Anthropometrically predicted visceral adipose tissue and blood-based biomarkers: a cross-sectional analysis

Anthropometric measures, predicted visceral adipose tissue and biomarkers of chronic inflammation

BACKGROUND

Evidence has linked low-grade systemic inflammation and visceral adipose tissue (VAT) with development of chronic conditions. Cytokines and select proteins released by VAT may promote a low-grade inflammatory response. A number of equations have been developed to estimate VAT levels. In this study, we compared predicted VAT equation relationships with biomarkers of inflammation.

METHODS

This was a cross-sectional study of 2038 men and women aged 46-73 years. Correlation and linear regression analyses were performed to examine inflammatory biomarker relationships with four commonly assessed anthropometric measures and 10 predicted VAT equations.

RESULTS

Compared with anthropometric measures, predicted VAT equations were found to explain a greater proportion of variance in CRP (R2  = .075, p = .001), IL-6 (R2  = .060, p = .001), TNF-α (R2  = .017, p = .005), resistin (R2  = .011, p = .012), monocyte (R2  = .027, p = .001), eosinophil (R2  = .012, p = .01) and basophil (R2  = .015, p = .002) levels in males, and a greater variance in concentrations of C3 (R2  = .175, p = .001), IL-6 (R2  = .090, p = .001), TNF-α (R2  = .036, p = .001), adiponectin (R2  = .121, p = .001), the adiponectin-to-leptin ratio (R2  = .444, p = .001), resistin (R2  = .025, p = .001), white blood cell count (R2  = .057, p = .001), neutrophils (R2  = .061, p = .001) and lymphocytes (R2  = .020, p = .001) in females.

CONCLUSION

Equations for assessing VAT levels might be useful to characterise metabolic health. Further studies that examine predicted VAT relationships with disease and mortality outcomes are warranted.

Blood Lead Level Is Associated with Visceral Adipose Dysfunction in Patients with Type 2 Diabetes

We aimed to explore whether an elevated blood lead level (BLL) is associated with visceral adipose dysfunction in patients with type 2 diabetes mellitus (T2DM). Four thousand one hundred and fourteen diabetic participants were enrolled from seven communities in Shanghai in 2018 in the cross-sectional METAL study. BLL was measured by graphite furnace atomic absorption spectrometry. Visceral adiposity index (VAI) and lipid accumulation product (LAP)were calculated by simple anthropometric and biochemical parameters. We found that medians (IQR) of BLL were 26.0 μg/L (18.0-37.0) for men and 25.0 μg/L (18.0-35.0) for women, respectively. In men, each doubling of BLL was associated with a 2.0% higher VAI (95% CI, 0.6 to 3.5%) and 1.8% higher LAP (95% CI, 0.2 to 3.3%) after full adjustment. Using the lowest BLL quartile as the referent group, significant positive trends were observed for BLL with VAI and LAP. In women, each doubling of BLL was associated with a 1.9% higher LAP (95% CI, 0.6 to 3.1%). Additionally, there was a marginally significant positive association between BLL and VAI, either using log2-transformed concentrations as continuous variables or categorized in quartiles. In conclusion, lead exposure is associated with visceral adipose dysfunction in patients with T2DM. Further prospective studies are warranted to confirm our findings.

Estimated visceral adiposity is associated with risk of cardiometabolic conditions in a population based study

Visceral adiposity is a major risk factor of cardiometabolic diseases. Visceral adipose tissue (VAT) is usually measured with expensive imaging techniques which present financial and practical challenges to population-based studies. We assessed whether cardiometabolic conditions were associated with VAT by using a new and easily measurable anthropometric index previously published and validated. Data (1529 participants) came from the European Health Examination Survey in Luxembourg (2013–2015). Logistic regressions were used to study associations between VAT and cardiometabolic conditions. We observed an increased risk of all conditions associated with VAT. The total adjusted odds ratio (AOR, [95% CI]) for hypertension, prediabetes/diabetes, hypercholesterolemia, and hypertriglyceridemia for the fourth quartile of VAT compared to the lowest were 10.22 [6.75, 15.47]), (5.90 [4.02, 8.67]), (3.60 [2.47, 5.25]) and (7.67 [5.04, 11.67]. We observed higher odds in women than in men for all outcomes with the exception of hypertension. Future studies should investigate the impact of VAT changes on cardiometabolic health and the use of anthropometrically predicted VAT as an accurate outcome when no biomedical imaging is available.

