Precision of the Hologic DXA in the Assessment of Visceral Adipose Tissue

Long-term depot specific changes in adipose tissue after treatment of acromegaly

CONTEXT

Patients with active acromegaly present a decreased adipose tissue (AT) mass, and short-term studies show that treatment leads to AT depot-specific gain. However, it remains unclear if the increase is persistent in the long-term perspective and/or is sex-dependent.

DESIGN

To characterize the depot-specific changes of AT after treatment of acromegaly and identify contributing factors.

METHODS

Adipose tissue, including visceral (VAT), subcutaneous (SAT), and total (TAT), and android to gynoid ratio (A/G ratio) were measured by dual energy X-ray absorptiometry at diagnosis (n = 62), and after treatment at short-term (median (IQR) 1.9 (1.5-2.3)) and long-term 5.5 (3.9-9.5) years, and correlated to clinical and biochemical measurements. Growth hormone (GH), insulin-like growth factor 1 (IGF-1), glucose and HbA1c levels, gonadal status, and the presence of diabetes mellitus were recorded. Remission status was assessed at the long-term visit (IGF-1/ULN ≤ 1.3). Differences in the temporal course of AT from baseline to short- and long-term follow-up according to sex, diabetes, gonadal, and remission status were evaluated by mixed model analysis, adjusted for age.

RESULTS

Despite a stable body mass index, VAT and A/G ratio increased at both time points, whereas SAT mainly increased at short-term, plateauing afterwards (P < .05 for all). Visceral adipose tissue and A/G ratio were higher in men (P = .035 and P < .001), and the A/G ratio increased more than in women (P = .003). Glucose and HbA1c decreased short-term (P < .05) and remained stable at long-term. The increase in AT depots correlated with the decrease of disease activity at long-term. Remission status had no effect on changes in AT mass during follow-up.

CONCLUSION

Treatment of acromegaly leads to an increase in AT mass in a depot- and sex-specific manner both at short-term and long-term follow-up. Glucose metabolism improves rapidly after disease control and persists.

Visceral adipose tissue increases the risk of periodontal disease: Results from the 2011-2014 National Health and Nutrition Examination Survey and Mendelian randomization analysis

AIM

This study aimed to investigate the relationship and potential causal effect of visceral adipose tissue (VAT) on periodontal disease (PD). Despite prior research on this, there has been no definitive conclusion. Therefore, this study aimed to provide additional insight into these associations.

MATERIALS AND METHODS

This study used data from the National Health and Nutrition Examination Survey 2011-2014 to examine the association between VAT and PD in a cross-sectional study design. Various analytical methods were employed, such as multivariable logistic regression, restricted cubic spline analysis, and p-value for trend. Additionally, two-sample Mendelian randomization (MR) analysis was performed to evaluate the potential causal effect of VAT on PD risk. These methods enabled us to evaluate the association between VAT and PD and to establish whether VAT could be a causal factor in PD development.

RESULTS

The study examined a sample of 3535 participants, and the findings suggested that higher VAT levels were associated with an increased risk of PD. In addition, multivariable regression analysis conducted in six models revealed a statistically significant association between VAT and PD risk. Restricted cubic spline analysis showed an inverted U-shaped association between VAT and PD, with a turning point at 733 g of VAT. Finally, a two-sample MR analysis provided evidence for a potential causal relationship between VAT and PD risk, with an odds ratio of 1.16 (95% confidence interval: 1.02-1.33, p = .027) per kg increase in genetically predicted VAT.

CONCLUSIONS

The results of this study suggest that there is a significant association between VAT and PD and that VAT could be a potential causal factor in PD risk. Our results also suggest that although there is a potential link between VAT levels and PD risk, the effect size is modest. Therefore, interventions designed to reduce VAT levels should not be considered a primary strategy for PD risk reduction but could be one of many strategies used in a comprehensive approach to PD risk management.

Differential Association of Glycation Products with Bone Mineral Density and Fat Mass in Healthy and Diabetes Type 2 Subjects from Mexican Southeastern: A Cross Sectional Study

