Increased subcutaneous fat accumulation has a protective role against subclinical atherosclerosis in asymptomatic subjects undergoing general health screening

The association between the visceral to subcutaneous abdominal fat ratio and the risk of cardiovascular diseases: a systematic review

BACKGROUND

Cardiovascular diseases (CVDs) are the primary cause of mortality globally. The prevalence of obesity is rising worldwide; there seems to be a significant positive association between obesity and CVDs. The distribution of fat in the abdominal area in the form of visceral (VAT) or subcutaneous adipose tissue (SAT) affects the risk of CVDs. The aim of the present study was to conduct a systematic review of the available literature regarding the association between the VAT-to-SAT ratio and CVDs.

METHODS

A comprehensive search strategy was used to retrieve all human observational studies indexed in PubMed, Scopus and Google Scholar databases/search engines (from Jan 2000 up to Oct 2023). The VAT-to-SAT or SAT-to-VAT ratio was an independent variable and various cardiovascular diseases, including hypertension, atherosclerosis, coronary heart disease, cerebrovascular disease and heart failure, were considered as outcomes of interest.

RESULTS

Out of 1173 initial studies, 910 papers were screened. Based on the inclusion criteria, 883 papers were excluded. Finally, 27 papers (18 cross-sectional and 9 cohort studies) published between 2010 and 2023 which met the inclusion criteria were reviewed.

CONCLUSIONS

The distribution of abdominal fat seems to be associated with the risk of CVDs; the majority of the evidence suggests that a higher abdominal VAT-to-SAT ratio is associated with the development of CVDs. Therefore, this ratio can be used as a prognostic indicator for CVDs.

TRIAL REGISTRATION

Not applicable.

Association of Anthropometric and CT-Based Obesity Indices with Subclinical Atherosclerosis

AIM

Few studies have compared the strength in the associations of anthropometric and computed tomography (CT)-based obesity indices with coronary artery calcification (CAC), aortic artery calcification (AoAC), and aortic valve calcification (AVC).

METHODS

We assessed cross-sectcional associations of anthropometric and CT-based obesity indices with CAC, AoAC, and AVC. Anthropometric measures included body mass index (BMI), waist circumference, hip ircumference, waist-to-hip circumference ratio, and waist-to-height ratio in 931 men (mean age, 63.7 years) from a population-based cohort. CT images at the L4/5 level were obtained to calculate the areas of abdominal visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), total adipose tissue (TAT), VAT-to-SAT ratio (VSR), and VAT-to-TAT ratio (VTR). CAC, AoAC, and AVC were quantified using the Agatston score based on CT scanning.

RESULTS

CAC, AVC, and AoAC were present in 348 (62.6%), 173 (18.6%), and 769 (82.6%) participants, respectively. In multivariable models adjusting for age, lifestyle factors, and CT types (electron beam CT and multidetector row CT), anthropometric and CT-based obesity indices were positively associated with CAC (p＜0.01). Conversely, VAT-to-SAT ratio and VAT-to-TAT ratio were positively associated with AoAC (p＜0.01). Any obesity indices were not associated with AVC.

CONCLUSIONS

The strength of the associations of obesity indices with subclinical atherosclerosis varied according to the anatomically distinct atherosclerotic lesions, among men.

Serum triglyceride glucose index is a valuable predictor for visceral obesity in patients with type 2 diabetes: a cross-sectional study

BACKGROUND

Since the triglyceride glucose (TyG) index can reflect insulin resistance, it has been proven to be an efficient predictor of glycolipid-metabolism-related diseases. Therefore, this study aimed to investigate the predictive value of the TyG index for visceral obesity (VO) and body fat distribution in patients with type 2 diabetes mellitus (T2DM).

METHODS

Abdominal adipose tissue characteristics in patients with T2DM, including visceral adipose area (VAA), subcutaneous adipose area (SAA), VAA-to-SAA ratio (VSR), visceral adipose density (VAD), and subcutaneous adipose density (SAD), were obtained through analyses of computed tomography images at the lumbar 2/3 level. VO was diagnosed according to the VAA (> 142 cm² for males and > 115 cm² for females). Logistic regression was performed to identify independent factors of VO, and receiver operating characteristic (ROC) curves were used to compare the diagnostic performance according to the area under the ROC curve (AUC).

RESULTS

A total of 976 patients were included in this study. VO patients showed significantly higher TyG values than non-VO patients in males (9.74 vs. 8.88) and females (9.59 vs. 9.01). The TyG index showed significant positive correlations with VAA, SAA, and VSR and negative correlations with VAD and SAD. The TyG index was an independent factor for VO in both males (odds ratio [OR] = 2.997) and females (OR = 2.233). The TyG index ranked second to body mass index (BMI) for predicting VO in male (AUC = 0.770) and female patients (AUC = 0.720). Patients with higher BMI and TyG index values showed a significantly higher risk of VO than the other patients. TyG-BMI, the combination index of TyG and BMI, showed significantly higher predictive power than BMI for VO in male patients (AUC = 0.879 and 0.835, respectively) but showed no significance when compared with BMI in female patients (AUC = 0.865 and 0.835, respectively).

CONCLUSIONS

. TyG is a comprehensive indicator of adipose volume, density, and distribution in patients with T2DM and is a valuable predictor for VO in combination with anthropometric indices, such as BMI.

Aortic Agatston score correlates with the progression of acute type A aortic dissection

Aortic calcification in the tunica media is correlated with aortic stiffness, elastin degradation, and wall shear stress. The study aim was to determine if aortic calcifications influence disease progression in patients with acute type A aortic dissection (ATAAD). We retrospectively reviewed a total of 103 consecutive patients who had undergone surgery for ATAAD at our institution between January 2009 and December 2019. Of these, 85 patients who had preoperatively undergone plain computed tomography angiography (CTA) for evaluation of their aortic calcification were included. Moreover, we assessed the progression of aortic dissection after surgery via postoperative CTA. Using a classification and regression tree to identify aortic Agatston score thresholds predictive of disease progression, the patients were classified into high-score (Agatston score ≥ 3344; n  =   36) and low-score (<3344; n  =   49) groups. Correlations between aortic Agatston scores and CTA variables were assessed. Higher aortic Agatston scores were significantly correlated with the smaller distal extent of aortic dissection (p < 0.001), larger true lumen areas of the ascending (p  =  0.009) and descending aorta (p =   0.002), and smaller false lumen areas of the descending aorta (p =  0.028). Patients in the high-score group were more likely to have DeBakey type II dissection (p =  0.001) and false lumen thrombosis (p  =  0.027) than those in the low-score group, thereby confirming the correlations. Aortic dissection in the high-score group was significantly less distally extended (p < 0.001). A higher aortic Agatston score correlates with the larger true lumen area of the ascending and descending aorta and the less distal progression of aortic dissection in patients with ATAAD. Interestingly, the findings before and after surgery were consistent. Hence, aortic Agatston scores are associated with aortic dissection progression and may help predict postoperative residual dissected aorta remodeling.

