Body Dual X-ray Absorptiometry Research Articles

Canadian adult reference data for body composition, trabecular bone score and advanced hip analysis using DXA

DXA-derived reference data for visceral adipose tissue (VAT) and advanced hip analysis (AHA) parameters spanning the entire adult lifespan are limited. The purpose of this study was to develop age-, site- and sex-specific reference data for dual X-ray absorptiometry (DXA) -derived body composition, trabecular bone score (TBS) and advanced hip analysis (AHA) parameters across the adult lifespan. Adults (N = 908; female: 561 and male: 347) from Calgary and the surrounding area over the age of 20 years participated in this study. Participants received DXA scans of their hip (total hip [TH] and femoral neck [FN]), lumbar spine [LS], forearm [33 % site] and total body (iDXA, GE Lunar, GE Healthcare). Areal bone mineral density (aBMD, g/cm2) was captured at all sites, and body composition variables, including lean mass, fat mass and percent fat, were analyzed from the total body scan. VAT mass was assessed from total body DXA scans. Advanced hip analysis (AHA) was performed on hip scans and trabecular bone score (TBS) on the LS scans to assess bone quality. Site- and sex-specific centile curves and tables were generated using the Generalized Additive Models for Location, Scale, and Shape (GAMLSS) method. Clinicians and researchers can use these Canadian reference data as a tool to assess body composition, TBS and AHA parameters across the adult lifespan.

Determination of body composition by dual x-ray absorptiometry in persons with haemophilia.

There is limited research on body composition in persons with haemophilia (PwH). The literature describes an increased body fat distribution and decreased lean mass in PwH compared to healthy controls using bioimpedance analysis. Using dual x-ray absorptiometry (DXA), which is known to be the most accurate method, this investigation aims to postulate reference data for body composition parameters within haemophilia severity phenotypes and age groups. Persons underwent whole body DXA screening using Horizon. Body fat percentage, estimated visceral adipose tissue (VAT), appendicular fat and lean mass, and lean and fat mass in relation to body height were assessed. Haemophilia severity and five age groups were distinguished. Two hundred and one persons with mild (n=44), moderate (n=41), or severe (n=116) haemophilia A/B (median age 40 [28-55; 1.IQ-3.IQ] years) were analysed. The median body fat percentage was 28.7% [25.5%-33.9%] and median estimated VAT was 657g [403-954g] with no significant difference between severity phenotypes (p=.474; p=.781). Persons with severe haemophilia had less lean mass compared to moderate and mild haemophilia (p=.013; p=.034). Total and appendicular fat is increased in older PwH (aged ≥40years) compared to younger PwH (aged ≤29years; p<.05). Lean mass did not differ between age groups. This study provides valuable reference data for body composition parameters in PwH. Persons with severe haemophilia show significantly less lean mass compared to persons with moderate or mild haemophilia. Body fat percentage and VAT did not differ between severity phenotypes, but increased with age.

Effects of moderate/vigorous activity on 3-year body composition changes in postmenopausal women: a target trial emulation.