Background: Glycation products have been linked to decreased bone mineral density (BMD) in a number of clinical settings. This study examined the correlation between early glycation products (HbA1c and glycated albumin (ALB-g)) and advanced glycation end products (pentosidine (PTD)) with BMD in two groups of participants: those with type 2 diabetes mellitus (DM2) and those without diabetes or any other comorbidities (noDM). All of the participants had resided in southeastern Mexico for a minimum of 10 years. Material and Methods: This study included 204 participants: 112 (55%) with DM2 and 92 (45%) healthy subjects. We utilized dual X-ray absorptiometry (DXA) to measure both the total and segment-specific BMD and adipose mass. In addition, the fasting blood glucose, HbA1c, PTD, and ALB-g parameters were measured. Correlation and logistic regression analyses were conducted. Results: There was an inverse correlation between PTD and BMD in all anatomical regions among postmenopausal women (PMW) in the DM2 group, whereas in non-PMW, only the waist-to-height ratio was statistically significant. A negative correlation was observed between HbA1c levels and BMD in the arms and legs of DM2 individuals. However, in the noDM group, a negative correlation was found between HbA1c levels and BMD in the pelvis, while a positive association was observed between HbA1c and indicators of adipose tissue. ALB-g, demonstrated a negative correlation with fat mass. After performing binary logistic regressions, the following odds ratios (OR) for osteopenia/osteoporosis risk were determined: PTD OR 1.1 (p = 0.047) for DM2 PMW, HbA1c OR 1.4 (p = 0.048), and fat mass content OR 1.011 (p = 0.023) for the entire sample. Conclusions: Glycation products are associated with BMD differentially depending on the analyzed anatomical segment, but PTD, HbA1c, and fat mass are significant predictors of low bone mass. In prospective studies, this association could be determined using other techniques involving three-dimensional analysis of bone architecture to evaluate bone architecture.

Visceral Adipose Tissue is Negatively Associated With Bone Mineral Density in NHANES 2011-2018

Context

The relationship of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) with bone mineral density (BMD) is not well established.

Objective

To examine the associations of VAT and SAT with total body BMD in a large, nationally representative population with a wide range of adiposity.

Methods

We analyzed 10 641 subjects aged 20 to 59 years in National Health and Nutrition Examination Survey 2011-2018 who had undergone total body BMD and had VAT and SAT measured by dual-energy X-ray absorptiometry. Linear regression models were fitted while controlling for age, sex, race or ethnicity, smoking status, height, and lean mass index.

Results

In a fully adjusted model, each higher quartile of VAT was associated with an average of 0.22 lower T-score (95% CI, -0.26 to -0.17, P < 0.001), whereas SAT had a weak association with BMD but only in men (-0.10; 95% CI, -0.17 to -0.04, P = 0.002). However, the association of SAT to BMD in men was no longer significant after controlling for bioavailable sex hormones. In subgroup analysis, we also found differences in the relationship of VAT to BMD in Black and Asian subjects, but these differences were eliminated after accounting for racial and ethnic differences in VAT norms.

Conclusions

VAT has a negative association with BMD. Further research is needed to better understand the mechanism of action and, more generally, to develop strategies for optimizing bone health in obese subjects.

Effect of Resistance Exercise Order on Cardiovascular Disease Risk Factors in Older Women: A Randomized Controlled Trial

We compared the effects of two specific resistance training (RT) exercise orders on cardiovascular risk factors. Forty-four untrained older women (>60 years) were randomly assigned to three groups: control (CON, n = 15), multi-joint to single-joint (MJ-SJ, n = 14), and single-joint to multi-joint (SJ-MJ, n = 15) exercise orders. Training groups performed a whole-body RT program (eight exercises, 3 × 10−15 repetitions for each exercise) over 12 weeks in 3 days/week. Body fat, triglycerides, total cholesterol, HDL-c, LDL-c, VLDL-c, glucose, IL-6, IL-10, TNF-α, C-reactive protein, total radical-trapping antioxidant (TRAP), advanced oxidation protein products (AOPP), ferrous oxidation-xylenol (FOX), and nitric oxide concentrations (NOx) were determined pre- and post-intervention. Significant interaction group × time (p < 0.05) revealed reducing fat mass and trunk fat and improvements in glucose, LDL-c, IL-10, TNF-α, C-reactive protein, FOX, and AOPP concentrations in both training groups, without differences between them (p > 0.05). The results suggest that 12 weeks of RT, regardless of exercise order, elicit positive adaptations on body fat and metabolic biomarkers similarly in older women.

Antioxidant vitamin supplementation on muscle adaptations to resistance training: A double-blind, randomized controlled trial

OBJECTIVES

The aim of this study was to examine whether antioxidant vitamin supplementation with vitamin C (VitC) and vitamin E (VitE) affects the hypertrophic and functional adaptations to resistance training in trained men.

METHODS

This was a double-blind, randomized controlled trial in which participants were supplemented daily with VitC and VitE ( n = 12) or placebo ( n = 11) while completing a 10-wk resistance training program accompanied by a dietary intervention (300 kcal surplus and adequate protein intake) designed to optimize hypertrophy. Body composition (dual-energy x-ray absorptiometry), handgrip strength, and one-repetition maximum (1-RM), maximal force (F0), velocity (V0), and power (Pmax) were measured in bench press (BP) and squat (SQ) tests conducted before and after the intervention. To detect between-group differences, multiple-mixed analysis of variance, standardized differences, and qualitative differences were estimated. Relative changes within each group were assessed using a paired Student's t test.

