Asian women have greater abdominal and visceral adiposity than Caucasian women with similar body mass index

Background:

In the Multiethnic Cohort Study, Japanese Americans (JA) have lower mean body mass index (BMI) compared with Caucasians, but show a higher waist-to-hip ratio at similar BMI values and a greater risk of diabetes and obesity-associated cancers.

Objective:

We investigated the abdominal, visceral and hepatic fat distribution in these Asian and Caucasian Americans.

Design:

A cross-sectional sample of 60 female cohort participants (30 JA and 30 Caucasians), of ages 60–65 years and BMIs 18.5–40 kg m⁻², underwent anthropometric measurements and a whole-body dual energy X-ray absorptiometry (DXA) scan: a subset of 48 women also had abdominal magnetic resonance imaging (MRI).

Results:

By design, JA women had similar BMIs (mean 26.5 kg m⁻²) to Caucasian women (27.1 kg m⁻²). JA women were found to have a significantly smaller hip circumference (96.9 vs 103.6 cm; P=0.007) but not a significantly lower DXA total fat mass (25.5 vs 28.8 kg; P=0.16). After adjusting for age and DXA total fat mass, JA women had a greater waist-to-hip ratio (0.97 vs 0.89; P<0.0001), DXA trunk fat (15.4 vs 13.9 kg; P=0.0004) and MRI % abdominal visceral fat (23.9 vs 18.5% P=0.01) and a lower DXA leg fat mass (8.2 vs 10.0 kg; P=<.0001). Their MRI % subcutaneous fat (33.4 vs 30.2% P=0.21) and % liver fat (5.8 vs 3.8% P=0.06) did not significantly differ from that of Caucasian women.

Conclusions:

Our findings build on limited past evidence, suggesting that Asian women carry greater abdominal and visceral fat when compared with Caucasian women with similar overall adiposity. This may contribute to their elevated metabolic risk for obesity-related diseases.     

Cardiovascular responsivity to stress in adolescents with and without persistently elevated blood pressure

OBJECTIVES: The goal of this study was to compare the cardiovascular responses to behavioural stressors of three groups of adolescents who differed in blood pressure status across assessments. DESIGN: Casual blood pressure of adolescents who were identified as having elevated blood pressure during a school screen was re-evaluated in the laboratory. The adolescents were classified into two groups: (i) those with consistently elevated blood pressure across school and laboratory assessments and (i) those with labile blood pressure whose blood pressure in the laboratory was below 130/80 mmHg. A comparison group of adolescents with consistently normal blood pressure was also included. METHODS: Cardiovascular parameters were assessed during rest and during two behavioural stressors, the evaluated speaking task and the mirror tracing task. RESULTS: Adolescents with elevated blood pressure were more vascularly responsive across stressors than adolescents with labile blood pressure, who, in turn, were more reactive than adolescents with normal blood pressure. CONCLUSIONS: These results suggest that vascular reactivity to behavioural stressors may be useful in predicting risk of hypertension because of its sensitivity in distinguishing adolescents with consistently elevated blood pressure from those with labile blood pressure and those with normal blood pressure.     

The relation of body mass index and abdominal adiposity with dyslipidemia in 27 general populations of the WHO MONICA Project

Background and aimsThe association between adiposity measures and dyslipidemia has seldom been assessed in a multipopulational setting.Methods and results27 populations from Europe, Australia, New Zealand and Canada (WHO MONICA project) using health surveys conducted between 1990 and 1997 in adults aged 35–64 years (n = 40,480). Dyslipidemia was defined as the total/HDL cholesterol ratio >6 (men) and >5 (women).Overall prevalence of dyslipidemia was 25% in men and 23% in women. Logistic regression showed that dyslipidemia was strongly associated with body mass index (BMI) in men and with waist circumference (WC) in women, after adjusting for region, age and smoking. Among normal-weight men and women (BMI<25 kg/m²), an increase in the odds for being dyslipidemic was observed between lowest and highest WC quartiles (OR = 3.6, p < 0.001). Among obese men (BMI ≥ 30), the corresponding increase was smaller (OR = 1.2, p = 0.036). A similar weakening was observed among women. Classification tree analysis was performed to assign subjects into classes of risk for dyslipidemia. BMI thresholds (25.4 and 29.2 kg/m²) in men and WC thresholds (81.7 and 92.6 cm) in women came out at first stages. High WC (>84.8 cm) in normal-weight men, menopause in women and regular smoking further defined subgroups at increased risk.Conclusionstandard categories of BMI and WC, or their combinations, do not lead to optimal risk stratification for dyslipidemia in middle-age adults. Sex-specific adaptations are necessary, in particular by taking into account abdominal obesity in normal-weight men, post-menopausal age in women and regular smoking in both sexes.     

