Subcutaneous and visceral fat assessment by DXA and MRI in older adults and children

Body Composition and Regional Adiposity in Adolescents With Type 1 Diabetes: Relation to Insulin Resistance, Glycaemic Control and Vascular Complications

AIM

Obesity is increasingly recognized among people with type 1 diabetes mellitus (T1DM). Little is known about the body composition of adolescents with T1DM and its metabolic outcomes. Hence, this study assessed the body composition of adolescents with T1DM and its relationship with glycaemic control, insulin resistance and vascular complications.

MATERIALS AND METHODS

One hundred twenty adolescents with T1DM were assessed for anthropometric measures, insulin therapy, bioelectrical impedance analysis (BIA), fasting lipids, glycated haemoglobin, with estimated glucose disposal rate (eGDR) calculation. Regional body fat quantification was performed via Magnetic resonance imaging (MRI) 3-T.

RESULTS

Thirty-three adolescents with T1DM were overweight (27.5%), and 8 were obese (6.6%). Adolescents with T1DM having insulin resistance were found to have significantly higher BMI z score, total body fat %, and visceral/subcutaneous fat % than those without insulin resistance (p < 0.05). Moreover, adolescents with T1DM having microvascular complications showed significantly higher total fat % and visceral/subcutaneous fat % than those without microvascular complications (p < 0.05). Visceral fat % and visceral/subcutaneous fat ratio were positively correlated with waist/hip ratio, eGDR and LDL level (p < 0.05). Waist/hip ratio and eGDR were the most significant independent variables associated with visceral fat % and visceral/subcutaneous fat ratio among adolescents with T1DM using multivariate regression analysis.

CONCLUSIONS

Overweight and visceral adiposity are frequently encountered among the studied adolescents with T1DM. Visceral adiposity is associated with insulin resistance, hyperlipidaemia and microvascular complications among adolescents with T1DM independent of glycaemic control and insulin dosage.

Association between body roundness index and constipation using data from NHANES 2005-2010

Obesity, particularly visceral fat, is a well-established risk factor for various gastrointestinal disorders, including constipation, possibly due to its metabolic and hormonal effects on bowel motility, though the mechanisms remain unclear. The Body Roundness Index (BRI), a novel and reliable anthropometric measure, has been validated as a precise indicator of visceral fat. However, its relationship with constipation remains uncertain. This population-based, cross-sectional study analyzed data from 6,898 participants in the National Health and Nutrition Examination Survey (NHANES, 2005-2010) to assess this association. Binary logistic regression analyses, adjusted for multiple covariates, revealed that higher BRI levels were significantly associated with a lower likelihood of constipation. Participants in the highest quartile had 32% lower odds of constipation than those in the lowest quartile (adjusted OR: 0.68; 95% CI: 0.54-0.86; P: 0.0013). As this was a cross-sectional study, the findings indicate an association between BRI levels and constipation rather than causality. These results suggest that BRI could be a practical and accessible marker for identifying individuals with different susceptibility to constipation, potentially aiding clinical assessment and guiding preventive strategies.

Usefulness of the Córdoba Equation for Estimating Body Fat When Determining the Level of Risk of Developing Diabetes Type 2 or Prediabetes

Background and Objectives: Type 2 diabetes (T2D) and prediabetes represent major global health concerns, with obesity being a key risk factor. However, recent evidence suggests that the adipose tissue composition and distribution play a more critical role in metabolic dysfunction than the total body weight or body mass index (BMI). This study evaluates the predictive capacity of the Córdoba Equation for Estimating Body Fat (ECORE-BF) for identifying individuals at high risk of developing T2D and prediabetes. Materials and Methods: A cross-sectional study was carried out involving 418,343 Spanish workers. Body fat percentage was estimated using the ECORE-BF equation, and diabetes risk was assessed using validated predictive models, including the Finnish Diabetes Risk Score (FINDRISC), QDiabetes score (QD-score), and others. The discriminatory power of ECORE-BF in predicting T2D and prediabetes was assessed using receiver operating characteristic (ROC) curve analysis. Results: ECORE-BF showed a strong correlation with high-risk classifications across all diabetes risk scales. The area under the ROC curve (AUC) exceeded 0.95 for both men and women, demonstrating high predictive accuracy. Conclusions: Adipose tissue distribution, particularly visceral adiposity, is a central factor in metabolic dysfunction. ECORE-BF provides a cost-effective alternative for large-scale T2D and prediabetes risk assessment. Future research should explore the impact of visceral adipose tissue reduction on diabetes prevention and the integration of estimation scales into clinical and public health strategies.