Abdominal subcutaneous adipose tissue negatively associates with subclinical coronary artery disease in men with psoriasis

Objective

Understand the relationship between abdominal subcutaneous adipose tissue (ASAT) and coronary atherosclerosis defined as noncalcified and lipid-rich necrotic core burden in psoriasis.

Methods

We performed a cross-sectional study of 232 participants (92 women) with psoriasis and without known cardiovascular disease. Participants underwent coronary computed tomography angiography to characterize coronary atherosclerosis burden and low dose abdominal computed tomography to quantify subcutaneous and visceral adipose tissue. Fat depot volumes were first adjusted for each participant's BMI (ASAT_adjBMI).

Results

In women, there was a positive correlation between ASAT_adjBMI and systemic inflammation as assessed by hs-C-reactive protein (r=0.30; p=.004) and GlycA (r=0.29; p=.007) as well as total cholesterol (r=0.24; p=.02) and low-density lipoprotein cholesterol (r=0.22; p=.04). In men, ASAT_adjBMI correlated with hs-C-reactive protein (r=0.18; p=.04) and insulin resistance (r=0.17; p=.04). In models fully adjusted for traditional cardiovascular risk factors, ASAT_adjBMI negatively associated with noncalcified and lipid-rich necrotic core burden in men (β= -0.17; p=.03, β= -0.20; p=.03, respectively), but not women (β= -0.06; p=.57, β= 0.09; p=.49, respectively) with psoriasis.

Conclusions

For a given BMI, ASAT negatively associated with coronary atherosclerosis burden in male participants with psoriasis. The observed sex-specific effects warrant further study of ASAT in states of chronic inflammation.

Predictive Value of Abdominal Fat Distribution on Coronary Artery Disease Severity Stratified by Computed Tomography-Derived SYNTAX Score

This study aimed to evaluate the association between abdominal fat distribution (AFD) and coronary artery disease (CAD) complexities using the computed tomography (CT)-derived SYNTAX score (CT-SXscore). Coronary computed tomographic angiography (CCTA) was performed in patients with suspected CAD. Plain abdominal CT was performed to measure visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) areas. To assess AFD, VAT/SAT (V/S) ratios were calculated. The CT-SXscore was calculated in patients with significant stenoses assessed by CCTA. Of 942 enrolled patients, 310 (32.9%) had 1 or more significant stenoses. The CT-SXscore showed a positive correlation with the V/S ratio (r = 0.33, p < 0.001). In the multivariate regression analysis, the V/S ratio was the only independent predictor for CAD severity based on the CT-SXscore (β = 0.25; t = 4.14; p < 0.001), even though the absolute SAT and VAT areas showed no relationship to the CT-SXscore. Regarding the 4 CAD-patient groups divided according to their median VAT and SAT areas, the CT-SXscore was significantly higher for the high VAT/low SAT group than for any other group (19.6 ± 11.5 vs 13.3 ± 9.6 in the low VAT/low SAT, 10.1 ± 8.5 in the low VAT/high SAT, and 12.2 ± 8.7 in the high VAT/high SAT groups; p < 0.001 for all). In conclusion, it was found that the V/S ratio is a useful index for predicting CAD severity and that AFD may be a more important risk factor for CAD than the absolute amount of each abdominal fat.

Adiposity Phenotypes and Subclinical Atherosclerosis in Adults from Sub-Saharan Africa: An H3Africa AWI-Gen Study

Background:

Obesity and adipose tissue distribution contribute to an increased risk of cardiovascular disease (CVD) by promoting atherosclerosis. This association has been poorly studied in sub–Saharan Africa (SSA) despite the rising prevalence of cardiovascular disease.

Objectives:

We determined the association between various adiposity phenotypes and carotid intima–media thickness (CIMT), a proxy of subclinical atherosclerosis, in a large SSA population.

Methods:

A population–based cross–sectional study was performed from 2013–2016 in Burkina Faso, Ghana, Kenya and South Africa. Body mass index (BMI), waist (WC), hip circumferences (HC), visceral (VAT) and subcutaneous adipose tissue (SCAT) using B-mode ultrasound were measured. Ultrasonography of left and right far wall CIMT of the common carotid artery was used as an indicator of subclinical atherosclerosis. Individual participant data meta–analyses were used to determine the associations between adiposity phenotypes and CIMT in the pooled sample while adjusted multivariable linear regression analyses were used for site specific analyses.

Results:

Data were obtained from 9,010 adults (50.3% women and a mean age of 50± 6years). Men had higher levels of visceral fat than women while women had higher BMI, waist and hip circumference and subcutaneous fat than men at all sites except Burkina Faso. In the pooled analyses, BMI (β–value [95% CIs]: 19.5 [16.8, 22.3] μm) showed the strongest relationship with CIMT followed by VAT (5.86 [4.65, 7.07] μm), SCAT (5.00 [2.85, 7.15] μm), WC (1.27 [1.09, 1.44] μm) and HC (1.23 [1.04, 1.42] μm). Stronger associations were observed in men than in women.

Conclusion:

Obesity within SSA will likely result in higher levels of atherosclerosis and promote the occurrence of cardio- and cerebrovascular events, especially in males, unless addressed through primary prevention of obesity in both rural and urban communities across Africa. The inverse association of VAT with CIMT in Burkina Faso and Ghana requires further investigation.

Highlights

Regional adiposity and heart failure with preserved ejection fraction

The role of obesity in the pathogenesis of heart failure (HF), and in particular HF with preserved ejection fraction (HFpEF), has drawn significant attention in recent years. The prevalence of both obesity and HFpEF has increased worldwide over the past decades and when present concomitantly suggests an obese-HFpEF phenotype. Anthropometrics, including body mass index, waist circumference, and waist-to-hip ratio, are associated with incident HFpEF. However, the cardiovascular effects of obesity may actually be driven by the distribution of fat, which can accumulate in the epicardial, visceral, and subcutaneous compartments. Regional fat can be quantified using non-invasive imaging techniques, including computed tomography, magnetic resonance imaging, and dual-energy X-ray absorptiometry. Regional variations in fat accumulation are associated with different HFpEF risk profiles, whereby higher epicardial and visceral fat have a much stronger association with HFpEF risk compared with elevated subcutaneous fat. Thus, regional adiposity may serve a pivotal role in the pathophysiology of HFpEF contributing to decreased cardiopulmonary fitness, impaired left ventricular compliance, upregulation of local and systemic inflammation, promotion of neurohormonal dysregulation, and increased intra-abdominal pressure and vascular congestion. Strategies to reduce total and regional adiposity have shown promise, including intensive exercise, dieting, and bariatric surgery programmes, but few studies have focused on HFpEF-related outcomes among obese. Further understanding the role these variable fat depots play in the progression of HFpEF and HFpEF-related hospitalizations may provide therapeutic targets in treating the obese-HFpEF phenotype.