RESULTS

In both groups, similar improvements were produced in BP 1-RM , SQ 1-RM SQ, and BP F0 (P < 0.05) after the resistance training program. A small effect size was observed for BP 1-RM (d = 0.53), BP F0 (d = 0.48), and SQ 1-RM (d = -0.39), but not for SQ F0 (d = 0.03). Dominant handgrip strength was significantly increased only in the placebo group (P < 0.05). According to body composition data, a significant increase was produced in upper body fat-free mass soft tissue (FFMST; P < 0.05) in the placebo group, whereas neither total nor segmental FFMST was increased in the vitamin group. Small intervention effect sizes were observed for upper body FFSMT (d = 0.32), non-dominant and dominant leg FFMST (d = -0.39; d = -0.42). Although a significant increase in total body fat was observed in both groups (P < 0.05) only the placebo group showed an increase in visceral adipose tissue (P < 0.05), showing a substantial intervention effect (d = 0.85).

CONCLUSIONS

The data indicated that, although VitC/VitE supplementation seemed to blunt upper body strength and hypertrophy adaptations to resistance training, it could also mitigate gains in visceral adipose tissue elicited by an energy surplus.

The influence of growth hormone on pediatric body composition: A systematic review

BACKGROUND

Growth hormone (GH) affects metabolism and regulates growth in childhood. The most prominent feature of GH deficiency (GHD) in children is diminished height velocity that eventually leads to short stature. In adult-onset GHD, lean body mass (LBM) is reduced, and visceral fat mass (FM) increased. Beneficial effects of GH treatment on body composition in adults with GHD, including an increase in muscle mass and a decrease in FM, are well established. Relatively few studies have investigated the effects of GH treatment on the body composition of pediatric patients with idiopathic or hypothalamic-pituitary disease-associated GH deficiency. This systematic review aimed to summarize available evidence relating to the effects of GH treatment on body composition in children with GHD.

METHODS

The PubMed, Science Direct, Cochrane Trials, and Embase databases, were searched with keywords including "GH", "body composition", "children", and "growth hormone" for English-language articles, published between January 1999 and March 2021. Two reviewers independently evaluated the search results and identified studies for inclusion based on the following criteria: participants had a confirmed diagnosis of GHD (as defined in each study); participants were pediatric patients who were receiving GH or had stopped GH treatment, regardless of whether they were pre- or post-pubertal; the intervention was recombinant human GH (rhGH; somatropin); and outcomes included changes in body composition during or after stopping GH therapy. Data extracted from each study included study quality, study sample characteristics, study interventions, and body composition. Data on fat-free mass and LBM were combined into a single category of LBM.

RESULTS

Sixteen studies reporting changes in body composition (i.e., FM and LBM) associated with GH treatment in children with GHD were identified and included in the review. Collectively, these studies demonstrated that FM decreased, and LBM increased in response to GH replacement therapy.

CONCLUSION

Despite study limitations (i.e., potential effects of diet and physical activity were not considered), we concluded that a periodic body composition assessment is required to ensure that a satisfactory body composition is achieved during GH replacement therapy in children with GHD.

The negative association of lower body fat mass with cardiometabolic disease risk factors is partially mediated by adiponectin

Gluteofemoral fat correlates negatively with a number of cardiometabolic disease risk factors, but the mechanisms involved in these relationships are unknown. The aim of this study was to test the hypothesis that gluteofemoral fat attenuates the risk of cardiometabolic disease by increasing blood adiponectin levels. This was a cross-sectional study in which arm, leg, gluteofemoral, abdominal s.c. and visceral fat levels were measured by dual-energy X-ray absorptiometry in 648 African females. Fasting serum adiponectin, lipid, insulin and plasma glucose levels and blood pressure were measured. Relationships between variables were analysed using multivariable linear regression and structural equation modelling. Adiponectin correlated positively (β = 0.45, P < 0.0001) with gluteofemoral fat in a multivariable regression model that included age, height, and arm, s.c. and visceral fat levels. In further regression models, there was a negative correlation of gluteofemoral fat with fasting glucose (β = -0.28; P < 0.0001) and triglyceride levels (β = -0.29; P < 0.0001) and insulin resistance (HOMA; β = -0.26; P < 0.0001). Structural equation modelling demonstrated that adiponectin mediated 20.7% (P < 0.01) of the association of gluteofemoral fat with insulin resistance and 16.1% (P < 0.01) of the association with triglyceride levels but only 6.67% (P = 0.31) of the association with glucose levels. These results demonstrate that gluteofemoral and leg fat are positively associated with adiponectin levels and that the negative association of lower body fat with insulin resistance and triglyceride levels may partially be mediated by this adipokine. Further studies are required to determine other factors that mediate the effect of lower body fat on cardiometabolic disease risk factors.

