Long-Term Improvement in Cardiorespiratory Fitness Ameliorates Insulin Sensitivity beyond Changes in Visceral/Ectopic Fat among Men with Visceral Obesity.

The SYNERGIE study documented the effects on cardiometabolic risk (CMR) indices of a 1-year lifestyle intervention targeting physical activity (PA) and diet followed by a 2-year maintenance period in men with visceral obesity. Improvements in CMR markers and a decrease in low-attenuation muscle (LAM) area were observed after 1 year. Despite a rebound in visceral adipose tissue (VAT) during the maintenance period, insulin resistance (IR) improved. We tested the hypothesis that variations in cardiorespiratory fitness (CRF) and LAM could explain the long-term improvement in IR. A health (n = 88; mean age 49.0 ± 8.2 years) and fitness (n = 72) evaluation was performed at 0, 1, and 3 years. Participants were classified into two groups based on their CRF response over the maintenance period (worsening: CRF- vs. maintenance/improvement: CRF+). During the maintenance period, changes in the psoas and core LAM areas correlated with changes in IR (r = 0.27; p < 0.05 and r = 0.34; p < 0.005) and changes in CRF (r = -0.31; p < 0.01 and r = -0.30; p < 0.05). IR improved in the CRF+ group (p < 0.05) but remained stable in the CRF- group. Men in the CRF+ group regained half of the changes in VAT volume and LAM at the psoas and mid-thigh compared to the CRF- group (p < 0.05). These results support the importance of targeting VAT and CRF/PA for the long-term management of CMR in men with visceral obesity.

Plasma IGFBP-2 levels reveal heterogeneity in hepatic fat content in adults with excess visceral adiposity.

Lay summary: Obesity is frequently accompanied by a fatty liver. However, some individuals with high abdominal fat levels nevertheless have low levels of liver fat. Reasons for such discordant phenotypes are unclear. In this paper, we report that among asymptomatic individuals with high levels of visceral fat, low concentrations of IGFBP-2 in the circulation were associated with significantly higher hepatic fat content compared to those with high IGFBP-2 levels. We conclude that quantification of plasma IGFBP-2 concentrations may be useful to identify the early risk for liver fat accumulation in apparently healthy individuals without cardiovascular symptoms. Aim/hypothesis: Although excess visceral adiposity (VAT) is generally associated with increased liver fat (LF), recent evidence has revealed heterogeneity in LF content among adults with visceral obesity, potentially contributing to specific differences in cardiometabolic outcomes. Reasons for such discordant VAT-LF phenotypes are largely unknown. The present study aimed at assessing whether circulating levels of insulin growth-factor binding protein-2 (IGFBP-2) could be a useful biomarker in the identification of heterogenous and discordant VAT-LF phenotypes. Methods: A sample of 308 middle-aged Caucasian apparently healthy men and women without cardiovascular symptoms were studied for the present cross-sectional analyses. Fasting plasma glucose and lipid levels were assessed and an oral glucose tolerance test was performed. Hepatic fat fraction (HFF) was measured using magnetic resonance spectroscopy whereas VAT was assessed by magnetic resonance imaging. Plasma IGFBP-2 levels were quantified by ELISA. Participants were then classified on the basis of median VAT (81 mL) and IGFBP-2 levels (233 ng/mL). Results: Individuals with high levels of VAT were characterized by higher waist circumference, lower insulin sensitivity, as well as by higher plasma triglyceride and lower HDL-cholesterol levels. Plasma IGFBP-2 levels were inversely correlated with HFF (r = -0.39, p < 0.0001). Among men and women with high levels of VAT, those with low levels of IGFBP-2 had significantly higher HFF (7.5 ± 0.7%), compared to participants with high IGFBP-2 concentrations (3.2 ± 0.5%, p < 0.0001). Conclusion: In the presence of excess VAT, high IGFBP-2 concentrations are associated with low levels of LF. Although additional studies will be necessary to establish causality and further clarify the clinical implications of these observations, these findings are concordant with a novel function of IGFBP-2 in modulating susceptibility to non-alcoholic fatty liver disease (NAFLD) in the presence of visceral obesity.