Association between abdominal fat distribution and coronary plaque instability in patients with acute coronary syndrome

BACKGROUND AND AIMS

This study aimed to assess possible association of detailed abdominal fat profiles with coronary plaque characteristics in patients with acute coronary syndrome (ACS).

METHODS AND RESULTS

In 60 patients with ACS, culprit arteries were evaluated at 1-mm intervals (length analyzed: 66 ± 28 mm) by grayscale and integrated backscatter intravascular ultrasound (IB-IVUS) before percutaneous coronary intervention. Standard IVUS indexes (as a volume index: volume/length), plaque components (as percent tissue volume) and fibrous cap thickness (FCT) were assessed by IB-IVUS. Plain abdominal computed tomography was performed to evaluate subcutaneous adipose tissue (SAT) area, visceral adipose tissue (VAT) area, and VAT/SAT ratio. While SAT area only correlated with vessel volume (r = 0.27, p = 0.04), VAT area correlated positively with vessel (r = 0.30, p = 0.02) and plaque (r = 0.33, p = 0.01) volumes and negatively with FCT (r = -0.26, p = 0.049), but not with percent plaque volume and plaque tissue components. In contrast, higher VAT/SAT ratio significantly correlated with higher percent lipid (r = 0.34, p = 0.008) and lower percent fibrous (r = -0.34, p = 0.007) volumes with a trend toward larger percent plaque volume (r = 0.19, p = 0.15), as well as thinner FCT (r = -0.53, p < 0.0001). In the multiple regression analysis, higher VAT/SAT ratio was independently associated with higher percent lipid with lower percent fibrous volumes (p = 0.03 for both) and thinner fibrous cap thickness (p = 0.0001).

CONCLUSION

Coronary plaque vulnerability, defined as increased lipid content with thinner fibrous cap thickness, appears to be more related to abnormal abdominal fat distribution, or so-called hidden obesity, compared with visceral or subcutaneous fat amount alone in patients with ACS.

Visceral-to-Subcutaneous Abdominal Fat Ratio Is Associated with Nonalcoholic Fatty Liver Disease and Liver Fibrosis

BACKGROUND

We evaluated the association of visceral-to-subcutaneous fat ratio (VSR) with nonalcoholic fatty liver disease (NAFLD) and advanced fibrosis degree based on noninvasive serum fibrosis markers in the general population with NAFLD.

METHODS

This is a cross-sectional study, in 7,465 Korean adults who underwent health screening examinations. NAFLD was defined as fatty liver detected on ultrasonography, and visceral and subcutaneous abdominal fat was measured using computed tomography. We predicted fibrosis based on the fibrosis-4 (FIB-4) score and aspartate aminotransferase-to-platelet ratio index (APRI) and categorized the risk for advanced fibrosis as low, indeterminate, or high.

RESULTS

The multivariable-adjusted prevalence ratios for indeterminate to high risk of advanced fibrosis based on FIB-4, determined by comparing the second, third, and fourth quartiles with the first quartile of VSR, were 3.38 (95% confidence interval [CI], 0.64 to 17.97), 9.41 (95% CI, 1.97 to 45.01), and 19.34 (95% CI, 4.06 to 92.18), respectively. The multivariable-adjusted prevalence ratios for intermediate to high degree of fibrosis according to APRI also increased across VSR quartiles (5.04 [95% CI, 2.65 to 9.59], 7.51 [95% CI, 3.91 to 14.42], and 19.55 [95% CI, 9.97 to 38.34], respectively). High VSR was more strongly associated with the prevalence of NAFLD in nonobese subjects than in obese subjects, and the associations between VSR and intermediate to high probability of advanced fibrosis in NAFLD were stronger in obese subjects than in nonobese subjects.

CONCLUSION

High VSR values predicted increased NAFLD risk and advanced fibrosis risk with NAFLD, and the predictive value of VSR for indeterminate to high risk of advanced fibrosis was higher in obese subjects than in nonobese subjects.

Analysis of risk factors for carotid intima-media thickness in patients with type 2 diabetes mellitus in Western China assessed by logistic regression combined with a decision tree model

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in patients with type 2 diabetes (T2DM). Carotid intima-media thickness (CIMT) is considered a preclinical stage of atherosclerosis. Therefore, it is necessary to identify the related risk factors for CIMT to facilitate the early prevention of CVD. Previous studies have shown that visceral fat area (VFA) is a risk factor for T2DM and CVD. However, few studies have focused on the effects of VFA on CIMT associated with T2DM. Moreover, considering that the body fat distribution shows regional and racial heterogeneity, the purpose of this study was to investigate the predictive value of VFA and other risk factors for CIMT associated with T2DM in Western China.

METHODS

In a cross-sectional study, a total of 1372 patients with T2DM were divided into the CIMT (-) group (n = 965) and the CIMT (+) group (n = 407) based on CIMT values. In addition to the univariate analyses, logistic regression analysis and a decision tree model were simultaneously performed to establish a correlation factor model for CIMT.

RESULTS

Univariate analyses showed that sex, smoking status, age, heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), height, weight, body mass index (BMI), waist circumference, hip circumference, waist-hip ratio, VFA, subcutaneous fat area, and the levels of 2-h C-peptide, serum creatinine, urea nitrogen and uric acid were significantly different between the two groups (all p < 0.05). Smoking, increased VFA, female sex and increased BMI were risk factors in the logistic regression analyses (OR = 5.759, OR = 1.364, OR = 2.239, OR = 1.186, respectively). In the decision tree model, smoking was the root node, followed by sex, waist circumference, VFA and chronic kidney disease (CKD) in order of importance.

CONCLUSIONS

In addition to smoking, sex and BMI, VFA has a significant effect on CIMT associated with T2DM in the Chinese Han population in Western China. In addition, the decision tree model could help clinicians make more effective decisions, with its simplicity and intuitiveness, making it worth promoting in future medical research.Trial registration ChiCTR, ChiCTR1900027739. Registered 24 November 2019-Retrospectively registered, http://www.chictr.org.cn/index.aspx.

Abdominal fatness and cerebral white matter hyperintensity

Although obesity has been proven as a risk factor of metabolic and cardiovascular diseases, there have been few studies addressing the association between obesity and cerebral white matter hyperintensity (WMH) volume with controversial findings. In this study, we evaluated the relationship between abdominal fat distribution and WMH volume in a neurologically healthy population. We performed an observational study in a consecutive series of subjects who were examined during voluntary health check-ups between January 2006 and December 2013. We directly measured both visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) using abdominal computed tomography. The WMH volumes were also recorded quantitatively. A total of 2504 subjects were included in this study. In multivariate analysis, the relationship between SAT and WMH volume remained significant (β = -0.170, standard error [SE] = 0.065, P = .006) after adjusting for confounding factors. The protective effects of SAT on the WMH volume were more prominent in female participants (β = -0.295, SE = 0.138, P = .033) and in severely obese participants (β = -0.358, SE = 0.167, P = .033). Conclusively, we demonstrated a negative association between SAT and WMH volume in a healthy population.

