Comparison of Visceral Fat Measures with Cardiometabolic Risk Factors in Healthy Adults

Association between body mass index (BMI) and [123I]Ioflupane (DaTSCAN) availabilities in patients with parkinsonism using single-photon emission computed tomography-computed tomography (SPECT-CT)

AIM

[123I]Ioflupane (DaTSCAN) has a high binding affinity to the dopamine (DA) transporter (DaT) and tenfold less affinity to serotonin (5-HT) transporter (SERT). Both neurotransmitters are considered to contribute to body weight regulation. This study assesses the association between body mass index (BMI) and DaTSCAN availability in brain.

METHOD

Scans from 74 consecutive patients who had undergone DaTSCAN single-photon emission computed tomography-computed tomography (SPECT-CT) were used to obtain semi- and absolute quantitative data in several volumes of interest (VOIs). Relative semi-quantitative specific binding ratios (SBRs) from Chang attenuated SPECT were obtained from GE DaTQUANT. Absolute normalised concentration (NC) was calculated from attenuation/scatter corrected SPECT-CT images, using an adapted version of the EARL Ltd (European Association of Nuclear Medicine (EANM) Research 4 Life) template. Scans were subdivided into either degenerative parkinsonism (abnormal = 49), borderline (n = 14) or scan without evidence of dopaminergic deficit (SWEDD = 11) using visual assessment and SBR values by two nuclear medicine consultants.

RESULTS

SBRs did not correlate with BMI. However, NC values correlated negatively in the entire cohort, with the strongest correlation in the frontal (r = - 0.649. p = 0.000), occipital (r = - 0.555, p = 0.000) regions and pons (r = - 0.555, p = 0.000). In the abnormal (n = 49) and SWEDD group (n = 11), NC of the frontal region was the most correlated with BMI (r = - 0.570, p = 0.000; r = - 0.813, p = 0.002, respectively). In the borderline group (n = 14), the left posterior putamen displayed the strongest correlation (r = - 0.765, p = 0.001).

CONCLUSION

Absolute NC values demonstrate a strong inverse correlation with BMI, strongest in the extrastriatal regions. Due to the predominately non-overlapping distribution of DaT and SERT, this study suggests greater involvement of SERT in obesity with possible interplay with DA transmission.

Exploring the Diversity of Visceral, Subcutaneous and Perivascular Adipose Tissue in a Vascular Surgery Population

The prevalence of obesity has doubled, with a concomitant increase in cardiovascular disease. This study aimed to compare the characteristics of visceral, subcutaneous and peri-aortic adipose tissue determined with computed tomography (CT) scans and to correlate them with cardiovascular risk factors, anthropometric measures and medication. An observational and prospective study was conducted, and 177 subjects were included. Peri-aortic adipose tissue had the highest density, while the subcutaneous adipose tissue had the lowest. The density of subcutaneous adipose tissue differs from the density of visceral (p = 0.00) and peri-aortic adipose tissue (p = 0.00). Smokers/ex-smokers had a lower area (p = 0.00) and density (p = 0.02) of subcutaneous adipose tissue. Multiple linear regression analysis showed that sex was a predictor of subcutaneous adipose tissue area (β = -0.27, t = -3.12, p = 0.00) but smoking habits were not. After controlling for sex, we found that the association between smokers/ex-smokers and area of subcutaneous adipose tissue was lost, but the association with density persisted. Patients with hypertension had a higher visceral adipose tissue area, and this relationship was maintained even after adjusting for gender. Peri-aortic adipose tissue is similar to visceral and distinct from subcutaneous adipose tissue. Cardiovascular risk factors have different influences in distinct adipose compartments.

Development of automated segmentation of visceral adipose tissue in computed tomography

PURPOSE

Imaging modalities such as computed tomography (CT) or magnetic resonance imaging have been used to measure adiposity. However, manual segmentation of visceral adipose tissue (VAT) in the entire abdomen is laborious and time-consuming. We aimed to develop a new method for accurate visceral fat segmentation by automatically dividing the three anatomical compartments of the lung, soft tissue, and post-vertebral spaces.

