Visceral adipose tissue, a potential risk factor for carotid atherosclerosis: results of the Multicultural Community Health Assessment Trial (M-CHAT)

CD36 restricts lipid-associated macrophages accumulation in white adipose tissues during atherogenesis

Visceral white adipose tissues (WAT) regulate systemic lipid metabolism and inflammation. Dysfunctional WAT drive chronic inflammation and facilitate atherosclerosis. Adipose tissue-associated macrophages (ATM) are the predominant immune cells in WAT, but their heterogeneity and phenotypes are poorly defined during atherogenesis. The scavenger receptor CD36 mediates ATM crosstalk with other adipose tissue cells, driving chronic inflammation. Here, we combined the single-cell RNA sequencing technique with cell metabolic and functional assays on major WAT ATM subpopulations using a diet-induced atherosclerosis mouse model (Apoe-null). We also examined the role of CD36 using Apoe/Cd36 double-null mice. Based on transcriptomics data and differential gene expression analysis, we identified a previously undefined group of ATM displaying low viability and high lipid metabolism and labeled them as "unhealthy macrophages". Their phenotypes suggest a subpopulation of ATM under lipid stress. We also identified lipid-associated macrophages (LAM), which were previously described in obesity. Interestingly, LAM increased 8.4-fold in Apoe/Cd36 double-null mice on an atherogenic diet, but not in Apoe-null mice. The increase in LAM was accompanied by more ATM lipid uptake, reduced adipocyte hypertrophy, and less inflammation. In conclusion, CD36 mediates a delicate balance between lipid metabolism and inflammation in visceral adipose tissues. Under atherogenic conditions, CD36 deficiency reduces inflammation and increases lipid metabolism in WAT by promoting LAM accumulation.

Insulin resistance in the adipose tissue predicts future vascular resistance: The Hiroshima Study on Glucose Metabolism and Cardiovascular Diseases

BACKGROUND AND AIMS

Diameter, plaque score, and resistance index (RI) in the common carotid artery (CCA) are indicators of arterial remodeling, atherosclerosis, and vascular resistance, respectively. This study investigated the longitudinal association between adipose tissue insulin resistance or serum free fatty acid (FFA) levels and the CCA parameters.

METHODS

This retrospective cohort analysis included 1089 participants (mean age 57.6 years; 40.0 % women) with data on health checkups from January 1982 to March 2003 and carotid artery ultrasonography from January 2015 to June 2019. Baseline serum FFA and immunoreactive insulin levels were assessed before and 30, 60, and 120 min after glucose ingestion. Adipose insulin resistance index (Adipo-IR) was calculated as the product of fasting serum insulin and FFA levels. An RI value >0.75 was defined as high RI.

RESULTS

A significant association was found between Adipo-IR and RI; however, Adipo-IR showed no association with CCA diameter or plaque score. The incidence of high RI increased with Adipo-IR quartile (Q) groups (47.3 % in Q1, 52.8 % in Q2, 53.3 % in Q3, 62.4 % in Q4; Cochrane-Armitage test for trend, p < 0.001). In multivariate analysis, Adipo-IR levels (Q4 vs. Q1 odds ratio: 1.67, 95 % confidence interval: 1.12-2.51) were positively associated with high RI incidence. Moreover, a significant association was found between RI and serum FFA levels after glucose intake, but not fasting FFA levels.

CONCLUSIONS

Future vascular resistance was predicted by insulin resistance in the adipose tissue. After glucose intake, serum FFA levels may significantly impact vascular resistance development.

Visceral adipose tissue and residual cardiovascular risk: a pathological link and new therapeutic options

Obesity is a heterogeneous disease that affects almost one-third of the global population. A clear association has been established between obesity and cardiovascular disease (CVD). However, CVD risk is known to be related more to the local distribution of fat than to total body fat. Visceral adipose tissue (VAT) in particular has a high impact on CVD risk. This manuscript reviews the role of VAT in residual CV risk and the available therapeutic strategies for decreasing residual CV risk related to VAT accumulation. Among the many pathways involved in residual CV risk, obesity and particularly VAT accumulation play a major role by generating low-grade systemic inflammation, which in turn has a high prognostic impact on all-cause mortality and myocardial infarction. In recent years, many therapeutic approaches have been developed to reduce body weight. Orlistat was shown to reduce both weight and VAT but has low tolerability and many drug-drug interactions. Naltrexone-bupropion combination lowers body weight but has frequent side effects and is contraindicated in patients with uncontrolled hypertension. Liraglutide and semaglutide, glucagon-like peptide 1 (GLP-1) agonists, are the latest drugs approved for the treatment of obesity, and both have been shown to induce significant body weight loss. Liraglutide, semaglutide and other GLP-1 agonists also showed a positive effect on CV outcomes in diabetic patients. In addition, liraglutide showed to specifically reduce VAT and inflammatory biomarkers in obese patients without diabetes. GLP-1 agonists are promising compounds to limit inflammation in human visceral adipocytes.

Nicotine dependence and visceral adiposity as risk factors for the development and severity of carotid artery stenosis

Nicotine dependence (ND) and visceral adiposity are emerging as independent risk factors for cardiovascular diseases, including carotid artery stenosis (CAS). This study aimed to determine the relationship between ND and the contribution of abdominal fat to the onset of CAS, which is indicated by a luminal narrowing of at least 60% as determined by duplex and/or Doppler ultrasound. We prospectively collected data from 60 patients with CAS and 60 age- and gender-matched healthy subjects. The Fagerström Test for Nicotine Dependence (FTND), a common research tool, was used in the study. The original questionnaire was designed to gather social and demographic data. Anthropometric measurements, visceral adiposity index (VAI), and lipid accumulation products (LAP) were used to assess obesity. Most patients showed a high or mild-moderate degree of ND: 46.67% and 35%, respectively. The median visceral adiposity index (VAI) and lipid accumulation product (LAP) in patients was 3.92 and 32.83, respectively. Prolonged smoking duration, increased intensity, and high ND are hallmarks of CAS patients.

Anthropometric indices and cut-off points for screening of metabolic syndrome among South African taxi drivers

Background

Detecting the early onset of metabolic syndrome (MetS) allows for quick intervention which may slow progression to a variety of health consequences, hence, determining the best measurement to detect MetS is essential.

Aim

This research aimed at examining the MetS predictive power of anthropometric indices, such as body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), body shape index (ABSI), body roundness index (BRI), percentage body fat (%BF), conicity index (CI), and Clínica Universidad de Navarra-body adiposity estimator (CUN-BAE) to determine the cut-off points to identify male South African taxi drivers with MetS.

Method

A cross-sectional study was conducted among 185 male taxi drivers. Their weight, height, WC, blood lipid profile were measured. International Diabetes Federation (IDF) definition was used to define MetS. Receiver Operating Characteristic (ROC) curves were used to compare the predictive ability of Anthropometric indices to detect MetS.

Results

The mean age of the participants was 39.84 years. Overall, 41.6% (N = 77) of the participants presented with MetS. The mean values for BMI, WC, WHtR, %BF, BRI, CUN-BAE, ABSI and CI were 28.60 ± 6.20 kg/m², 99.13 ± 17.59 cm, 0.58 ± 0.10, 27.28 ± 8.28%, 5.09 ± 2.33, 27.78 ± 8.34, 0.08 ± 0.01 and 1.70 ± 0.19, respectively. The mean values for these indices were significantly (p < 0.001) higher in participants with MetS. The highest area under the curve (AUC) outcomes for screening MetS were for the %BF and CUN-BAE, followed by the BMI and WHtR, and lastly the BRI. All these anthropometric indices had outstanding discriminatory powers for predicting MetS with AUCs and sensitivity values above 80%. The BMI, WHtR, %BF, BRI, and CUN-BAE, had cut-off points for detection of metS in South African men at 28.25 kg/m², 0.55, 25.29%, 4.55, and 27.10, respectively. Based on the logistic regression models abnormal BMI, WHtR, %BF, BRI, CUN-BAE, TG, FBG, systolic BP, diastolic BP and WC showed increased risk of MetS.

