Search

Background: The associations of abdominal skeletal muscle mass index (SMI), visceral and subcutaneous adipose tissue (VAT and SAT, respectively), and mortality among patients with stage I–III colorectal cancer may differ for men and women, but only few studies stratified their data into men and women. We investigated associations of abdominal SMI, VAT, and SAT with overall mortality among men and among women with stage I–III colorectal cancer. Methods: SMI, VAT, and SAT were assessed from abdominal CT images for 1,998 patients with stage I–III colorectal cancer diagnosed between 2006 and 2015. Restricted cubic splines (RCS) were used to investigate associations of SMI, VAT, and SAT with overall mortality. Results: Average age of the participants was 67.9 ± 10.6 years and 58% were men. During a median follow-up of 4.3 years, 546 (27%) patients died. Among men, the association of SMI and mortality was statistically significant in a nonlinear way in the RCS analyses, with lower SMI levels associated with higher mortality. SMI was not associated with mortality among women. SAT was associated with mortality in a nonlinear way for men and for women, with lower SAT levels being associated with higher mortality. VAT was not significantly associated with mortality in men or women. Conclusion: Associations of abdominal skeletal muscle mass with mortality among patients with colorectal cancer were not the same for men and for women. Impact: This study stresses the importance for more attention on sex-related differences in body composition and cancer outcomes.

Objective Differences in the content and distribution of body fat and ectopic lipids may be responsible for ethnic variations in metabolic disease susceptibility. The aim of this study was to examine the ethnic distribution of body fat in two separate UK-based populations. Methods Anthropometry and body composition were assessed in two separate UK cohorts: the Hammersmith cohort and the UK Biobank, both comprising individuals of South Asian descent (SA), individuals of Afro-Caribbean descent (AC), and individuals of European descent (EUR). Regional adipose tissue stores and liver fat were measured by magnetic resonance techniques. Results The Hammersmith cohort (n = 747) had a mean (SD) age of 41.1 (14.5) years (EUR: 374 men, 240 women; SA: 68 men, 22 women; AC: 14 men, 29 women), and the UK Biobank (n = 9,533) had a mean (SD) age of 55.5 (7.5) years (EUR: 4,483 men, 4,873 women; SA: 80 men, 43 women, AC: 31 men, 25 women). Following adjustment for age and BMI, no significant differences in visceral adipose tissue or liver fat were observed between SA and EUR individuals in the either cohort. Conclusions Our data, consistent across two independent UK-based cohorts, present a limited number of ethnic differences in the distribution of body fat depots associated with metabolic disease. These results suggest that the ethnic variation in susceptibility to features of the metabolic syndrome may not arise from differences in body fat.

We combined clinical, cytokine, genomic, methylation and dietary data from 43 young adult monozygotic twin pairs (aged 22–36 years, 53% female), where 25 of the twin pairs were substantially weight discordant (delta body mass index > 3 kg m −2 ). These measurements were originally taken as part of the TwinFat study, a substudy of The Finnish Twin Cohort study. These five large multivariate datasets (comprising 42, 71, 1587, 1605 and 63 variables, respectively) were jointly analysed using an integrative machine learning method called group factor analysis (GFA) to offer new hypotheses into the multi-molecular-level interactions associated with the development of obesity. New potential links between cytokines and weight gain are identified, as well as associations between dietary, inflammatory and epigenetic factors. This encouraging case study aims to enthuse the research community to boldly attempt new machine learning approaches which have the potential to yield novel and unintuitive hypotheses. The source code of the GFA method is publically available as the R package GFA.