Background and Objective Postmenopausal women tend to experience significant changes in body composition, particularly abdominal adipose tissue (AAT) deposition patterns, which are hypothesized to be critical factors influencing future cardiometabolic disease risk. Physical activity has a demonstrable effect on body composition and overall health. However, there is little evidence for how different intensities and durations of physical activity over a sustained period of time influence AAT patterns and other measures of body composition in postmenopausal women. We emulated a target trial of physical activity interventions, including the 2018 Physical Activity Guidelines for Americans recommendations, on 3-year changes in AAT and body composition. Methods We analyzed observational data from 4,451 postmenopausal women aged 50-79 years in the Women's Health Initiative (WHI) to emulate a three-year target trial of adhering to increasing minutes of moderate (at least 15, 30, 75, 150, 300 minutes/week) and vigorous (at least 15, 30, 75, 150 minutes/week) physical activity aligned with the physical activity guidelines. All participants had repeated whole body Dual X-Ray Absorptiometry (DXA) scans with derived abdominal visceral (VAT) and subcutaneous adipose tissue (SAT). The measured differences in average levels of VAT, SAT, and other body composition measures determined at end of follow-up were estimated with the parametric-g formula. Results Over 3 years, interventions of increasing minutes of moderate activity would result in dose-dependent reductions in abdominal VAT, SAT, and overall body fat, and increases in lean soft tissue, with the greatest estimated benefit at the 2018 physical activity guideline recommendation of 150 mins/wk or more. Compared to no intervention, if all participants had adhered to at least 150 mins/wk of moderate physical activity, they would have 16.8 cm2 lower VAT (95% CI -23.1, -10.4), 26.8 cm2 lower SAT (95% CI -36.3, -17.3), 1.3% lower total body fat% (95% CI -1.8, -0.7), 1.2 % higher total lean soft tissue% (95% CI 0.7, 1.8), and 2.6 kg lower total bodyweight (95% CI -3.6, -1.5). We saw similar patterns in our vigorous-intensity activity interventions - if all participants adhered to at least 150 mins/wk, they would have experienced 6.7 cm2 lower VAT (95% CI -17.7, 4.3), 13.3 cm2 lower SAT (95% CI -28.8, 2.1), 1.0 % lower total body fat percent (95% CI -2.0, 0.0 ), % higher total lean soft tissue percent (95% CI) and a 0.9 kg lower total bodyweight (95% CI -2.7, 0.8). Conclusion This hypothetical emulated intervention indicated that postmenopausal women who adhere to physical activity guideline recommendations would experience beneficial changes in abdominal VAT, SAT, and overall body composition over 3 years. The study results underscore the imperative to explore further how physical activity may serve as a potential determinant of body composition.

P350 Dual x-ray absorptiometry body composition assessment in children and adolescents with cystic fibrosis treated with elexacaftor/tezacaftor/ivacaftor

P350 Dual x-ray absorptiometry body composition assessment in children and adolescents with cystic fibrosis treated with elexacaftor/tezacaftor/ivacaftor

Evaluation of bone mineral density in the population of severe adolescent idiopathic scoliosis by using total body dual x-ray absorptiometry

Evaluation of bone mineral density in the population of severe adolescent idiopathic scoliosis by using total body dual x-ray absorptiometry

Automated body composition estimation from device-agnostic 3D optical scans in pediatric populations

Excess adiposity in children is strongly correlated with obesity-related metabolic disease in adulthood, including diabetes, cardiovascular disease, and 13 types of cancer. Despite the many long-term health risks of childhood obesity, body mass index (BMI) Z-score is typically the only adiposity marker used in pediatric studies and clinical applications. The effects of regional adiposity are not captured in a single scalar measurement, and their effects on short- and long-term metabolic health are largely unknown. However, clinicians and researchers rarely deploy gold-standard methods for measuring compartmental fat such as magnetic resonance imaging (MRI) and dual X-ray absorptiometry (DXA) on children and adolescents due to cost or radiation concerns. Three-dimensional optical (3DO) scans are relatively inexpensive to obtain and use non-invasive and radiation-free imaging techniques to capture the external surface geometry of a patient's body. This 3D shape contains cues about the body composition that can be learned from a structured correlation between 3D body shape parameters and reference DXA scans obtained on a sample population. This study seeks to introduce a radiation-free, automated 3D optical imaging solution for monitoring body shape and composition in children aged 5-17. We introduce an automated, linear learning method to predict total and regional body composition of children aged 5-17 from 3DO scans. We collected 145 male and 206 female 3DO scans on children between the ages of 5 and 17 with three scanners from independent manufacturers. We used an automated shape templating method first introduced on an adult population to fit a topologically consistent 60,000 vertex (60k) mesh to 3DO scans of arbitrary scanning source and mesh topology. We constructed a parameterized body shape space using principal component analysis (PCA) and estimated a regression matrix between the shape parameters and their associated DXA measurements. We automatically fit scans of 30 male and 38 female participants from a held-out test set and predicted 12 body composition measurements. The coefficient of determination (R2) between 3DO predicted body composition and DXA measurements was at least 0.85 for all measurements with the exception of visceral fat on 3D scan predictions. Precision error was 1-4 times larger than that of DXA. No predicted variable was significantly different from DXA measurement except for male trunk lean mass. Optical imaging can quickly, safely, and inexpensively estimate regional body composition in children aged 5-17. Frequent repeat measurements can be taken to chart changes in body adiposity over time without risk of radiation overexposure.

