Relationships of BMI to Cardiovascular Risk Factors Differ by Ethnicity

The burden of cardiovascular risk associated with obesity disproportionately affects African Americans and little is known about ethnic/racial differences in the relationship of obesity to cardiometabolic risk. This report assesses whether obesity is similarly associated with cardiometabolic risk factors in African Americans and whites of European ancestry. Cross‐sectional observational data from the Jackson Heart Study (JHS) and the Framingham Heart Study (FHS) were compared. This analysis uses participants aged 35–74 years with BMI >18.5 kg/m², and free of prevalent cardiovascular disease (CVD), from the initial JHS clinical examination (2000–2004) and the FHS Offspring (1998–2001) and Third Generation (2002–2005) cohorts. Participants were evaluated for the presence of lipid abnormalities, hypertension, and diabetes. Overall, 4,030 JHS (mean age 54 years, 64% women) and 5,245 FHS (mean age 51 years, 54% women) participants were available for analysis. The prevalence of all risk factors except high triglycerides and low high‐density lipoprotein (HDL) was substantially higher in JHS (all P < 0.001) and BMI was associated with increasing prevalence of most CVD risk factors within each race. For diabetes mellitus, hypertension, and low HDL, steeper relationships to BMI were observed in FHS than in JHS (P values <0.001–0.016). There were larger proportional increases in risk factor prevalence with increasing BMI in whites than in African Americans. The higher prevalence rates of cardiometabolic risk factors at nearly all levels of BMI in African Americans, however, suggest that additional factors contribute to the burden of CVD risk in African Americans.     

Impacts of Visceral Adipose Tissue and Subcutaneous Adipose Tissue on Metabolic Risk Factors in Middle‐aged Japanese

Regional fat distribution rather than overall fat volume has been considered to be important to understanding the link between obesity and metabolic disorders. We aimed to evaluate the independent associations of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) with metabolic risk factors in apparently healthy middle‐aged Japanese. Participants were 1,119 men and 854 women aged 38–60 years who were not taking medications for diabetes, hypertension, or dyslipidemia. VAT and SAT were measured by use of computed tomography (CT) scanning. VAT and SAT were significantly and positively correlated with each other in men (r = 0.531, P < 0.001) and women (r = 0.589, P < 0.001). In multiple regression analyses, either measure of abdominal adiposity (VAT or SAT) was positively associated with blood pressure, fasting plasma glucose, and log triglyceride (P < 0.001) and inversely with high‐density lipoprotein (HDL)‐cholesterol (P < 0.001). When VAT and SAT were simultaneously included in the model, the association of VAT with triglycerides was maintained (P < 0.001) but that of SAT was lost. The same was true for HDL‐cholesterol in women. For fasting plasma glucose, the association with VAT was strong (P < 0.001) and the borderline association with SAT was maintained (P = 0.060 in men and P = 0.020 in women). Both VAT and SAT were independently associated with blood pressure (P < 0.001). Further adjustment for anthropometric indices resulted in the independent association only with VAT for all risk factors. In conclusion, impacts of VAT and SAT differed among risk factors. VAT showed dominant impacts on triglyceride concentrations in both genders and on HDL‐cholesterol in women, while SAT also had an independent association with blood pressure.     

Both Subcutaneous and Visceral Adipose Tissue Correlate Highly with Insulin Resistance in African Americans

Objective: The contribution of visceral adipose tissue (VAT) to insulin resistance is well‐established; however, the role of subcutaneous abdominal adipose tissue (SAT) in insulin resistance remains controversial. Sex may determine which of these two components of abdominal obesity is more strongly related to insulin resistance and its consequences. The aim of this study was to determine whether both VAT and SAT contribute to insulin resistance in African Americans and to examine the effects of sex on this relationship. Research Methods and Procedures: This was a cross‐sectional study of 78 nondiabetic African‐American volunteers (44 men, 35 women; age 33.8 ± 7.3 years; BMI 30.9 ± 7.4 kg/m²). VAT and SAT volumes were measured using serial computerized tomography slices from the dome of the diaphragm to the iliac crest. The insulin sensitivity index (S_I) was determined from the minimal model using data obtained from the frequently sampled intravenous glucose tolerance test. Results: In men, both VAT and SAT were negatively correlated with S_I (r for both correlations = ?0.57; p < 0.01). In women, the correlation coefficient between VAT and S_I was ?0.50 (p < 0.01) and between SAT and S_I was ?0.67 (p < 0.01). In women, the correlation coefficient for S_I with SAT was significantly greater than the correlation coefficient with VAT (p = 0.02). Discussion: Both SAT and VAT are strongly correlated with insulin resistance in African Americans. For African‐American women, SAT may have a greater effect than VAT on insulin resistance.     