Corticosteroid receptor genetic polymorphisms and stress responsivity

A fundamental question in the neuroendocrinology of stress-related psychopathology is why some individuals florish and others perish under similar adverse conditions. In this contribution we focus on the variants of mineralocorticorticoid (MR) and glucocorticoid receptors (GR) that operate in balance and coordinate behavioral, autonomic, and neuroendocrine response patterns involved in homeostasis and health. In the GR-gene, three single nucleotide polymorphism (SNPs) have been associated with changes in metabolic profile and cardiovascular parameters: the ER22/23EK with a favorable and the N363S and the Bcl1 with a more adverse profile. Importantly, the N363S and the Bcl1 are found to increase cortisol responses to a psychosocial stressor. As a result, the whole body will suffer from overexposure with possible adverse effects on metabolism, cardiovascular control, immune function, and behavior. Also in the MR gene, variants are being identified that are associated with dysregulated autonomic, behavioral, and neuroendocrine responses. The data suggest that these MR and GR variants contribute to individual differences in resilience and vulnerability to stressors, and that these receptors therefore are potential drug targets for recovery of homeostasis and health.     

Both overall adiposity and abdominal adiposity increase blood viscosity by separate mechanisms

While recent studies suggested that both general adiposity and abdominal adiposity are associated with the risk of death and support the use of waist circumference or waist-to-hip ratio (WHR) in addition to body index mass (BMI) in assessing the risk of death, this issue remains cintroversial since most authors conclude that BMI explains almost all the obesity-related risk of diabetes and conary heart disease (CHD). We investigated the separate effects of BMI and WHR on blood rheology in 430 patients attending to a metabolic check-up and exhibiting all the spectrum of age (11-77 yr) and BMI (15-50 kg/m2). BMI and WHR are correlated to each other (r = 0.269; p = 0.009) and are both predictors of blood viscosity (BMI: r = 0.15516; p = 0.004; WHR: r = 0.3638; p = 0.03). However while looking at determinants of viscosity these correlations had not the same meaning. For BMI it was explained by its correlation with plasma viscosity (r = 0.17718; p = 0.00105) and red blood cells (RBC) aggregation (all Myrenne and SEFAM indices with r ranging between 0.226 and 0.430) while these parameters were not correlated to WHR. By contrast WHR was strongly correlated with hematocrit (r = 0.524; p = 0.0003) which was not correlated with BMI. A forward stepwise regression selected WRH as a better predictor of blood viscosity, excluding BMI. Thus both BMI and WHR are associated with increased blood viscosity but these correlations reflect separate mechanisms. These data suggest that both overall adiposity and abdominal adiposity induce hyper viscosity, consistent with epidemiological studies linking the risk of CHD to abdominal adiposity and BMI.     

Prediction of lean body mass from multifrequency segmental impedance: influence of adiposity

The aim of the study was to determine the influence of adiposity on the relationship between bioelectrical impedance (BIA) measurements of body segments and estimation of body composition by dual-energy X-ray absorptiometry (DXA). Multiple frequencies of whole body and segmental impedances were measured in 68 normal-weight and obese subjects (46 women and 22 men), mean age 37.2+/-14.8 years (range, 18-69). Total and appendicular lean body mass (LBM) assessed by DXA correlated significantly with total and segmental impedance values adjusted for stature in both obese and normal-weight subjects. Best fitting equations for the prediction of appendicular LBM from segmental impedance measurements were derived for the arm and leg with and without the inclusion of adiposity (the percentage of body fat measured by DXA) in the regression models. Best prediction was obtained at low frequency for the arm and high frequency for the leg. Adiposity appears to significantly influence the prediction of leg LBM by BIA. These preliminary observations need further validation to provide an accurate assessment of appendicular LBM assessment by BIA.     

Body mass index, abdominal adiposity and blood pressure: consistency of their association across developing and developed countries.