Muscle-to-Bone and Soft Tissue-to-Bone Ratio in Children and Adolescents with Obesity

Objectives: To explore the total and regional muscle-to-bone ratio in children and adolescents with obesity and compare the muscle-to-bone ratio (MBR) and soft tissue-to-bone ratio (SBR) to their peers with normal weight or overweight. Study design: A total of 219 male and female pediatrics (mean age=12.3±2.5 years) participated in this study. Body composition was assessed with a total body dual X-ray absorptiometry. The MBR was calculated by dividing lean mass by bone mineral content. The SBR was determined by dividing the soft tissue mass (i.e., lean mass+fat mass) by bone mineral content. Differences in total and regional body composition measures between body mass index (BMI) percentile groups was assessed by ANOVA. Results: The obesity group had significantly higher MBR compared to the normal weight group for total (19.24±1.56 vs. 18.26±1.64), arm (17.11±1.67 vs. 15.88±1.81), and leg (18.41±1.68 vs. 16.62±1.55). Similarly, the obesity group had significantly higher MBR in the leg (18.41±1.68) compared to the overweight group (17.24±1.45). However, the overweight group was not significantly different from the normal weight or the obesity group for total and arm MBR. The total, arm, and leg SBR was significantly different between all BMI groups. Across the entire sample, MBR and SBR were negatively associated with high-density lipoprotein. SBR was positively associated with insulin, HOMA-IR, low-density lipoprotein, very low-density lipoprotein, triglycerides, and systolic blood pressure. Conclusions: Children with obesity had a higher MBR and SBR compared to their normal weight peers. In addition, there were significant associations between SBR, higher levels of insulin, atherogenic lipoproteins, and increased systolic blood pressure. Thus, SBR may be useful as a marker for increased cardiometabolic disease risk, though more research in this area is warranted.

Dual X-ray absorptiometry-derived total and regional body volume.

Although dual X-ray absorptiometry (DXA) has been used to determine total body volume, using DXA to determine regional (i.e., arm and leg) volumes needs further assessment. Thus, the aim of the present study is to evaluate the validity of total and regional DXA-derived body volume compared to a traditional method for measuring body volume. A total of 30 males and females (Age: 25.9±4.0yrs; Height: 1.75±0.10m; Weight: 70.98±14.02kg) underwent one whole body DXA scan, underwater weighing, and regional measures of volume via water displacement. Manually created DXA region of interest boxes were used to determine regional DXA body composition. Total body volume was calculated by taking the participant's dry weight and dividing it by the average density from underwater weighing. Linear regression models with body volume from underwater weighing for total body volume and water displacement for regional volume as the dependent variable and DXA lean mass, fat mass, and bone mass as independent variables created total and regional DXA-derived body volume. T-tests assessed DXA-derived body volume to the traditional method of body volume assessment. Regression models were cross-validated using the Repeated k-fold Cross Validation method. DXA-derived total body volume was not significantly (p=0.999) different from total body volume measured via total body water displacement. In addition, both arm and leg regional DXA-derived volume was not significantly different (p=0.999) compared to regional volume measured by regional water displacement. Cross-validation of each model produced R2 values of 0.992, 0.923, and 0.932 for total body, arm, and leg, respectively. The DXA may be used as valid method for estimating total and regional body volume. Thus, these results expand the DXA's capabilities and potentially allow for a convenient regional four-compartment model with DXA-derived regional volume.