Conclusion

While the %BF, CUN-BAE, BMI, WC, WHtR, BRI, CI and CUN-BAE could predict MetS among South African male taxi drivers, these indices were less effective in predicting the individual MetS risk factors such as TG, BP, and FBG.

Is Obesity a Risk Factor for Carotid Atherosclerotic Disease?—Opportunistic Review

Obesity is a risk factor for coronary atherosclerosis. However, the influence of adipose tissue in carotid atherosclerosis is not completely understood. No systematic review/meta-analysis was previously performed to understand if obesity is a risk factor for carotid atherosclerosis. This paper aims to provide an opportunistic review of the association between obesity and carotid atherosclerosis and define the role of the different adipose tissue depots in the characteristics of carotid stenosis. The databases PubMed and Cochrane Library were searched on 15–27 April and 19 May 2021. A total of 1750 articles published between 1985 and 2019 were identified, 64 were preselected, and 38 papers (35,339 subjects) were included in the final review. The most frequent methods used to determine obesity were anthropometric measures. Carotid plaque was mostly characterized by ultrasound. Overall obesity and visceral fat were not associated with the presence of carotid plaque when evaluated separately. Waist-hip ratio, however, was a significant anthropometric measure associated with the prevalence of carotid plaques. As it reflected the ratio of visceral and subcutaneous adipose tissue, the balance between these depots could impact the prevalence of carotid plaques.

Association of Chinese Visceral Adiposity Index and Its Dynamic Change With Risk of Carotid Plaque in a Large Cohort in China

Background

We aimed to evaluate the association between the Chinese visceral adiposity index (CVAI) and its dynamic change and risk of carotid plaque based on a large Chinese cohort.

Methods and Results

This cohort included 23 522 participants aged 20 to 80 years without elevated carotid intima‐media thickness and carotid plaque at baseline and who received at least 2 health checkups. CVAI was calculated at baseline and at every checkup. The dynamic change in CVAI was calculated by subtracting CVAI at baseline from that at the last follow‐up. Cox proportional hazard regression model was used to estimate hazard ratios (HRs) and 95% CIs. The restricted cubic spline was applied to model the dose‐response association between CVAI and carotid plaque risk. During the 82 621 person‐years of follow‐up, 5987 cases of carotid plaque developed (7.25/100 person‐years). We observed a significant positive correlation between CVAI and carotid plaque risk (HR, 1.53; 95% CI, 1.48–1.59 [P<0.001]) in a nonlinear dose‐response pattern (P_nonlinearity<0.001). The sensitivity analyses further confirmed the robustness of the results. The association was significant in all subgroup analyses stratified by sex, hypertension, and fatty liver disease except for the diabetes subgroup. The association between CVAI and carotid plaque risk was much higher in men than in women. No significant association was identified between change in CVAI and carotid plaque risk.

Conclusions

CVAI was positively associated with carotid plaque risk in a nonlinear dose‐response pattern in this study. Individuals should keep their CVAI within a normal level to prevent the development of carotid plaque.

Methodology, clinical applications, and future directions of body composition analysis using computed tomography (CT) images: A review

PURPOSE OF THE REVIEW

We aim to review the methods, current research evidence, and future directions in body composition analysis (BCA) with CT imaging.

RECENT FINDINGS

CT images can be used to evaluate muscle tissue, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) compartments. Manual and semiautomatic segmentation methods are still the gold standards. The segmentation of skeletal muscle tissue and VAT and SAT compartments is most often performed at the level of the 3rd lumbar vertebra. A decreased amount of CT-determined skeletal muscle mass is a marker of impaired survival in many patient populations, including patients with most types of cancer, some surgical patients, and those admitted to the intensive care unit (ICU). Patients with increased VAT are more susceptible to impaired survival / worse outcomes; however, those patients who are critically ill or admitted to the ICU or who will undergo surgery appear to be exceptions. The independent significance of SAT is less well established. Recently, the roles of the CT-determined decrease of muscle mass and increased VAT area and epicardial adipose tissue (EAT) volume have been shown to predict a more debilitating course of illness in patients suffering from severe acute respiratory syndrome coronavirus 2 (COVID-19) infection.

SUMMARY

The field of CT-based body composition analysis is rapidly evolving and shows great potential for clinical implementation.

Relationships between carotid artery intima-media thickness and echogenicity and body composition using a new magnetic resonance imaging voxel-based technique

BACKGROUND

We evaluated how carotid artery intima-media thickness (IMT) and the echogenicity of the intima-media (IM-GSM), measured by ultrasound, were related to body composition, evaluated by both traditional imaging techniques, as well as with a new voxel-based "Imiomics" technique.

METHODS

In 321 subjects all aged 50 years in the POEM study, IMT and IM-GSM were measured together with a DXA scan for determination of fat and lean mass. Also a whole-body MRI scan was performed and the body volume was divided into >1 million voxels in a standardized fashion. IMT and IM-GSM were related to each of these voxels to create a 3D-view of how these measurements were related to size of each part of the body.

RESULTS

IM-GSM was inversely related to almost all traditional measurements of body composition, like fat and lean mass, liver fat, visceral and subcutaneous fat, but this was not seen for IMT. Using Imiomics, IMT was positively related to the intraabdominal fat volume, as well of the leg skeletal muscle in women. In males, IMT was mainly positively related to the leg skeletal muscle volume. IM-GSM was inversely related to the volume of the SAT in the upper part of the body, leg skeletal muscle, the liver and intraabdominal fat in both men and women.

CONCLUSION

The voxel-based Imiomics technique provided a detailed view of how the echogenicity of the carotid artery wall was related to body composition, being inversely related to the volume of the major fat depots, as well as leg skeletal muscle.

Association of the new visceral adiposity index with coronary artery calcification and arterial stiffness in Korean population

BACKGROUND AND AIMS

The new visceral adiposity index (NVAI) is an indirect marker of visceral adipose tissue recently developed using a Korean population. Here we examined the association of NVAI with coronary artery calcification and arterial stiffness in asymptomatic Korean patients.

METHODS AND RESULTS

We analyzed data from 60,938 asymptomatic Korean adults. Odds ratios and 95% confidence intervals (CIs) for coronary artery calcification score (CACS) > 100 and brachial-ankle pulse wave velocity (baPWV) ≥14 m/s were calculated across NVAI tertiles using multiple logistic regression analysis. Receiver operating characteristic (ROC) and area under the curve (AUC) analyses were used to assess the ability of NVAI to predict moderate to high risk of cardiovascular disease. The prevalence of moderate and high risk of cardiovascular disease increased significantly as the NVAI tertile increased. The odds ratio (95% CI) of the highest NVAI tertile for CACS >100 was 5.840 (5.101-6.686) for men and 18.916 (11.232-31.855) for women, after adjusting for confounders. All NVAI AUC values were significantly higher than the AUC values for other visceral adiposity markers.

CONCLUSIONS

This study provides the evidence that NVAI is independently and positively associated with coronary calcification and arterial stiffness in asymptomatic Korean adults.

Abdominal visceral adipose tissue over the menopause transition and carotid atherosclerosis: the SWAN heart study

OBJECTIVES

To characterize abdominal visceral adipose tissue (VAT) trajectory relative to the final menstrual period (FMP), and to test whether menopause-related VAT accumulation is associated with greater average, common carotid artery intima-media thickness (cIMT) and/or internal carotid artery intima-media thickness (ICA-IMT).