Associations of insulin-like growth factor binding protein-2 with metabolic profile and hepatic fat deposition in asymptomatic men and women.

Low circulating levels of insulin-like growth-factor binding protein-2 (IGFBP-2) have been associated with increased adiposity and metabolic alterations such as insulin resistance, dyslipidemia, and nonalcoholic fatty liver disease in individuals with obesity. However, whether IGFBP-2 affects energy metabolism in the early stages of these disorders remains unclear. Herein, we hypothesized that plasma IGFBP-2 concentrations are inversely associated with early liver fat accumulation and alterations in lipid and glucose homeostasis in apparently healthy and asymptomatic men and women. Three hundred thirty-three middle-aged Caucasian men and women apparently healthy and without cardiovascular symptoms were enrolled for a cross-sectional cardiometabolic imaging study. Individuals with BMI ≥ 40 kg/m2, cardiovascular disease, dyslipidemia, hypertension, and diabetes were excluded. Fasting glucose and lipid profiles were measured and an oral glucose tolerance test was performed. Liver fat content was assessed by magnetic resonance spectroscopy. Volume of visceral adipose tissue (VAT) was evaluated by magnetic resonance imaging. Plasma IGFBP-2 levels were quantified by ELISA. Participants with low IGFBP-2 levels were characterized by a higher body fat mass (P < 0.0001), insulin resistance (P < 0.0001), higher plasma triglyceride (TG) (P < 0.0001), and lower HDL-cholesterol levels (P < 0.0001) in a sex-independent manner. IGFBP-2 levels were inversely correlated with hepatic fat fraction in both men (r = -0.36, P < 0.0001) and women (r = -0.40, P < 0.0001). IGFBP-2 concentrations were negatively associated with hepatic fat fraction independently of age and VAT in both men (R2 = 0.23, P = 0.012) and women (R2 = 0.27, P = 0.028). In conclusion, our findings show that even in asymptomatic, apparently healthy individuals, low IGFBP-2 levels are associated with a more deteriorated cardiometabolic risk profile and with a high hepatic fat content in a VAT-independent manner. However, IGFBP-2 does not appear to influence the established sexual dimorphism observed for metabolic variables and hepatic fat fraction. Additional studies are required to better understand the relationships between IGFBP-2 and liver fat content.NEW & NOTEWORTHY Faced with a paucity of reliable clinical etiologic markers for fatty liver, this research article demonstrates, for the first time, that low blood levels of the protein IGFBP-2 are associated with a more deteriorated cardiometabolic risk profile and with a high hepatic fat content independently of visceral fat volume and sex, even in asymptomatic, apparently healthy individuals.

Leisure-time physical activity is more strongly associated with cardiometabolic risk than occupational physical activity: Results from a workplace lifestyle modification program.

BACKGROUND: Regular physical activity (PA) plays a key role in the management and prevention of numerous chronic diseases. However, recent studies have suggested that occupational physical activity (OPA) may not always have health benefits. The aim of the present study was to examine the respective contributions of OPA vs. leisure-time physical activity (LTPA) to the variation in the cardiometabolic profile, including cardiorespiratory fitness (CRF), of employees involved in a workplace lifestyle modification program. Our study hypothesis was that LTPA would show a stronger association with indices of cardiometabolic health than OPA. METHODS: A mobile health assessment unit was used to assess 5145 workers (3397 men and 1748 women) on site at their workplace. Assessments included lifestyle questionnaires (overall diet quality, type of OPA and level of LTPA), blood pressure measurements, blood tests, anthropometric measurements, and a submaximal treadmill exercise test to assess CRF. Results were adjusted for education, household income and age. RESULTS: When workers were classified on the basis of their OPA (sedentary work, standing work, physical work, and heavy manual work), only a few significant differences in the cardiometabolic profile were observed in men, with those in the physical work category having more favorable values than sedentary workers. However, substantial and significant differences were observed among employees classified on the basis of their LTPA, these differences being observed in both men and women. For instance, waist circumference, the cholesterol/HDL cholesterol ratio, triglyceride concentrations and resting heart rate were lower in active individuals compared to inactive and moderately inactive individuals (p < 0.01). Furthermore, irrespective of whether or not employees were sedentary at work, a high level of LTPA was associated with a greater CRF (p < 0.001). Finally, we found that the lowest prevalence of hypertriglyceridemic waist (p < 0.01) and the highest score of overall diet quality (p < 0.001) were observed in active individuals, irrespective of their OPA category. CONCLUSION: Levels of LTPA were more strongly associated with cardiometabolic health than OPA in a cohort of blue- and white-collar employees. Furthermore, high levels of LTPA were found to counteract the potentially deleterious effects of a sedentary work on cardiometabolic health.