Associations Between Low Serum Urate, Body Composition, and Mortality.

Controversy remains as to whether low serum urate or uric acid (UA) levels contribute to adverse outcomes. We evaluated the relation between low serum UA levels and sarcopenia and assessed whether sarcopenia confounds associations between these low levels and mortality. We utilized data from the National Health and Nutrition Examination Survey (1999-2006). Participants with available whole-body dual x-ray absorptiometry body composition measurements and serum UA concentrations were included. Body composition assessments included body mass index (BMI), waist circumference, maximum lifetime BMI, and age-, sex-, and race-specific appendicular lean mass index (ALMI) and fat mass index (FMI) Z scores. We also calculated Z scores for ALMI relative to FMI (ALMIFMI ). We evaluated associations between serum UA levels and body composition using logistic regression and assessed associations between serum UA levels and mortality before and after adjusting for differences in body composition using Cox proportional hazards regression. Among the 13,979 participants, low serum UA concentrations (<2.5 mg/dl in women, <3.5 mg/dl in men) were associated with low lean mass (ALMI and ALMIFMI Z scores), underweight BMI (<18.5 kg/m2 ), and higher rates of weight loss. The proportion of patients with low ALMI Z scores was 29% in the low serum UA group and 16% in the normal serum UA group (P=0.001). Low serum UA levels were associated with increased mortality before we adjusted for body composition (hazard ratio 1.61 [95% confidence interval 1.14-2.28]; P=0.008) but was attenuated and not significant after adjustment for body composition and weight loss (hazard ratio 1.30 [95% confidence interval 0.92-1.85], P=0.13). Sarcopenia and weight loss are more common among patients with low serum UA concentrations. Differences in body composition may help to explain associations between low levels of serum UA and higher mortality.

Effects of estradiol on fat in men undergoing androgen deprivation therapy: a randomized trial.

Indirect evidence suggests that the effects of testosterone on fat mass in men are dependent on aromatization to estradiol (E2). However, no controlled study has assessed the effects of E2 in the absence of testosterone. Six-month randomized, placebo-controlled trial with the hypothesis that men randomized to E2 would reduce their fat mass. Seventy-eight participants receiving androgen deprivation therapy for prostate cancer were randomized to 0.9 mg of 0.1% E2 gel per day, or matched placebo. Dual x-ray absorptiometry body composition was measured at baseline, month 3, and month 6. The primary outcome was total fat mass. Serum E2 increased in the estradiol group over 6 months compared to placebo, and mean-adjusted difference (MAD) was 207 pmol/L (95% CI: 123-292), P < 0.001. E2 treatment changed total fat mass, MAD 1007 g (95% CI: 124-1891), but not significantly, so P = 0.09. There were other consistent non-significant trends toward increased proportional fat mass, MAD 0.8% (95% CI: 0.0-1.6), P= 0.15; gynoid fat, MAD 147 g (95% CI: 2-293), P = 0.08; visceral fat, 53 g (95% CI: 1-105) P = 0.13; and subcutaneous fat, MAD 65 g (95% CI: 5-125), P = 0.11. Android fat increased, MAD 164 g (95% CI: 41-286), P = 0.04. Contrary to our hypothesis, we provide suggestive evidence that E2 acting in the absence of testosterone, may increase total and regional fat mass in men. Given the premature closure of clinical trials due to the COVID pandemic, this potentially important observation should encourage additional studies to confirm or refute whether E2 promotes fat expansion in the absence of testosterone.

DXA body composition corrective factors between Hologic Discovery models to conduct multicenter studies.