BACKGROUND/OBJECTIVES: The phenomenon of adipocyte 'beiging' involves the conversion of non-classic brown adipocytes to brown-like adipose tissue with thermogenic, fat-burning properties, and this phenomenon has been shown in rodents to slow the progression of obesity-associated metabolic diseases. Rodent studies consistently report adipocyte beiging after endurance exercise training, indicating that increased thermogenic capacity in these adipocytes may underpin the improved health benefits of exercise training. The aim of this study was to determine whether prolonged endurance exercise training induces beige adipogenesis in subcutaneous adipose tissues of obese men.SUBJECTS/METHODS: Molecular markers of beiging were examined in adipocytes obtained from abdominal subcutaneous (AbSC) and gluteofemoral (GF) subcutaneous adipose tissues before and after 6 weeks of endurance exercise training in obese men (n=6, 37.3 +/- 2.3 years, 30.1 +/- 2.3 kg m(-2)).RESULTS: The mRNAs encoding the brown or beige adipocyte-selective proteins were very lowly expressed in AbSC and GF adipose tissues and exercise training did not alter the mRNA expression of UCP1, CD137, CITED, TBX1, LHX8 and TCF21. Using immunohistochemistry, neither multilocular adipocytes, nor UCP1 or CD137-positive adipocytes were detected in any sample. MicroRNAs known to regulate brown and/or beige adipose development were highly expressed in white adipocytes but endurance exercise training did not impact their expression.CONCLUSIONS: The present study reaffirms emerging data in humans demonstrating no evidence of white adipose tissue beiging in response to exercise training, and supports a growing body of work demonstrating divergence of brown/beige adipose location, molecular characterization and physiological function between rodents and humans.

This paper gives a brief overview of common non-invasive techniques for body composition analysis and a more in-depth review of a body composition assessment method based on fat-referenced quantitative magnetic resonance imaging (MRI). Earlier published studies of this method are summarized, and a previously un-published validation study, based on 4.753 subjects from the UK Biobank imaging cohort, comparing the quantitative MRI method with dual-energy x-ray absorptiometry (DXA) is presented. For whole-body measurements of adipose tissue (AT) or fat and lean tissue (LT), DXA and quantitative MRI show excellent agreement with linear correlation of 0.99 and 0.97, and coefficient of variation (CV) of 4.5 % and 4.6 % for fat (computed from AT) and lean tissue respectively, but the agreement was found significantly lower for visceral adipose tissue, with a CV of more than 20 %. The additional ability of MRI to also measure muscle volumes, muscle AT infiltration and ectopic fat in combination with rapid scanning protocols and efficient image analysis tools make quantitative MRI a powerful tool for advanced body composition assessment.

We assessed the associations between changes in total and abdominal fat and changes in biomarkers for breast cancer risk using data of the SHAPE-2 trial. In the SHAPE-2 trial, 243 postmenopausal overweight women were included. The intervention in this trial consisted of 5-6 kg weight loss either by diet only or exercise plus diet. After 16 weeks, we measured serum sex hormones, inflammatory markers, total body fat (measured by DEXA scan) and intra and subcutaneous abdominal fat (measured by MRI). Associations between changes in different body fat depots and biomarkers were analysed by linear regression using the study cohort irrespective of randomisation to make maximal use of the distribution of changes in fat measures. We found that a loss in total body fat was associated with favourable changes in free oestradiol, free testosterone, leptin and sex hormone binding globulin (SHBG). The loss of intra-abdominal fat was associated with a decrease in free testosterone, hsCRP and leptin, and an increase in SHBG. In the multivariable analysis, the best fitted models for the biomarkers free oestradiol, SHBG leptin and adiponectin included only total body fat. For free testosterone, this was subcutaneous abdominal fat, and for hsCRP and IL-6, only intra-abdominal fat change was important. For IL-6 and adiponectin, however, associations were weak and not significant. We conclude that, in our population of healthy overweight postmenopausal women, loss of fat at different body locations was associated with changes in different types of biomarkers, known to be related to risk of breast cancer.