BACKGROUND: Obesity is increasing worldwide because developing countries are adopting Western high-fat foods and sedentary lifestyles. In parallel, in many of them, hypertension is rising more rapidly, particularly with age, than in Western countries. OBJECTIVE: To assess the relationship between adiposity and blood pressure (BP) in a developing country with high average BP (The Seychelles, Indian Ocean, population mainly of African origin) in comparison to a developed country with low average BP (Switzerland, population mainly of Caucasian origin). DESIGN: Cross-sectional health examination surveys based on population random samples. SETTING: The main Seychelles island (Mahé) and two Swiss regions (Vaud-Fribourg and Ticino). SUBJECTS: Three thousand one hundred and sixteen adults (age range 35-64) untreated for hypertension. MEASUREMENTS: Body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), systolic and diastolic blood pressure (SBP and DBP, mean of two measures). METHODS: Scatterplot smoothing techniques and gender-specific linear regression models. RESULTS: On average, SBP and DBP were found to increase linearly over the whole variation range of BMI, WHR and WC. A modest, but statistically significant linear association was found between each indicator of adiposity and BP levels in separate regression models controlling for age. The regression coefficients were not significantly different between the Seychelles and the two Swiss regions, but were generally higher in women than in men. For the latter, a gain of 1.7 kg/m(2) in BMI, of 4.5 cm in WC or of 3.4% in WHR corresponded to an elevation of 1 mmHg in SBP. For women, corresponding figures were 1.25 kg/m(2), 2.5 cm and 1.8% respectively. Regression coefficients for age reflected a higher effect of this variable on both SBP and DBP in the Seychelles than in Switzerland. CONCLUSION: These findings suggest a stable linear relation of adiposity with BP, independent of age and body fat distribution, across developed and developing countries. The more rapid increase of BP with age observed in the latter countries are likely to reflect higher genetic susceptibility and/or higher cumulative exposure to another risk factor than adiposity.     

High prevalence of insulin resistance in postpubertal Asian Indian children is associated with adverse truncal body fat patterning, abdominal adiposity and excess body fat

OBJECTIVE: The objectives were to study the relationships of insulin resistance with generalized and abdominal obesity, and body fat patterning in urban postpubertal Asian Indian children. DESIGN: Cross-sectional, population-based epidemiological study. SUBJECTS: In all, 250 (155 males and 95 females) healthy urban postpubertal children. MEASUREMENTS: Anthropometric profile, percentage of body fat (%BF), fasting serum insulin, and lipoprotein profile. RESULTS: Fasting insulin correlated significantly with body mass index (BMI), %BF, waist circumference (WC), central and peripheral skinfold thicknesses and sum of four skinfold thicknesses (Sigma 4SF) in both sexes, and with systolic blood pressure and waist-to hip circumference ratio (W-HR) in males only. Consistent increase in fasting insulin was noted with increasing values of central skinfold thickness at each tertile of peripheral skinfold thickness, WC, and %BF. Central skinfold thickness correlated with fasting insulin even after adjusting for WC, W-HR, and %BF. The odds ratios (OR) (95% CI) of hyperinsulinemia (fasting insulin concentrations in the highest quartile) were 4.7 (2.4-9.4) in overweight subjects, 8 (4.1-15.5) with high %BF, 6.4 (3.2-12.9) with high WC, 3.7 (1.9-7.3) with high W-HR, 6.8 (3.3-13.9) with high triceps skinfold thickness, 8 (4.1-15.7) with high subscapular skinfold thickness, and 10.1 (5-20.5) with high Sigma 4SF. In step-wise multiple logistic regression analysis, %BF [OR (95% CI): 3.2 (1.4-7.8)] and Sigma 4SF [OR (95% CI): 4.5 (1.8-11.3)] were independent predictors of hyperinsulinemia, similar to insulin resistance assessed by HOMA (homeostatic model of assessment) in the study. CONCLUSION: A high prevalence of insulin resistance in postpubertal urban Asian Indian children was associated with excess body fat, abdominal adiposity, and excess truncal subcutaneous fat. Primary prevention strategies for coronary heart disease and diabetes mellitus in Asian Indians should focus on the abnormal body composition profile in childhood.     

