS AND DISCUSSION

Central Banat population was characterized by great height (males: 178.40 +/- 7.24 cm; females: 163.06 +/- 6.32 cm). The average BMI was at the lower limit of overweight category (males: 26.59 kg/m2; females: 25.29 kg/m2). Overweight and obesity were found in 55.5% of examined subjects. In males, normal weight was recorded only in the youngest age group (20-29y), while in older age groups the percentage of overweight and obese males increased with age. In females, normal weight was recorded till the age of 50, after which overweight category was mainly present. Regarding both of the sexes, obesity was most frequent in the age group 50-59 (22%). The average waist circumference was lower than the cut-off values recommended by WHO (96.43 cm in males and 82.49 cm in females). According to fat distribution, normal values were recorded ini males younger that 39y, after which there was an increase in risk central obesity. In females, normal jar distribution was mainly present in all ages, although the percentage of the risk category increased with age. The highest percentage of the subjects of both sexes showed no health risk.

CONCLUSION

Our results indicate the need for preventive action towards obesity consequences and obesiay inducing surroundings.

Racial differences in abdominal depot-specific adiposity in white and African American adults

BACKGROUND

There is increasing interest in understanding racial differences in adiposity in specific body depots as a way to explain differential health risks associated with obesity.

OBJECTIVE

Our aim was to examine the differences in abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) between white and African American adults.

DESIGN

The sample included 1967 adults aged 18-84 y, including 790 white women, 435 African American women, 606 white men, and 136 African American men. Total body fat was measured by using dual-energy X-ray absorptiometry, whereas abdominal VAT and SAT cross-sectional areas (L4-L5 level) were measured by using computed tomography. Sex-specific differences in SAT and VAT between racial groups were analyzed by the use of general linear models, which controlled for age and total body fat. Additional models tested for racial differences in VAT and SAT and controlled for age, total body fat, smoking, and menopausal status. Statistical significance was accepted at P < 0.05.

RESULTS

Abdominal VAT was significantly higher in white than in African American men and women, even after adjustment for covariates. White women had significantly lower SAT than did African American women, both before and after adjustment for covariates. White men had significantly higher SAT than did African American men, but after adjustment for covariates, their SAT was lower than that of African American men.

CONCLUSIONS

Abdominal visceral adiposity is significantly greater in white men and women. After adjustment for covariates, white men and women had significantly lower SAT than did African American men and women. The results of this study highlight the heterogeneity of human body fat distribution across racial groups.This trial was registered at clinicaltrials.gov as NCT00959270.

Relationship between Insulin Sensitivity and Muscle Lipids may Differ with Muscle Group and Ethnicity

Intramyocellular lipid (IMCL) has been inversely associated with insulin sensitivity in some, but not all, studies. This study utilized fast, high-resolution, magnetic resonance spectroscopic imaging (MRSI) to: investigate relationships between muscle lipids (IMCL and extramyocellular lipid (EMCL)) and insulin sensitivity in muscles of varying oxidative capacity, explore ethnic differences in these relationships, and determine whether a eucaloric, low-fat dietary intervention would reduce IMCL and increase insulin sensitivity. Subjects were 30 healthy, African-American (AA; n=14) and European-American (EA; n=16) males, BMI 26.49 (±5.57) kg/m(2), age 21.80 (±7.84) yrs. Soleus and tibialis anterior muscle lipids were quantified using MRSI. Insulin sensitivity was assessed via intravenous glucose tolerance test. A 2-week, eucaloric, low-fat diet intervention was conducted in a sub-group (n=12) subjects with assessments at baseline and post-intervention. Neither IMCL nor EMCL levels differed between ethnicities. In the total group, and within EA (but not AA), both tibialis anterior IMCL and EMCL were inversely associated with insulin sensitivity (P<0.05 for both); soleus muscle lipids were not associated with insulin sensitivity. Soleus, but not tibialis anterior, IMCL declined in both ethnic groups (average 25.3%; p<0.01) following dietary intervention; insulin sensitivity was unchanged. Results suggest that an association of muscle lipids with insulin sensitivity may be influenced by the oxidative capacity of the muscle group studied and may vary with ethnicity.