Comparison of Regional Fat Distribution and Health Risk Factors in Middle‐Aged White and African American Women: The Healthy Transitions Study

Objective: Both ethnicity and menopause appear to influence intra‐abdominal fat distribution. This study evaluated intra‐abdominal fat distribution and obesity‐related health risks in perimenopausal white and African American women. Research Methods and Procedures: Baseline data from a longitudinal study of changes in body composition and energy balance during menopause are reported. Healthy women (55 African Americans and 103 whites) who were on no medication and had at least five menstrual cycles in the previous 6 months were recruited. Body composition was assessed by DXA, and visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were assessed by computed tomography scan. SAT was divided into deep and superficial layers demarcated by the fascia superficialis. Results: African American women were slightly younger (46.7 ± 0.2 vs. 47.7 ± 0.2 years, p = 0.002) and fatter (42.4% ± 1.0% vs. 39.4% ± 0.8% body fat, p = 0.02) than white women. In unadjusted data, African Americans had significantly more total abdominal fat and total, deep, and superficial SAT than whites. After adjustment for percent body fat and age, only total and superficial SAT remained significantly higher in African Americans. VAT although slightly less in African American women, did not differ significantly by race. In multiple regression analysis, VAT was the strongest predictor of serum lipids, glucose, and insulin in women of both races, although superficial SAT was significantly associated with fasting glucose in whites. Conclusions: Middle‐aged African American women have larger SAT depots, adjusted for total body fatness, but do not differ from white women with regard to VAT. The complexity of the relationship between abdominal fat and metabolic risk is increased by ethnic differences in such associations.     

Intermuscular Adipose Tissue and Metabolic Associations in HIV Infection

Intermuscular adipose tissue (IMAT) is associated with metabolic abnormalities similar to those associated with visceral adipose tissue (VAT). Increased IMAT has been found in obese human immunodeficiency virus (HIV)‐infected women. We hypothesized that IMAT, like VAT, would be similar or increased in HIV‐infected persons compared with healthy controls, despite decreases in subcutaneous adipose tissue (SAT) found in HIV infection. In the second FRAM (Study of Fat Redistribution and Metabolic Change in HIV infection) exam, we studied 425 HIV‐infected subjects and 211 controls (from the Coronary Artery Risk Development in Young Adults study) who had regional AT and skeletal muscle (SM) measured by magnetic resonance imaging (MRI). Multivariable linear regression identified factors associated with IMAT and its association with metabolites. Total IMAT was 51% lower in HIV‐infected participants compared with controls (P = 0.003). The HIV effect was attenuated after multivariable adjustment (to ?28%, P < 0.0001 in men and ?3.6%, P = 0.70 in women). Higher quantities of leg SAT, upper‐trunk SAT, and VAT were associated with higher IMAT in HIV‐infected participants, with weaker associations in controls. Stavudine use was associated with lower IMAT and SAT, but showed little relationship with VAT. In multivariable analyses, regional IMAT was associated with insulin resistance and triglycerides (TGs). Contrary to expectation, IMAT is not increased in HIV infection; after controlling for demographics, lifestyle, VAT, SAT, and SM, HIV⁺ men have lower IMAT compared with controls, whereas values for women are similar. Stavudine exposure is associated with both decreased IMAT and SAT, suggesting that IMAT shares cellular origins with SAT.     