Sarcopenic obesity predicts negative health outcomes among older patients with type 2 diabetes: The Ageing and Body Composition of Diabetes (ABCD) cohort study

BACKGROUND AND AIMS

The definition of and diagnostic criteria for sarcopenic obesity (SO) remain unclear, hindering the assessment of its prevalence as well as its clinical relevance to negative health outcomes, especially in diabetic patients, who are more prone to body composition changes. The aim of this study was to investigate the prevalence of SO and its impact on negative health outcomes among elderly patients with type 2 diabetes (T2DM) from the Ageing and Body Composition of Diabetes (ABCD) cohort.

METHODS

This retrospective cohort study included 386 elderly patients with T2DM (177 males and 209 females, mean age of 67.91 ± 6.10 years). SO was defined as the coexistence of sarcopenia defined by the 2019 Asian Working Group for Sarcopenia up-to-date consensus and obesity identified by five alternative measurements as follows: body mass index (BMI)≥28 kg/m² (BMI28), BMI≥25 kg/m² (BMI25), body fat percentage (BF%)≥25% for men or 35% for women, visceral fat area (VFA)≥100 cm², or android fat mass (AF) higher than the sex-specific median. The primary endpoint was all-cause death or fragility fracture, and the secondary endpoint was a composite of cardiovascular diseases (CVDs). Cox proportional hazards regression analysis was used to estimate the association between SO and negative health outcomes.

RESULTS

The prevalence of SO was 0.2% (BMI28), 2.5% (BMI25), 9.8% (AF), and 18.7% (BF% or VFA) among elderly patients with T2DM, according to the different obesity surrogate markers. During a mean follow-up period of 3.46 ± 1.15 years, 50 patients reached the primary endpoint, and 33 patients had incident CVD. SO classified using BF% was significantly associated with the primary endpoint [hazard ratio (HR) = 2.94, 95% CI = 1.25-6.92] and incident CVD (HR = 6.02, 95% CI = 1.56-23.15), even after comprehensive adjustment for bone-, comorbidity-, and diabetes-specific confounding variables. When SO was classified using BMI25, VFA and AF, similar results were found for adverse outcomes. However, SO classified using BMI25 resulted in misclassification of SO for 61 participants, 19 of whom experienced adverse events during follow-up, and SO classified using VFA or AF was not significantly associated with incident CVD.

CONCLUSIONS

SO is not uncommon in geriatric patients with T2DM, and its prevalence varies widely depending on the diverse surrogate indices of body fat excess. Furthermore, SO may be a better independent risk factor for negative health outcomes when classified using BF%.

Effect of high dose vitamin D supplementation on indices of sarcopenia and obesity assessed by DXA among older adults: A randomized controlled trial

BACKGROUND

Hypovitaminosis D is associated with Sarcopenic Obesity (SO), but evidence from randomized Vitamin D 3 (VD3) trials is scarce.

OBJECTIVE

Compare the effect of VD3 supplementation, at two doses, on SO indices at 12 months.

METHODS

Overweight older adults (>65 years) with baseline 25-hydroxyvitamin D (25OHD) of 10-30 ng/mL were recruited in this double-blind, randomized, controlled multicenter trial (clinicaltrial.gov identifier: NCT01315366). All subjects received 1000 mg calcium citrate/day and underwent total body Dual-energy X-ray Absorptiometry for body composition assessment. Low Dose Group (LDG) and High Dose Group (HDG) received 600 IU -Institute of Medicine (IOM) Recommended Dietary Allowance (RDA)- and 3750 IU VD3/day, respectively.

RESULTS

Mean age was 71 ± 4.6 years, 55% females, BMI: 30.2 ± 4.5 Kg/m², and 43% had metabolic syndrome. There were no differences in baseline characteristics between groups. At 12 months, 248 participants had body composition data, 122 in LDG and 126 in HDG. Proportions of patients with diminished muscle mass, muscle strength, and visceral adiposity did not differ between the 2 groups at baseline or 12 months. Similarly, no significant differences were noted in the proportion of patients with SO at study entry (1.8% in LDG vs 1.6% HDG; p = 0.99) and at 12 months (3.7% in LDG vs. 0.9% HDG; p = 0.18) across arms.

CONCLUSIONS

Weekly VD3, at the daily equivalent of 3750 IU/day, did not improve indices of sarcopenia nor adiposity compared to the IOM RDA dose in adults.

Visceral fat and arterial stiffness in youth with healthy weight, obesity, and type 2 diabetes

BACKGROUND AND OBJECTIVES

Visceral fat is associated with increased cardiovascular risk in adults, but studies in youth are limited. We assessed associations between visceral fat and arterial stiffness in youth with healthy weight, obesity and type 2 diabetes and determined whether relationships were independent of clinical estimates of body fatness.