Exploring Visceral Fat as a Screening Marker for Cardiometabolic Risk in Children and Adolescents

Objective: To establish and validate age- and sex-specific visceral fat area (VFA) cutoff values for the effective identification of cardiometabolic risk (CMR) in children and adolescents. Methods: A cross-sectional study involving 8133 participants was conducted to derive age- and sex-specific VFA cutoffs, which were validated in a longitudinal cohort comprising 10,805 individuals. The predictive performance of the derived VFA cutoffs for CMR was evaluated using the area under the receiver operating characteristic curve (AUC). Additionally, logistic regression models were utilized to calculate the relative risk (RR) of CMR associated with elevated VFA levels. Results: The 75th percentile of the VFA was identified as the optimal cutoff for screening for hypertension, hyperglycemia, dyslipidemia, and CMR clustering in boys. In girls, the 75th percentile was optimal for screening hypertension, dyslipidemia, and CMR clustering, while the 80th percentile proved best for hyperglycemia. No significant difference in predicative performance was observed between the optimal and simplified VFA cutoffs. Longitudinal validation demonstrated that individuals exceeding the VFA cutoff had a significantly higher risk for CMR, with RRs ranging from 1.33 to 3.89 (all p < 0.001) for boys and from 1.63 to 3.16 (all p < 0.001) for girls. Notably, normal-weight boys with VFA above the cutoff had a significantly higher CMR risk compared to their peers in other weight status categories. Conclusions: Both the optimal and simplified VFA cutoffs are robust tools for screening CMR in Chinese children and adolescents, with significant implications for early intervention strategies.

A systematic review of observational studies on the association between diet quality patterns and visceral adipose tissue

Beyond obesity, visceral adipose tissue (VAT) has emerged as an important predictor of chronic disease, but the role of diet quality patterns (DQP) in VAT development is not well defined. Therefore, we conducted a systematic review of how various DQP are associated with VAT via literature searches in PubMed and EMBASE. We included observational investigations in disease-free adults/adolescents that related DQP to VAT assessed by imaging methods. The studies were evaluated separately for a priori and a posteriori DQP and according to design differences. Study quality was assessed using the Risk of Bias in Non-randomised Studies of Interventions tool. Of the 1807 screened articles, thirty-five studies met the inclusion criteria. The majority of a priori indices, for example, the Healthy Eating Index, showed significant inverse associations with VAT, while only a small proportion of a posteriori patterns were related to VAT. Results did not differ substantially by the method of exposure and outcome assessment or between studies with (n 20) or without (n 15) body-size adjustment, but significant findings were more common in younger v. older individuals, USA v. other populations and investigations with moderate v. serious risk of bias. The heterogeneity of the existing literature limited the ability to quantify the magnitude of the associations across studies. These findings suggest that a high-quality diet, as assessed by a priori DQP, is generally inversely associated with VAT, but results for a posteriori DQP are less consistent. As associations persisted after adjusting for body size, diet quality may beneficially influence VAT beyond its association with obesity.

Racial-Ethnic Disparities of Obesity Require Community Context-Specific Biomedical Research for Native Hawaiians and Other Pacific Islanders

Compared to the general population of Hawai'i, Native Hawaiians and Other Pacific Islanders (NHPI) shoulder a disproportionately high risk for obesity-related cardiometabolic disorders, such as type 2 diabetes and cardiovascular disease. The gut microbiome is an area of rapid research interest for its role in regulating adjacent metabolic pathways, offering novel opportunities to better understand the etiology of these health disparities. Obesity and the gut microbiome are influenced by regional, racial-ethnic, and community-specific factors, limiting the generalizability of current literature for understudied populations. Additionally, anthropometric and directly measured obesity indices are variably predictive of adiposity and metabolic health risk in this diverse population. Thus, further NHPI-inclusive research is required to adequately characterize community-specific factors in the context of obesity-related disease etiology. Culturally responsible research ethics and scientific communication are crucial to conducting such research, especially among indigenous and understudied populations. In this review, we explore these limitations in current literature, emphasizing the urgent need for NHPI-inclusive research to assess community-specific factors accurately. Such accuracy in Indigenous health research may ensure that findings relevant to individual or public health recommendations and/or policies are meaningful to the communities such research aims to serve.