Intra-abdominal adipose depot variation in adipogenesis, lipogenesis, angiogenesis, and fibrosis gene expression and relationships with insulin resistance and inflammation in premenopausal women with severe obesity

Although severe obesity is associated with insulin resistance (IR) and inflammation, secretory function of intra-abdominal adipose tissues and their relationships with IR and inflammation markers remain poorly understood. Aims were to measure gene expression of adipogenic (C/EBPα/β, PPARγ-1/2, SREBP-1c, LXRα), lipogenic (SCD1, DGAT-1/2), angiogenic (VEGFα, leptin), and fibrotic (LOX, COL6A3) factors in the round ligament (RL), omental (OM), and mesenteric (ME) fat depots and to evaluate their relationships with IR and inflammation markers in 48 women with severe obesity undergoing bariatric surgery. Gene expression was assessed by RT-qPCR, and plasma glucose and insulin (HOMA-IR calculated), PAI-1, IL-6, TNFα, adiponectin, and leptin levels were determined. C/EBPβ and PPARγ-1/2 mRNA levels were more expressed in the OM (0.001

Overweight, Obesity, and CVD Risk: a Focus on Visceral/Ectopic Fat.

PURPOSE OF REVIEW: Despite its prevalence and well-documented impact on population health, obesity has not emerged as a strong independent risk factor for cardiovascular disease after control for intermediate risk factors. The purpose of this brief narrative review is to highlight results from imaging studies that have not only documented the remarkable heterogeneity of body fat topography but also the importance of visceral adiposity as a key body fat depot associated with cardiovascular disease risk and type 2 diabetes. RECENT FINDINGS: Simple tools are also discussed in order to refine cardiometabolic risk assessment in persons with overweight/obesity. It is proposed that four lifestyle vital signs should be considered in clinical practice to improve discrimination of health risk in individuals with overweight/obesity: waist circumference as a simple marker of abdominal adiposity, cardiorespiratory fitness, overall diet quality, and level of reported physical activity. Heterogeneity of obesity is proposed as an example of a condition that would benefit from a precision lifestyle medicine approach.

Intra-abdominal adipose depot variation in adipogenesis, lipogenesis, angiogenesis, and fibrosis gene expression and relationships with insulin resistance and inflammation in premenopausal women with severe obesity.

Although severe obesity is associated with insulin resistance (IR) and inflammation, secretory function of intra-abdominal adipose tissues and their relationships with IR and inflammation markers remain poorly understood. Aims were to measure gene expression of adipogenic (C/EBPα/ß, PPARγ-1/2, SREBP-1c, LXRα), lipogenic (SCD1, DGAT-1/2), angiogenic (VEGFα, leptin), and fibrotic (LOX, COL6A3) factors in the round ligament (RL), omental (OM), and mesenteric (ME) fat depots and to evaluate their relationships with IR and inflammation markers in 48 women with severe obesity undergoing bariatric surgery. Gene expression was assessed by RT-qPCR, and plasma glucose and insulin (HOMA-IR calculated), PAI-1, IL-6, TNFα, adiponectin, and leptin levels were determined. C/EBPß and PPARγ-1/2 mRNA levels were more expressed in the OM (0.001

Targeting Diet Quality at the Workplace: Influence on Cardiometabolic Risk.