METHODS

This cross-sectional sample included youth ages 10-23 years (67% female, 56% non-black) with healthy weight (body mass index [BMI] = 5th-85th percentile, n = 236), obesity (BMI ≥ 95th percentile, n = 224) and type 2 diabetes (BMI ≥ 95th percentile, n = 145). Visceral fat was assessed via dual-energy X-ray absorptiometry. Carotid-femoral pulse wave velocity (PWV) was assessed via applanation tonometry. Obesity and type 2 diabetes groups were combined for final analyses. Analyses accounted for age, sex, ancestry and mean arterial pressure.

RESULTS

Visceral fat and PWV were greater in youth with obesity versus healthy weight (p < 0.001). In youth with obesity, but not healthy weight, visceral fat was positively associated with PWV (p < 0.001) and was predictive of PWV beyond BMI and waist circumference.

CONCLUSIONS

Visceral fat likely contributes to subclinical cardiovascular complications in youth. Since cardiovascular health tracks from adolescence to adulthood, longitudinal studies in youth with obesity are required to define the role of visceral fat in lifelong cardiovascular disease risk.

Comparison between DXA and MRI for the Visceral Fat Assessment in Athletes

The use of dual-energy X-ray absorptiometry (DXA) may be invalid for assessing athletes with larger bodies, larger lean body mass, and thicker trunks. This study compared the athletes' visceral adipose tissue (VAT) assessed using DXA and magnetic resonance imaging (MRI). Eighty-two Japanese male collegiate athletes from 18 sports participated in this study. VAT was assessed using the dual-energy scan that coincided with the 4th lumbar vertebra. The sum of eight magnetic resonance slices corresponding to the region of the dual-energy scan was used for comparison. The VAT volume was higher with the dual-energy scan than with MRI (difference: 35 cm³, p<0.01). A significant correlation was noted between the volumes measured using both modalities (r=0.88, p<0.01). Magnetic resonance-derived volumes less than 600 cm³ showed a stronger significant correlation with dual-energy-derived volumes. However, magnetic resonance-derived VAT volumes exceeding 600 cm³ were not significantly correlated with dual-energy-derived volumes. In conclusion, VAT volumes derived from DXA were larger and significantly correlated with those derived from MRI across a wide range of values. Methods using DXA for assessing the visceral fat volume may require adjustment to estimate abdominal visceral fat volume in athletes, with care taken when using such methods for heavyweight athletes.

Body composition in individuals with cystic fibrosis

•

BMI is used to characterize nutritional status but may not accurately depict body composition in CF.

•

DXA and bioelectrical impedance are the most commonly used methods for assessing BC.

•

Lower fat-free mass associates with worse pulmonary function and greater CF disease severity.

•

Fat-free mass associates with greater bone mineral density in individuals with CF.

Because nutritional status is intimately linked with pulmonary function and survival, nutrition has been at the mainstay of cystic fibrosis (CF) care. Body Mass Index (BMI) is traditionally used to define nutritional status because of the ease with which it can be calculated, but it has a number of limitations including its inability to differentiate fat mass (FM) from lean body mass (LBM), the latter thought to confer health advantage. A number of tools are available to quantify body composition including dual-energy x-ray absorptiometry (DXA), bioelectrical impedance, MRI, CT, air displacement plethysmography, and stable isotopes, and these have been used to varying degrees in studies of CF. In CF, LBM tends to be lower for a given BMI, particularly at lower BMI. In adults, lower fat-free mass (FFM) correlates with greater CF disease severity, lower pulmonary function and higher inflammatory markers. FFM is also positively associated with greater bone mineral density, while greater FM is associated with greater loss of lumbar spine bone mineral density over 2 years. In youth, LBM is positively associated with pulmonary function. The predictive value of body composition for functional and clinical outcomes and the role of improving LBM on these outcomes remain undefined. With improvements in BMI accompanying highly-effective modulator therapy, closer evaluations of body composition may inform risk for more traditional, non-CF adult outcomes in CF.

Effect of Protein Intake on Visceral Abdominal Fat and Metabolic Biomarkers in Older Men With Functional Limitations: Results From a Randomized Clinical Trial

BACKGROUND

It remains controversial whether high protein diets improve cardiometabolic profile. We investigated whether increasing protein intake to 1.3 g/kg/day in functionally limited older adults with usual protein intake ≤RDA (0.8 g/kg/day) improves visceral fat accumulation and serum cardiovascular risk markers more than the recommended daily allowance (RDA).