METHODS

To automatically separate visceral fat, a three-step process was performed that sequentially divided tissues and regions in a three-dimensional CT image. Manual segmentation was performed in 99 individuals who underwent 18-fluoro-2-deoxyglucosepositron emission tomography/CT for cancer screening between January 2010 and December 2018 to validate the automated segmentation. The similarity index and Pearson's correlation analysis were performed to compare automated segmentation with manual segmentation. Clinical data, such as weight, height, and glucose and insulin levels, were measured. Pearson's correlation analysis was performed to investigate the association between the two methods.

RESULTS

VAT volume of automated segmentation (3,594.6 ± 1,776.5 cm³) strongly correlated with that of manual segmentation (3,375.7 ± 1567.5 cm³) (r = 0.9676, p < 0.0001). The similarity index positively correlated with the VAT volume (r = 0.6396, p < 0.0001) and negatively correlated with the mean Hounsfield units (HU) (r = -0.4328, p < 0.0001). Bland-Altman plots are presented with 5.1 % for VAT volume and 7.1 % for mean HU were outside 1.96 standard deviation from the mean value.

CONCLUSION

We developed an automated segmentation method for VAT in the entire abdomen. This automated segmentation method is feasible for measuring the VAT volume and VAT HU. This method could be employed in daily clinical practice to provide more detailed information about VAT.

The role of metabolic syndrome in sudden cardiac death risk: Recent evidence and future directions

Metabolic syndrome (MetS) is a frequent condition whose deleterious effects on the cardiovascular system are often underestimated. MetS is nowadays considered a real pandemic with an estimated prevalence of 25% in general population. Individuals with MetS are at high risk of sudden cardiac death (SCD) as this condition accounts for 50% of all cardiac deaths in such a population. Of interest, recent studies demonstrated that individuals with MetS show 70% increased risk of SCD even without previous history of coronary heart disease (CHD). However, little is known about the interplay between the two conditions. MetS is a complex disease determined by genetic predisposition, unhealthy lifestyle and ageing with deleterious effects on different organs. MetS components trigger a systemic chronic low-grade pro-inflammatory state, associated with excess of sympathetic activity, cardiac hypertrophy, arrhythmias and atherosclerosis. Thus, MetS has an important burden on the cardiovascular system as demonstrated by both preclinical and clinical evidence. The aim of this review is to summarize recent evidence concerning the association between MetS and SCD, showing possible common aetiological processes, and to indicate prospective for future studies and therapeutic targets.

HELICAL COMPUTERIZED TOMOGRAPHY CAN MEASURE SUBCUTANEOUS, VISCERAL AND TOTAL FAT AREAS?

Background:

Abdominal obesity or android obesity, that is, the increase in adipose tissue in the abdominal region, is considered a risk factor for several morbidities. Different ways of quantifying it have been proposed, one method is the measurement of the abdominal fat area by computed tomography.

Aim:

To establish correspondence between the groups defined by degree of obesity in relation to the total, subcutaneous and visceral fat area.

Methods:

Cross-sectional observational study carried out through the analysis of tomographic examinations. Horos v3.3.5 medical image visualization software was used, with abdominal tomography in a single cut including the L4 vertebral body and the umbilical scar, to obtain the areas of total, visceral and subcutaneous fat.

Results:

Of the 40 patients, 10 had grade II obesity, 23 grade III and 7 superobese. The amount of total fat showed an increase in relation to the degree of obesity. Visceral fat did not show significant differences between the degrees of obesity, but the data showed a lower average in the group of obesity grade II. The area of subcutaneous fat, as well as total fat, showed an increase in its measurements, according to the progression of the patients’ BMI, but there was no statistical significance in this difference between the groups of grade II and super-obese individuals.

Conclusion:

The area of total and subcutaneous fat showed an increase in its measurements according to the progression of the BMI groups, which did not happen with visceral fat.