Obesity considerations during the COVID-19 outbreak

The worldwide population is facing a double burden of epidemic, the COVID-19 and obesity. This is even more alarming as obesity increases the COVID-19 severity. However, the relationship between obesity and COVID-19 severity is more complex than a simple association with BMI. In particular, obesity has been associated with low death rates in patients with acute respiratory distress syndrome, a fatal comorbidity to COVID-19, possibly due to the obesity paradox. Also, visceral adiposity could be a major risk factor for COVID-19 severity, due to its immune activation component, release of angiotensin-converting enzyme 2 and involvement in the cytokine storm, hypercoagulability and embolism. A poor antioxidant nutritional status also weakens the immune system, increasing inflammation and infection risk. Moreover, the COVID-19 lockdown might impact lifestyle patterns, mental health and weight bias, worsening the obesity then COIVD-19 situation. On the other hand, health care expenses and productivity loss are expected to increase during the concomitant epidemics. The co-occurrence of obesity and COVID-19 is a major challenge at both public health and economic levels that should urgently be taken into consideration. The identification of COVID-19 weight related risk factors and the development of appropriate weight management programs are needed to tackle the concomitant epidemics.

Prognostic value of anthropometric measures extracted from whole-body CT using deep learning in patients with non-small-cell lung cancer

INTRODUCTION

The aim of the study was to extract anthropometric measures from CT by deep learning and to evaluate their prognostic value in patients with non-small-cell lung cancer (NSCLC).

METHODS

A convolutional neural network was trained to perform automatic segmentation of subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), and muscular body mass (MBM) from low-dose CT images in 189 patients with NSCLC who underwent pretherapy PET/CT. After a fivefold cross-validation in a subset of 35 patients, anthropometric measures extracted by deep learning were normalized to the body surface area (BSA) to control the various patient morphologies. VAT/SAT ratio and clinical parameters were included in a Cox proportional-hazards model for progression-free survival (PFS) and overall survival (OS).

RESULTS

Inference time for a whole volume was about 3 s. Mean Dice similarity coefficients in the validation set were 0.95, 0.93, and 0.91 for SAT, VAT, and MBM, respectively. For PFS prediction, T-stage, N-stage, chemotherapy, radiation therapy, and VAT/SAT ratio were associated with disease progression on univariate analysis. On multivariate analysis, only N-stage (HR = 1.7 [1.2-2.4]; p = 0.006), radiation therapy (HR = 2.4 [1.0-5.4]; p = 0.04), and VAT/SAT ratio (HR = 10.0 [2.7-37.9]; p < 0.001) remained significant prognosticators. For OS, male gender, smoking status, N-stage, a lower SAT/BSA ratio, and a higher VAT/SAT ratio were associated with mortality on univariate analysis. On multivariate analysis, male gender (HR = 2.8 [1.2-6.7]; p = 0.02), N-stage (HR = 2.1 [1.5-2.9]; p < 0.001), and the VAT/SAT ratio (HR = 7.9 [1.7-37.1]; p < 0.001) remained significant prognosticators.

CONCLUSION

The BSA-normalized VAT/SAT ratio is an independent predictor of both PFS and OS in NSCLC patients.

KEY POINTS

• Deep learning will make CT-derived anthropometric measures clinically usable as they are currently too time-consuming to calculate in routine practice. • Whole-body CT-derived anthropometrics in non-small-cell lung cancer are associated with progression-free survival and overall survival. • A priori medical knowledge can be implemented in the neural network loss function calculation.

Metabolic Score for Visceral Fat (METS-VF) Estimation - A Novel Cost-Effective Obesity Indicator for Visceral Adipose Tissue Estimation

BACKGROUND

Visceral adipose tissue (VAT) assessment is limited in clinical practice due to expensive, time consuming and limited availability of MRI and DXA machines. We explored the utility of a recently developed Metabolic Score for Visceral Fat (METS-VF) to assess VAT in south Asian individuals with morbid obesity.