The Clínica Universidad de Navarra-Body Adiposity Estimator index is a reliable tool for screening metabolic dysfunction-associated steatotic liver disease: an analysis from a gender perspective

BACKGROUND

The Clínica Universidad de Navarra-Body Adiposity Estimator (CUN-BAE) Index, serves as an effective tool for evaluating body fat (BF) levels. This research seeks to clarify the association between the CUN-BAE Index and metabolic dysfunction-associated steatotic liver disease (MASLD) from a gender perspective.

METHODS

The study utilized data from a comprehensive health assessment initiative known as "Human Dock", involving 14,251 participants. MASLD was diagnosed using abdominal ultrasound, primarily evaluated based on the following sonographic features: hepatorenal echo contrast, vascular blurring, deep attenuation, liver brightness. First, we evaluated the association of MASLD with the CUN-BAE Index using multivariate logistic regression. Second, we visualized this association and estimated potential threshold effect points using the restricted cubic spline (RCS) regression model. Ultimately, we evaluated the ability of the CUN-BAE Index to detect MASLD through receiver operating characteristic (ROC) curves.

RESULTS

The female-to-male ratio was 1:1.08, with a MASLD prevalence rate of 17.59%. Following the adjustment for confounding variables, an increase of one unit in the CUN-BAE Index corresponded to a 14% increase in the risk of MASLD for males and an 18% increase for females. RCS analysis revealed an S-shaped relationship between MASLD prevalence and the CUN-BAE Index for both genders, with potential threshold effect points at approximately 30 in females and 15 in males. Beyond these threshold points, the prevalence of MASLD increased rapidly. Further subgroup analyses indicated significant differences in the relationship of the CUN-BAE Index with MASLD within age and body mass index (BMI) subgroups in females, with a stronger association observed in younger and non-obese female participants. Additionally, ROC analysis revealed that the CUN-BAE Index possesses a strong ability to distinguish MASLD in both genders, especially in females.

CONCLUSIONS

This research is the first to identify a positive relationship between the CUN-BAE Index and MASLD. The CUN-BAE Index appears to be more suitable for early screening of MASLD in females.

Effect of Intermittent vs. Continuous Energy Restriction on Visceral Fat: Protocol for The Healthy Diet and Lifestyle Study 2 (HDLS2)

Obesity in the United States and Western countries represents a major health challenge associated with an increased risk of metabolic diseases, including cardiovascular disease, hypertension, diabetes, and certain cancers. Our past work revealed a more pronounced obesity-cancer link in certain ethnic groups, motivating us to develop a tailored dietary intervention called the Healthy Diet and Lifestyle 2 (HDLS2). The study protocol is described herein for this randomized six-month trial examining the effects of intermittent energy restriction (5:2 Diet) plus the Mediterranean dietary pattern (IER + MED) on visceral adipose tissue (VAT), liver fat, and metabolic biomarkers, compared to a standard MED with daily energy restriction (DER + MED), in a diverse participant group. Using MRI and DXA scans for body composition analysis, as well as metabolic profiling, this research aims to contribute to nutritional guidelines and strategies for visceral obesity reduction. The potential benefits of IER + MED, particularly regarding VAT reduction and metabolic health improvement, could be pivotal in mitigating the obesity epidemic and its metabolic sequelae. The ongoing study will provide essential insights into the efficacy of these energy restriction approaches across varied racial/ethnic backgrounds, addressing an urgent need in nutrition and metabolic health research. Registered Trial, National Institutes of Health, ClinicalTrials.gov (NCT05132686).

Predictors of visceral and subcutaneous adipose tissue and muscle density: The ShapeUp! Kids study

BACKGROUND AND AIMS

Body fat distribution, i.e., visceral (VAT), subcutaneous adipose tissue (SAT) and intramuscular fat, is important for disease prevention, but sex and ethnic differences are not well understood. Our aim was to identify anthropometric, demographic, and lifestyle predictors for these outcomes.