Association between visceral adipose tissue volume, measured using computed tomography, and cardio-metabolic risk factors

We evaluated the associations between metabolic parameters with visceral adipose tissue (VAT) volume in women with prediabetes or type 2 diabetes (T2DM), and we compared the VAT volume with the VAT area. We enrolled women aged > 20 years with prediabetes or T2DM, who underwent oral glucose tolerance test and whose VAT was evaluated using computed tomography (CT) at our institution between 2017 and 2019. All participants underwent unenhanced spiral CT with a 3-mm slice thickness from the level of the diaphragm to the level of the mid-thigh. The two VAT areas were defined as the free drawn area on the levels of the umbilicus and L2 vertebra. The VAT areas were also manually drawn from the level of the diaphragm to the level of the pelvic floor and were used to calculate the VAT volumes by summing all areas with a slice thickness of 3 mm after setting the attenuation values from -45 to -195 Hounsfield Unit. All metabolic characteristics, except blood pressure, were significantly correlated with the VAT volume. The VAT areas measured at the level of the L2 vertebra and umbilicus were correlated with serum triglyceride, high-density lipoprotein cholesterol, and Framingham steatosis index alone. Multivariable regression analyses revealed that the VAT volume was significantly associated with several metabolic parameters. In conclusion, in women with prediabetes and T2DM, the VAT volume acquired from CT-based calculation has more significant correlations with metabolic risk factors compared with the VAT area.

Is relative fat mass (RFM) a better indicator of high blood pressure levels when compared to other anthropometric indexes?

BACKGROUND

relative fat mass (RFM) has been proposed recently, and the effectiveness in relation to other anthropometric indexes already consolidated regarding the predictive capacity of high blood pressure levels (HBPL) has not been investigated yet.

OBJECTIVES

the objective was to analyze the predictive capacity of RFM for HBPL, and to compare it with others indexes.

METHODS

a cross-sectional study was conducted with 896 individuals. Weight, height, hip, waist circunference (WC), and neck circunference measurements were evaluated, and RFM, body mass index (BMI), body adiposity index, waist/hip ratio, and waist/height ratio were calculated. Systolic (SBP) and diastolic (DBP) blood pressures were measured on one occasion. Descriptive statistics, Pearson's correlation, a logistic regression model, and the analysis of the receiver operating characteristic (ROC) curves were used.

RESULTS

HBPL proportion was higher in men (34.68 %, p < 0.01). There was a positive correlation (p < 0.01) between all anthropometric measurements and SBP and DBP. WC in males (OR, 3.66; p < 0.01) and BMI in females (OR, 5.06; p < 0.01) showed the greatest associations with HBPL. There was no statistical difference (p > 0.05) in the area under the curve.

CONCLUSIONS

the findings of our study suggest that RFM is not the best index for predicting HBPL, although it has shown positive associations.

Association between the Frequency of Daily Toothbrushing and Development of Nonalcoholic Fatty Liver Disease

Background &amp; Aim: This study aimed to evaluate the association between the frequency of daily toothbrushing and the development of nonalcoholic fatty liver disease (NAFLD).

METHODS

A retrospective longitudinal study was conducted from 2005 to 2012 at the Center for Preventive Medicine at St. Luke's International Hospital, Japan. Data on all participants who underwent a health checkup during the study period were collected. NAFLD was diagnosed by abdominal ultrasonography, and all participants who were diagnosed with NAFLD at the time of their initial visit, consumed alcohol in any amount, or had received only one health checkup were excluded. The questionnaire for the frequency of daily toothbrushing was conducted as part of health checkups. The primary outcome was the risk of developing NAFLD according to the frequency of daily toothbrushing (1-2 times a day or 3 times a day) compared to those who brush teeth once or less than once a day.

RESULTS

Data were collected from 25,804 people. A total of 3,289 (12.7%) participants developed NAFLD. The mean age was 45.2 years, and 6,901 (26.7%) of the participants were male. The risk of developing NAFLD significantly decreased with increased frequency of daily toothbrushing. Adjusted odds ratios (ORs) are as follows: brushing teeth 1-2 times a day (OR: 0.85, 95% confidence interval [CI]: 0.77-0.95) and 3 times a day (OR: 0.74, 95% CI: 0.67-0.82).

CONCLUSION

Frequent toothbrushing was shown to significantly reduce the risk of developing NAFLD.