Abdominal Fat Depots and Subclinical Carotid Artery Atherosclerosis in Women With and Without HIV Infection

BACKGROUND

Data on associations between abdominal fat depot mass and subclinical atherosclerosis are limited, especially in women with HIV.

METHODS

We assessed cross-sectional associations of dual X-ray absorptiometry scan-derived estimates of visceral adipose tissue (VAT) and abdominal subcutaneous adipose tissue (SAT) with 3 measures of subclinical carotid artery atherosclerosis-carotid artery stiffness (Young's modulus of elasticity), presence of carotid artery lesions, and carotid artery intima-media thickness-in a subsample of participants in the Women's Interagency HIV Study. Statistical models adjusted for demographic variables, HIV serostatus, behavioral variables, and cardiovascular risk factors.

RESULTS

There were 244 women with and 99 without HIV infection (median age 42, 62% black). VAT mass (but not SAT) was associated with greater carotid artery stiffness in a fully adjusted linear regression model, including adjustment for SAT (β = 11.3 log 10·N·m per kg VAT, 95% confidence interval: 1.0 to 21.7). Greater SAT mass was associated with lower odds of having a carotid artery lesion in a fully adjusted model, including adjustment for VAT [adjusted odds ratio, 0.49 per kg of SAT (0.25 to 0.94)]. Neither VAT nor SAT was associated with carotid artery intima-media thickness. The VAT/SAT ratio was not statistically associated with any of the outcomes after covariate adjustment.

CONCLUSIONS

In our cross-sectional study of women, the majority of whom had HIV, greater VAT mass was associated with increased carotid artery stiffness, whereas greater SAT mass was associated with a reduced odds of prevalent carotid artery lesions.

Chronic stress: a critical risk factor for atherosclerosis

Chronic stress refers to the non-specific systemic reaction that occurs when the body is stimulated by various internal and external negative factors over a long time. The physiological response to chronic stress exposure has long been recognized as a potent modulator in the occurrence of atherosclerosis. Furthermore, research has confirmed the correlation between atherosclerosis and cardiovascular events. Chronic stress is pervasive during negative life events and may lead to the formation of plaque. Several epidemiological studies have shown that chronic stress is an independent risk factor for the development of vascular disease and for increased morbidity and mortality in patients with pre-existing coronary artery disease. One possible mechanism for this process is that chronic stress causes endothelial injury, directly activating macrophages, promoting foam cell formation and generating the formation of atherosclerotic plaque. This mechanism involves numerous variables, including inflammation, signal pathways, lipid metabolism and endothelial function. The mechanism of chronic stress in atherosclerosis should be further investigated to provide a theoretical basis for efforts to eliminate the effect of chronic stress on the cardiocerebral vascular system.

Coronary age, based on coronary calcium measurement, is increased in patients with morbid obesity

Purpose

Obesity is a well-known of risk factor for atherosclerosis. However, recently an “obesity paradox” has been discussed, which is considered as a protective effect of obesity on the development coronary artery disease (CAD). An aim of the study was to investigate the risk of CAD in morbidly obese patients using coronary artery calcium measurement.

Material and methods

Fifty-one patients with morbid obesity (BMI ≥ 40 kg/m²) and thirty controls were scanned to determine the amount of coronary artery calcification (CAC), which was expressed as calcium score (CS) and coronary age (CA). The control group consisted of patients scanned for the clinical suspicion of CAD, who did not fulfil the criteria of obesity.

Results

Mean BMI of obese patients and controls was 47.3 and 26.5, respectively (p < 0.0001). Arterial hypertension, dyslipidaemia, and smoking were more frequent in the control group than in the obesity group (p < 0.02). The prevalence of CAC was higher in the obesity group (53% vs. 23%, p < 0.01). The groups did not differ regarding CS and CA. However, the difference between coronary age and metrical age was higher in obese patients than in controls (+5.6 vs. –4.8 years, respectively, p < 0.005).

Conclusions

Patients with morbid obesity present an increased risk of CAD that is reflected by the difference between their coronary age and metrical age.

The impact of abdominal fat on abdominal aorta calcification measured on non-enhanced CT

Cardiovascular (CV) morbidity, atherosclerosis, and obesity are all targets of clinical concern and vast research, as is the association between them. Aim of this study is to assess the impact of adipose tissue (including visceral and subcutaneous fat) on abdominal aorta calcification measured on non-enhanced computed tomography (CT). We retrospectively included 492 patients who underwent non-enhanced CT scans during workup for clinically suspected renal colic. All scans were reviewed for abdominal aorta calcification, liver attenuation, and thickness of visceral and subcutaneous fat. Multivariate general linear regression models were used to assess the association between abdominal aorta calcium score and adiposity measures. In the model that included only adiposity measures; visceral fat thickness had statistically significant direct association with abdominal aorta calcium score (B = 67.1, P <.001), whereas subcutaneous pelvic fat thickness had a significant inverse association with abdominal aorta calcium score (B = -22.34, P <.001). Only the association of subcutaneous pelvic fat thickness with abdominal aorta calcium score remained statistically significant when controlling for age, sex, smoking, hypertension, diabetes mellitus, and hyperlipidemia (B = -21.23, P <.001). In this model, the association of visceral fat remained statistically significant in females (B = 84.28, P = .001) but not in males (B = 0.47, P = .973). Visceral fat thickness and subcutaneous pelvic fat thickness were found to have opposing associations with abdominal aorta calcium score. This suggests that while visceral fat may have a lipotoxic effect on aortic atherosclerotic processes, subcutaneous pelvic fat may have a protective role in these processes.

Adiposity and Incident Heart Failure and its Subtypes: MESA (Multi-Ethnic Study of Atherosclerosis)

OBJECTIVES

This study sought to compare various measures of adiposity with risk for incident hospitalized heart failure (HF) with preserved ejection fraction (HFpEF) and reduced ejection fraction (HFrEF).

BACKGROUND

Obesity is a risk factor for HF, particularly HFpEF. It is unknown which measures of adiposity, including anthropometrics and computed tomography (CT)-measured fat area, are most predictive of HF subtypes.

METHODS

The authors studied 1,806 participants of the MESA (Multi-Ethnic Study of Atherosclerosis) study without baseline cardiovascular disease who underwent anthropometrics (body mass index [BMI] and waist circumference) and an abdominal CT. Subcutaneous and visceral adipose tissue (VAT) were measured from a single CT slice at L2-L3. Cox hazard models were used to examine associations of adiposity with incident hospitalized HFpEF and HFrEF events. Fully adjusted models included demographics, HF risk factors, and N-terminal pro-B-type natriuretic peptide.