METHODS

Participants were 362 women (at baseline: age was (mean ± SD) 51.1 ± 2.8 y; 61% White, 39% Black) with no cardiovascular disease from the Study of Women's Health Across the Nation Heart study. Women had up to two measurements of VAT and cIMT over time. Splines revealed a nonlinear trajectory of VAT with two inflection points demarcating three time segments: segment 1: >2 years before FMP; segment 2: 2 years before FMP to FMP; and segment 3: after FMP. Piecewise-linear random-effects models estimated changes in VAT. Random-effects models tested associations of menopause-related VAT with each cIMT measure separately. Estimates were adjusted for age at FMP, body mass index, and sociodemographic, lifestyle, and cardiovascular disease risk factors.

RESULTS

VAT increased significantly by 8.2% (95% CI: 4.1%-12.5%) and 5.8% (3.7%-7.9%) per year in segments 2 and 3, respectively, with no significant change in VAT within segment 1. VAT predicted greater ICA-IMT in segment 2, such that a 20% greater VAT was associated with a 2.0% (0.8%-3.1%) greater ICA-IMT. VAT was not an independent predictor of ICA-IMT in the other segments or of the other cIMT measures after adjusting for covariates.

CONCLUSIONS

Women experience an accelerated increase in VAT starting 2 years before menopause. This menopause-related increase in VAT is associated with greater risk of subclinical atherosclerosis in the internal carotid artery.

Non-Invasive Prediction of Coronary Artery Disease by Multiple Abdominal Fat and Anthropometric Indices: Revisit

Purpose

The aim of this study was to evaluate the efficiency of multiple abdominal fat indices measured by ultrasound and anthropometric indices to predict the presence and severity of coronary artery disease (CAD) assessed by coronary angiography.

Patients and Methods

All participants subjected to clinical and laboratory assessments. Anthropometric measurements were taken followed by an ultrasound examination to measure fat thickness at multiple abdominal areas. Lastly, selective coronary angiography performed by the Judkins technique. Statistical analysis was performed to detect the association between all variables and CAD, followed by regression analysis, and Odds ratio (OR) was used to quantifies the strength of the association between two events.

Results

From the abdominal indices, the posterior right perinephric fat thickness (PRPFT) above the best cutoff value had the highest hazard ratio (HR: 12.3, p = 0.001), followed by visceral adipose tissue volume (VAT) (HR: 10.7, p < 0.001), waist circumference (WC) (HR: 6.7, p = 0.001), visceral fat thickness (VFT) (HR: 5.7, p = 0.002), and body mass index (BMI) (HR: 5.48, p = 0.017). It also showed an independent association between the severity of CAD and WC (HR: 4.28, p = 0.012), VFT (HR: 3.7, p = 0.032), VAT (HR: 3.7, p = 0.034), and waist to height ratio (WHtR) (HR: 3.3, p = 0.033).

Conclusion

Posterior perinephric fat thickness and visceral adipose tissue volume measured by ultrasound are strong noninvasive predictors for coronary artery disease, followed by body mass index, waist circumference and visceral fat thickness.

Noninvasive prediction of carotid artery atherosclerosis by multiple abdominal fat indices measured via ultrasonography

PURPOSE

The purpose of this study was to evaluate the efficiency of multiple abdominal fat indices as measured via ultrasonography for predicting the presence and severity of carotid artery atherosclerosis and to compare the predictive capacity of ultrasonographic measurements to that of anthropometric measurements.

METHODS

A total of 92 patients were included in this study. All participants underwent clinical and laboratory assessments, and anthropometric measurements were obtained. Ultrasound examinations were performed to measure the values of all abdominal fat indices and the intimamedia thickness, as well as to detect the presence of atherosclerotic plaques. Univariate and multivariate logistic regression analyses were performed.

RESULTS

In the multivariate analysis, significant associations were detected between carotid artery atherosclerosis and posterior right perinephric fat thickness (PRPFT) (hazard ratio [HR], 15.23; P<0.001), preperitoneal fat thickness (PPFT) (HR, 4.31; P=0.003), visceral adipose tissue volume (VAT) (HR, 7.61; P<0.001), visceral fat thickness (VFT) (HR, 8.84; P<0.001), the ratio of VFT to subcutaneous fat thickness (VFT/SCFT) (HR, 9.39; P<0.001), and waist-to-height ratio (WHtR) (HR, 2.65; P=0.046). In the multivariate analysis, significant associations were also detected between carotid artery plaque and PRPFT (HR, 7.09; P<0.001), the abdominal wall fat index (AFI) (HR, 3.58; P=0.010), and VFT/SCFT (HR, 4.17; P=0.006).

CONCLUSION

Many abdominal fat indices as measured by ultrasound were found to be strong predictors of carotid artery atherosclerosis, including PRPFT, VFT/SCFT, VFT, VAT, PPFT, and WHtR. Moreover, PRPFT, VFT/SCFT, and AFI were identified as strong predictors of the presence of carotid artery plaque.

Visceral adiposity index and cervical arterial atherosclerosis in northeast China: a population based cross-sectional survey

BACKGROUND AND PURPOSE

The burden of cervical arterial atherosclerosis, which is an important risk factor of stroke, is huge in China. The visceral adiposity index (VAI) is a convenient index that is related to a series of metabolic abnormalities and a variety of diseases, including cerebrovascular diseases. This study aimed to explore the relationship between VAI and cervical arterial atherosclerosis.

METHODS

This cross-sectional study used the multistage stratified random cluster sampling method to acquire a representative sample of residents aged ≥40 in the general population of northeast China. All participants completed a detailed questionnaire and provided blood samples. Cervical vascular ultrasound was performed by experienced ultrasound doctors. VAI was calculated by a well-established formula and analyzed by quartiles (Q1-Q4).

RESULTS

A total of 3688 people aged ≥40 years who underwent cervical arterial ultrasound were finally included, amongst whom 3.2% had increased intima-media thickness (IMT), 48.6% had carotid plaque and 4.0% had cervical artery stenosis (CAS). After adjusting for several parameters, little statistical significance was found between VAI and increased IMT; compared with the VAI-Q1 group, the VAI-Q2, VAI-Q3 and VAI-Q4 groups were more likely to have CAS [odds ratio (OR) 2.01, 95% confidence interval (CI) 1.17-3.43; OR 1.82, 95% CI 1.05-3.15; OR 1.79, 95% CI 1.03-3.12] and the VAI-Q3 and VAI-Q4 groups were at greater risk of carotid plaque (OR 1.30, 95% CI 1.05-1.62; OR 1.34, 95% CI 1.07-1.67).

CONCLUSIONS

The VAI was related to carotid plaque and CAS in the general population that is older than 40 years.

Role of the physical examination in the determination of etiology of ischemic stroke

The actual investigation of the body of a patient by the clinician in search for the signs of the disease beginning with the primary vital signs and continues with the careful and attentive observation of the patient. This article reviews the key findings in the physical examination of patients with ischemic stroke that have the potential to indicate the etiology of the infarct and to help to choose the use of ancillary tests. Through a systematic search of articles published in English related to the physical examination of patients with stroke, we identified key findings in the vital signs and classic components of the physical exam (appearance of the patient, auscultation, and eye examination) that have shown clinical significance when determining ischemic stroke etiology. We further suggest that the prompt identification of such findings can translate into better use of diagnostic tools and selection of ancillary confirmatory tests, thus, reducing the time to etiology based treatment and secondary prevention of ischemic stroke. in this manuscript, we aim to show that even though nowadays the clinical skills tend to be overlooked due to the overreliance on technology, the physical exam continues to be a valuable tool in the clinician armamentarium when facing the challenge of a patient with ischemic stroke.