Extended Ketogenic Diet and Physical Training Intervention in Military Personnel

INTRODUCTION

Ketogenic diets (KDs) that elevate ketones into a range referred to as nutritional ketosis represent a possible nutrition approach to address the emerging physical readiness and obesity challenge in the military. An emerging body of evidence demonstrates broad-spectrum health benefits attributed to being in nutritional ketosis, but no studies have specifically explored the use of a KD in a military population using daily ketone monitoring to personalize the diet prescription.

MATERIALS AND METHODS

To evaluate the feasibility, metabolic, and performance responses of an extended duration KD, healthy adults (n = 29) from various military branches participated in a supervised 12-wk exercise training program. Fifteen participants self-selected to an ad libitum KD guided by daily measures of capillary blood ketones and 14 continued their normal mixed diet (MD). A battery of tests were performed before and after the intervention to assess changes in body mass, body composition, visceral fat, liver fat, insulin sensitivity, resting energy metabolism, and physical performance.

RESULTS

All KD subjects were in nutritional ketosis during the intervention as assessed by daily capillary beta-hydroxybutyrate (βHB) (mean βHB 1.2 mM reported 97% of all days) and showed higher rates of fat oxidation indicative of keto-adaptation. Despite no instruction regarding caloric intake, the KD group lost 7.7 kg body mass (range -3.5 to -13.6 kg), 5.1% whole-body percent fat (range -0.5 to -9.6%), 43.7% visceral fat (range 3.0 to -66.3%) (all p < 0.001), and had a 48% improvement in insulin sensitivity; there were no changes in the MD group. Adaptations in aerobic capacity, maximal strength, power, and military-specific obstacle course were similar between groups (p > 0.05).

CONCLUSIONS

US military personnel demonstrated high adherence to a KD and showed remarkable weight loss and improvements in body composition, including loss of visceral fat, without compromising physical performance adaptations to exercise training. Implementation of a KD represents a credible strategy to enhance overall health and readiness of military service members who could benefit from weight loss and improved body composition.

Development and Validation of a Risk Scoring System Derived from Meta-Analyses of Papillary Thyroid Cancer

BACKGROUND

The aim of this study was to develop a scoring system to stratify the risk of papillary thyroid cancer (PTC) and to select the proper management.

METHODS

We performed a systematic search of MEDLINE and Embase. Data regarding patients' prognoses were obtained from the included studies. Odds ratios (ORs) with statistical significance were extracted from the publications. To generate a risk scoring system (RSS), ORs were summed (RSS1), and summed after natural-logarithmic transformation (RSS2). RSS1 and RSS2 were compared to the eighth edition of the American Joint Committee on Cancer (AJCC) staging system and the 2015 American Thyroid Association (ATA) guidelines for thyroid nodules and differentiated thyroid carcinoma.

RESULTS

Five meta-analyses were eligible for inclusion in the study. Eight variables (sex, tumour size, extrathyroidal extension, BRAF mutation, TERT mutation, histologic subtype, lymph node metastasis, and distant metastasis) were included. RSS1 was the best of the analysed models.

CONCLUSION

We developed and validated a new RSS derived from previous meta-analyses for patients with PTC. This RSS seems to be superior to previously published systems.

Non-alcoholic fatty liver disease in lean individuals

Non-alcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease, encompassing a spectrum from non-alcoholic fatty liver to non-alcoholic steatohepatitis, which can progress to cirrhosis. It has recently been recognised that NAFLD also occurs in individuals who are not obese, especially in Asian populations. In these patients, NAFLD manifests at lower overall body mass index thresholds in the presence of increased visceral adipose tissue. Currently, the principles of clinical management are similar to those in obese individuals, although, in specific regions and clinical situations, unique aetiologies of NAFLD must be treated specifically.