Dual X-ray absorptiometry body composition measurements are widely used for clinical and research settings. It is well known that measurements vary across instruments, needing caution for longitudinal monitoring or multicentric studies. This study was to quantify intra- and inter-center variability of bone mineral content, bone mineral density, fat and lean body composition measurements between Hologic Discovery models in order to calculate the corrective factors to be applied for multicenter research projects. A whole body phantom composed of materials representing the thickness and percentage of bone, lean and fat mass in the human physiological range was analyzed ten times in three different centers using dual energy X-ray absorptiometry scanners (Two Hologic Discovery QDR A and one QDR W). In addition, we used a morphometric vertebral phantom to monitor stability and a three steps block phantom to check accuracy. We found a good long-term stability and accuracy for the three devices. Intra-center coefficients of variation were within the range of the manufacturer acceptable values (bone mineral density: 1.40%, bone mineral content: 1%, area: 1.50%, fat mass: 0.89%, lean mass: 0.76%, total mass: 0.12%). Whereas the inter-center coefficient of variation exceeded 8% (bone mineral density: 8.18%, bone mineral content: 3.03%, area: 8.63%: fat mass: 3,92%, lean mass: 7.89%, total mass: 2.85%). Our study showed that the discrepancies across centers remain a major concern, particularly with regard to body composition results. Our study highlight the need of cross calibration between densitometers and proposes corrective factors evaluated from a whole body phantom to lead multicentric studies adjustment.

Growing up in Bradford: protocol for the age 7\u201311 follow up of the Born in Bradford birth cohort

BackgroundBorn in Bradford (BiB) is a prospective multi-ethnic pregnancy and birth cohort study that was established to examine determinants of health and development during childhood and, subsequently, adult life in a deprived multi-ethnic population in the north of England. Between 2007 and 2010, the BiB cohort recruited 12,453 women who experienced 13,776 pregnancies and 13,858 births, along with 3353 of their partners. Forty five percent of the cohort are of Pakistani origin. Now that children are at primary school, the first full follow-up of the cohort is taking place. The aims of the follow-up are to investigate the determinants of children’s pre-pubertal health and development, including through understanding parents’ health and wellbeing, and to obtain data on exposures in childhood that might influence future health.MethodsWe are employing a multi-method approach across three data collection arms (community-based family visits, school based physical assessment, and whole classroom cognitive, motor function and wellbeing measures) to follow-up over 9000 BiB children aged 7–11 years and their families between 2017 and 2021. We are collecting detailed parent and child questionnaires, cognitive and sensorimotor assessments, blood pressure, anthropometry and blood samples from parents and children. Dual x-ray absorptiometry body scans, accelerometry and urine samples are collected on subsamples. Informed consent is collected for continued routine data linkage to health, social care and education records. A range of engagement activities are being used to raise the profile of BiB and to disseminate findings.DiscussionOur multi-method approach to recruitment and assessment provides an efficient method of collecting rich data on all family members. Data collected will enhance BiB as a resource for the international research community to study the interplay between ethnicity, socioeconomic circumstances and biology in relation to cardiometabolic health, mental health, education, cognitive and sensorimotor development and wellbeing.

Body Composition and Metabolomics in the Alberta Physical Activity and Breast Cancer Prevention Trial (OR09-02-19)