Comparison of body fatness measurements by near-infrared reactance and dual-energy X-ray absorptiometry in normal-weight and obese black and white women

The aim of the present study was to compare body fat percent (BF %) using single-site near-IR reactance (NIR) and dual-energy X-ray absorptiometry (DXA) in a cohort of normal-weight (BMI < 25 kg/m2) black (n 102) and white (n 71); and obese (BMI > or = 30 kg/m2) black (n 117) and white (n 41) South African women (18-45 years). NIR-derived BF % was significantly correlated with DXA-derived BF % in all groups: normal-weight black (r 0.55, 95 % CI: 0.40, 0.67, P < 0.001) and white (r 0.69, 95 % CI: 0.53, 0.79, P < 0.001) women; obese black (r 0.59, 95 % CI: 0.46, 0.70, P < 0.001) and white (r 0.56, 95 % CI: 0.30, 0.74, P < 0.001) women. NIR under-predicted BF% compared to DXA in black women (normal-weight, - 4.36 (sd 4.13) % and obese, - 3.41 (sd 3.72) %), while smaller mean differences were observed in white women (normal-weight, - 0.29 (sd 4.19) % and obese, - 0.81 (sd 3.09) %), irrespective of normal-weight or obese status (P < 0.001). In obese subjects, NIR-derived BF % did not measure values greater than approximately 45 %, while the maximum DXA-derived measure was 58 %. In conclusion, although there was a significant relationship between NIR- and DXA-derived BF %, NIR under-predicted BF % in normal-weight and obese black South African women compared to DXA, but to a greater extent in subjects with very high levels of adiposity (>45 %). The results of single-site NIR as a measure of BF % should therefore be interpreted with caution, particularly in women of African descent and in those with very high levels of adiposity.

Hostility is associated with visceral, but not subcutaneous, fat in middle-aged African American and white women

OBJECTIVE

To examine the cross-sectional association between hostility and measures of abdominal fat (visceral, subcutaneous) in middle-aged African American and white women. Because fat-patterning characteristics are known to differ by race, we were particularly interested in examining whether these associations were similar for women of both racial/ethnic groups.

METHODS

Participants were 418 (45% African American, 55% white) middle-aged women from the Chicago site of the Study of Women's Health Across the Nation. Visceral and subcutaneous fat were measured by computed tomographic scans and hostility was assessed via questionnaire. Multivariate linear regression models were conducted to test associations among race/ethnicity, hostility, and measures of abdominal fat.

RESULTS

In models adjusted for race/ethnicity and total percent fat, higher levels of hostility were associated with a greater amount of visceral fat (B = 1.8, standard error = 0.69, p = .01). This association remained significant after further adjustments for education, and multiple coronary heart disease (CHD) risk factors. Hostility was not associated with subcutaneous fat (p = .8). Although there were significant racial/ethnic differences in hostility (p < .001) and the amount of total body (p < .001), subcutaneous (p < .001) and visceral fat (p < .001), the associations between hostility and measures of abdominal fat did not differ for African American compared with white women (race/ethnicity x hostility interaction, p = .67 for visceral, p = .85 for subcutaneous).

CONCLUSIONS

Hostility may affect CHD risk in women via the accumulation of visceral fat. Despite significant black-white differences in fat patterning and overall CHD risk, the association between hostility and visceral fat seems to be similar for both African American and white women.