Associations of visceral and abdominal subcutaneous adipose tissue with markers of cardiac and metabolic risk in obese adults

Objective : Visceral (VAT) and abdominal subcutaneous (SAT) adipose tissues contribute to obesity but may have different metabolic and atherosclerosis risk profiles. We sought to determine the associations of abdominal VAT and SAT mass with markers of cardiac and metabolic risk in a large, multiethnic, population‐based cohort of obese adults. Design and Methods : Among obese participants in the Dallas Heart Study, we examined the cross‐sectional associations of abdominal VAT and SAT mass, assessed by magnetic resonance imaging (MRI) and indexed to body surface area (BSA), with circulating biomarkers of insulin resistance, dyslipidemia, and inflammation (n = 942); and with aortic plaque and liver fat by MRI and coronary calcium by computed tomography (n = 1200). Associations of VAT/BSA and SAT/BSA were examined after adjustment for age, sex, race, menopause, and body mass index. Results : In multivariable models, VAT significantly associated with the homeostasis model assessment of insulin resistance (HOMA‐IR), lower adiponectin, smaller LDL and HDL particle size, larger VLDL size, and increased LDL and VLDL particle number (p < 0.001 for each). VAT also associated with prevalent diabetes, metabolic syndrome, hepatic steatosis, and aortic plaque (p < 0.001 for each). VAT independently associated with C‐reactive protein but not with any other inflammatory biomarkers tested. In contrast, SAT associated with leptin and inflammatory biomarkers, but not with dyslipidemia or atherosclerosis. Associations between SAT and HOMA‐IR were significant in univariable analyses but attenuated after multivariable adjustment. Conclusion : VAT associated with an adverse metabolic, dyslipidemic, and atherogenic obesity phenotype. In contrast, SAT demonstrated a more benign phenotype, characterized by modest associations with inflammatory biomarkers and leptin, but no independent association with dyslipidemia, insulin resistance, or atherosclerosis in obese individuals. These findings suggest that abdominal fat distribution defines distinct obesity sub‐phenotypes with heterogeneous metabolic and atherosclerosis risk.     

Android fat depot is more closely associated with metabolic syndrome than abdominal visceral fat in elderly people

Background

Fat accumulation in android compartments may confer increased metabolic risk. The incremental utility of measuring regional fat deposition in association with metabolic syndrome (MS) has not been well described particularly in an elderly population.

Methods and Findings

As part of the Korean Longitudinal Study on Health and Aging, which is a community-based cohort study of people aged more than 65 years, subjects (287 male, 75.9±8.6 years and 278 female, 76.0±8.8 years) with regional body composition data using Dual energy X-ray absorptiometry for android/gynoid area, computed tomography for visceral/subcutaneous adipose tissue (VAT/SAT), and cardiometabolic markers including adiponectin and high-sensitivity CRP were enrolled. We investigated the relationship between regional body composition and MS in multivariate regression models. Mean VAT and SAT area was 131.4±65.5 cm² and 126.9±55.2 cm² in men (P = 0.045) and 120.0±46.7 cm² and 211.8±65.9 cm² in women (P<0.01). Mean android and gynoid fat amount was 1.8±0.8 kg and 2.5±0.8 kg in men and 2.0±0.6 kg and 3.3±0.8 kg in women, respectively (both P<0.01). VAT area and android fat amount was strongly correlated with most metabolic risk factors compared to SAT or gynoid fat. Furthermore, android fat amount was significantly associated with clustering of MS components after adjustment for multiple parameters including age, gender, adiponectin, hsCRP, a surrogate marker of insulin resistance, whole body fat mass and VAT area.

Conclusions

Our findings are consistent with the hypothesized role of android fat as a pathogenic fat depot in the MS. Measurement of android fat may provide a more complete understanding of metabolic risk associated with variations in fat distribution.     

Breast Volume is an Independent Predictor of Visceral and Ectopic Fat in Premenopausal Women

It is suggested that a large breast size among women may predict type 2 diabetes risk independent of BMI and waist circumference (WC). The purpose of this study was to determine the independent associations of breast volume with cardiometabolic risk factors and regional fat distribution. A total of 92 overweight or obese premenopausal women (age = 39.9 ± 6.8 years) underwent full‐body magnetic resonance imaging (MRI) for the assessment of breast volume, visceral adipose tissue (VAT), abdominal and lower‐body subcutaneous AT (SAT), and intermuscular AT (IMAT), a 2‐h oral glucose tolerance test (OGTT), and fasting phlebotomy for assessment of triglyceride, total, high‐density lipoprotein–, and low‐density lipoprotein–cholesterol levels. Breast volume was not associated with any of the cardiometabolic risk factors assessed (P > 0.05). However, VAT was consistently associated with a number of cardiometabolic risk factors (OGTT glucose, OGTT insulin, and triglyceride levels) after controlling for age, BMI, WC, breast volume, and the other AT depots. In univariate models, breast volume was positively associated with VAT, IMAT, and abdominal and lower‐body SAT (P < 0.05). After controlling for age, BMI, and WC level, breast volume remained positively associated with VAT and IMAT (P < 0.05), such that women with the highest breast volume had ～1.1 and 1.3 kg more VAT and IMAT, respectively, but no more abdominal or lower‐body SAT, by comparison to women with the smallest breast volume. Thus, the previously documented association between breast size and type 2 diabetes risk may be in part explained by excess VAT and/or IMAT deposition.     