METHODS AND RESULTS

The cross-sectional ShapeUp!Kids study was conducted among five ethnic groups aged 5-18 years. All participants completed questionnaires, anthropometric measurements, and abdominal MRI scans. VAT and SAT areas at four lumbar levels and muscle density were assessed manually. General linear models were applied to estimate coefficients of determination (R2) and to compare the fit of VAT and SAT prediction models. After exclusions, the study population had 133 male and 170 female participants. Girls had higher BMI-z scores, waist circumference (WC), and SAT than boys but lower VAT/SAT and muscle density. SAT, VAT, and VAT/SAT but not muscle density differed significantly by ethnicity. R2 values were higher for SAT than VAT across groups and improved slightly after adding WC. For SAT, R2 increased from 0.85 to 0.88 (girls) and 0.62 to 0.71 (boys) when WC was added while VAT models improved from 0.62 to 0.65 (girls) and 0.57 to 0.62 (boys). VAT values were significantly lower among Blacks than Whites with little difference for the other groups.

CONCLUSION

This analysis in a multiethnic population identified BMI-z scores and WC as the major predictors of MRI-derived SAT and VAT and highlights the important ethnic differences that need to be considered in diverse populations.

Standardization of dual-energy x-ray visceral adipose tissue measures for comparison across clinical imaging systems

OBJECTIVE

Excess visceral adipose tissue (VAT) is a major risk factor for metabolic syndrome (MetS) and clinical guidelines have been proposed to define VAT levels associated with increased risk. The aim was to standardize VAT measures between two dual-energy x-ray absorptiometry (DXA) manufacturers who provide different VAT estimates to support standardization of measures across imaging modalities.

METHODS

Scans from 114 individuals (ages 18-81 years) on GE HealthCare (GEHC) and Hologic DXA systems were compared via Deming regression to standardize VAT between the two systems, validated in a separate sample (n = 15), with κ statistics to assess agreement of VAT measurements for classifying patients into risk categories.

RESULTS

The GEHC and Hologic VAT measures were highly correlated and validated in the separate data set (r2  = 0.97). VAT area measures substantially agreed for metabolic risk classification (weighted κ = 0.76) with no significant differences in the population mean values.

CONCLUSIONS

VAT measures can be estimated from GEHC and Hologic scans that classify individuals in a substantially similar way into metabolic risk categories, and systematic bias between the measures can be removed using simple regression equations. These findings allow for DXA VAT measures to be used in complement to other imaging modalities, regardless of whether scans used GEHC or Hologic systems.

Accuracy and Precision of 3-dimensional Optical Imaging for Body Composition by Age, BMI, and Ethnicity

BACKGROUND

The obesity epidemic brought a need for accessible methods to monitor body composition, as excess adiposity has been associated with cardiovascular disease, metabolic disorders, and some cancers. Recent 3-dimensional optical (3DO) imaging advancements have provided opportunities for assessing body composition. However, the accuracy and precision of an overall 3DO body composition model in specific subgroups are unknown.

OBJECTIVES

This study aimed to evaluate 3DO's accuracy and precision by subgroups of age, body mass index, and ethnicity.

METHODS

A cross-sectional analysis was performed using data from the Shape Up! Adults study. Each participant received duplicate 3DO and dual-energy X-ray absorptiometry (DXA) scans. 3DO meshes were digitally registered and reposed using Meshcapade. Principal component analysis was performed on 3DO meshes. The resulting principal components estimated DXA whole-body and regional body composition using stepwise forward linear regression with 5-fold cross-validation. Duplicate 3DO and DXA scans were used for test-retest precision. Student's t tests were performed between 3DO and DXA by subgroup to determine significant differences.

RESULTS

Six hundred thirty-four participants (females = 346) had completed the study at the time of the analysis. 3DO total fat mass in the entire sample achieved R2 of 0.94 with root mean squared error (RMSE) of 2.91 kg compared to DXA in females and similarly in males. 3DO total fat mass achieved a % coefficient of variation (RMSE) of 1.76% (0.44 kg), whereas DXA was 0.98% (0.24 kg) in females and similarly in males. There were no mean differences for total fat, fat-free, percent fat, or visceral adipose tissue by age group (P > 0.068). However, there were mean differences for underweight, Asian, and Black females as well as Native Hawaiian or other Pacific Islanders (P < 0.038).