ObjectivesRecent metabolomics studies have identified metabolic correlates of body mass index (BMI), but the degree to which correlations are driven by fat mass as opposed to lean mass has not been established. Our objectives were to 1) replicate findings of BMI-metabolite correlations, and 2) to describe the contributions of FM and LM to the BMI-metabolite associations. MethodsThe Alberta Physical Activity and Breast Cancer Prevention Trial was a two-center randomized trial of healthy but inactive, postmenopausal women (N = 304). BMI (kg/m2) was calculated using measured weight and height, while whole body dual X-ray absorptiometry estimated fat mass and lean mass. Serum metabolite levels were measured by ultra-performance liquid chromatography and high-resolution/accurate mass spectrometer. We estimated partial Pearson correlations between 1053 metabolites and BMI, adjusting for age, smoking, and study site. Fat mass/m2 and lean mass/m2 correlations were estimated similarly, with mutual adjustment for one another to evaluate independent effects after accounting for their positive intercorrelation. ResultsUsing a Bonferroni-corrected alpha-level <4.75 × 10–5, we observed 39 metabolites correlated with BMI (|r|:0.24–0.42; lowest p-value:7.53 × 10–14), including 25 metabolites that replicate previously-reported associations. Of metabolites correlated with BMI, only 14 were robustly correlated with fat mass/m2 (|r| > 0.20), and five had virtually no fat mass/m2 correlation (|r| < 0.10). Six metabolites were more strongly correlated with lean mass/m2 than with fat mass/m2. When we extended the analysis to all metabolites, we found another eight metabolites that were robustly correlated with fat mass/m2 (|r|:0.24–0.29) and three with lean mass/m2 (r:0.24–0.27) despite no statistically significant correlation with BMI. ConclusionsBMI may be insufficiently specific, in some cases, for studies of the metabolic effects of adiposity. Many BMI-related metabolites are only weakly correlated with fat mass; some are more directly related to lean mass than fat mass. For those metabolites already being studied in relation to disease risk (e.g., branched chain amino acids), our study demonstrates which aspect of body composition may primarily underlie metabolite-disease associations. Funding SourcesNational Institutes of Health Intramural Research Program, Canadian Breast Cancer Research Alliance.

DXA-Determined Regional Adiposity Relates to Insulin Resistance in a Young Adult Population with Overweight andObesity

Obesity is a well-established risk factor for insulin resistance and type 2 diabetes mellitus, and body fat distribution has important implications for this metabolic risk. In this cross-sectional study, we used dual X-ray absorptiometry body composition data from 123 young adult participants with overweight or obesity, and correlatedwith 2 indices of insulin resistance calculated from oral glucose tolerance tests. Participants were 70% women, with mean (standard error) age 30.1 (0.6) yr, body mass index (BMI) 34.0 (0.6) kg/m2, homeostatic model assessment of insulin resistance (HOMA-IR) of 2.1 (0.2), and Matsuda insulin sensitivity index (Matsuda ISI) of 5.8 (0.4). In women, the strongest correlations were observed with the android-to-gynoid ratio (r = 0.52, p < 0.001 for HOMA-IR; r = −0.46, p < 0.001 for Matsuda ISI), and these correlations remained significant after adjustment for BMI. For men, the strongest correlations were with android fat mass (r = 0.40, p = 0.01 for HOMA-IR; r = −0.37, p = 0.02 for Matsuda ISI). Visceral adipose tissue was correlated with HOMA-IR and Matsuda ISI in women, and only with Matsuda ISI in men. BMI correlated with HOMA-IR and with Matsuda ISI in both women and men. Regional adiposity determined by dual X-ray absorptiometry correlates with indices of insulin resistance in sedentary young adults with overweight and obesity.

Infant Weight and Length Growth Trajectories Modeled Using Superimposition by Translation and Rotation Are Differentially Associated with Body Composition Components at 3 and 7 Years of Age

To evaluate how infant weigh and length growth trajectories associate with body composition at 3 and 7 years because previous studies have noted that rapid infant weight gain increases risk for high body mass index (BMI) in children. There were 322 children enrolled at 3 years of age with dual x-ray absorptiometry body composition data and pediatrician growth data for 0-2 years of age who were included in analysis. Superimposition by translation and rotation modeling was used to characterize infant weight and length trajectories in terms of size, tempo and velocity measures. Associations of these measures with fat mass, lean mass, percent body fat, bone mineral content, BMI z-score, and overweight prevalence at 3 and 7 years of age were determined. Infant growth trajectories differed by sex, race, and breastfeeding status. Higher overall weight size and weight velocity from 0 to 2 years of age were associated positively with all age 3 body composition and anthropometry outcomes. However, longer length size from 0 to 2 years of age was associated independently with higher bone mineral content and lean mass, but lower percent body fat, BMI z-score, and a lower odds of overweight at 3 years of age. By 7 years of age, later than average infant weight tempo was also associated with lower fat mass, lean mass, and BMI z-score. Greater average weight size and greater weight velocity in infancy are markers for greater overall body size at 3 and 7 years of age. However, longer average lengths and later weight gain tempo between 0 and 2 years of age may help to establish a leaner body composition by 3 and 7 years of age.