Visceral and not subcutaneous abdominal adiposity reduction drives the benefits of a 1-year lifestyle modification program

Excess visceral adipose tissue (VAT) is associated with an increased cardiometabolic risk. The study examined whether changes in cardiometabolic risk markers after a 1-year lifestyle intervention in viscerally obese men were associated with changes in VAT or with changes in subcutaneous abdominal adipose tissue (SAT). The relative contributions of changes in global adiposity vs. changes in cardiorespiratory fitness to changes in VAT were also quantified. One hundred and forty four men were selected on the basis of an increased waist circumference (≥ 90 cm) associated with dyslipidemia (triglycerides ≥ 1.69 and/or high-density lipoprotein (HDL)-cholesterol <1.03 mmol/l); 117 men completed the 1-year intervention which consisted in a healthy eating, physical activity/exercise program. Body weight, body composition, and fat distribution were assessed by anthropometry and dual-energy X-ray absorptiometry (DEXA)/computed tomography. Cardiorespiratory fitness, plasma adipokine/inflammatory markers, fasting lipoprotein-lipid profile, and oral glucose tolerance test (OGTT) were assessed. VAT volume decreased by 26%, cardiorespiratory fitness improved by 20% (P < 0.0001) after 1 year. Plasma adipokine/inflammatory markers, lipids/lipoproteins, and glucose homeostasis were improved. One-year changes in triglyceride (r = 0.29), apolipoprotein B (r = 0.21), 120-min OGTT-glucose (r = 0.27), and fasting insulin (r = 0.27) levels correlated with changes in VAT (all P < 0.05) after adjustment for changes in SAT. Using a multilinear regression model, VAT reduction was independently associated with SAT reduction and with improvement in cardiorespiratory fitness (R(2) = 0.58, P < 0.0001). Therefore, this healthy eating-physical activity/exercise program improved the cardiometabolic risk profile of viscerally obese men in relation to the reduction of VAT. Furthermore, the reduction in VAT was independently related to the reduction in global adiposity and to the improvement in cardiorespiratory fitness.     

Hypertriglyceridemia and waist circumference predict cardiovascular risk among HIV patients: a cross-sectional study

Background

Although half of HIV-infected patients develop lipodystrophy and metabolic complications, there exists no simple clinical screening tool to discern the high from the low-risk HIV-infected patient. Thus, we evaluated the associations between waist circumference (WC) combined with triglyceride (TG) levels and the severity of lipodystrophy and cardiovascular risk among HIV-infected men and women.

Methods

1481 HIV-infected men and 841 HIV-infected women were recruited between 2005 and 2009 at the metabolic clinic of the University of Modena and Reggio Emilia in Italy. Within each gender, patients were categorized into 4 groups according to WC and TG levels. Total and regional fat and fat-free mass were assessed by duel-energy x-ray absorptiometry, and visceral adipose tissue (VAT) and abdominal subcutaneous AT (SAT) were quantified by computed tomography. Various cardiovascular risk factors were assessed in clinic after an overnight fast.

Results

The high TG/high WC men had the most VAT (208.0±94.4 cm²), as well as the highest prevalence of metabolic syndrome (42.2%) and type-2 diabetes (16.2%), and the highest Framingham risk score (10.3±6.5) in comparison to other groups (p<0.05 for all). High TG/high WC women also had elevated VAT (150.0±97.9 cm²) and a higher prevalence of metabolic syndrome (53.3%), hypertension (30.5%) and type-2 diabetes (12.0%), and Framingham risk score(2.9±2.8) by comparison to low TG/low WC women (p<0.05 for all).

Conclusions

A simple tool combining WC and TG levels can discriminate high- from low-risk HIV-infected patients.     