The American Heart Association criteria for cardiovascular health include overall diet quality (DQ). The present study evaluated the effect of a workplace health promotion program targeting DQ and physical activity on features of cardiometabolic risk (CMR). Before and after the 3-month intervention, 2260 employees (1462 men and 798 women) completed a health and fitness evaluation including assessment of DQ using a validated food-based questionnaire. After the 3-month lifestyle modification program, DQ increased significantly in both sexes (p < 0.0001) as well as physical activity level (p < 0.0001). A reduction in waist circumference (p < 0.0001) and improved lipid levels were also observed. Significant associations were found between changes in DQ index and changes in CMR variables in both men (standardized regression coefficients ranged from -0.19 (95% confidence interval: -0.26 to -0.12) to -0.29 (95% confidence interval: -0.34 to -0.25)) and women (standardized regression coefficients ranged from -0.18 (95% confidence interval: -0.25 to -0.11) to -0.27 (95% confidence interval: -0.41 to -0.13)). Multiple linear regression analyses showed a significant contribution of changes in the DQ index to the variation in some CMR variables, independent from changes in physical activity level and cardiorespiratory fitness. This study provides evidence that targeting DQ at the workplace is relevant to improve cardiometabolic health.

CT-derived abdominal adiposity: Distributions and better predictive ability than BMI in a nationwide study of 59,429 adults in China.

BACKGROUND: Although abdominal adiposity is associated with an altered cardiometabolic risk profile, the specific contribution of abdominal adipose tissue distribution remains not fully understood. Computed tomography (CT) is a well-established and precise method to measure abdominal adipose tissue distribution. The present study investigated abdominal adiposity assessed by CT in a large-scale Chinese population. METHOD: A total of 59,429 adults who underwent a low dose chest CT for lung cancer screening at one of 13 health checkup centers throughout China were evaluated. Abdominal visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) areas were measured at the center of the 2nd lumbar vertebra with Mindways quantitative CT software using the existing CT dataset without any additional radiation exposure. The ratio of visceral to total adipose tissue (TAT) areas (VAT/TAT ratio) was calculated and expressed as a percentage. Anthropometric indices including body mass index (BMI) and waist circumference were also obtained. RESULTS: BMI, waist circumference, VAT area, SAT area, and the VAT/TAT ratio were 25.0 ±â€¯3.0 kg/m2, 90 ±â€¯8 cm, 194 ±â€¯77 cm2, 85 ±â€¯41 cm2, and 69.5 ±â€¯9.1%, respectively, in men and 23.3 ±â€¯3.1 kg/m2, 79 ±â€¯8 cm, 120 ±â€¯57 cm2, 123 ±â€¯53 cm2, and 48.9 ±â€¯9.7% in women. With increasing age, VAT area and the VAT/TAT ratio increased in both sexes whereas SAT area decreased in men (P < 0.001 for all). After adjustment for BMI and waist circumference, older individuals showed higher VAT area and higher VAT/TAT ratio than younger subjects (P < 0.001 for all). Adjusted VAT areas in participants aged 75 or older was 45 cm2 (95% confidence interval [CI]: 41 cm2, 50 cm2) higher in men and 43 cm2 (95% CI: 37 cm2, 49 cm2) higher in women compared with participants aged 31-44 years. Additionally, differences in VAT area across age groups increased as BMI or waist circumference increased. VAT and SAT areas, but not the VAT/TAT ratio, were positively associated with BMI and waist circumference in every age group. CONCLUSION: In a nationwide study conducted in China, distributions of CT-derived measures of visceral and subcutaneous adiposity were found to vary significantly between sex and age groups. Our study also revealed that the proportion of VAT (an important driver of cardiometabolic risk) could not be predicted from BMI in a Chinese population.