Dual X-ray absorptiometry body composition and its associated factors in children and adolescence with type 1 diabetes mellitus in South of Iran, a case-control study

To date, limited studies have been conducted for evaluation of the body composition with the dual X-ray energy absorptiometry (DEXA) method in children with type 1 diabetes mellitus (T1DM). Also, there are lack of data about factors associated with body composition parameters in T1DM children. This case-control study was performed on T1DM children whom had referred to Diabetes Clinics of Shiraz University of Medical Sciences, 2013–2014. Weight, height, physical activity, sun exposure, insulin regimen, and the Tanner stage of children were recorded by a trained physician. Serum lipids and glycemic tests were assessed. Body composition was assessed by the DEXA Hologic system. Statistical analysis was carried out using SPSS 18.0 software. Eighty-seven T1DM children (39 male and 48 females) and 87 age- and sex-matched healthy controls with a mean age of 12.4 ± 4.2 years were enrolled in this study. Fat mass index was more in T1DM (P = 0.012), and lean mass index was more in non-diabetic children (P = 0.013). The android/gynecoid fat ratio in T1DM children was less than that of controls (P = 0.002). On multiple regression analysis, there was an independent effect of Tanner stage (P < 0.001) and FBS (P = 0.045) on total fat, an independent positive effect of age onset of T1DM (P < 0.001) on total lean mass. This study revealed an increase in the body fat index and a decrease in the lean mass index in T1DM children.

Relation of Muscle Mass and Fat Mass to Cardiovascular Disease Mortality

We evaluated the relation between components of body composition and mortality in patients with cardiovascular disease (CVD). Dual x-ray absorptiometry body composition data from the National Health and Nutrition Examination Survey 1999 to 2004 was linked to total and CVD mortality data 1999 to 2006 in 6,451 patients with CVD. Kaplan-Meier survival analysis for the end points of total and CVD mortality was plotted by quartiles of muscle mass, fat mass, and categories of body mass index (BMI). Subjects were stratified into 4 groups (low muscle/low fat mass, low muscle/high fat mass, high muscle/low fat mass, and high muscle/high fat mass). Adjusted Cox proportional hazards regression determined hazard ratios for total and CVD mortality. Rates of cardiovascular/total mortality were lower in higher quartiles of muscle mass, fat mass, and higher categories of BMI (p <0.001). The high muscle/low fat mass group had a lower risk of CVD and total mortality (risk-adjusted hazard ratios of 0.32, 95% confidence interval 0.14 to 0.73 and 0.38, 95% confidence interval 0.22 to 0.68, for CVD and total mortality, respectively). Thus, increasing fat mass, muscle mass, and BMI were all correlated with improved survival. The specific subgroup of high muscle and low fat mass had the lowest mortality risk compared with other body composition subtypes. This suggests the importance of body composition assessment in the prediction of cardiovascular and total mortality in patients with CVD.

Eight weeks of pre- and postexercise whey protein supplementation increases lean body mass and improves performance in Division III collegiate female basketball players.