Visceral fat, waist circumference, and BMI: impact of race/ethnicity

Objective: BMI and waist circumference are used to define risk from excess body fat. Limited data in women suggest that there may be racial/ethnic differences in visceral adipose tissue (VAT) at a given BMI or waist circumference. This study tested the hypothesis that racial/ethnic differences exist in both men and women in the relationship of anthropometric measures of body composition and computed tomography (CT)‐determined VAT or subcutaneous adipose tissue (SAT). Methods and Procedures: Subjects included 66 African American, 72 Hispanic, and 47 white men and women, aged ≥ 45. Waist circumference and BMI were measured using standard methods. Total abdominal and L4L5 VAT and SAT were measured using CT. Results: Among both men and women, groups did not differ in waist circumference or BMI. White men had greater L4L5 VAT than African‐American men, and both white and Hispanic men had greater total VAT than African‐American men. Among women, Hispanics and whites had greater L4L5 VAT than African Americans, and Hispanics had greater total VAT than African Americans. The slope of the linear relationship between BMI or waist circumference and VAT was lower in African Americans than in Hispanics and/or whites. Discussion: Middle‐aged and older African‐American men and women had lower VAT despite similar BMI and waist circumference measurements. Altered relationships between anthropometric measures and VAT may have implications for defining metabolic risk in different populations. Different waist circumference or BMI cutoff points may be necessary to adequately reflect risk in different racial/ethnic groups.     

Serum Leptin in Elderly People: Associations with Sex Hormones,Insulin, and Adipose Tissue Volumes

BAUMGARTNER, RICHARD N., ROBERT R. ROSS, DEBRA L. WATERS, WILLIAM M. BROOKS, JOHN E. MORLEY, GEORGE D. MONTOYA, AND PHILIP J. GARRY. Serum leptin in elderly people: associations with sex hormones, insulin, and adipose tissue volumes. Obes Res. Objective There are few data for associations of serum leptin with body fat, fat distribution, sex hormones, or fasting insulin in elderly adults. We hypothesized that the sex difference in serum leptin concentrations would disappear after adjustment for subcutaneous, but not visceral body fat. Serum leptin would not be associated with sex hormone concentrations or serum fasting insulin after adjusting for body fat and fat distribution. Research Methods and Procedures Subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) volumes were measured using magnetic resonance imaging in a cross-sectional sample of 56 nondiabetic, elderly men and women aged 64 years to 94 years. Serum leptin, sex hormones (testosterone and estrone), sex hormone-binding globulin, and fasting insulin were also measured. Nine women were taking hormone replacement, and five men were clinically hypogonadal. Results Leptin was significantly associated with both SAT and VAT in each sex. Adjustment for SAT reduced the sex difference in leptin by 56%, but adjustment for VAT increased the difference by 25%. Leptin was not associated with serum estrone or hormone replacement therapy in the women, but had a significant, negative association with testosterone in the men that was independent of SAT, but not VAT. Leptin was significantly associated with fasting insulin in both sexes independent of age, sex hormones, sex hormone-binding globulin, VAT and SAT. Discussion Sex difference in serum leptin is partly explained by different amounts of SAT. Studies including both men and women should adjust for SAT rather than total body fat that includes VAT. The sex difference in serum leptin is not due to estrogen, but may be partly explained by testosterone. Testosterone is negatively associated with leptin in men, but the association is confounded with VAT. Leptin is associated with fasting insulin in non-diabetic elderly men and women independent of body fat, fat distribution. or sex hormones.     

Cardiometabolic risks during anabolic hormone supplementation in older men

Objective:

To determine the cardiometabolic risks of testosterone and growth hormone (GH) replacement therapy to youthful levels during aging.

Design and Methods:

A double‐masked, partially placebo controlled study in 112 men 65‐90 years‐old was conducted. Transdermal testosterone (5 g vs. 10 g/day) using a Leydig Cell Clamp and subcutaneous recombinant GH (rhGH) (0 vs. 3 vs. 5 μg/kg/day) were administered for 16‐weeks. Measurements included testosterone and IGF‐1 levels, body composition by DEXA, and cardiometabolic risk factors (upper body fat, blood pressure, insulin sensitivity, fasting triglycerides, HDL‐cholesterol, and serum adiponectin) at baseline and after 16 weeks of treatment.