Differences in visceral adipose tissue and biochemical cardiometabolic risk markers in elite rugby union athletes of Caucasian and Polynesian descent

Polynesian individuals are leaner with greater musculature than Caucasians of an equivalent size, and this genetically different morphology provides a physique that is often compatible with success in a number of sports, including rugby union. Evidence indicates that Polynesians have greater stores of absolute and relative abdominal fat mass and this is known to confer cardiometabolic risk. The aims of this study were to (1) explore the relationship between ethnicity, visceral adipose tissue (VAT), and cardiometabolic disease risk markers in elite Caucasian and Polynesian rugby union athletes, and (2) assess the impact of a pre-season training programme on these markers. Twenty-two professional rugby union athletes of Caucasian (n = 11) and Polynesian (n = 11) descent underwent physique assessment via surface anthropometry, dual-energy X-ray absorptiometry, and magnetic resonance imaging before and after an 11-week pre-season. A fasted blood test was undertaken at both time points. Compared to Caucasians, at baseline Polynesians displayed significantly higher VAT (771 ± 609 cm³ vs 424 ± 235 cm³; p = 0.043), triglycerides (1.0 ± 0.9 mmol/L vs 0.6 ± 0.2 mmol/L; p = 0.050), and low-density lipoprotein cholesterol (3.1 ± 0.9 mmol/L vs 2.3 ± 0.7 mmol/L; p = 0.019). Similar changes were observed in both groups over the pre-season period in VAT and blood biochemical markers. Polynesian rugby union athletes were more likely than Caucasians to exhibit risk factors associated with cardiometabolic disease, such as elevated VAT and unfavourable lipid profiles. Further longitudinal research is required to identify and explain the short- and long-term risk of cardiometabolic disease in athletes of Polynesian descent.

Obesity, visceral adiposity and carotid atherosclerosis

Carotid artery atherosclerosis is a complex and multifactorial chronic disease. Our aim was to assess the associations between obesity, fat depots and carotid artery stenosis (CAS) in patients with high cardiovascular (CV) risk.

METHODS

The study group included 391 patients (F/M: 136/255 pts.; age: 61.8 ± 8 years) scheduled for elective coronary angiography. A comprehensive clinical assessment included a carotid artery and abdominal ultrasound involving the following fat depots: (1) carotid extra-media thickness (EMT) indexed to the body mass index (perivascular adipose tissue [PVAT]), and (2) abdominal visceral and subcutaneous fat.

RESULTS

Patients with a ≥50% stenosis of internal carotid artery (ICA) were older (65.9 ± 7 vs 60.3 ± 7 years, p < 0.0001) and had increased PVAT (836 ± 120 vs 779 ± 127 μm, p < 0.01) compared to individuals with <50% internal carotid artery stenosis. None of the CAS parameters were associated with any measures of obesity. Multivariable regression model showed that age (p < 0.0001), PVAT (p < 0.0001) and smoking (p = 0.04) were independently associated with the severity of ICA stenosis.

CONCLUSIONS

Our study showed that carotid extra-media thickness, an index measure of PVAT, is associated with CAS severity. It is a strong and independent predictor of significant ICA stenosis. None of the obesity measurements revealed associations with carotid atherosclerosis.

Epicardial fat thickness is significantly increased and related to LDL cholesterol level in patients with familial hypercholesterolemia

PURPOSE

Increased epicardial fat thickness (EFT) is accepted as a risk factfcardiovascular diseases in some studies. There are conflicting results about the relation between plasma low-density lipoprotein cholesterol (LDL-C) level and EFT. As well, the relation between EFT and familial hypercholesterolemia is not clearly documented in the literature. Our aim was to investigate EFT in familial hypercholesterolemia patients and to determine which parameters were related to EFT increase.

METHODS

A total of 150 subjects enrolled in our study. Subjects were separated into two groups: 75 hypercholesterolemia patients (16 men, mean age 52.8 ± 7.4 years) and 75 familial hypercholesterolemia patients (26 men, mean age 50.7 ± 9.2 years). Medical history assessments and complete physical examinations were done. Routine laboratory tests and echocardiographic measurements were performed.

RESULTS

Coronary artery disease frequency was significantly higher in the familial hypercholesterolemia group (p < 0.001). This group had significantly higher TC and LDL-C levels than the hypercholesterolemia group (p < 0.05 for all). EFT values were higher in the familial hypercholesterolemia group, and were significantly different than in the other group (p < 0.001). LDL-C was found to be independently related to EFT in the linear regression analysis.

CONCLUSIONS

Epicardial fat thickness increased in the familial hypercholesterolemia patients. In addition, LDL-C levels were significantly crelated with increased EFT.

Epicardial and visceral adipose tissue in relation to subclinical atherosclerosis in a Chinese population

Background

Body fatness is associated with risk of coronary heart disease and it has been postulated that epicardial adipose tissue (EAT) may have a particularly detrimental effect because of its localized toxic effects. We therefore aimed to examine the association between EAT and coronary artery calcification and compared this with associations for visceral adipose tissue (VAT) and other regional fat depots.

Methods

We conducted a cross-sectional study of 487 Chinese participants aged 50 years old and above, living in Singapore. Participants, free from known diabetes mellitus and coronary heart diseases, completed interviews, a health screening to evaluate obesity and cardiovascular disease risk factors, and computed tomography scans of the abdomen and coronary arteries. Associations between regional fat depots and subclinical atherosclerosis defined as CAC> = 100 were determined by multiple logistic regression analysis.

Results

Epicardial adipose tissue (EAT) was highly correlated with visceral adipose tissue (VAT) (Pearson r = 0.72) and trunk fat mass (r = 0.66). The age and sex-adjusted odd ratio (OR) (in 1-SD increase) of subclinical atherosclerosis was 1.28 (1.01–1.61) for EAT and 1.40 (1.04–1.88) for VAT. These associations were weaker and non-significant after adjusting for markers of dyslipidemia and hyperglycemia. Total body fat, subcutaneous abdominal fat, and leg, arm and trunk fat mass were not significantly associated with atherosclerosis.

Conclusion

VAT and EAT showed similar associations with coronary artery calcification and the associations could be mediated by traditional risk factors in this ethnic Chinese population.

Hypertriglyceridemic Waist: A Simple Marker of High-Risk Atherosclerosis Features Associated With Excess Visceral Adiposity/Ectopic Fat

Background

Subclinical atherosclerosis identification remains challenging; abdominal visceral adiposity may improve risk stratification beyond traditional cardiovascular risk factors. Hypertriglyceridemic waist, a visceral adiposity marker combining elevated triglycerides (≥2 mmol/L) and waist circumference (≥90 cm), has been related to carotid atherosclerosis, although associations with high‐risk features, including lipid‐rich necrotic core (LRNC), remain unknown. We tested the hypothesis that hypertriglyceridemic waist is an independent marker of high‐risk atherosclerosis features.

Methods and Results

In this cross‐sectional study including 467 white men (mean age, 45.9±14.8 years; range 19.4–77.6 years), carotid atherosclerosis characteristics were examined by magnetic resonance imaging and associations with hypertriglyceridemic waist and benefits beyond Framingham Risk Score (FRS) and Pathobiological Determinants of Atherosclerosis in Youth (PDAY) were determined. Subclinical carotid atherosclerosis was present in 61.9% of participants, whereas 50.1% had LRNC. Hypertriglyceridemic waist was associated with carotid maximum wall thickness (P=0.014), wall volume (P=0.025), normalized wall index (P=0.004), and Carotid Atherosclerosis Score (derived from wall thickness and LRNC; P=0.049). Hypertriglyceridemic waist was associated with carotid LRNC volume beyond FRS (P=0.037) or PDAY (P=0.015), contrary to waist circumference alone (both P>0.05). Although 69.7% and 62.0% of participants with carotid atherosclerosis and/or LRNC were not high‐risk by FRS or PDAY, respectively, hypertriglyceridemic waist correctly reclassified 9.7% and 4.5% of them, respectively. Combining hypertriglyceridemic waist with FRS (net reclassification improvement=0.17; P<0.001) or PDAY (net reclassification improvement=0.05; P=0.003) was superior to each score alone in identifying individuals with carotid atherosclerosis and/or LRNC.

Conclusions

Hypertriglyceridemic waist is an independent marker of carotid high‐risk atherosclerosis features in men, improving on FRS and PDAY risk score.