Hyperinsulinemia, upper body adiposity, and cardiovascular risk factors in non-diabetics

Previous studies have suggested that hyperinsulinemia and upper body adiposity are each separately associated with elevated BP and triglyceride (TG) levels, and with lower high density lipoprotein (HDL) cholesterol levels. The joint effect of hyperinsulinemia and upper body adiposity on lipids, lipoproteins, and BP, however, has not been previously studied. We hypothesized that the effect of body fat distribution on cardiovascular risk factors might be mediated through hyperinsulinemia. We measured BP, lipids and lipoproteins, HDL subfractions, and insulin and glucose concentrations as part of the San Antonio Heart Study, a population-based study of diabetes and cardiovascular risk factors. Insulinemia and glycemia were assessed as the sum of the fasting, half-hour, one-hour, and two-hour insulin and glucose levels, respectively, measured during a standardized oral glucose tolerance test. Individuals who had diabetes according to National Diabetes Data Group criteria were excluded from the analyses. In univariate analyses, both hyperinsulinemia and waist-to-hip ratio (WHR), a measure of upper body adiposity, were positively associated with TG and negatively associated with total HDL and HDL2 cholesterol levels. However, when the effects of glycemia and insulinemia were controlled for by analysis of variance, WHR was no longer significantly related to TG levels. By contrast, WHR continued to be inversely related to total HDL and HDL2 cholesterol even after adjustment for glycemia and insulinemia. Hyperinsulinemia was only weakly related to HDL cholesterol. These results suggest that insulinemia and glycemia might mediate the effects of upper body adiposity on TG, although not on HDL and HDL2 cholesterol. Hyperinsulinemia was also positively associated with diastolic and systolic BP in men.     

Relaxation, noise-induced stress, and autonomic responsivity in male alcoholics and normal controls

Skin conductance and heart rate activity were monitored in male alcoholics and normal controls before, during, and after the presentation of high-intensity (100 db) white noise. Analysis of nonstressful, pre- and postnoise periods indicated a relatively nonlabile pattern characterizing alcoholics as they exhibited lower skin conductance levels than normals and showed no changes in activity either within or between resting sessions. A similar pattern was observed in response to noise-induced stress as alcoholics exhibited significantly smaller changes in skin conductance and heart rate activity.     

Pulmonary function and abdominal adiposity in the general population

BACKGROUND: The prevalence of obesity is increasing, and there is evidence that obesity, in particular abdominal obesity as a marker of insulin resistance, is negatively associated with pulmonary function. The mechanism for this association and the best marker of abdominal adiposity in relation to pulmonary function is not known. STUDY OBJECTIVE: We assessed the association between pulmonary function and weight, body mass index (BMI), waist circumference, waist/hip ratio, and abdominal height as markers of adiposity and body fat distribution. We used multiple linear regression to analyze the association of pulmonary function (ie, FEV(1) and FVC) [with maneuvers performed in the sitting position] with overall adiposity markers (ie, weight and BMI) and abdominal adiposity markers, stratified by gender, and adjusted for height, age, race, smoking, and other covariates.Setting and participants: A random sample of individuals (n = 2,153) from the general population living in western New York state, 35 to 79 years of age. RESULTS: In women, abdominal height and waist circumference were negatively associated with FEV(1) percent predicted, while all five adiposity markers were negatively associated with FVC percent predicted. In men, all overall and abdominal adiposity markers were inversely associated with FEV(1) percent predicted and FVC percent predicted. CONCLUSION: These results suggest that abdominal adiposity is a better predictor of pulmonary function than weight or BMI, and investigators should consider it when investigating the determinants of pulmonary function.     

Upper body and centralized adiposity in Mexican Americans and non-Hispanic whites: relationship to body mass index and other behavioral and demographic variables

Mexican Americans have a higher prevalence of NIDDM, more overall obesity and more centralized adiposity than non-Hispanic whites, but have thus far not been characterized as to whether they have greater upper body adiposity. Waist-to-hip circumferences (WHR, a measure of upper body adiposity) and subscapular-to-triceps skinfold ratios (centrality index, a measure of centralized adiposity) were determined in 725 Mexican Americans and 226 non-Hispanic whites as part of the San Antonio Heart Study, a population-based study of diabetes and cardiovascular risk factors. Mexican American females had higher centrality indices and WHRs than non-Hispanic white females, even after adjustment for demographic (age, menopausal status) and behavioral variables (body mass index, parity, cigarette smoking, alcohol consumption, exercise, and oral contraceptive and estrogen use). Mexican American males had higher centrality indices than non-Hispanic white males, but differences in WHR disappeared after adjustment for overall adiposity (body mass index). Of the demographic and behavioral variables, only age and body mass index were consistently related to regional body fat distribution. The lack of an association between body fat distribution and behavioral variables suggests that genetic factors may play the principal role in determining body fat distribution. Surprisingly, the distributions of centrality index and WHR were relatively independent of one another suggesting that they may be used as distinct, independent predictors of metabolic diseases.     