Results:

Some cardiometabolic factors improved (total and trunk fat, triglycerides, HDL‐cholesterol) and others worsened (systolic blood pressure, insulin sensitivity index [QUICKI], adiponectin). Cardiometabolic risk composite scores (CRCSs) improved (?0.69 ± 1.55, P < 0.001). In multivariate analyses, QUICKI, triglycerides, and HDL‐cholesterol contributed 33%, 16%, and 14% of the variance in CRCS, respectively. Pathway analyses indicated that changes in fat and lean mass were related to individual cardiometabolic variables and CRCS in a complex manner. Changes in BMI, reflecting composite effects of changes in fat and lean mass, were more robustly associated with cardiometabolic risks than changes in fat mass or LBM individually.

Conclusions:

Testosterone and rhGH administration was associated with diverse changes in individual cardiometabolic risk factors, but in aggregate appeared not to worsen cardiometabolic risk in healthy older men after 4‐months. The long‐term effects of these and similar anabolic therapies on cardiovascular events should be investigated in populations with greater functional limitations along with important health disabilities including upper body obesity and other cardiometabolic risks.

     

Adiposity and hand osteoarthritis: the Netherlands Epidemiology of Obesity study

Introduction

Obesity, usually characterized by the body mass index (BMI), is a risk factor for hand osteoarthritis (OA). We investigated whether adipose tissue and abdominal fat distribution are associated with hand OA.

Methods

The Netherlands Epidemiology of Obesity (NEO) study is a population-based cohort aged 45 to 65 years, including 5315 participants (53% women, median BMI 29.9 kg/m²). Fat percentage and fat mass (FM) (kg) were estimated using bioelectrical impedance analysis. The waist-to-hip ratio (WHR) was calculated. In 1721 participants, visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) (cm²) were assessed using abdominal MR imaging. Hand OA was defined according to the ACR criteria.Odds ratios (OR) with 95% confidence intervals (CI) were calculated for the association of fat percentage, FM, WHR, VAT and SAT with hand OA using logistic regression analyses per standard deviation, stratified by sex and adjusted for age.

Results

Hand OA was present in 8% of men and 20% of women. Fat percentage was associated with hand OA in men (OR 1.34 (95% CI 1.11 to 1.61)) and women (OR 1.26 (1.05 to 1.51)), as was FM. WHR was associated with hand OA in men (OR 1.45 (1.13 to 1.85)), and to a lesser extent in women (OR 1.17 (1.00 to 1.36)). Subgroup analysis revealed that VAT was associated with hand OA in men (OR1.33 (1.01 to 1.75)). This association increased after additional adjustment for FM (OR 1.51 (1.13 to 2.03)).

Conclusions

Fat percentage, FM and WHR were associated with hand OA. VAT was associated with hand OA in men, suggesting involvement of visceral fat in hand OA.     

Femoral-gluteal subcutaneous and intermuscular adipose tissues have independent and opposing relationships with CVD risk.

Femoral-gluteal adipose tissue (AT) may be cardioprotective through fatty acids uptake. Femoral-gluteal AT has previously been defined as leg fat measured by dual energy x-ray absorptiometry (DXA); however, subcutaneous adipose tissue (SAT) and intermuscular adipose tissue (IMAT) are inseparable using DXA. This study investigated the independent relationships between femoral-gluteal SAT, femoral-gluteal IMAT, and cardiovascular disease (CVD) risk factors [fasting serum measures of glucose, total cholesterol (TC), high density lipoprotein cholesterol (HDLC), triglycerides (TG) and insulin] and whether race differences exist in femoral-gluteal AT distribution. Adult Caucasians (56 men and 104 women), African-Americans (37 men and 76 women), and Asians (11 men and 35 women) had total AT (TAT) including femoral-gluteal AT (upper leg SAT and IMAT) and visceral AT (VAT) by magnetic resonance imaging (MRI). General linear models identified the independent effects of femoral-gluteal SAT and femoral-gluteal IMAT on each risk factor after covarying for TAT, VAT, age, race, sex, and two-way interactions. Femoral-gluteal IMAT and glucose (P < 0.05) were positively associated independent of VAT. There were also significant inverse associations between femoral-gluteal SAT and insulin (P < 0.01) and TG (P < 0.05), although the addition of VAT rendered these effects nonsignificant, possibly due to collinearity. Asian women had less femoral-gluteal SAT and greater VAT than Caucasians and African-Americans (P < 0.05) and Asian and African-American men had greater femoral-gluteal IMAT than Caucasians, adjusted for age and TAT (P < 0.05 for both). Femoral-gluteal SAT and femoral-gluteal IMAT distribution varies by sex and race, and these two components have independent and opposing relationships with CVD risk factors.     