Metabolic Syndrome: Past, Present and Future.

Most clinicians and health professionals have heard or read about metabolic syndrome [...].

Reversing Type 2 Diabetes: The Time for Lifestyle Medicine Has Come!

The IDF (International Diabetes Federation) Diabetes Atlas Committee has recently published the global estimates of diabetes prevalence for 2019 [...].

Relationships between circulating 25(OH) vitamin D, leptin levels and visceral adipose tissue volume: results from a 1-year lifestyle intervention program in men with visceral obesity.

BACKGROUND/OBJECTIVES: Obesity has been associated with elevated leptinemia and vitamin D deficiency. To date, whether there is an association between vitamin D and leptin levels independent from adiposity remains uncertain. Our objective was to investigate the associations between changes in 25(OH) vitamin D levels, changes in adiposity variables, and changes in leptin levels produced by a 1-year lifestyle intervention program. SUBJECTS/METHODS: Sedentary men (n = 113) with abdominal obesity, dyslipidemic, and non-vitamin D supplemented were involved in a 1-year lifestyle modification program. Subjects were individually counseled by a kinesiologist and a nutritionist once every 2 weeks during the first 4 months with subsequent monthly visits in order to elicit a 500 kcal daily energy deficit and to increase physical activity/exercise habits. Adiposity mapping by computed tomography and cardiometabolic biomarkers, as well as vitamin D measurements were performed at baseline and at the 1-year visit. RESULTS: The 1-year intervention resulted in a 26% decrease in visceral adipose tissue volume (from 1951 ± 481 to 1463 ± 566 cm3), a 27% decrease in leptin levels (from 12.0 ± 8.1 to 8.5 ± 7.8 ng/mL) and a 27% increase in plasma 25(OH) vitamin D concentrations (from 50 ± 18 to 60 ± 18 nmol/L, p < 0.0001). One-year increases in 25(OH) vitamin D levels were inversely correlated with 1-year changes in leptin levels (r = -0.41, p < 0.001). The association remained significant after adjustment for 1-year changes in various adiposity indices: visceral adipose tissue (r = -0.30, p = 0.0019), subcutaneous adipose tissue (r = -0.35, p = 0.0004), total abdominal adipose tissue (r = -0.31, p = 0.0015), and fat mass (r = -0.31, p = 0.001). CONCLUSIONS: In response to a 1-year lifestyle intervention, changes in 25(OH) vitamin D levels were independently associated with changes in leptinemia after adjustment for adiposity changes. This finding supports a possible physiological link between leptinemia and 25(OH) vitamin D levels independent from adiposity and underscores the role of lifestyle modifications leading to lowered leptinemia in the clinical management of vitamin D deficiency.

One-Year Lifestyle Intervention, Muscle Lipids, and Cardiometabolic Risk.

PURPOSE: Low-attenuation muscle (LAM) area at mid-thigh, a computed tomography (CT)-derived index of intramuscular lipids, is associated with insulin resistance, obesity, and type 2 diabetes. The present study aimed at testing the hypothesis that changes in LAM area in trunk muscles from a single abdominal scan could provide relevant information to evaluate the effects of a lifestyle intervention without the use of a mid-thigh CT scan. METHODS: Cardiometabolic risk variables, including waist circumference, lipoprotein-lipid profile, glucose tolerance, and cardiorespiratory fitness, were assessed in a sample of 102 dyslipidemic viscerally obese men at baseline and after a 1-yr lifestyle intervention. Abdominal (L4-L5) and mid-thigh CT scans were performed and abdominal muscles classified as psoas and core muscles. Scans were segmented to calculate muscle areas, LAM areas, and mean attenuation values. RESULTS: All muscle groups showed a decrease in LAM areas (P < 0.0001) in response to the lifestyle intervention. Changes in LAM areas were significantly associated with changes in triglycerides, high-density lipoprotein (HDL) cholesterol, cholesterol/HDL cholesterol ratio and log triglycerides/HDL cholesterol ratio (mid-thigh, 0.20 ≤ |r| ≤ 0.29; psoas, 0.28 ≤ |r| ≤ 0.38; core, 0.29 ≤ |r| ≤ 0.34, P < 0.05). Changes in core LAM area were significantly associated with changes in 2-h glucose levels, glucose area measured during the oral glucose tolerance test and homeostasis model assessment of insulin resistance (0.21 ≤ r ≤ 0.34, P < 0.05). Stepwise regression analyses showed that changes in LAM psoas area were associated with changes in HDL cholesterol and the cholesterol/HDL cholesterol ratio independently from changes in visceral adiposity. CONCLUSIONS: Changes in trunk LAM areas are useful indices of changes in mid-thigh LAM area observed with a 1-yr lifestyle intervention. Thus, an additional mid-thigh scan is not necessary to evaluate muscle lipid content by CT when an abdominal CT scan is available.