RESULTS

Over a mean follow-up of 11 years, there were 34 HFpEF and 36 HFrEF events. The fully adjusted hazard ratio (95% confidence interval [CI]) per 1-SD higher of each anthropometric and CT-measured adiposity measures for incident HFpEF were as follows: BMI HR: 1.66; 95% CI: 1.12 to 2.45; waist circumference HR: 1.59; 95% CI: 1.05 to 2.40; and VAT HR: 2.24; 95% CI: 1.44 to 3.49. None of these adiposity measures were associated with HFrEF. Even among overweight/obese adults (BMI ≥25 kg/m2), assessment of VAT (per 1-SD) was strongly associated with HFpEF (HR: 2.78; 95% CI: 1.62 to 4.76). Subcutaneous adipose tissue was neither associated with HFpEF nor HFrEF.

CONCLUSIONS

In a multiethnic cohort free of cardiovascular disease, CT-measured VAT was independently associated with incident hospitalized HFpEF but not HFrEF. Measuring visceral fat at the time of CT imaging for other indications may offer additional prognostication of HF risk. (Multi-Ethnic Study of Atherosclerosis [MESA]; NCT00005487).

The Relationship Between Increased Ratio of Visceral-to-Subcutaneous Fat Area and Renal Outcome in Chinese Adults With Type 2 Diabetes and Diabetic Kidney Disease

OBJECTIVE

Abdominal obesity is a risk factor of diabetes and hypertension. The aim of this study was to investigate the association between excessive abdominal fat and renal outcomes in patients with type 2 diabetes and diabetic kidney disease.

METHODS

Thirty-five patients with type 2 diabetes and diabetic kidney disease who were followed up on for at least 1 year were enrolled. Visceral fat area and subcutaneous fat area were assessed by computed tomography to evaluate the degree of abdominal fat. Patients were divided into 2 groups. Patients in group 1 had a ratio of visceral fat area to subcutaneous fat area (V/S ratio) <0.70 (n=16), and those in group 2 had a V/S ratio ≥0.70 (n=19) according to the second quartile. Renal outcome was defined as end-stage renal disease and initiation of renal replacement therapy.

RESULTS

At baseline, patients with a high V/S ratio had higher levels of triglycerides (p=0.060) and C-reactive protein (p=0.028), but lower high-density lipoprotein cholesterol levels (p=0.006). Strong correlations between V/S ratio and C-reactive protein (r=0.521, p=0.015) and high-density lipoprotein cholesterol (r=-0.576, p<0.001) were observed. Univariate Cox regression indicated the higher the V/S ratio, the greater the risk for a poor renal outcome (hazard ratio, 3.536; 95% confidence interval, 1.140 to 10.960; p=0.029). However, multivariate Cox analysis demonstrated that a higher V/S ratio was not an independent risk factor for progression to end-stage renal disease (hazard ratio, 2.212; 95% confidence interval, 0.543 to 9.005; p=0.268) when adjustments were made for important clinical variables.

CONCLUSION

The V/S ratio was positively correlated with C-reactive protein and high-density lipoprotein cholesterol. The higher V/S ratio was associated with a greater risk for progression to end-stage renal disease, although it did not emerge as an independent predictor of diabetic kidney disease progression.

Analysis of the Correlation Between Central Obesity and Abdominal Aortic Diseases

BACKGROUND

Atherosclerosis and abdominal aortic aneurysms (AAAs) have several similar risk factors but different pathogenesis. Inflammation of the arteries is common to both. Central obesity can act as an endocrine organ through the secretion of inflammatory cytokines, and the perivascular fat has a local effect that could contribute to diseases of the abdominal aorta. Although the relation between central obesity and atherosclerosis occlusive arterial disease has been demonstrated, the correlation with AAA has conflicting results. The aim of this study was to analyze the correlation between central obesity and the presence of abdominal aortic diseases using computed tomography.

METHODS

Six hundred thirty-nine consecutive patients classified into 3 groups (AAA, aortic atherosclerotic occlusive disease (AAOD), and without aortic disease [control group]) who underwent computed tomography had the aorta diameter, the visceral fat area (VFA), and the subcutaneous fat area (SFA) measured at the level of third and fourth lumbar vertebrae.

RESULTS

VFA showed no difference between the groups. SFA was lower in atherosclerotic group (AAOD) than control (P < 0.01 in general and P < 0.04 in male). In AAA group, we found in men that the first tertile of aorta diameter had higher VFA than third tertile (P = 0.02).

CONCLUSIONS

There was no difference in VFA between patients in AAA, AAOD, and without aortic disease groups. In men with aneurysm, there was an inverse relationship between VFA and aortic diameter. In AAOD, visceral to subcutaneous ratio is higher due to lower SFA.

Abdominal subcutaneous adipose tissue: a favorable adipose depot for diabetes?

Background

Previous studies have documented that visceral adipose tissue is positively associated with the risk of diabetes. However, the association of subcutaneous adipose tissue with diabetes risk is still in dispute. We aimed to assess the associations between different adipose distributions and the risk of newly diagnosed diabetes in Chinese adults.

Methods

The Shanghai Nicheng Cohort Study was conducted among Chinese adults aged 45–70 years. The baseline data of 12,137 participants were analyzed. Subcutaneous and visceral fat area (SFA and VFA) were measured by magnetic resonance imaging. Diabetes was newly diagnosed using a 75 g oral glucose tolerance test.

Results

The multivariable-adjusted odds ratios (OR) and 95% confidence intervals (CI) of newly diagnosed diabetes per 1—standard deviation increase in SFA and VFA were 1.29 (1.19–1.39) and 1.61 (1.49–1.74) in men, and 1.10 (1.03–1.18) and 1.56 (1.45–1.67) in women, respectively. However, the association between SFA and newly diagnosed diabetes disappeared in men and was reversed in women (OR 0.86 [95% CI, 0.78–0.94]) after additional adjustment for body mass index (BMI) and VFA. The positive association between VFA and newly diagnosed diabetes remained significant in both sexes after further adjustment for BMI and SFA. Areas under the receiver operating characteristic curve of newly diagnosed diabetes predicted by VFA (0.679 [95% CI, 0.659–0.699] for men and 0.707 [95% CI, 0.690–0.723] for women) were significantly larger than by the other adiposity indicators.

Conclusions

SFA was beneficial for lower risk of newly diagnosed diabetes in women but was not associated with newly diagnosed diabetes in men after taking general obesity and visceral obesity into account. VFA, however, was associated with likelihood of newly diagnosed diabetes in both Chinese men and women.

Electronic supplementary material

The online version of this article (10.1186/s12933-018-0734-8) contains supplementary material, which is available to authorized users.

Ratio of visceral-to-subcutaneous fat area predicts cardiovascular events in patients with type 2 diabetes

AIMS/INTRODUCTION

To investigate whether the ratio of visceral fat area (VFA) to subcutaneous fat area (SFA; V/S ratio) could be predictive of cardiovascular disease (CVD) as compared with VFA or SFA in patients with diabetes.

MATERIALS AND METHODS

A total of 682 patients with type 2 diabetes (mean age 64 ± 13 years; 41% women) were enrolled. VFA (cm2 ) and SFA (cm2 ) were assessed by a dual bioelectrical impedance analyzer. The patients were divided into four groups according to the quartiles of the V/S ratio. The study end-point was the first occurrence or recurrence of CVD.