The epidemic of obesity is recognized as one of the most important public health problems facing the world today. According to 2014 World Health Organization (WHO) data,1 39% of adults worldwide are overweight (body mass index, BMI ≥ 25 kg/m2) and 13% of adults are obese (BMI ≥ 30 kg/m2). Thus, more than half a billion adults worldwide are classified as obese. The prevalence of obesity varies by geographical region, gender and income level. The highest prevalence is found in the USA (61% overweight, 27% obese), closely followed by Europe (59% overweight, 23% obese), with the lowest prevalence in South–East Asia (22% overweight, and 5% obese). In Europe, the vast majority of countries have an overweight prevalence of more than 60%.1 Asians generally have a higher percentage of body fat than Caucasians of the same age, sex and BMI. Even below the usual cut-off of BMI = 25 kg/m2 Asian people seem to be at increased risk for type 2 diabetes.2 This may have implications for obesity diagnostic criteria. Indeed, the proposed optimal BMI cut-off values by WHO in Asian populations seems to vary from 22 to 25 kg/m2 based on the ethnic background. A Consensus Statement for Diagnosis of Obesity, Abdominal Obesity and the Metabolic Syndrome for Asian Indians has suggested the following BMI cut-off values: normal BMI = 18.0–22.9 kg/m2; overweight = 23.0–24.9 kg/m2; and obesity > 25 kg/m2.3 Thus it is indeed debatable whether uniform BMI cut-off values to diagnose obesity and/or for cardiovascular risk stratification purposes can be use worldwide. The use of additional anthropometric measurements e.g. waist-circumference or CT based quantification of abdominal/subcutaneous fat volume could help to better delineate obesity and risk parameters and to implement preventive strategies against obesity in each specific ethnic scenario.

CONTEXT: Obesity and type 2 diabetes mellitus are associated with increased levels of IL-6, a marker of inflammation. OBJECTIVE: This study addressed the question of whether IL-6 was released from skeletal muscle after a high-fat meal in men with impaired glucose tolerance (IGT), a prediabetic state, and whether IL-6 release could be reduced by weight loss. DESIGN: Skeletal muscle metabolism was studied in men with IGT (n = 11) and compared with men with normal glucose tolerance (NGT, n = 9), matched for body mass index and age. IL-6 flux over skeletal muscle was measured with the forearm model. Eight IGT men were willing to participate in a 12-wk weight loss program and were tested again. RESULTS: IL-6, but not C-reactive protein or TNF-alpha receptor 1 and 2, was released by skeletal muscle. Muscle IL-6 release was higher in IGT than in NGT during fasting (IGT = 2.26 +/- 1.89 vs. NGT = 0.87 +/- 0.48 fmol x 100 ml tissue(-1) x min(-1), P = 0.04) and after a meal (mean area under the curve per minute: IGT = 3.48 +/- 2.63 vs. NGT = 1.37 +/- 0.75 fmol x 100 ml tissue(-1) x min(-1); P = 0.03). In the IGT men, body weight loss resulted in a decrease of postprandial IL-6 release from skeletal muscle (-52%; P = 0.04), reaching levels of the obese, NGT controls. CONCLUSION: The present data suggest that a high-fat meal can evoke IL-6 release from muscle and that the IL-6 release is a consequence rather than a cause of the obese, insulin-resistant, and/or IGT state.

Objective - Inflammation plays a major role in the pathogenesis of atherosclerosis. Obesity is an independent risk factor for cardiovascular disease, which may be mediated by increased secretion of proinflammatory cytokines by adipose tissue. The aim of this study is to investigate changes in the inflammatory markers interleukin-6 (IL-6) and high-sensitivity C-reactive protein (hs-CRP) during weight reduction with orlistat treatment in obese patients. Methods and results - Thirty-six obese (BMI: 36.1 +/- 3.4 kg/m(2)) and II non-obese (BMI: 22.9 +/- 1.7 kg/m(2)) subjects were studied. IL-6 and hs-CRP levels were evaluated at baseline. In obese subjects after treatment of orlistat 120 mg three times daily for 6 months, IL-6 and hs-CRP levels were repeated. Levels of circulating IL-6 (p < 0.05) and hs-CRP (p < 0.01) were significantly higher in the obese group than in the non-obese group. Plasma IL-6 (r = 0.29 and p < 0.05) and CRP (r = 0.35 and p < 0.05) concentrations correlated positively with the level of obesity assessed by BMI at baseline. After 6 months of orlistat treatment in obese subjects, the mean weight of the patients decreased by 6.8 kg, the BMI by 3.2 kg/m(2). Compared with baseline, weight loss was associated with significant reductions of IL-6 (p < 0.001) and hs-CRP (p < 0.001) levels. Conclusion - In summary plasma IL-6 and hs-CRP levels were increased in obese patients. Orlistat-induced weight reduction was associated with decreasing levels of both IL-6 and hs-CRP in obese subjects. Because inflammatory mediators may be directly involved in atherogenesis, this would suggest that interventions to reduce IL-6 and CRP levels could be cardioprotective.