Associations between trunk, leg and total body adiposity with arterial stiffness

BackgroundObesity and arterial stiffness are associated, but fat distribution patterns may be more strongly related to arterial stiffness than general obesity because of the possible increased inflammation associated with increased abdominal adiposity. The aims of this study were to examine whether fat patterning is associated with arterial stiffness, and determine whether these associations are mediated by low-grade inflammation.MethodsAdult participants from the Fels Longitudinal Study (228 males and 254 females) were assessed for brachial-ankle pulse wave velocity (BaPWV) to determine arterial stiffness. Dual energy X-ray absorptiometry was used to estimate fat percentage of the trunk and legs (e.g., TRUNKFAT% and LEGFAT%). High-sensitivity C-reactive protein (hs-CRP) levels were assayed as a general marker of inflammation. General linear regression analyses were used.ResultsBaPWV was positively associated with TRUNKFAT% (r = 0.44 in men and r = 0.38 in women), whereas it was inversely related to LEGFAT% (r = -0.40 in men and r = -0.39 in women). In multiple regression analyses, each SD increase in TRUNKFAT% was associated with an ~1.03 m/s increase in BaPWV in both men and women. Each SD increase in LEGFAT% was related to a similar magnitude of decrease (1.03 m/s) in BaPWV in both sexes. The relationships of TRUNKFAT% and LEGFAT% with BaPWV were attenuated slightly when including hs-CRP in the models, but remained significant.ConclusionsWe found that trunk and leg fat are related to BaPWV in opposite directions when total body adiposity was accounted for. However, the associations between regional fat patterning and arterial stiffness did not appear to be mediated by low-grade inflammation.American Journal of Hypertension, 2012; doi:10.1038/ajh.2012.92.     

Interrelationships between body mass to waist circumference ratio,body mass index,and total body muscularity in older women

PurposeTo examine the relationships between body mass to waist circumference (BM:W) ratio or body mass index (BMI) and muscularity, 140 overweight (BMI ≥ 25 kg/m² and <30 kg/m²), 265 normal weight (BMI > 18.5 kg/m² and <25 kg/m²) and 26 underweight (BMI ≤ 18.5 kg/m²) Japanese women aged 60–80 years volunteered (overall 431 women).MethodsMuscle thickness was measured by ultrasound at six sites on the anterior and posterior aspects of the body. Total muscle mass (TMM) was estimated from an ultrasound-derived prediction equation. BMI and BM:W ratio were calculated using anthropometrical variables.ResultsWhen the overall sample was used, BMI was positively correlated with the TMM (r = 0.573, p < 0.001) and TMM index (r = 0.659, p < 0.001). BM:W ratio was also positively correlated with the TMM (r = 0.566, p < 0.001) and TMM index (r = 0.400, p < 0.001). In normal weight women, BMI was positively correlated with the TMM (r = 0.460, p < 0.001) and TMM index (r = 0.496, p < 0.001). Similarly, BM:W ratio was positively correlated with the TMM (r = 0.514, p < 0.001) and TMM index (r = 0.318, p < 0.001). In overweight and underweight women, TMM was significantly and positively correlated with BM:W ratio (r = 0.442 and r = 0.715, respectively; p < 0.001), but not BMI (r = 0.077 and r = 0.315). TMM index was also positively correlated with BM:W ratio in both overweight (r = 0.184, p < 0.05) and underweight (r = 0.500, p < 0.01) women. BMI was positively correlated with TMM index (r = 0.230, p < 0.01) and inversely correlated to the percentage of TMM in body mass (r = −0.262, p < 0.01) in overweight women.ConclusionThese results suggest that, compared to BMI, BM:W ratio may provide a simple and potential index for assessing muscularity in Japanese older underweight women. However, in normal and overweight women, BMI and BM:W ratio are both preferred in assessing muscularity.