METHODS

The Optimizing Protein Intake in Older Men Trial was a placebo-controlled, randomized trial in which 92 functionally limited men, ≥65 years, with usual protein intake ≤RDA were randomized for 6 months to: 0.8 g/kg/day protein plus placebo; 1.3 g/kg/day protein plus placebo; 0.8 g/kg/day protein plus testosterone enanthate 100 mg weekly; or 1.3 g/kg/day protein plus testosterone enanthate 100 mg weekly. In this substudy, metabolic and inflammatory serum markers were measured in 77 men, and visceral adipose tissue (VAT) was assessed using dual-energy x-ray absorptiometry in 56 men.

RESULTS

Treatment groups were similar in their baseline characteristics. Randomization to 1.3 g/kg/day protein group was associated with greater reduction in VAT compared to 0.8 g/kg/day group (between-group difference: -17.3 cm2, 95% confidence interval [CI]: -29.7 to -4.8 cm2, p = .008), regardless of whether they received testosterone or placebo. Changes in fasting glucose, fasting insulin, HOMA-IR, leptin, adiponectin, IL-6, and hs-CRP did not differ between the 0.8 versus 1.3 g/kg/day protein groups regardless of testosterone use.

CONCLUSIONS

Protein intake >RDA decreased VAT in functionally limited older men but did not improve cardiovascular disease risk markers.

CLINICAL TRIALS REGISTRATION NUMBER

NCT01275365.

Cognitive response to testosterone replacement added to intensive lifestyle intervention in older men with obesity and hypogonadism: prespecified secondary analyses of a randomized clinical trial

BACKGROUND

Both obesity and hypogonadism are common in older men which could additively exacerbate age-related declines in cognitive function. However, little is known about the effects of lifestyle intervention plus testosterone replacement therapy in this population.

OBJECTIVES

In this secondary analysis of the LITROS (Lifestyle Intervention and Testosterone Replacement in Obese Seniors) trial, we examined whether testosterone replacement therapy would improve cognitive function when added to intensive lifestyle intervention in older men with obesity and hypogonadism.

METHODS

Eighty-three older, obese hypogonadal men with frailty were randomly assigned to lifestyle therapy (weight management and exercise training) plus testosterone (LT + Test) or lifestyle therapy plus placebo (LT + Pbo) for 6 mo. For this report, the primary outcome was change in the global cognition composite z score. Secondary outcomes included changes in z score subcomponents: attention/information processing, memory, executive function, and language. Changes between groups were analyzed using mixed-model repeated-measures ANCOVAs following the intention-to-treat principle.

RESULTS

Global cognition z score increased more in the LT + Test than in the LT + Pbo group (mean change: 0.49 compared with 0.21; between-group difference: -0.28; 95% CI: -0.45, -0.11; Cohen's d = 0.74). Moreover, attention/information z score and memory z score increased more in the LT + Test than in the LT + Pbo group (mean change: 0.55 compared with 0.23; between-group difference: -0.32; 95% CI: -0.55, -0.09; Cohen's d = 0.49 and mean change: 0.90 compared with 0.37; between-group difference: -0.53; 95% CI: -0.93, -0.13; Cohen's d = 1.43, respectively). Multiple regression analyses showed that changes in peak oxygen consumption, strength, total testosterone, and luteinizing hormone were independent predictors of the improvement in global cognition (R2 = 0.38; P < 0.001).

CONCLUSIONS

These findings suggest that in the high-risk population of older men with obesity and hypogonadism, testosterone replacement may improve cognitive function with lifestyle behaviors controlled via lifestyle intervention therapy.This trial was registered at clinicaltrials.gov as NCT02367105.

Current Applications and Selected Technical Details of Dual-Energy X-Ray Absorptiometry

The application of dual-energy X-ray absorptiometry (DXA) examinations in the assessment of bone mineral density (BMD) in the lumbar spine, hip, and forearm is the basic diagnostic method for recognition of osteoporosis. The constant development of DXA technique is due to the aging of societies and the increasing importance of osteoporosis as a public health problem. In order to assess the degree of bone demineralization in patients with hyperparathyroidism, forearm DXA examination is recommended. The vertebral fracture assessment (VFA) of the thoracic and lumbar spine, performed by a highly-skilled technician, is an interesting alternative to the X-ray examination. The DXA total body examination can be useful in the evaluation of fat redistribution among patients after bariatric surgery, in patients infected with HIV and receiving antiretroviral therapy, and in patients with metabolic diseases and suspected to have sarcopenia. The assessment of visceral adipose tissue (VAT) and detection of abdominal aortic calcifications may be useful in the prediction of cardiovascular events. The positive effect of anti-resorptive therapy may affect some parameters of DXA hip structure analysis (HSA). Long-term anti-resorptive therapy, especially with the use of bisphosphonates, may result in changes in the DXA image, which may herald atypical femur fractures (AFF). Reduction of the periprosthetic BMD in the DXA measurements can be used to estimate the likelihood of loosening the prosthesis and periprosthetic fractures. The present review aims to present current applications and selected technical details of DXA.