Changes in IGFBP-2 levels following a one-year lifestyle modification program are independently related to improvements in plasma apo B and LDL apo B levels.

BACKGROUND AND AIMS: Recent transversal studies have associated insulin-like growth factor binding protein (IGFBP)-2 levels with glucose tolerance and parameters of the lipoprotein-lipid profile. Here, we aimed at determining the longitudinal effects of a one-year lifestyle modification program on IGFBP-2 levels and to identify specific metabolic improvements impacted by the changes in IGFBP-2. METHODS: 99 middle-aged Caucasian men were involved in a lifestyle modification program consisting in personalized healthy eating and physical activity counseling, combined to elicit a daily 500 kcal deficit. Anthropometric and metabolic parameters as well as circulating IGFBP-2 levels were measured before and after one year of the lifestyle modification program. RESULTS: The intervention triggered positive changes in many metabolic parameters and a 43% (p < 0.0001) increase of IGFBP-2 levels. Subjects with the most substantial increases in IGFBP-2 also experienced the most important metabolic improvements. Changes in IGFBP-2 levels (both absolute and relative) were correlated with markers of body fat distribution and lipoprotein-lipid profile, and independently associated with changes in LDL apolipoprotein (apo) B but not VLDL apo B concentrations. Further analyses showed that for similar changes in BMI, waist circumference and visceral adipose tissue volume, large changes in IGFBP-2 levels were required to observe improvements in LDL apo B levels. CONCLUSIONS: The 1-year lifestyle modification program was associated with increased IGFBP-2 concentrations. Increases in IGFBP-2 levels were closely associated with reduced LDL apo B concentrations and independently of the modifications in fat mass and insulin sensitivity. Further mechanistic studies are required to assess the effects of IGFBP-2 levels on LDL metabolism.

Overview of Epidemiology and Contribution of Obesity and Body Fat Distribution to Cardiovascular Disease: An Update.

Obesity is recognized as a heterogeneous condition in which individuals with similar body mass index may have distinct metabolic and cardiovascular risk profiles. Susceptibility to obesity-related cardiometabolic complications is not solely mediated by overall body fat mass, but is largely dependent upon individual differences in regional body fat distribution and ability of subcutaneous adipose tissue to expand. The present review will discuss to what extent the individual variation in body fat distribution is one of the clinical key variables explaining the metabolic heterogeneity of obesity and its related cardiovascular risk. We will present the evidence for the complex nature of the relationship between obesity and cardiovascular disease, outline our current understanding of the mechanisms involved, and identify future direction of research pertinent to this interaction.

High ApoD protein level in the round ligament fat depot of severely obese women is associated with an improved inflammatory profile.