Differential effects of abdominal adipose tissue distribution on insulin sensitivity in black and white South African women

Black South African women are more insulin resistant than BMI-matched white women. The objective of the study was to characterize the determinants of insulin sensitivity in black and white South African women matched for BMI. A total of 57 normal-weight (BMI 18-25 kg/m(2)) and obese (BMI > 30 kg/m(2)) black and white premenopausal South African women underwent the following measurements: body composition (dual-energy X-ray absorptiometry), body fat distribution (computerized tomography (CT)), insulin sensitivity (S(I), frequently sampled intravenous glucose tolerance test), dietary intake (food frequency questionnaire), physical activity (Global Physical Activity Questionnaire), and socioeconomic status (SES, demographic questionnaire). Black women were less insulin sensitive (4.4 +/- 0.8 vs. 9.5 +/- 0.8 and 3.0 +/- 0.8 vs. 6.0 +/- 0.8 x 10(-5)/min/(pmol/l), for normal-weight and obese women, respectively, P < 0.001), but had less visceral adipose tissue (VAT) (P = 0.051), more abdominal superficial subcutaneous adipose tissue (SAT) (P = 0.003), lower SES (P < 0.001), and higher dietary fat intake (P = 0.001) than white women matched for BMI. S(I) correlated with deep and superficial SAT in both black (R = -0.594, P = 0.002 and R = 0.495, P = 0.012) and white women (R = -0.554, P = 0.005 and R = -0.546, P = 0.004), but with VAT in white women only (R = -0.534, P = 0.005). In conclusion, body fat distribution is differentially associated with insulin sensitivity in black and white women. Therefore, the different abdominal fat depots may have varying metabolic consequences in women of different ethnic origins.

Gender differences in insulin resistance, body composition, and energy balance

BACKGROUND

Men and women differ substantially in regard to degrees of insulin resistance, body composition, and energy balance. Adipose tissue distribution, in particular the presence of elevated visceral and hepatic adiposity, plays a central role in the development of insulin resistance and obesity-related complications.

OBJECTIVE

This review summarizes published data on gender differences in insulin resistance, body composition, and energy balance, to provide insight into novel gender-specific avenues of research as well as gender-tailored treatments of insulin resistance, visceral adiposity, and obesity.

METHODS

English-language articles were identified from searches of the PubMed database through November 2008, and by reviewing the references cited in these reports. Searches included combinations of the following terms: gender, sex, insulin resistance, body composition, energy balance, and hepatic adipose tissue.

RESULTS

For a given body mass index, men were reported to have more lean mass, women to have higher adiposity. Men were also found to have more visceral and hepatic adipose tissue, whereas women had more peripheral or subcutaneous adipose tissue. These differences, as well as differences in sex hormones and adipokines, may contribute to a more insulin-sensitive environment in women than in men. When normalized to kilograms of lean body mass, men and women had similar resting energy expenditure, but physical energy expenditure was more closely related to percent body fat in men than in women.

CONCLUSION

Greater amounts of visceral and hepatic adipose tissue, in conjunction with the lack of a possible protective effect of estrogen, may be related to higher insulin resistance in men compared with women.

Impact of race/ethnicity on the relationship between visceral fat and inflammatory biomarkers

The purpose of this study was to determine whether racial/ethnic differences exist in the relationship between visceral adipose tissue (VAT) and selected inflammatory biomarkers. Subjects included 136 African-American, 133 Hispanic, and 100 white men and women, aged > or =45. Waist circumference and BMI were measured using standard methods. Total VAT, and VAT and subcutaneous adipose tissue (SAT) at the L4L5 spinal level were measured using computed tomography. Interleukin-6 (IL-6), C-reactive protein (CRP), and fibrinogen were measured from fasting blood samples. Results revealed that waist circumference and BMI were similar among groups but African Americans had significantly lower L4L5 VAT compared with Hispanics and whites. Despite lower VAT, African-American men had similar concentrations of inflammatory biomarkers. On the other hand, African-American women had higher CRP and IL-6 than white women, and higher fibrinogen than both Hispanic and white women. After controlling for L4L5 VAT, L4L5 SAT, and age, African-American women had higher concentrations of IL-6 and fibrinogen. Stratified analyses for CRP indicated that L4L5 SAT was associated with CRP in African-American and white women after controlling for L4L5 VAT and age, but that the reverse was not true. These data indicate that African Americans had lower VAT but similar or higher concentrations of inflammatory biomarkers. African-American women consistently displayed greater inflammation compared with whites, even after controlling for VAT or SAT.