PATIENTS AND METHODS

Individuals with BMI ≥35 kg/m² aged between 30 and 60 years were randomly selected from a database of individuals with morbid obesity, attending a multi-disciplinary bariatric clinic in a tertiary care teaching hospital in southern India. Body composition was assessed by using a Hologic Discovery A dual-energy X-ray absorptiometry (DXA) machine. METS-VF was used to estimate VAT by using a previously published algorithm.

RESULTS

The mean age and body mass index of the study subjects (N=350) were 38.2 years and 40.1 kg/m². The MET-VF score performed satisfactorily (AUC of 0.78 (95% CI 0.72-0.85)) for predicting an increased visceral adipose tissue (VAT area ≥ 163 cm²) as detected by DXA. A METS-VF value of 7.3 was found to have a good sensitivity and reasonable specificity in predicting elevated VAT in this population.

CONCLUSION

This is the first study to validate the utility of METS-VF as a surrogate measure of visceral adiposity in south Indian individuals with morbid obesity. Given the simplicity, easy availability, reliability and inexpensive nature of this obesity indicator, it may find its widespread use in lower middle-income countries.

The Value of Anthropometric Measures in Nutrition and Metabolism: Comment on Anthropometrically Predicted Visceral Adipose Tissue and Blood-Based Biomarkers: A Cross-Sectional Analysis

Visceral adipose tissue (VAT)—fat stored deep in the abdominal cavity that surrounds vital organs—is associated with a variety of chronic health conditions. Computed tomography and magnetic resonance imaging are the gold standards to quantify VAT. However, the high cost, limited accessibility, and potential exposure to radiation limit the use of these imaging modalities. In this commentary, we review the application of a previously validated regression equation that estimates anthropometrically predicted VAT (apVAT) to explain variance in blood-based biomarkers and predict mortality in a large sample of adults. In our first study (Brown et al. 2018 Eur J Nutr; doi:10.1007/s00394-016-1308-8), apVAT accounted for more variance in biomarkers of glucose homeostasis, inflammation, and lipid metabolism, than body mass index (BMI), waist circumference (WC), or the combination of BMI + WC. In our second study (Brown et al. 2017 Am J Hum Biol; doi:10.1002/ajhb.22898), compared with BMI, WC, and BMI + WC, apVAT more accurately predicted mortality from all causes, cardiovascular disease, and cancer. These studies demonstrate that apVAT can be used in clinical practice and in clinical nutrition and metabolism research when imaging modalities to quantify VAT may not be feasible.

Famine exposure in early life is associated with visceral adipose dysfunction in adult females

PURPOSE

Epidemiologic studies have revealed that early life malnutrition increases later risk of metabolic diseases. The visceral adiposity index (VAI) is a novel sex-specific index that shows promise as a marker of visceral adipose dysfunction. We aimed to explore whether exposure to the Chinese famine between 1959 and 1962 during fetal and childhood periods was related to VAI in adulthood.

METHODS

Our data source was SPECT-China, a population-based cross-sectional study in East China. Overall, 5295 subjects from 16 sites were divided into fetal-exposed (1959-1962), childhood-exposed (1949-1958), adolescence/young adult-exposed (1921-1948), and non-exposed (1963-1974) groups. The associations of life periods when exposed to famine with VAI were assessed via linear regression.

RESULTS

Compared with the non-exposed women (1963-1974), the fetal- and the childhood-exposed women had significantly greater VAI values (P < 0.05), but this difference was not observed in men. In the fetal- and childhood-exposed women, there was a significant positive association of famine exposure with VAI after adjusting for age, current smoking, rural/urban residence, and economic status (both P < 0.05). Further adjustments for diabetes and hypertension did not attenuate this association (both P < 0.05). However, such association was not observed in men.

CONCLUSIONS

Exposure to famine in early life may have a significant association with visceral adipose dysfunction in adult females. The fetal age and childhood may be important time windows for nutrition relief to prevent visceral adipose dysfunction.