Precision of Lunar Dual-energy X-ray Absorptiometry (iDXA) in measuring body composition among colorectal cancer patients and healthy subjects

BACKGROUND & AIMS

High quality and precise methods are needed when monitoring changes in body composition among colorectal cancer (CRC) patients and healthy subjects. The aim of this study was to estimate precision of the Dual-energy X-ray absorptiometry (Lunar iDXA, GE Healthcare software enCORE version 16) in measuring body composition in CRC patients and healthy subjects.

METHODS

Precision error of iDXA in measuring body composition was investigated in the current study. Thirty CRC patients and 30 healthy subjects, including both men and women underwent two consecutive whole-body DXA scan with repositioning. Precision estimates of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) in the abdominal region, and total fat mass (FM), fat-free mass (FFM), lean mass (LM), bone mineral density (BMD) and bone mineral content (BMC) were calculated.

RESULTS

Precision error expressed as coefficient of variation (% CV) of VAT and SAT were estimated to be 3.56% and 3.28% among CRC patients, and 5.30% and 3.46% among healthy subjects. Estimated precision errors for body masses in the total region ranged between 0.49-1.01% and 0.40-0.88% in CRC patients and healthy subjects, respectively. Least significant change (LSC) in VAT mass, SAT mass, FM and LM were 140.9 g, 121.4 g, 637.0 g and 701.0 g, respectively, among CRC patients. Among healthy subjects the LSC in VAT, SAT, FM and LM were 80.93 g, 98.90 g, 484.0 g and 618.0 g, respectively. Only minor and non-significant differences between the two consecutive measurements for each body compartment were observed within both populations, and we found no systematic bias in the distribution of the differences.

CONCLUSION

The Lunar iDXA demonstrated high precision in body composition measurements among both CRC patients and healthy subjects. Hence, iDXA is a useful tool in clinical following-up and interventions targeted towards changes in body composition.

Sex-dependent effects of forced exercise in the body composition of adolescent rats

Determining the body composition during adolescence can predict diseases such as obesity, diabetes, and metabolic syndromes later in life; and physical activity became an effective way to restore changes in body composition. However, current available literature assessing the body composition before, during and after adolescence in female and male rodents by in vivo techniques is scarce. Thus, by using computerized tomography, we aimed to define the baseline of the weight and body composition during the adolescence and young adulthood of female and male Sprague-Dawley rats (on P30, P60 and P90) under standard diet. Then, we determined the effect of 18 days of forced exercise on the body weight and composition during the early adolescence (P27-45). The highest percentual increments in weight, body volume and relative adipose contents occurred during the female and male adolescence. Forced running during the early adolescence decreased weight, body volume and relative adipose delta and increment values in males only. The adolescence of rats is a period of drastic body composition changes, where exercise interventions have sex-dependent effects. These results support a model that could open new research windows in the field of adolescent obesity.

Risk Factors for Low Muscle Mass in a Population-based Prospective Cohort of Brazilian Community-dwelling Older Women: The São Paulo Ageing & Health (SPAH) Study

INTRODUCTION

Sarcopenia is characterized by progressive loss of skeletal muscle mass, which results in decreased muscle strength, functional impairment, and increased risk of death. Few studies have performed a concomitant evaluation of clinical, laboratory, and body composition variables to accurately determine the contribution of each parameter to low muscle mass (LMM) in older subjects. This study aimed to identify risk factors (clinical, laboratory parameters, BMD, and body composition by DXA including visceral fat) for LMM in a prospective cohort of older Brazilian women.

METHODS

A total of 408 women aged ≥65 yr from the São Paulo Ageing & Health study were evaluated with clinical data, laboratory bone tests, BMD, and body composition by DXA using Hologic QDR 4500A equipment. Risk factors were measured at baseline (2005-2007). After a follow-up of 4.3 ± 0.8 yr, subjects were classified according to the LMM definition of the Foundation for the National Institutes of Health criteria. LMM was defined when appendicular lean mass divided by body mass index was less than 0.512. Multivariate logistic regression models were used to identify independent risk factors for LMM.

RESULTS

At the end of follow-up, 116 women (28.4%) had LMM. Age averages were 73.3 ± 4.9 yr in the LMM group and 72.5 ± 4.5 yr in the normal group (p = 0.11). Mean BMI was 30.6 ± 5.2 kg/m² in the LMM group and 28.1 ± 4.7 kg/m² in the normal group (p < 0.001). In multivariate analyses, predictors of LMM were: falls (OR = 1.14, p = 0.016), TSH levels (OR = 1.08, p = 0.018, per 1 μUI/L-increase), serum creatinine levels (OR = 11.11, p < 0.001, per 1 mg/dL-decrease), and visceral adipose tissue (VAT) mass (OR = 1.17, p < 0.001, per 100 g increase).