Relation of Overall and Abdominal Adiposity With Electrocardiogram Parameters of Subclinical Cardiovascular Disease in Individuals Aged 45 to 65 Years (from the Netherlands Epidemiology of Obesity Study)

Overall and abdominal obesity are well-established risk factors for cardiometabolic disease. However, associations of overall and abdominal adiposity with electrocardiographic (ECG) markers of subclinical cardiovascular disease (CVD) have not yet been fully elucidated. Therefore, we investigated these associations in a population without preexisting CVD. We performed cross-sectional analyses in the Netherlands Epidemiology of Obesity Study. Body mass index (BMI), total body fat, and waist circumference were assessed in all participants, and abdominal subcutaneous adipose tissue and visceral adipose tissue (by magnetic resonance imaging) were assessed in a random subgroup. ECG parameters were determined using 12-lead electrocardiograms. We performed linear regression analyses, adjusting for potential confounding factors and, when investigating abdominal adiposity, additionally for total body fat. After exclusion of participants with preexisting CVD (n = 654), 5,939 individuals (42% men) were analyzed, with a mean (SD) age of 55 (6) years and BMI of 26.3 (4.4) kg/m². Measures of both overall and abdominal adiposity were associated with ECG parameters but none of these measures was more strongly associated than the others. For example, heart rate (beats/min) increased per SD higher BMI (2.2; 95% confidence interval 1.9,2.5), total body fat (2.9; 2.4,3.4), subcutaneous adipose tissue (2.3;1.7,2.9), waist circumference (2.1; 1.4,2.8), and visceral adipose tissue (1.7; 0.8,2.5). In subgroup analyses based on gender and cardiovascular risk factors, no consistent interactions were observed. In conclusion, in a middle-aged population without preexisting CVD, measures of both overall and abdominal adiposity were associated with ECG parameters. Future studies should evaluate the added value of adiposity measures in electrocardiography-based diagnoses and the prognostic value of adding adiposity measures to risk prediction tools.

Morphometric measurements of systemic atherosclerosis and visceral fat: Evidence from an autopsy study

Background

Morphometric measurements of systemic atherosclerosis and direct quantification of visceral fat are only possible using materials from autopsy studies. However, the few autopsy studies that have investigated the association of visceral fat with atherosclerosis had small sample sizes and focused on coronary arteries of young or middle-aged White subjects. We aimed to investigate the association of pericardial fat (PF) and abdominal visceral fat (AVF) with atherosclerosis in the aorta, coronary, carotid, and cerebral arteries in a large autopsy study.

Materials and methods

We evaluated deceased subjects aged 30 years or above. We dissected and weighted the PF and the AVF and evaluated the atherosclerotic burden in the aorta, as well as the carotid, coronary, and cerebral arteries using morphometric measurements. We also investigated the interaction of PF and AVF with age regarding the atherosclerotic burden.

Results

The mean age of the 240 included subjects was 64.8±15.3 years, and 63% was male. Greater PF was associated with a higher degree of aortic atherosclerosis after adjusting for confounding variables (coefficient = 4.39, 95% CI = 0.83; 7.94, p = 0.02). Greater AVF was associated with a higher coronary stenosis index (coefficient = 1.49, 95% CI = 0.15; 2.83, p = 0.03) and a greater number of coronary plaques (coefficient = 0.71, 95% CI = 0.24; 1.19, p = 0.003). We did not find an association of PF or AVF with carotid or cerebral atherosclerotic burden. We found a significant interaction of AVF (coefficient = -0.08; 95% CI = -0.14; -0.02, p = 0.009) and PF (coefficient = -0.87, 95% CI = -1.70; -0.04, p = 0.04) with age regarding carotid artery atherosclerotic burden.

Conclusions

Greater AVF was associated with greater atherosclerotic burden and extent in coronary arteries, while greater PF correlated with a higher degree of atherosclerosis in the aorta.

The Correlation and Risk Factors between Carotid Intima-Media Thickening and Alcoholic Liver Disease Coupled with Helicobacter pylori Infection

The aim of this study was to explore the associations and differences in influencing factors between alcoholic liver disease (ALD) coupled with Helicobacter pylori infection and atherosclerosis and to determine whether there is a "double hit phenomenon" in atherosclerosis patients with ALD and H. pylori infections. Included cases (n = 160) were categorized into 4 groups: 41 cases of ALD coupled with H. pylori infections (group A), 35 cases of H. pylori infections without ALD (group B), 37 cases of ALD without H. pylori infections (group C), and 47 normal control cases (group D). CIMT was significantly greater in group A than in groups B and D (P = 0.005 and P = 0.001, respectively). The GLM univariate analysis found that CIMT was significantly greater in group A than in groups B, C and D (P = 0.018, P = 0.001 and P = 0.009, respectively). We found that BMI and ALT, AST and ApoB levels were independent predictors of CIMT (P = 0.000, P = 0.000, P = 0.012 and P = 0.014, respectively). ALD coupled with H. pylori infection may result in significant CIMT thickening, but H. pylori infection without ALD and ALD without H. pylori infection does not, suggesting that a "double hit phenomenon" occurs. Additionally, BMI, and ALT, AST and ApoB levels were independent risk factors for increased CIMT.

Visceral Adiposity is Preferentially Associated with Vascular Stiffness Rather than Thickness in Men with Type 2 Diabetes

Aim: Visceral fat accumulation is known to underlie the clustering of cardiovascular risk factors. However, it is not completely understood how visceral fat accumulation influences the development of cardiovascular disease. In this study, we investigated the clinical impact of visceral adiposity on vascular stiffness and thickness in patients with type 2 diabetes (T2D).

Methods: One hundred and sixty-one patients with T2D, including 92 men and 69 women, were included in this cross-sectional study. Visceral fat area (VFA) and subcutaneous fat area (SFA) were measured by dual bioelectrical impedance analysis. Stiffness parameter β and intima-media thickness (IMT) of the common carotid artery were measured by ultrasonography.

Results: The mean age and duration of diabetes in the study population were 61 years and 13.9 years, respectively. In men, VFA and waist circumference (WC) were positively correlated with stiffness parameter β, whereas body mass index (BMI), WC, and SFA were negatively correlated with IMT. In contrast, in women, none of the obesity-related indices were significantly correlated with stiffness parameter β or IMT. In multiple regression analyses, VFA as well as WC, BMI, and SFA were independently associated with stiffness parameter β after adjustment for age and other potential confounders in men but not in women. None of the obesity-related indices were independently associated with IMT for either sex.

Conclusion: In men with T2D, visceral adiposity is associated with carotid arterial stiffness but not thickness.

Adiposity has no direct effect on carotid intima-media thickness in adolescents and young adults: Use of structural equation modeling to elucidate indirect & direct pathways

BACKGROUND

Carotid intima-media thickness (cIMT) is associated with CV events in adults. Thicker cIMT is found in youth with CV risk factors including obesity. Which risk factors have the most effect upon cIMT in youth and whether obesity has direct or indirect effects is not known. We used structural equation modeling to elucidate direct and indirect pathways through which obesity and other risk factors were associated with cIMT.

METHODS

We collected demographics, anthropometrics and laboratory data on 784 subjects age 10-24 years (mean 18.0 ± 3.3 years). Common, bulb and internal carotid cIMT were measured by ultrasound. Multivariable regression analysis was performed to assess independent determinants of cIMT. Analyses were repeated with structural equation modeling to determine direct and indirect effects.

RESULTS

Multivariable regression models explained 11%-22% of variation of cIMT. Age, sex and systolic blood pressure (BP) z-score were significant determinants of all cIMT segments. Body mass index (BMI) z-score, race, presence of type 2 diabetes mellitus (T2DM), hemoglobin A1c (HbA1c) and non-HDL were significant for some segments (all p = 0.05). The largest direct effect on cIMT was age (0.312) followed by BP (0.228), Blood glucose control (0.108) and non-HDL (0.134). BMI only had a significant indirect effect through blood glucose control, BP & non-HDL. High sensitivity C-reactive protein (CRP) had a small indirect effect through blood glucose control (all p = 0.05).