RESULTS

Over a median follow up of 2.5 years, 21 patients reached the end-point. The number of patients who reached the end-point was increased along with the increasing of the V/S ratio quartiles. The V/S ratio was significantly associated with incident or recurrent CVD (hazard ratio [HR] 1.82, 95% CI: 1.09-3.04, P = 0.021) after adjusting for estimated glomerular filtration rate (HR 0.98, 95% CI: 0.96-1.00), brain-type natriuretic peptide (HR 1.00, 95% CI: 1.00-1.01), use of antiplatelet agents (HR 4.26, 95% CI: 1.63-11.13), coefficient of variation of R-R intervals (HR 0.85, 95% CI: 0.69-1.10) and glycated hemoglobin (HR 1.37, 95% CI: 1.05-1.79). The addition of the V/S ratio to age, estimated glomerular filtration rate, brain-type natriuretic peptide, antiplatelet agents and glycated hemoglobin significantly improved classification performance for CVD using net reclassification improvement (0.60, 95% CI: 0.21-1.00) and the integrated discrimination improvement (0.02, 95% CI: 0.00-0.05).

CONCLUSIONS

The V/S ratio measured by dual bioelectrical impedance analyzer is an independent predictor of CVD in patients with type 2 diabetes.

Chest adipose tissue distribution in patients with morbid obesity

Purpose

Obesity is a well-known of risk factor for atherosclerosis and the amount of visceral adipose tissue is considered as an independent predictor of coronary artery disease (CAD). An aim of the study was to investigate the distribution of intrathoracic adipose tissue in morbidly obese patients.

Material and methods

Fifty-one patients with morbid obesity (BMI ≥ 40 kg/m²) and thirty controls were scanned in a coronary calcium scoring protocol. Control group consisted of patients scanned due to a clinical suspicion of CAD, who did not fulfill obesity criteria. The amount of adipose tissue was measured as epicardial adipose tissue (EAT) thickness, pericoronary fat (PCF) thickness, total intra-pericardial fat (IPF) volume, and total intrathoracic fat (ITF) volume.

Results

Mean BMI of obese patients and controls was 47.3 and 26.5, respectively (p < 0.0001). Patients with obesity and controls did not differ with respect to mean EAT, mean PCF, and IPF. However, ITF was lower in obesity group than in control group (268 vs. 332 cm³, respectively; p < 0.03). Moreover, ROC analysis presented relation between obesity and the superior EAT thickness, PCF at LCX, mean PCF, ITF, and chest soft tissue (CST) thickness (p < 0.03). CST thickness of > 60 mm was the parameter that presented the strongest association with morbid obesity (AUC 0.95; p < 0.0001).

Conlcusions

Increased chest soft tissue thickness but not the increased intrathoracic adipose tissue volume was associated with morbid obesity. Since the quantity of the pericardiac fat is not directly related to the obesity, its accumulation may be related to a mechanism different than that of subcutaneous adipose tissue growth.

CT-Derived Body Fat Distribution and Incident Cardiovascular Disease: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Visceral fat has been shown to be associated with increased cardiometabolic risk, but the role of subcutaneous fat remains unclear, and evidence from diverse populations is lacking. We hypothesized that visceral fat, but not subcutaneous fat, would be independently associated with incident cardiovascular disease (CVD) and all-cause mortality.

METHODS

Among 1910 participants from the Multi-Ethnic Study of Atherosclerosis with abdominal fat measurements from computed tomography scans and followed for an average of 9.3 years, we used multivariable Cox proportional hazards models to investigate the relationship of both visceral and subcutaneous fat tertiles with CVD and all-cause mortality. We tested for interaction and performed sensitivity analysis for subgroups and missing values of visceral fat.

RESULTS

Participants had mean age of 65 years, visceral fat 150 cm2, subcutaneous fat 263 cm2, and 50% were female, 21% African American, 13% Asian, and 26% Hispanic. In models adjusted for age, sex, race/ethnicity, income, education, smoking, and subcutaneous fat, there was a statistically significant positive association between visceral fat and CVD, but not mortality. The association for combined CVD may be driven by incident coronary heart disease [tertile 2: hazard ratio, 2.43 (1.38 to 4.28); tertile 3: hazard ratio, 3.00 (1.66 to 5.43)]. Additionally, we found no substantial associations between subcutaneous fat and CVD or mortality. There were no statistically significant interactions by age, sex, or race/ethnicity.

CONCLUSIONS

Visceral fat, but not subcutaneous fat, is significantly associated with increased risk for CVD in a multiethnic cohort. These data support the need for effective strategies for lifestyle changes that prevent and reduce visceral fat.

Greater visceral abdominal fat is associated with a lower probability of conversion of prehypertension to normotension

OBJECTIVE

Prehypertension is associated with increased risk for incident hypertension. However, little is known about how frequently prehypertension converts to normotension, and which variables predict this conversion.

METHODS

We identified 186 Japanese Americans with prehypertension (110 men, 76 women) aged 34-75 years (mean age of 52.3 years) who were followed at 5 and 10 years after enrollment. Blood pressure was measured with a mercury sphygmomanometer and average blood pressure was calculated. Subcutaneous adipose tissue, visceral adipose tissue (VAT), and subcutaneous thigh adipose tissue area were measured by computed tomography.

RESULTS

Approximately one-third of those with prehypertension converted to normotension over 10 years of follow-up. Those who converted to normotension were younger, less obese, and had significantly lower baseline SBP, fasting glucose, cholesterol levels, and homeostasis model assessment insulin resistance compared with study participants who continued to have prehypertension or progressed to hypertension. With regard to body fat compartments, study participants with conversion to normotension showed a significantly smaller VAT area compared with the nonconversion group (P < 0.001); but, subcutaneous adipose tissue and subcutaneous thigh adipose tissue were not significant. In multivariate logistic regression analysis, baseline VAT was inversely associated with the conversion independent of age, sex, waist circumference, diabetes, fasting glucose, homeostasis model assessment insulin resistance, non-high-density lipoprotein cholesterol, and SBP [odds ratio per 1 SD VAT increment (95% confidence interval), 0.35 (0.15-0.80), P = 0.012].

CONCLUSION

This is the first prospective study showing the role of body fat distribution, determined by computed tomography scan, in predicting the natural history of prehypertension. Baseline VAT was inversely and independently associated with the conversion to normal blood pressure. No other adipose variable was significant. The mechanisms responsible for these observations remain to be elucidated.

Implications of Pericardial, Visceral and Subcutaneous Adipose Tissue on Vascular Inflammation Measured Using 18FDG-PET/CT

Objective

Pericardial adipose tissue (PAT) is associated with adverse cardiometabolic risk factors and cardiovascular disease (CVD). However, the relative implications of PAT, abdominal visceral and subcutaneous adipose tissue on vascular inflammation have not been explored.