PURPOSE: Apolipoprotein D (ApoD) is a lipocalin participating in lipid transport. It binds to a variety of ligands, with a higher affinity for arachidonic acid, and is thought to have a diverse array of functions. We investigated a potential role for ApoD in insulin sensitivity, inflammation, and thrombosis-processes related to lipid metabolism-in severely obese women. METHODS: We measured ApoD expression in a cohort of 44 severely obese women including dysmetabolic and non-dysmetabolic patients. Physical and metabolic characteristics of these women were determined from anthropometric measurements and blood samples. ApoD was quantified at the mRNA and protein levels in samples from three intra-abdominal adipose tissues (AT): omental, mesenteric and round ligament (RL). RESULTS: ApoD protein levels were highly variable between AT of the same individual. High ApoD protein levels, particularly in the RL depot, were linked to lower plasma insulin levels (-40%, p = 0.015) and insulin resistance (-47%, p = 0.022), and increased insulin sensitivity (+10%, p = 0.008). Lower circulating pro-inflammatory PAI-1 (-39%, p = 0.001), and TNF-α (-19%, p = 0.030) levels were also correlated to high ApoD protein in the RL AT. CONCLUSIONS: ApoD variability between AT was consistent with different accumulation efficiencies and/or metabolic functions according to the anatomic location of fat depots. Most statistically significant correlations implicated ApoD protein levels, in agreement with protein accumulation in target tissues. These correlations associated higher ApoD levels in fat depots with improved metabolic health in severely obese women.

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.

Trunk muscle quality assessed by computed tomography: Association with adiposity indices and glucose tolerance in men.

BACKGROUND/OBJECTIVES: Thigh muscle attenuation measured by computed tomography (CT) has been shown to be a reliable and useful index of skeletal muscle fat infiltration. Thigh muscle fat content assessed by CT has been linked to obesity and type 2 diabetes and is a correlate of insulin resistance in sedentary individuals. However, as measurement of mid-thigh fat content requires the assessment of another region of interest beyond the usual abdominal scan required to measure levels of visceral and subcutaneous abdominal adipose tissue, this study aimed at testing the hypothesis that skeletal muscle fat measured from a single abdominal scan (L4-L5) would also provide information relevant to the estimation of muscle fat infiltration as it relates to cardiometabolic risk. METHODS: Abdominal (L4-L5) and mid-thigh CT scans were performed in a sample of 221 sedentary men covering a wide range of adiposity values. Trunk muscles on the L4-L5 scan were classified into 2 groups: 1) psoas and 2) core muscles. The two scans were segmented to calculate muscle areas, mean attenuation values as well as low-attenuation muscle (LAM) areas, the latter being considered as an index of skeletal muscle fat infiltration. Body mass index (BMI), body composition and waist circumference were assessed and a 75 g oral glucose tolerance test (OGTT) was performed. RESULTS: Mid-thigh, psoas and core LAM areas were all significantly associated with body composition indices (0.46 ≤ r ≤ 0.71, p < 0.0001) whereas trunk muscle indices were more strongly associated with visceral adiposity and waist circumference (0.54 ≤ r ≤ 0.79, p < 0.0001) than were mid-thigh muscle variables (0.44 ≤ r ≤ 0.62, p < 0.0001). Mid-thigh LAM area as well as psoas and core LAM areas were significantly associated with fasting glucose, 2-h plasma glucose levels, the glucose area under the curve and with the HOMA-IR index (mid-thigh LAM area: 0.18 ≤ r ≤ 0.25, p < 0.01; psoas LAM area: 0.27 ≤ r ≤ 0.33, p < 0.0001; core LAM area: 0.24 ≤ r ≤ 0.34, p < 0.01). Multivariable stepwise regression analyses revealed that the associations between trunk muscle indices and glucose tolerance/insulin resistance were no longer significant after controlling for visceral adiposity measured at L4-L5. CONCLUSION: Our results suggest that CT-imaging derived indices of trunk muscle quality are related to glucose tolerance and visceral adiposity. However, the relationship between skeletal muscle fat and insulin resistance appears to be largely mediated by the concomitant variation in visceral adiposity. Finally, our results suggest that a single CT scan performed at L4-L5 is adequate to assess skeletal muscle fat content related to cardiometabolic risk.