CONCLUSIONS

Age and BP are the major factors with direct effect on cIMT. Glucose and non-HDL were also important in this cohort with a high prevalence of T2DM. BMI only has indirect effects, through other risk factors. Traditional CV risk factors have important direct effects on cIMT in the young, but adiposity exerts its influence only through other CV risk factors.

Causes of changes in carotid intima-media thickness: a literature review

Atherosclerosis causes significant morbidity and mortality. Carotid intima-media thickness (CIMT) predicts future cardiovascular and ischaemic stroke incidence. CIMT, a measure of atherosclerotic disease, can be reliably determined in vivo by carotid ultrasound. In this review, we determined that CIMT is associated with traditional cardiovascular risk factors such as age, sex, race, smoking, alcohol consumption, habitual endurance exercise, blood pressure, dyslipidemia, dietary patterns, risk-lowering drug therapy, glycemia, hyperuricemia, obesity-related anthropometric parameters, obesity and obesity-related diseases. We also found that CIMT is associated with novel risk factors, including heredity, certain genotypic indices, anthropometric cardiovascular parameters, rheumatoid arthritis, immunological diseases, inflammatory cytokines, lipid peroxidation, anthropometric hemocyte parameters, infectious diseases, vitamin D, matrix metalloproteinases, and other novel factors and diseases. However, the conclusions are inconsonant; the underlying causes of these associations remain to be further explored.

Ectopic adiposity is associated with autonomic risk factors and subclinical cardiovascular disease in young adults

OBJECTIVE

To examine the relationship between ectopic adiposity and markers of cardiometabolic risk, autonomic control, and subclinical cardiovascular disease (CVD).

METHODS

Cross-sectional analyses were performed in 324 subjects with overweight and obesity. Single-slice CT images were analyzed to calculate thigh muscle attenuation (MA), a measure of ectopic adiposity. Autonomic control was assessed using low-frequency to respiratory-frequency heart rate variability (LFa/RFa ratio). Carotid intima-media thickness (IMT) was a marker of subclinical CVD.

RESULTS

Among overweight participants, those with low MA had lower HDL-c, higher LFa/RFa ratio, and subcutaneous thigh fat compared to high MA individuals despite no difference in visceral fat or insulin resistance. Significant associations were not observed in the class I obese group. In the class II obese group, those with high MA had higher triglycerides and insulin levels, yet there was no difference in visceral fat compared to the low MA group. Mean IMT was significantly higher in the low MA compared to the high MA overweight group (0.63 mm vs. 0.58 mm, P = 0.04) but was similar between the low and high MA class II obese groups.

CONCLUSIONS

Excess ectopic adiposity in muscle tissue is associated with metabolic and autonomic risk factors and subclinical CVD, most notably in overweight individuals, independent of insulin resistance and visceral abdominal fat.

A Common Variant of NGEF Is Associated with Abdominal Visceral Fat in Korean Men

Central adiposity, rather than body mass index (BMI), is a key pathophysiological feature of the development of obesity-related diseases. Although genetic studies by anthropometric measures such as waist circumference have been widely conducted, genetic studies for abdominal fat deposition measured by computed tomography (CT) have been rarely performed. A total of 1,243 participants who were recruited from two health check-up centers were included in this study. We selected four and three single-nucleotide polymorphisms (SNPs) in NGEF and RGS6, respectively, and analyzed the associations between the seven SNPs and central adiposity measured by CT using an additive, dominant, or recessive model. The participants were generally healthy middle-aged men (50.7 ± 5.3 years). In the additive model, the rs11678490 A allele of NGEF was significantly associated with total adipose tissue, visceral adipose tissue (VAT), and subcutaneous adipose tissue (all P < 0.05). The AA genotype of this SNP in the recessive model showed a more significant association with all adiposity traits, and its association with VAT remained significant even after adjustment for BMI (P = 0.005). In the overall or visceral obesity group analysis, the AA genotype of rs11678490 showed no association with overall obesity (P = 0.148), whereas it was significantly associated with visceral obesity both before (P = 0.010) and after (P = 0.029) adjustment for BMI. In particular, an AA genotype effect was conspicuous between lower and upper groups with 5% extreme VAT phenotypes (OR = 9.59, 95% CI = 1.50-61.31). However, we found no significant association between SNPs of RGS6 and central adiposity. We identified a visceral-fat-associated SNP, rs11678490 of NGEF, in Korean men. This study suggests that the genetic background of central adiposity and BMI is different, and that additional efforts should be made to find the unique genetic architecture of intra-abdominal fat accumulation.

Individual contributions of visceral fat and total body fat to subclinical atherosclerosis: The NEO study

BACKGROUND

Both overall and abdominal adiposity are established risk factors for cardiovascular disease. Visceral adipose tissue (VAT) and total body fat (TBF) are strongly correlated and previous studies did not make this distinction.

OBJECTIVE

We aimed to distinguish individual contributions of TBF, VAT, and the ratio of VAT to abdominal subcutaneous adipose tissue (VAT/SAT) to subclinical atherosclerosis in men and women.

METHODS

In this cross-sectional analysis of the Netherlands Epidemiology of Obesity (NEO) study, we assessed VAT and SAT with magnetic resonance imaging, TBF with bio-electrical impendence analysis, and carotid Intima-Media Thickness (cIMT) with ultrasound. We performed linear regression analyses of standardized values of TBF, VAT, VAT/SAT with cIMT. We adjusted the models for confounding factors (age, sex, ethnicity, education, smoking, alcohol, physical activity), and either for VAT or TBF.

RESULTS

This analysis included 2451 participants, 53% men with mean (SD) cIMT of 615 (91)μm. After adjustment for confounding factors, the difference in cIMT (95% CI) per SD in VAT was 14 (8,21)μm in men and 18 (13,24)μm in women. After adjustment for TBF, this attenuated to 5 (-3,13)μm in men and 13 (5,20)μm in women. In the full model, differences in cIMT (95% CI) per SD of TBF were 14 (6,22)μm in men and 8 (0,16)μm in women, and per SD of VAT/SAT were 7 (-1,15)μm and 9 (3,16)μm respectively.

CONCLUSIONS

In this population-based study, VAT contributed beyond overall adiposity to subclinical atherosclerosis, particularly in women. This implies a specific role of VAT in the early development of atherosclerosis.

Clinical significance of visceral adiposity assessed by computed tomography: A Japanese perspective

Abdominal obesity, rather than total amount of fat, is linked to obesity-related disorders. Visceral adiposity is an important component of obesity-related disorders in Japanese individuals with a mild degree of adiposity compared with Western subjects. In 1983, our group reported techniques for body fat analysis using computed tomography (CT) and established the concept of visceral fat obesity in which intra-abdominal fat accumulation is an important factor in the development of obesity-related complications, such as diabetes, lipid disorders, hypertension and atherosclerosis. Our group also established ideal imaging conditions for determining abdominal fat area at the umbilical level CT scan. Visceral fat area (VFA) measured in a single slice at L4 level correlated significantly with the total abdominal visceral fat volume measured on multislice CT scan. In a large-scale study of a Japanese population, the mean number of obesity-related cardiovascular risk factors (hypertension, low high-density lipoprotein cholesterolemia and/or hypertriglyceridemia, and hyperglycemia) was greater than 1.0 at 100 cm² of VFA, irrespective of gender, age and body mass index. Our group also demonstrated that reduction of visceral fat accumulation subsequent to voluntary lifestyle modification, “Hokenshido”, correlated with a decrease in the number of obesity-related cardiovascular risk factors. It is important to select the most appropriate subjects from the general population (e.g., non-obese subjects with a cluster of risk factors for the metabolic syndrome) that are most suitable for body weight reduction, with the goal of preventing atherosclerotic cardiovascular diseases.