Method and Results

We compared the association of PAT, abdominal visceral fat area (VFA), and subcutaneous fat area (SFA) with vascular inflammation, represented as the target-to-background ratio (TBR), the blood-normalized standardized uptake value measured using ¹⁸F-Fluorodeoxyglucose Positron Emission Tomography (¹⁸FDG-PET) in 93 men and women without diabetes or CVD. Age- and sex-adjusted correlation analysis showed that PAT, VFA, and SFA were positively associated with most cardiometabolic risk factors, including systolic blood pressure, LDL-cholesterol, triglycerides, glucose, insulin resistance and high sensitive C-reactive proteins (hsCRP), whereas they were negatively associated with HDL-cholesterol. In particular, the maximum TBR (maxTBR) values were positively correlated with PAT and VFA (r = 0.48 and r = 0.45, respectively; both P <0.001), whereas SFA showed a relatively weak positive relationship with maxTBR level (r = 0.31, P = 0.003).

Conclusion

This study demonstrated that both PAT and VFA are significantly and similarly associated with vascular inflammation and various cardiometabolic risk profiles.

The impact of obesity on subclinical coronary atherosclerosis according to the risk of cardiovascular disease

OBJECTIVE

To evaluate whether the association of obesity with coronary atherosclerosis depends on the risk of cardiovascular disease (CVD).

METHODS

A total of 1,406 asymptomatic Korean adults underwent both cardiac and abdominal multislice computed tomography (MSCT) as part of a routine health check-up. Obesity was measured using body mass index (BMI), waist circumference (WC), and MSCT-derived area/ratio of visceral and subcutaneous fat. The burden of CVD risk was assessed by the Framingham risk equation.

RESULTS

In the low-risk group for CVD, obesity measurements (standardized odds ratio, 95% confidence interval) of BMI (1.406, 1.197-1.652), WC (1.707, 1.434-2.032), visceral fat area (1.700, 1.438-2.009), and visceral-to-subcutaneous fat ratio (1.620, 1.379-1.903) were associated with the presence of coronary calcification after adjusting for traditional CVD risks. But in the moderate-to-high risk group, the associations were attenuated. For additional adjustments of obesity measurements, in the low-risk group, WC (1.717, 1.172-2.514) and visceral-to-subcutaneous fat ratio (1.400, 1.029-1.904) were independent determinants of coronary calcification.

CONCLUSIONS

Obesity is differentially associated with subclinical coronary atherosclerosis, according to the burden of CVD risk. In low-risk adults, the relative distribution of abdominal fat, as well as whole body fat, is important to coronary atherosclerosis.

Contribution of subcutaneous abdominal fat on ultrasonography to carotid atherosclerosis in patients with type 2 diabetes mellitus

BACKGROUND

Whereas visceral abdominal adipose tissue (VAT) is associated with cardiometabolic risk, there is debate regarding the role of subcutaneous abdominal adipose tissue (SAT). The aim of this study was to investigate the relationships of subcutaneous and visceral abdominal fat with carotid atherosclerosis in patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 234 patients (men 131, women 103, mean age: 53 years) with T2DM were enrolled. Carotid intima-media thickness (CIMT), abdominal subcutaneous fat thickness (SFT) and visceral fat thickness (VFT) were assessed by high-resolution B-mode ultrasonography (US).

RESULTS

Compared to women, men had significantly higher VFT and lower SFT (p = 0.002, p = 0.04, respectively). In partial correlation coefficient analyses between CIMT and abdominal fat thickness after adjustment for body mass index (BMI), SFT showed a negative correlation with CIMT in men (r = -0.27, p = 0.03). VFT was not correlated with CIMT in either men or women. In women, SFT was not correlated with CIMT (r = -0.01, p = 0.93). VFT/SFT ratio was not correlated with CIMT in either men or women. In multivariate regression analyses adjusted for BMI and other CVD risk factors, SFT but not VFT was independently inversely associated with CIMT in men but not in women (p < 0.001).

CONCLUSIONS

SFT assessed by US was inversely associated with carotid atherosclerosis in patients with T2DM, particularly men. Further research into the different roles of the two types of abdominal adipose tissue in both men and women is warranted.

Inverse association of long-acting natriuretic peptide with metabolic syndrome in congestive heart failure patients

AIMS

Long-acting natriuretic peptide (LANP) is one of the peptide hormones in atrial natriuretic peptide (ANP) pro-hormone. Low levels of natriuretic peptide may lead to reduced lipolysis and excessive weight gain in obese patients. The aim of this study was to investigate the relationship between fasting serum LANP level and the metabolic syndrome (MetS) among congestive heart failure (CHF) patients.

METHODS

Fasting blood samples were obtained from 186 patients with normal renal function in cardiac clinic outpatients. CHF defined by the American College of Cardiology Foundation and the American Heart Association 2005 Guidelines. MetS and its components were defined using diagnostic criteria from the International Diabetes Federation.

RESULTS

Ninety-eight patients (52.7%) had CHF. There was a tendency of increased fasting LANP levels as the NYHA CHF functional classes increased (p = 0.002). Forty-six of the CHF patients (46.9%) had MetS. Fasting LANP level negatively correlated with MetS among CHF patients (p < 0.001). Univariate linear regression analysis showed that BUN (p = 0.026) positively correlated with fasting serum LANP levels, while body weight (p = 0.009), BMI (p = 0.004), homeostasis model assessment of insulin resistance (HOMA-IR; p = 0.024) and HOMA-β (p = 0.001) negatively correlated with fasting serum LANP levels among the CHF patients. Multivariate forward stepwise linear regression analysis of the significant variables showed that the HOMA-β (R2 change = 0.292, p < 0.001) and HOMA-IR (R2 change = 0.081, p = 0.019) were independent predictors of fasting serum LANP levels in CHF patients.

CONCLUSIONS

LANP level is significantly reduced in CHF patients affected by MetS. HOMA-β and HOMA-IR were independent predictors of serum LANP levels in CHF patients.

Low serum long-acting natriuretic peptide level correlates with metabolic syndrome in hypertensive patients: a cross-sectional study

BACKGROUND AND AIMS

Long-acting natriuretic peptide (LANP) is one of the peptide hormones in atrial natriuretic peptide (ANP) prohormone. Its biological properties are blood pressure regulation, maintenance of plasma volume and anticancer effects. The aim of this study was to evaluate the relationship between metabolic syndrome (MetS) and fasting serum LANP concentration in hypertensive patients.

METHODS

Fasting blood samples were obtained from 224 patients with or without hypertension. MetS and its components were defined using diagnostic criteria from the International Diabetes Federation.