CONCLUSIONS

A single 3DO body composition model produced accurate and precise body composition estimates that can be used on diverse populations. However, adjustments to specific subgroups may be warranted to improve the accuracy in those that had significant differences. This trial was registered at clinicaltrials.gov as NCT03637855 (Shape Up! Adults).

Subcutaneous Fat Obesity in a High Body Mass Index Donor Is Not a Contraindication to Living Donor Hepatectomy

BACKGROUND

Living donor liver transplantation (LDLT) has revolutionized the field of transplantation without compromising donor safety. Donor safety is of paramount concern to the transplant team. BMI >35 kg/m2 is mostly considered a contraindication to liver donation. Here, we present a successful right donor hepatectomy from a donor with a BMI of 36.5 kg/m2. Case Summary. A 39-year-old wife donated her right lobe of liver to her 43-year-old husband with nonalcoholic steatohepatitis-related chronic liver disease (CLD). His indications were refractory ascites, hepatic encephalopathy, acute kidney injury, recurrent elbow and urine infections leading to cachexia. She was initially rejected due to a high BMI but failed to lose weight over the next 2 months, and the need for a transplant in her husband was imminent. With no other potential living donors, we decided to proceed with donor evaluation as she had no other comorbidity. We were surprised to find normal liver function tests and a good liver attenuation index (LAI) of +16 on a computed tomography (CT) scan. Magnetic resonance (MR) imaging revealed a fat fraction of 3%. Volumetry confirmed a remnant of 37.9% and a potential graft-to-recipient weight ratio of 1.23. V/S ratio on CT scan (visceral fat area/subcutaneous fat area at L4-level) was <0.4 confirming subcutaneous fat obesity. Both surgeries were uneventful and both donor and recipient recovered well except recipient re-exploration on postoperative day (POD)-1 due to surgical bleeding. The donor was discharged on POD-6 and recipient was discharged on POD-15. At 3 weeks of follow-up, the donor's wound is clean and well-healed, and she is already back to doing her daily life activities without any pain with normal laboratory parameters.

CONCLUSION

Subcutaneous fat obesity should not be considered as a contraindication to liver donation even with a BMI >35 kg/m2. A small percentage of healthy individuals will not have visceral fat obesity and may not have steatotic livers. The CT scan and MR fat fraction estimation can confirm the findings. Biopsy may be avoided if MR fat estimation is <10% in obese donors. Intraoperative visualization in these donors remains the gold standard to decide the need for biopsy. Living donor hepatectomy may be safely performed in a select group of high BMI patients (>35 kg/m2) with pure subcutaneous fat obesity in the absence of other suitable living donors.

Smartphone prediction of skeletal muscle mass: model development and validation in adults

BACKGROUND

Skeletal muscle is a large and clinically relevant body component that has been difficult and impractical to quantify outside of specialized facilities. Advances in smartphone technology now provide the opportunity to quantify multiple body surface dimensions such as circumferences, lengths, surface areas, and volumes.

OBJECTIVES

This study aimed to test the hypothesis that anthropometric body measurements acquired with a smartphone application can be used to accurately estimate an adult's level of muscularity.

METHODS

Appendicular lean mass (ALM) measured by DXA served as the reference for muscularity in a sample of 322 adults. Participants also had digital anthropometric dimensions (circumferences, lengths, and regional and total body surface areas and volumes) quantified with a 20-camera 3D imaging system. Least absolute shrinkage and selection operator (LASSO) regression procedures were used to develop the ALM prediction equations in a portion of the sample, and these models were tested in the remainder of the sample. Then, the accuracy of the prediction models was cross-validated in a second independent sample of 53 adults who underwent ALM estimation by DXA and the same digital anthropometric estimates acquired with a smartphone application.

RESULTS

LASSO models included multiple significant demographic and 3D digital anthropometric predictor variables. Evaluation of the models in the testing sample indicated respective RMSEs in women and men of 1.56 kg and 1.53 kg and R2's of 0.74 and 0.90, respectively. Cross-validation of the LASSO models in the smartphone application group yielded RMSEs in women and men of 1.78 kg and 1.50 kg and R2's of 0.79 and 0.95; no significant differences or bias between measured and predicted ALM values were observed.