CONCLUSIONS

Falls, high TSH, low creatinine, and high VAT were risk factors for LMM in older women. More attention should be paid to these factors, since they are potentially reversible with adequate intervention.

Exploring the brain-body composition relationship in Huntington's disease

OBJECTIVE

Changes in body composition are a common feature of Huntington's disease (HD) and are associated with disease progression. However, whether these changes in body composition are associated with degeneration of the striatum is unknown. This study aimed to explore the associations between body composition metrics and striatal brain volume in individuals with premanifest HD and healthy controls.

METHODS

Twenty-one individuals with premanifest HD and 22 healthy controls participated in this cross-sectional study. Body composition metrics were measured via dual-energy X-ray absorptiometry. Structural magnetic resonance imaging of subcortical structures of the brain was performed to evaluate striatal volume.

RESULTS

There were no significant differences in body composition metrics between the premanifest HD and healthy controls group. Striatal volume was significantly reduced in individuals with premanifest HD compared to healthy controls. A significant association between bone mineral density (BMD) and right putamen volume was also observed in individuals with premanifest HD.

CONCLUSION

These findings show striatal degeneration is evident during the premanifest stages of HD and associated with BMD. Additional longitudinal studies are nevertheless needed to confirm these findings.

Optimal Cut-Offs of Body Mass Index and Waist Circumference to Identify Obesity in Chinese Type 2 Diabetic Patients

PURPOSE

The prevalence of general obesity (commonly defined by body mass index (BMI) in kg/m²) and abdominal obesity (commonly assessed by waist circumference (WC)) has increased rapidly in China. The aim of this study was to investigate the diagnostic accuracy of traditional cut-offs for BMI or WC to identify general or abdominal obesity in Chinese type 2 diabetic patients and propose optimal cut-offs.

PATIENTS AND METHODS

BMI and WC were obtained from 1539 type 2 diabetic patients. Body fat percentage and visceral fat area measured by dual-energy x-ray absorptiometry were set as the gold standard to identify general and abdominal obesity. We assessed the diagnostic power of traditional cut-offs for BMI and WC to define obesity, and analyzed receive operating characteristic (ROC) curves to obtain the optimal cut-offs to identify obesity in Chinese type 2 diabetic patients.

RESULTS

In Chinese type 2 diabetic patients, the optimal BMI was 25 kg/m² with the best trade-off between sensitivity and specificity (men: 74.6% (95% CI: 70.7-78.2%) and 65.1% (95% CI: 59.7-70.3%), AUC 0.78 (95% CI: 0.75-0.81), p<0.05; women: 65.8% (95% CI: 60.3-71.0%) and 80.3% (95% CI: 75.7-84.3%), AUC 0.80 (95% CI: 0.77-0.83), p<0.05) in both genders. The optimal WC was 93 cm in men and 90 cm in women with the best trade-off between sensitivity and specificity (men: 87.2% (95% CI: 84.3-89.8%) and 80.2% (95% CI: 74.9-84.8%), AUC 0.91 (95% CI: 0.88-0.92), p<0.05; women: 81.0% (95% CI: 76.9-84.6%) and 88.7% (95% CI: 83.9-92.4%), AUC 0.92 (95% CI: 0.90-0.94), p<0.05).

CONCLUSION

For the Chinese patients with type 2 diabetes, the optimal cut-offs for BMI or WC to identify general or abdominal obesity need to be reconsidered.

Greater Reduction in Abdominal Than in Upper Arms Subcutaneous Fat in 10- to 12-Year-Old Tennis Players: A Volumetric MRI Study

Background: Little is known about the impact of long term participation in sports and subcutaneous fat volume in children. This study aimed at determining whether tennis participation is associated with lower subcutaneous adipose tissue volume (SATv) in the abdominal and upper extremities in children. Methods: Magnetic resonance imaging (MRI) was used to determine the SATv stored in the abdominal region and upper arms in seven tennis players and seven inactive children matched by height and age (147 cm and 10.9 years). All participants were in Tanner stage 1 or 2. Results: Playing tennis was associated with 48% (P = 0.001) lower abdominal SATv and 17-18% (P > 0.05) lower upper arms SATv compared to controls. The ratio between abdominal/upper arms SATv was larger in the controls vs. tennis players (69% P = 0.001). The SATv was similar in the dominant and non-dominant arm within each group. Conclusion: Playing tennis during childhood is associated with reduced SATv in the abdominal region and a more favorable regional distribution of fat. Despite the large amount of contractile activity of the playing (dominant) arm, there was no indication of between-arms differences in SATv.