RESULTS

Eighty-eight hypertensive patients (59.5 %) had MetS. Hypertensive patients with MetS had higher body weight (p = 0.003), waist circumference (p = 0.003), body mass index (p = 0.002), triglyceride concentrations (p = 0.029), insulin levels (p = 0.001), HOMA-IR (p <0.003) and HOMA-β (p = 0.049) and lower HDL-C concentrations (p = 0.001), LANP levels (p = 0.012) than those without MetS. The univariable linear regression analysis showed that age (p = 0.038) and the BUN concentration (p = 0.022) were positively correlated with the serum LANP levels, whereas the insulin level (p = 0.001), HOMA-IR (p = 0.004), and HOMA-β (p = 0.001) were negatively correlated with the fasting serum LANP levels among the hypertensive patients. Multivariable forward stepwise linear regression analysis of the significant variables showed that the HOMA-β (β = -0.387, R(2) = 0.141, p <0.001) was an independent predictor of fasting serum LANP levels in hypertensive patients.

CONCLUSIONS

LANP level is significantly reduced in hypertensive patients affected by MetS and is negatively related to pancreatic beta cell function in hypertensive patients.

Stress and abdominal fat: preliminary evidence of moderation by the cortisol awakening response in Hispanic peripubertal girls

Stress and the cortisol awakening response (CAR) have been independently linked to increases in abdominal fat depots. This cross-sectional study examined the CAR as a moderator of the association between stress, visceral adipose tissue (VAT), and subcutaneous abdominal adipose tissue (SAT) in a sample (N = 23) of female peripubertal Hispanic girls aged from 8 to 11. The study included: (i) monitored salivary cortisol collection, (ii) VAT and SAT obtained by multislice magnetic resonance imaging, and (iii) a stressful life events checklist with four domain-specific subscales: peer, family, personal, and school. Regression analysis indicated an interaction of school-related life events and CAR on VAT and SAT, with greater numbers of school-related events being related to greater VAT and SAT for girls with high CAR, but no association with VAT or SAT for girls with low CAR. Similar to job stress in adults, school-related stress in children may contribute to central adiposity, especially for girls with high CAR.

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.

Anthropometric measurements and diabetes mellitus: clues to the "pathogenic" and "protective" potential of adipose tissue

BACKGROUND

Increased visceral adipose tissue (VAT) is "pathogenic" through adverse endocrine and immune contributions to metabolic diseases such as diabetes mellitus, hypertension, and dyslipidemia. Increased VAT increases waist circumference (WC), and WC is a recommended anthropometric measure of pathogenic adipose tissue distribution. Increased subcutaneous adipose tissue (SAT) is often described as "protective" against metabolic disease and frequently approximated by hip circumference (HC).

METHODS

The Study to Help Improve Early evaluation and management of risk factors Leading to Diabetes (SHIELD) evaluated a study sample weighted to reflect the U.S. adult population. Respondents diagnosed with type 2 diabetes mellitus (T2DM; n = 3825) and without T2DM (n = 13,327) self-reported their weight and height, WC, and HC.

RESULTS

T2DM men and women had a disproportionate increase in body mass index (BMI) and WC, with 30% of T2DM men and 40% of T2DM women having a WC within the highest quintile compared to the overall study population. Waist-to-hip ratio (WHR) appeared to be the best anthropometric predictor of T2DM. However, both T2DM men and women also had a disproportionate increase in HC, with 30% of T2DM men and 34% of T2DM women having a HC within the highest quintile, which was generally similar to the distribution of BMI and WHR.

CONCLUSIONS

This analysis suggests that: (1) An increase in adipose tissue generally increases the risk of T2DM; (2) central adiposity is more pathogenic than peripheral subcutaneous adiposity; and (3) SAT accumulation, as assessed by increased HC, does not always "protect" against metabolic diseases such as T2DM.

Peri-aortic fat, cardiovascular disease risk factors, and aortic calcification: the Framingham Heart Study

OBJECTIVE

Perivascular fat through the secretion of paracrine and pro-inflammatory mediators may play a role in obesity-mediated vascular disease. We sought to examine associations between adipose tissue depots immediately surrounding the thoracic aorta, metabolic risk factors, and vascular calcification.

METHODS

In participants free of cardiovascular disease (CVD) from the Framingham Heart Study Offspring cohort who underwent computed tomography (n=1067, mean age 59 years, 56.1% women), thoracic peri-aortic fat depots were quantified. Visceral abdominal tissue (VAT) and calcification of the thoracic and abdominal aorta were also measured.

RESULTS

Peri-aortic fat depots were correlated with body mass index, waist circumference (WC), VAT (all p<0.0001), hypertension (p=0.007), low HDL (p<0.0001), serum triglycerides (p<0.0001), impaired fasting glucose (p=0.005), and diabetes (p=0.02). These associations generally remained significant after adjustment for BMI and WC (all p-values<0.05), but not after VAT adjustment. Thoracic aortic fat was associated with thoracic calcification in models containing VAT (OR 1.31, 95% CI 1.01-1.71, p=0.04), but was not significant after adjustment for CVD risk factors (OR 1.16, 95% CI 0.88-1.51, p=0.30). Thoracic aortic fat, however, was associated with abdominal aortic calcification (OR 1.48, 95% CI 1.11-1.98, p=0.008) and coronary artery calcification (OR 1.47, 95% CI 1.09-1.98, p=0.001) even in models including CVD risk factors and VAT.

CONCLUSIONS

Thoracic peri-aortic fat is associated with measures of adiposity, metabolic risk factors, and coronary and abdominal aortic calcification.

Social stress, visceral obesity, and coronary artery atherosclerosis: product of a primate adaptation

Abdominal obesity is prevalent and often accompanied by an array of metabolic perturbations including elevated blood pressure, dyslipidemia, impaired glucose tolerance or insulin resistance, a prothrombotic state, and a proinflammatory state, together referred to as the metabolic syndrome. The metabolic syndrome greatly increases coronary heart disease (CHD) risk. Social stress also increases CHD although the mechanisms through which this occurs are not completely understood. Chronic stress may result in sustained glucocorticoid production, which is thought to promote visceral obesity. Thus, one hypothesis is that social stress may cause visceral fat deposition and the metabolic syndrome, which, in turn increases CHD. CHD is caused by coronary artery atherosclerosis (CAA) and its sequelae. Cynomolgus monkeys (Macaca fascicularis) are a well-established models of CAA. Social subordination may be stressful to cynomolgus monkeys and result in hypercortisolemia and exacerbated CAA in females. Herein is reviewed a body of literature which suggests that social stress increases visceral fat deposition in cynomolgus monkeys, that subordinate females are more likely than dominants to have visceral obesity, that females with visceral obesity have behavioral and physiological characteristics consistent with a stressed state, and that females with high ratios of visceral to subcutaneous abdominal fat develop more CAA. While these relationships have been most extensively studied in cynomolgus macaques, obesity-related metabolic disturbances are also observed in other primate species. Taken together, these observations support the view that the current obesity epidemic is the result of a primate adaptation involving the coevolution with encephalization of elaborate physiological systems to protect against starvation and defend stored body fat in order to feed a large and metabolically demanding brain. Social stress may be engaging these same physiological systems, increasing the visceral deposition of fat and its sequelae, which increase CHD risk.