Do Abnormal Serum Lipid Levels Increase the Risk of Chronic Low Back Pain? The Nord-Tr?ndelag Health Study

Background

Cross-sectional studies suggest associations between abnormal lipid levels and prevalence of low back pain (LBP), but it is not known if there is any causal relationship.

Objective

The objective was to determine, in a population-based prospective cohort study, whether there is any relation between levels of total cholesterol, high density lipoprotein (HDL) cholesterol and triglycerides and the probability of experiencing subsequent chronic (LBP), both among individuals with and without LBP at baseline.

Methods

Information was collected in the community-based HUNT 2 (1995–1997) and HUNT 3 (2006–2008) surveys of an entire Norwegian county. Participants were 10,151 women and 8731 men aged 30–69 years, not affected by chronic LBP at baseline, and 3902 women and 2666 men with LBP at baseline. Eleven years later the participants indicated whether they currently suffered from chronic LBP.

Results

Among women without LBP at baseline, HDL cholesterol levels were inversely associated and triglyceride levels positively associated with the risk of chronic LBP at end of follow-up in analyses adjusted for age only. Adjustment for the baseline factors education, work status, physical activity, smoking, blood pressure and in particular BMI largely removed these associations (RR: 0.96, 95% CI: 0.85–1.07 per mmol/l of HDL cholesterol; RR: 1.16, 95% CI: 0.94–1.42 per unit of lg(triglycerides)). Total cholesterol levels showed no associations. In women with LBP at baseline and men without LBP at baseline weaker relationships were observed. In men with LBP at baseline, an inverse association with HDL cholesterol remained after complete adjustment (RR: 0.83, 95% CI: 0.72–0.95 per mmol/l).

Conclusion

Crude associations between lipid levels and risk of subsequent LBP in individuals without current LBP are mainly caused by confounding with body mass. However, an association with low HDL levels may still remain in men who are already affected and possibly experience a higher pain intensity.     

Expression of Clock Genes in Human Subcutaneous and Visceral Adipose Tissues

Disrupted circadian rhythms are associated with obesity and metabolic alterations, but little is known about the participation of peripheral circadian clock machinery in these processes. The aim of the present study was to analyze RNA expression of clock genes in subcutaneous (SAT) and visceral (VAT) adipose tissues of male and female subjects in AM (morning) and PM (afternoon) periods, and its interactions with body mass index (BMI). Ninety-one subjects (41?±?11 yrs of age) presenting a wide range of BMI (21.4 to 48.6?kg/m²) were included. SAT and VAT biopsies were obtained from patients undergoing abdominal surgeries. Clock genes expressions were evaluated by qRT-PCR. The only clock gene that showed higher expression (p?<?.0001) in SAT in comparison to VAT was PER1 of female (372%) and male (326%) subjects. Different patterns of expression between the AM and PM periods were observed, in particular REV-ERBα, which was reduced (p?<?.05) at the PM period in SAT and VAT of both women and men (women: ～53% lower; men: ～78% lower), whereas CLOCK expression was not altered. Relationships between clock genes were different in SAT vs. VAT. BMI was negatively correlated with SATPER1 (r?=??.549; p?=?.001) and SATPER2 (r?=??.613; p?=?.0001) and positively with VATCLOCK (r?=?.541; p?=?.001) and VATBMAL1 (r?=?.468; p?=?.007) only in women. These data suggest that the circadian clock machinery of adipose tissue depots differs between female and male subjects, with a sex-specific effect observed for some genes. BMI correlated with clock genes, but at this moment it is not possible to establish the cause-effect relationship. (Author correspondence: mzanquetta@gmail.com)     

Abdominal Subcutaneous and Visceral Adipose Tissue and Insulin Resistance in the Framingham Heart Study