CONCLUSIONS

Smartphone image capture capabilities combined with device software applications can now provide accurate renditions of the adult muscularity phenotype outside of specialized laboratory facilities. Am J Clin Nutr 2023;x:xx. This trial was registered at clinicaltrials.gov as NCT03637855 (https://clinicaltrials.gov/ct2/show/NCT03637855), NCT05217524 (https://clinicaltrials.gov/ct2/show/NCT05217524), and NCT03771417 (https://clinicaltrials.gov/ct2/show/NCT03771417).

Monitoring body composition change for intervention studies with advancing 3D optical imaging technology in comparison to dual-energy X-ray absorptiometry

BACKGROUND

Recent 3-dimensional optical (3DO) imaging advancements have provided more accessible, affordable, and self-operating opportunities for assessing body composition. 3DO is accurate and precise in clinical measures made by DXA. However, the sensitivity for monitoring body composition change over time with 3DO body shape imaging is unknown.

OBJECTIVES

This study aimed to evaluate the ability of 3DO in monitoring body composition changes across multiple intervention studies.

METHODS

A retrospective analysis was performed using intervention studies on healthy adults that were complimentary to the cross-sectional study, Shape Up! Adults. Each participant received a DXA (Hologic Discovery/A system) and 3DO (Fit3D ProScanner) scan at the baseline and follow-up. 3DO meshes were digitally registered and reposed using Meshcapade to standardize the vertices and pose. Using an established statistical shape model, each 3DO mesh was transformed into principal components, which were used to predict whole-body and regional body composition values using published equations. Body composition changes (follow-up minus the baseline) were compared with those of DXA using a linear regression analysis.

RESULTS

The analysis included 133 participants (45 females) in 6 studies. The mean (SD) length of follow-up was 13 (5) wk (range: 3-23 wk). Agreement between 3DO and DXA (R2) for changes in total FM, total FFM, and appendicular lean mass were 0.86, 0.73, and 0.70, with root mean squared errors (RMSEs) of 1.98 kg, 1.58 kg, and 0.37 kg, in females and 0.75, 0.75, and 0.52 with RMSEs of 2.31 kg, 1.77 kg, and 0.52 kg, in males, respectively. Further adjustment with demographic descriptors improved the 3DO change agreement to changes observed with DXA.

CONCLUSIONS

Compared with DXA, 3DO was highly sensitive in detecting body shape changes over time. The 3DO method was sensitive enough to detect even small changes in body composition during intervention studies. The safety and accessibility of 3DO allows users to self-monitor on a frequent basis throughout interventions. This trial was registered at clinicaltrials.gov as NCT03637855 (Shape Up! Adults; https://clinicaltrials.gov/ct2/show/NCT03637855); NCT03394664 (Macronutrients and Body Fat Accumulation: A Mechanistic Feeding Study; https://clinicaltrials.gov/ct2/show/NCT03394664); NCT03771417 (Resistance Exercise and Low-Intensity Physical Activity Breaks in Sedentary Time to Improve Muscle and Cardiometabolic Health; https://clinicaltrials.gov/ct2/show/NCT03771417); NCT03393195 (Time Restricted Eating on Weight Loss; https://clinicaltrials.gov/ct2/show/NCT03393195), and NCT04120363 (Trial of Testosterone Undecanoate for Optimizing Performance During Military Operations; https://clinicaltrials.gov/ct2/show/NCT04120363).

Genome-wide association study of abdominal MRI-measured visceral fat: The multiethnic cohort adiposity phenotype study