Dietary medium chain fatty acid supplementation leads to reduced VLDL lipolysis and uptake rates in comparison to linoleic acid supplementation

Dietary medium chain fatty acids (MCFA) and linoleic acid follow different metabolic routes, and linoleic acid activates PPAR receptors. Both these mechanisms may modify lipoprotein and fatty acid metabolism after dietary intervention. Our objective was to investigate how dietary MCFA and linoleic acid supplementation and body fat distribution affect the fasting lipoprotein subclass profile, lipoprotein kinetics, and postprandial fatty acid kinetics. In a randomized double blind cross-over trial, 12 male subjects (age 51±7 years; BMI 28.5±0.8 kg/m²), were divided into 2 groups according to waist-hip ratio. They were supplemented with 60 grams/day MCFA (mainly C8:0, C10:0) or linoleic acid for three weeks, with a wash-out period of six weeks in between. Lipoprotein subclasses were measured using HPLC. Lipoprotein and fatty acid metabolism were studied using a combination of several stable isotope tracers. Lipoprotein and tracer data were analyzed using computational modeling. Lipoprotein subclass concentrations in the VLDL and LDL range were significantly higher after MCFA than after linoleic acid intervention. In addition, LDL subclass concentrations were higher in lower body obese individuals. Differences in VLDL metabolism were found to occur in lipoprotein lipolysis and uptake, not production; MCFAs were elongated intensively, in contrast to linoleic acid. Dietary MCFA supplementation led to a less favorable lipoprotein profile than linoleic acid supplementation. These differences were not due to elevated VLDL production, but rather to lower lipolysis and uptake rates.

Carotid artery remodelling in relation to body fat distribution, inflammation and sustained weight loss in obesity

BACKGROUND

Obesity is known to be associated with carotid artery remodelling, but less is known about how body fat distribution, inflammation and weight loss may affect this relation.

METHODS

Ultrasonography, dual-energy X-ray absorptiometry and computed tomography were performed to evaluate carotid artery intima-media thickness (IMT), body composition and fat distribution, respectively. Participants were divided into three matched study groups (n = 44 per group): obese patients with sustained weight loss 10 years after bariatric surgery [surgery group, body mass index (BMI) 31.5 kg m(-2)]; obese patients who maintained stable weight during the same time period (obese group, BMI 42.5 kg m(-2)); and normal weight subjects (lean group, BMI 24.4 kg m(-2)).

RESULTS

Patients in the surgery group, compared with those in the obese group, had slightly lower common carotid artery (CCA) IMT (0.75 ± 0.18 vs. 0.78 ± 0.17 mm) and common carotid bulb (CCB) IMT (0.92 ± 0.32 vs. 0.97 ± 0.32 mm); however, these differences were not statistically significant. Lean individuals, compared with those in the surgery group, had significantly lower CCA and CCB IMT values (P < 0.001). In forward stepwise multiple regression analyses including all subjects (n = 132), CCA IMT was predicted mainly by visceral adipose tissue, but was also related to blood pressure and levels of triglycerides and high-sensitivity C-reactive protein. Carotid lumen diameter was primarily influenced by lean body mass.

CONCLUSION

Visceral adiposity was the main determinant of premature carotid artery atherosclerosis, possibly through elevated blood pressure, dyslipidaemia and inflammation. Lean body mass predicted carotid artery lumen diameter. Obese patients with long-term sustained weight loss did not have thinner carotid artery walls compared with their weight-stable obese counterparts.

Long-term exposure to traffic-related air pollution and progression of carotid artery atherosclerosis: a prospective cohort study

OBJECTIVES

Epidemiological studies have demonstrated associations between long-term exposure to traffic-related air pollution and coronary heart disease (CHD). Atherosclerosis is the principal pathological process responsible for CHD events, but effects of traffic-related air pollution on progression of atherosclerosis are not clear. This study aimed to investigate associations between long-term exposure to traffic-related air pollution and progression of carotid artery atherosclerosis.

SETTING

Healthy volunteers in metropolitan Vancouver, Canada.

PARTICIPANTS AND OUTCOME MEASURES

509 participants aged 30-65 years were recruited and followed for approximately 5 years. At baseline and end of follow-up, participants underwent carotid artery ultrasound examinations to assess atherosclerosis severity, including carotid intima-media thickness, plaque area, plaque number and total area. Annual change of each atherosclerosis marker during the follow-up period was calculated as the difference between these two measurements divided by years of follow-up. Living close to major roads was defined as ≤150 m from a highway or ≤50 m from a major road. Residential exposures to traffic-related air pollutants including black carbon, fine particles, nitrogen dioxide and nitric oxide were estimated using high-resolution land-use regression models. The data were analysed using general linear models adjusting for various covariates.

RESULTS

At baseline, there were no significant differences in any atherosclerosis markers between participants living close to and those living away from major roads. After follow-up, the differences in annual changes of these markers between these two groups were small and not statistically significant. Also, no significant associations were observed with concentrations of traffic-related air pollutants including black carbon, fine particles, nitrogen dioxide and nitric oxide.

CONCLUSIONS

This study did not find significant associations between traffic-related air pollution and progression of carotid artery atherosclerosis in a region with lower levels and smaller contrasts of ambient air pollution.

The association between "hypertriglyceridemic waist" and sub-clinical atherosclerosis in a multiethnic population: a cross-sectional study

Background

"Hypertriglyceridemic waist" (HTGW) phenotype, an inexpensive early screening tool for detection of individuals at risk for type 2 diabetes and cardiovascular disease was found to be associated with subclinical atherosclerosis in various patient populations such as those with diabetes mellitus, chronic kidney disease, and those infected with human immunodeficiency virus. However, less is known regarding an association between HTGW and subclinical atherosclerosis in the apparently healthy, multiethnic population. Therefore, the aim of the study was to explore the association between HTGW and sub-clinical atherosclerosis in an apparently healthy, multiethnic population; and to investigate whether the effect of HTGW on sub-clinical atherosclerosis persists over and above the traditional atherosclerosis risk factors.

Methods

We studied 809 individuals of Aboriginal, Chinese, European and South Asian origin who were assessed for indices of sub-clinical atherosclerosis (intima-media thickness (IMT), total area and presence of carotid plaques), socio-demographic and lifestyle characteristics, anthropometrics, lipids, glucose, blood pressure, and family history of cardiovascular disease.

Results

We found that, compared to individuals without HTGW and after adjusting for age, ethnicity, smoking, and physical activity; men and women with HTGW had a significantly higher: IMT (men: B (95%CI = 0.084 (0.037, 1.133), p < 0.001; women: B (95%CI) = 0.041 (0.006, 0.077), p = 0.020); and total area (men: B (95%CI = 0.202 (0.058, 0.366), p = 0.005; women: B (95%CI) = 0.115 (0.006, 0.235), p = 0.037). The association between HTGW waist and presence of plaques was significant for men (OR (95%CI) = 1.904 (1.040, 3.486), p = 0.037 vs. men without HTGW), but not for women (p = 0.284). Once analyses were adjusted for additional, traditional risk factors for atherosclerosis, the effect of HTGW on sub-clinical atherosclerosis was no longer significant.

Conclusions

In conclusion, HTGW may serve as an early marker of subclinical atherosclerosis in men and women, irrespective of ethnicity. However, once individuals are assessed for all traditional risk factors for atherosclerosis, the additional assessment for HTGW is not warranted.

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.