Insulin resistance is associated with central obesity and an increased risk of cardiovascular disease. Our objective is to examine the association between abdominal subcutaneous (SAT) and visceral adipose tissue (VAT) and insulin resistance, to determine which fat depot is a stronger correlate of insulin resistance, and to assess whether there was an interaction between SAT, VAT, and age, sex, or BMI. Participants without diabetes from the Framingham Heart Study (FHS), who underwent multidetector computed tomography to assess SAT and VAT (n = 3,093; 48% women; mean age 50.4 years; mean BMI 27.6 kg/m²), were evaluated. Insulin resistance was measured using the homeostasis model and defined as HOMA_IR ≥75th percentile. Logistic regression models, adjusted for age, sex, smoking, alcohol, menopausal status, and hormone replacement therapy use, were used to assess the association between fat measures and insulin resistance. The odds ratio (OR) for insulin resistance per standard deviation increase in SAT was 2.5 (95% confidence interval (CI): 2.2–2.7; P < 0.0001), whereas the OR for insulin resistance per standard deviation increase in VAT was 3.5 (95% CI: 3.1–3.9; P < 0.0001). Overall, VAT was a stronger correlate of insulin resistance than SAT (P < 0.0001 for SAT vs. VAT comparison). After adjustment for BMI, the OR of insulin resistance for VAT was 2.2 (95% CI: 1.9–2.5; P < 0.0001). We observed an interaction between VAT and BMI for insulin (P interaction = 0.0004), proinsulin (P interaction = 0.003), and HOMA_IR (P interaction = 0.003), where VAT had a stronger association in obese individuals. In conclusion, SAT and VAT are both correlates of insulin resistance; however, VAT is a stronger correlate of insulin resistance than SAT.     

A Comparison between BMI,Waist Circumference,and Waist-To-Height Ratio for Identifying Cardio-Metabolic Risk in Children and Adolescents

Background

There is controversial evidence on the associations between anthropometric measures with clustering of cardiovascular disease risk factors in pediatric ages. We aimed to examine the associations between body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) with clustered cardiometabolic risk factors and to determine whether these anthropometric variables can be used to discriminate individuals with increased cardiometabolic risk (increased clustered triglycerides, HDL-cholesterol, systolic and diastolic blood pressure, and HOMA-IR).

Methods

The study sample of 4255 (2191 girls and 2064 boys) participants (8–17 years) was derived from pooled cross-sectional data comprising five studies. Outcomes included a continuous cardiometabolic risk factor z-score [corresponding to the sum of z-scores for triglycerides, HDL-cholesterol, systolic and diastolic blood pressure (mean arterial pressure), and HOMA-IR] and children with ≥1.0 SD in this score were defined as being at risk for clustering cardiometabolic risk factors.. Exposure variables were BMI, WC, WHtR. Statistics included mixed-effect regression and ROC analysis.

Results

All anthropometric variables were associated with clustered risk and the magnitudes of associations were similar for BMI, WC, and WHtR. Models including anthropometric variables were similar in discriminating children and adolescents at increased risk with areas under the ROC curve between 0.70 and 0.74. The sensitivity (boys: 80.5–86.4%; girls: 76.6–82.3%) was markedly higher than specificity (boys: 51.85–59.4%; girls: 60.8%).

Conclusions

The magnitude of associations for BMI, WC, and WHtR are similar in relation to clustered cardiometabolic risk factors, and perform better at higher levels of BMI. However, the precision of these anthropometric variables to classify increased risk is low.     

Habitual Sleep Measures are Associated with Overall Body Fat,and not Specifically with Visceral Fat,in Men and Women

Objective

This study aimed to investigate the associations of sleep duration and sleep quality with visceral adipose tissue (VAT) in middle‐aged individuals.

Methods

In this cross‐sectional analysis of baseline measurements of the Netherlands Epidemiology of Obesity (NEO) study, participants underwent anthropometry and completed the Pittsburgh Sleep Quality Index (PSQI) for assessing short sleep duration (as sex‐specific age‐adjusted percentiles) and poor quality (PSQI > 5). VAT was assessed by magnetic resonance imaging in a random subgroup. We performed linear regression analyses to examine associations of short sleep and poor sleep with measures of body fat, adjusted for confounding, including total body fat in models with VAT.

Results

A total of 5,094 participants (52% women; mean age of 56 [SD 6] years), 1,947 of whom had VAT measurements, were analyzed. The difference in VAT between poor sleep (PSQI > 5) and good sleep (PSQI ≤ 5) was 7.2cm² (95% CI: 1.2‐13.8) in women and 16.1cm² (95% CI: 6.2‐26.0) in men. These differences attenuated toward the null after the adjustment for total body fat. Similar patterns of associations were observed for short sleep (lowest 10% compared with median 60%).

Conclusions

Our results suggest that measures of sleep are not specifically associated with a higher amount of VAT.