We examined if 8 weeks of whey protein (WP) supplementation improved body composition and performance measures in NCAA Division III female basketball players. Subjects were assigned to consume 24 g WP (n = 8; age, 20 ± 2 years; height, 170 ± 6 cm; weight, 66.0 ± 3.1 kg) or 24 g of maltodextrin (MD) (n = 6; age, 21 ± 3 years; height, 169 ± 6 cm; weight, 68.2 ± 7.6 kg) immediately prior to and following training (4 days/week anaerobic and resistance training) for 8 weeks. Prior to (T1) and 8 weeks following supplementation (T2), subjects underwent dual X-ray absorptiometry body composition assessment as well as performance tests. The WP group gained lean mass from T1 to T2 (+1.4 kg, p = 0.003) whereas the MD group trended to gain lean mass (+0.4 kg, p = 0.095). The WP group also lost fat mass from T1 to T2 (-1.0 kg, p = 0.003) whereas the MD group did not (-0.5 kg, p = 0.41). The WP group presented greater gains in 1-repetition maximum (1RM) bench press (+4.9 kg) compared with the MD group (+2.3 kg) (p < 0.05). Moreover, the WP group improved agility from T1 to T2 (p = 0.001) whereas the MD group did not (p = 0.38). Both groups equally increased leg press 1RM, vertical jump, and broad jump performances. This study demonstrates that 8 weeks of WP supplementation improves body composition and select performance variables in previously trained female athletes.

Ten weeks of branched-chain amino acid supplementation improves select performance and immunological variables in trained cyclists.

We examined if supplementing trained cyclists (32 ± 2 year, 77.8 ± 2.6 kg, and 7.4 ± 1.2 year training) with 12 g/day (6 g/day L-Leucine, 2 g/day L-Isoleucine and 4 g/day L-Valine) of either branched-chain amino acids (BCAAs, n = 9) or a maltodextrin placebo (PLA, n = 9) over a 10-week training season affected select body composition, performance, and/or immune variables. Before and after the 10-week study, the following was assessed: (1) 4-h fasting blood draws; (2) dual X-ray absorptiometry body composition; (3) Wingate peak power tests; and (4) 4 km time-trials. No group × time interactions existed for total lean mass (P = 0.27) or dual-leg lean mass (P = 0.96). A significant interaction existed for body mass-normalized relative peak power (19 % increase in the BCAA group pre- to post-study, P = 0.01), and relative mean power (4 % increase in the BCAA group pre- to post-study, P = 0.01). 4 km time-trial time to completion approached a significant interaction (P = 0.08), as the BCAA group improved in this measure by 11 % pre- to post-study, though this was not significant (P = 0.15). There was a tendency for the BCAA group to present a greater post-study serum BCAA: L-Tryptophan ratio compared to the PLA group (P = 0.08). A significant interaction for neutrophil number existed (P = 0.04), as there was a significant 18 % increase within the PLA group from the pre- to post-study time point (P = 0.01). Chronic BCAA supplementation improves sprint performance variables in endurance cyclists. Additionally, given that BCAA supplementation blunted the neutrophil response to intense cycling training, BCAAs may benefit immune function during a prolonged cycling season.

Dual X-ray Absorptiometry Whole Body Composition of Adipose Tissue in Rheumatoid Arthritis.

Rheumatoid arthritis (RA) may influence not only abdominal fat, but also whole body adiposity, since it is associated with chronic inflammation and disability. The study aims to evaluate the whole body adiposity of RA patients and to assess potential influences of disease specific measures. The study was designed to include Caucasian postmenopausal female RA patients and age-matched postmenopausal female controls. Each subject underwent on the same day clinical examination, laboratory tests, whole body dual X-ray absorptiometry (DXA) composition and physical activity estimation using a self-administered questionnaire. A total of 107 RA women and 104 matched controls were included. Compared to controls, the RA group had less physical activity and a higher prevalence of normal weight obesity. Overfat RA women had a significantly higher toll of inflammation, disease activity, glucocorticoid treatment and sedentary behavior. RA women with inflammation, glucocorticoid treatment and higher disease activity class had higher whole body and trunk adipose tissue indices and higher prevalence of overfat status. Glucocorticoid treatment, inflammation, disease duration and severity correlated with whole body adipose tissue and significantly predicted high adiposity content and overfat phenotypes. RA disease duration and severity are associated with higher whole body and regional adiposity. Low-dose glucocorticoid treatment seems to contribute to adiposity gain and redistribution. Clinicians may need to assess body composition and physical activity in RA patients in order to fully manage cardiovascular outcomes and quality of life.