Visceral adipose tissue as a source of inflammation and promoter of atherosclerosis

The current epidemic of obesity with the associated increasing incidence of insulin resistance, diabetes mellitus and atherosclerosis affecting a large proportion of the North American and Western populations, has generated a strong interest in the potential role of visceral adipose tissue in the development of atherosclerosis and its complications. The intra-abdominal and epicardial space are two compartments that contain visceral adipose tissue with a similar embryological origin. These visceral fats are highly inflamed in obese patients, patients with the metabolic syndrome and in those with established coronary artery disease; additionally they are capable of secreting large quantities of pro-inflammatory cytokines and free fatty acids. There is accumulating evidence to support a direct involvement of these regional adipose tissue deposits in the development of atherosclerosis and its complicating events, as will be reviewed in this article.

Waist circumference is the best index for obesity-related cardiovascular disease risk in individuals with spinal cord injury

Obesity is an important identifier of cardiovascular disease (CVD) risk, but is challenging to determine accurately in individuals with spinal cord injury (SCI). Body mass index (BMI) is used worldwide as a simple indicator of obesity, but is difficult to measure in individuals with SCI. Furthermore, standard BMI cutoffs underestimate obesity in this population. Therefore, we aimed to identify the best marker of obesity in individuals with SCI, considering both practicality, and ability to detect adiposity and CVD risk. Five anthropometric measures were evaluated: BMI; waist circumference (WC); waist-to-height ratio (WHtR); waist-to-hip ratio; and neck circumference. We evaluated relationships between these measures and abdominal and total body-fat percentage, seven cardiovascular metabolic risk factors (fasting insulin, glucose, glucose tolerance, triglycerides, high-density lipoprotein, low-density lipoprotein, and total cholesterol), and the Framingham risk score. BMI, WC, and WHtR were correlated with abdominal fat percentage. WC and WHtR were correlated with five metabolic risk factors as well as the Framingham risk score. WC is a more practical measure for an SCI population. The optimal cutoff for identifying adverse CVD risk in individuals with SCI was identified as WC ≥94 cm, with 100% sensitivity and 79% specificity. We propose that WC is a simple, more sensitive alternative to BMI in this population that is easy to use in multiple settings. The cutoff provides a simple tool to predict adverse CVD risk profiles that can be used to guide risk management, as well as as a practical aid for individuals with SCI to maintain a healthy body composition.

Association between abdominal fat distribution and atherosclerotic changes in the carotid artery

AIM

We aimed to evaluate the association between abdominal fat distribution (e.g., abdominal visceral fat area [VFA], subcutaneous fat area [SFA], and total fat area [TFA]), waist circumference (WC), or body mass index (BMI) and atherosclerotic changes in the carotid artery after adjusting for common risk factors.

METHODS

The present study is a hospital-based, cross-sectional study. Study participants included 223 Japanese individuals who underwent a medical health checkup at Juntendo University Hospital, Tokyo, between December 2005 and August 2011. Multivariate logistic regression analysis was used to examine the association between abdominal VFA, SFA, TFA, the VFA/SFA ratio, WC, or BMI and intima-media thickness [IMT] (mean IMT≥1.1mm or maximum IMT≥1.2mm) as atherosclerotic changes in the carotid artery.

RESULTS

Multivariate logistic regression analysis showed that VFA (OR for ≥150cm(2) versus <100cm(2), 3.88; 95% CI, 1.39-10.85), BMI (OR for ≥27.6kg/m(2) versus <25kg/m(2), 5.22; 95% CI, 1.69-16.16), and TFA (OR for 200-285cm(2) versus <200cm(2), 4.15; 95% CI, 1.34-12.86: OR for ≥285cm(2) versus <200cm(2), 5.53; 95% CI, 1.76-17.35) were significantly associated with atherosclerotic changes in men. After adjustment for BMI, only TFA (OR for ≥285cm(2) versus <200cm(2), 3.76; 95%CI, 1.03-13.79) in men was significantly associated with atherosclerotic changes in the carotid artery.

CONCLUSIONS

Our results indicate that VFA, TFA, and BMI are independently associated with atherosclerotic changes in Japanese men. TFA may be considered as a valuable measure of atherosclerotic changes.

Metabolic syndrome and abdominal fat are associated with inflammation, but not with clinical outcomes, in peritoneal dialysis patients

Background

In the general population, metabolic syndrome (MetS) is correlated with visceral fat and a risk factor for cardiovascular disease (CVD); however, little is known about the significance of abdominal fat and its association with inflammation and medication use in peritoneal dialysis (PD) patients. We investigated the relationship of visceral fat area (VFA) with C-reactive protein (CRP) levels and medication use in PD patients and followed their clinical outcomes.

Methods

In a prospective study from February 2009 to February 2012, we assessed diabetes mellitus (DM) status, clinical and PD-associated characteristics, medication use, CRP levels, components of MetS, and VFA in 183 PD patients. These patients were categorized into 3 groups based on MetS and DM status: non-MetS (group 1, n = 73), MetS (group 2, n = 65), and DM (group 3, n = 45). VFA was evaluated by computed tomography (CT) and corrected for body mass index (BMI).

Results

Patients in group 1 had smaller VFAs than patients in groups 2 and 3 (3.2 ± 1.8, 4.6 ± 1.9, and 4.9 ± 2.0 cm²/[kg/m²], respectively, P < 0.05) and lower CRP levels (0.97 ± 2.31, 1.27 ± 2.57, and 1.11 ± 1.35 mg/dL, respectively, P < 0.05). VFA increased with the number of criteria met for MetS. After adjusting for age, body weight, and sex, CRP and albumin levels functioned as independent positive predictors of VFA; on other hand, the use of renin-angiotensin system blockers was inversely correlated with VFA in PD patients without DM. In the survival analysis, DM patients (group 3) had the poorest survival among the 3 groups, but no significant differences were found between groups 1 and 2.

Conclusion

This study showed that VFA and MetS are associated with CRP levels but cannot predict survival in PD patients without DM. The complex relationship of nutritional parameters to VFA and MetS may explain these results. The type of antihypertensive medication used was also associated with the VFA. The mechanisms behind these findings warrant further investigation.

The relationship between DXA-based and anthropometric measures of visceral fat and morbidity in women

Background

Excess accumulation of visceral fat is a prominent risk factor for cardiovascular and metabolic morbidity. While computed tomography (CT) is the gold standard to measure visceral adiposity, this is often not possible for large studies - thus valid, but less expensive and intrusive proxy measures of visceral fat are required such as dual-energy X-ray absorptiometry (DXA). Study aims were to a) identify a valid DXA-based measure of visceral adipose tissue (VAT), b) estimate VAT heritability and c) assess visceral fat association with morbidity in relation to body fat distribution.

Methods

A validation sample of 54 females measured for detailed body fat composition - assessed using CT, DXA and anthropometry – was used to evaluate previously published predictive models of CT-measured visceral fat. Based upon a validated model, we realised an out-of-sample estimate of abdominal VAT area for a study sample of 3457 female volunteer twins and estimated VAT area heritability using a classical twin study design. Regression and residuals analyses were used to assess the relationship between adiposity and morbidity.

Results

Published models applied to the validation sample explained >80% of the variance in CT-measured visceral fat. While CT visceral fat was best estimated using a linear regression for waist circumference, CT body cavity area and total abdominal fat (R² = 0.91), anthropometric measures alone predicted VAT almost equally well (CT body cavity area and waist circumference, R² = 0.86). Narrow sense VAT area heritability for the study sample was estimated to be 58% (95% CI: 51-66%) with a shared familial component of 24% (17-30%). VAT area is strongly associated with type 2 diabetes (T2D), hypertension (HT), subclinical atherosclerosis and liver function tests. In particular, VAT area is associated with T2D, HT and liver function (alanine transaminase) independent of DXA total abdominal fat and body mass index (BMI).

Conclusions

DXA and anthropometric measures can be utilised to derive estimates of visceral fat as a reliable alternative to CT. Visceral fat is heritable and appears to mediate the association between body adiposity and morbidity. This observation is consistent with hypotheses that suggest excess visceral adiposity is causally related to cardiovascular and metabolic disease.