The Effect of Obesity on the Availabilities of Dopamine and Serotonin Transporters

The authors investigated relations between obesity, age, and sex and the availabilities of striatal dopamine transporter (DAT) and extrastriatal serotonin transporter (SERT) by ¹²³I-FP-CIT single-photon emission computed tomography. The study population consisted of 192 healthy controls with screening ¹²³I-FP-CIT scans. Specific bindings of ¹²³I-FP-CIT to DAT and SERT were calculated using regions of interest. Specific binding ratios (SBRs) of DAT and SERT except pons (r = 0.2217, p = 0.0026), were not correlated with body mass index (BMI). SBRs of midbrains correlated negatively with the BMIs of obese subjects (r = −0.3126, p = 0.0496), and positively with the those of non-obese subjects (r = 0.2327, p = 0.0053). SBRs of caudate nucleus (r = −0.3175, p < 0.0001), striatum (r = −0.226, p = 0.0022), and thalamus (r = −0.1978, p = 0.0074) reduced with age, and SERT availability was higher in males. However, DAT availability was similar in males and females. In conclusion, obesity has an effect on midbrain SERT availability. In addition, BMI was correlated with pontine SERT availability but not with striatal DAT availability. SERT availability was higher in males, but DAT availability showed no gender predilection.

Influence of Contrast Administration on Computed Tomography-Based Analysis of Visceral Adipose and Skeletal Muscle Tissue in Clear Cell Renal Cell Carcinoma

BACKGROUND

Computed tomography (CT) scans are being utilized to examine the influence of skeletal muscle and visceral adipose quantity and quality on health-related outcomes in clinical populations. However, little is known about the influence of contrast administration on these parameters.

METHODS

Precontrast, arterial, and 3-minute postcontrast CT images of 45 patients with clear cell renal cell carcinoma were downloaded from The Cancer Imaging Archive and retrospectively analyzed for visceral adipose cross-sectional area (CSA) and density, and muscle CSA and density at the third lumbar vertebrae. Low muscle CSA index was defined as ≤38.9 cm² /m² for women and ≤55.4 cm² /m² for men. Low muscle density was defined as <41 Hounsfield units (HU) for body mass index (BMI) <24.9 kg/m² and <33 HU for BMI ≥25.0 kg/m² .

RESULTS

In both the arterial and 3-minute phases, contrast administration decreased visceral adipose CSA (-20.9 and -20.9 cm² ; P < .001) and increased visceral adipose density (4.8 and 5.8 HU; P < .001), relative to precontrast images. Muscle CSA index marginally increased in the arterial (0.6 cm² /m² ; P = .007) and 3-minute phases (0.8 cm² /m² ; P < .001). This likely represents clinically insignificant changes because it does not alter the identification of low muscle CSA (44.4% vs 42.2%; P = 1.00). Skeletal muscle density increased in the arterial (6.4 HU; P < .001) and 3-minute phases (8.7 HU; P < .001), which altered the identification of low muscle density (6.7% vs 31.1%; P < .001).

CONCLUSIONS

Future analyses should consider the phase of contrast during CT imaging because it may alter the interpretations of several parameters.

Is Fat Mass Accretion of Late Preterm Infants Associated with Insulin Resistance?

BACKGROUND

Late preterm infants show a major fat mass accretion from birth to term. The contribution of preterm birth to the development of the metabolic syndrome is still under investigation.

OBJECTIVES

To evaluate body composition changes in late preterm infants during the first 3 months and to investigate their insulin sensitivity and resistance.

METHODS

We conducted an observational, longitudinal study. A total of 216 late preterm infants underwent body composition assessment using an air displacement plethysmograph at term and at 3 months of corrected age. In a subgroup of infants (n = 48) the blood glucose and insulin concentration were determined at term and insulin resistance (homeostasis model assessment for insulin resistance; HOMA-IR) and sensitivity (quantitative insulin sensitivity check index; QUICKI) were then calculated. The reference group comprised 71 healthy term infants.

RESULTS

The mean birth weight and gestational age were 2,390 ± 391 g and 35.2 ± 0.8 weeks, respectively. At term the fat mass index (kg/m2) of late preterm infants, born adequate for their gestational age and small for their gestational age, was higher than that of term infants (2.08 ± 0.82 vs. 1.62 ± 0.64 vs. 1.03 ± 0.36, p < 0.005, respectively), whereas at 3 months of corrected age no difference was found among the groups. The mean values of glucose, insulin, HOMA-IR, and QUICKI were within the 5th and 95th percentiles.

CONCLUSIONS

On the basis of these preliminary findings, fat mass accretion of late preterm infants appears not to be associated with perturbation of the glucose homeostasis.