Few studies have explored the genetic underpinnings of intra-abdominal visceral fat deposition, which varies substantially by sex and race/ethnicity. Among 1,787 participants in the Multiethnic Cohort (MEC)-Adiposity Phenotype Study (MEC-APS), we conducted a genome-wide association study (GWAS) of the percent visceral adiposity tissue (VAT) area out of the overall abdominal area, averaged across L1-L5 (%VAT), measured by abdominal magnetic resonance imaging (MRI). A genome-wide significant signal was found on chromosome 2q14.3 in the sex-combined GWAS (lead variant rs79837492: Beta per effect allele = -4.76; P = 2.62 × 10-8) and in the male-only GWAS (lead variant rs2968545: (Beta = -6.50; P = 1.09 × 10-9), and one suggestive variant was found at 13q12.11 in the female-only GWAS (rs79926925: Beta = 6.95; P = 8.15 × 10-8). The negatively associated variants were most common in European Americans (T allele of rs79837492; 5%) and African Americans (C allele of rs2968545; 5%) and not observed in Japanese Americans, whereas the positively associated variant was most common in Japanese Americans (C allele of rs79926925, 5%), which was all consistent with the racial/ethnic %VAT differences. In a validation step among UK Biobank participants (N = 23,699 of mainly British and Irish ancestry) with MRI-based VAT volume, both rs79837492 (Beta = -0.026, P = 0.019) and rs2968545 (Beta = -0.028, P = 0.010) were significantly associated in men only (n = 11,524). In the MEC-APS, the association between rs79926925 and plasma sex hormone binding globulin levels reached statistical significance in females, but not in males, with adjustment for total adiposity (Beta = -0.24; P = 0.028), on the log scale. Rs79837492 and rs2968545 are located in intron 5 of CNTNAP5, and rs79926925, in an intergenic region between GJB6 and CRYL1. These novel findings differing by sex and racial/ethnic group warrant replication in additional diverse studies with direct visceral fat measurements.

The effects of high-intensity interval training and moderate-intensity continuous training on visceral fat and carotid hemodynamics parameters in obese adults

Objectives

The present study aimed to examine the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on visceral fat and hemodynamic parameters in obese adults.

Methods

Fifty-two males were included in this study and divided into three groups: HIIT group (n = 21, age = 20.86 ± 1.62 years, BF (%) = 30.10 ± 5.02), MICT group (n = 22, age = 20.76 ± 1.14 years, BF (%) = 30.19 ± 5.76), and control group (CON) (n = 9, age = 21.38 ± 1.77 years, BF (%) = 30.40 ± 5.10). The HIIT and MICT groups received the exercise intervention three to four times per week for eight weeks (HIIT: exercise intensity 80–95% HRmax, circuit; MICT: exercise intensity 60–70% HRmax, running), and the control (CON) group received health education and guidance without exercise intervention. The body compositions and serum lipid indexes were tested to calculated LAP and VAI. The color doppler ultrasound diagnostic technology was used to test the artery diameter and blood velocity before and after the intervention. Based on the test data, MATLAB software and Womersley theory were used to calculate the hemodynamic parameters of the common carotid artery, including wall shear stress, flow rate, blood pressure, oscillatory shear index, elasticity modulus, dynamic resistance, artery diameter, arterial stiffness, circumferential strain and pulsatility index.

Results

We found that lipid accumulation product (LAP) was significantly decreased in both the HIIT group (p < 0.01) and MICT (p < 0.05) group but not in the CON group (p > 0.05). In contrast, visceral adiposity index (VAI) decreased in both the HIIT and MICT groups and increased in the CON group, although the difference among groups was not significant (p > 0.05). After 8 weeks of intervention, the blood velocity and wall shear stress were greater after HIIT and MICT intervention (p < 0.01). Artery diameter, oscillatory shear index, arterial stiffness, and pulsatility index decreased significantly, and circumferential strain increased significantly in the HIIT group (all, p < 0.01, p < 0.05) but not in the MICT group (p > 0.05). Dynamic resistance was significantly decreased in the MICT group. There was no difference in the CON group after the period of intervention (all, p > 0.05). LAP was positively related to artery diameter (r = 0.48, p = 0.011), blood pressure (r = 0.46, p = 0.002), flow rate (r = 0.31, p = 0.04), oscillatory shear index (r = 0.44, p = 0.03), and elasticity modulus (r = 0.33, p = 0.029) but inversely related to circumferential strain (r = −0.36, p = 0.028). The VAI was also positively associated with artery diameter (r = 0.33, p = 0.03), elasticity modulus (r = 0.38, p = 0.009), and arterial stiffness (r = 0.39, p = 0.012). In addition, the VAI was negatively correlated with the circumferential strain (r = −0.33, p = 0.04).

Conclusion

The present study demonstrated that both HIIT and MICT exercises for 8 weeks could effectively enhance visceral fat indices and partial hemodynamic parameters. Therefore, HIIT and MICT exert important effects on reducing fat content and improving hemodynamic environment. But HIIT on oscillatory shear index, arterial stiffness, circumferential strain, and pulsatility index was superior to MICT. In addition, there are close correlations between visceral fat and partial hemodynamic parameters of the common carotid artery.