Measures Of Fat Mass Research Articles

Association Between Fat Mass in Early Life and Later Fat Mass Trajectories

A rapid increase in weight in early life is associated with an increased risk for adiposity and cardiovascular diseases at age 21 years and beyond. However, data on associations of early change in measured fat mass percentage (FM%) with adiposity development are lacking. To investigate whether a rapid increase in FM% in the first months of life is associated with higher trajectories of body fat mass during the first 2 years of life. A birth cohort consisting of 401 healthy, term-born infants of the Sophia Pluto Cohort Study was analyzed. Participants were born between January 7, 2013, and October 13, 2017. Data were analyzed from February 1, 2020, to May 20, 2020. Longitudinal measurements of FM% by air-displacement plethysmography and dual-energy x-ray absorptiometry, and abdominal subcutaneous and visceral fat mass (FM) by ultrasonography in infants at ages 1, 3, 6, 9, 12, 18, and 24 months. A rapid increase in FM% was defined as a change in FM% of greater than 0.67 standard deviation scores (SDS). Associations between change in FM% SDS in the first and second 6-month period of life with body composition at age 2 years and whether a rapid increase in FM% SDS during the first 6 months leads to higher body FM and abdominal FM trajectories during the first 2 years of life. Of the 401 participants, 228 infants (57%) were male. Change in FM% SDS from age 1 to 6 months was positively associated with FM% (β, 0.044; 95% CI, 0.017-0.068), FMI (β, 0.061; 95% CI, 0.032-0.091), and abdominal subcutaneous FM (β, 0.064; 95% CI, 0.036-0.092) at age 2 years, but not with visceral FM. In contrast, no associations were found within the 6- to 12-month period. Infants with a rapid increase in FM% of greater than 0.67 SDS in the first 6 months of life had higher trajectories of FM%, FM index, and subcutaneous FM during the first 2 years of life (all P≤.001), but visceral FM index was not significantly different compared with infants without a rapid increase (P = .12). In this study, only the change in FM% in the first 6 months of life was associated with more adiposity at age 2 years. Infants with a rapid increase in FM% had higher trajectories of FM% and FM index during the first 2 years of life. These findings appear to support a critical window for adiposity programming in early life.

Comparing Bioelectrical Impedance Analysis To Air Displacement Plethysmography For Body Composition Assessment In Female Athletes

PURPOSE: To compare bioelectrical impedance analysis (BIA) and air displacement plethysmography (ADP) for body composition assessment in female collegiate athletes. METHODS: Retrospective review of body composition data for 61 NCAA female collegiate athletes (basketball n = 14, soccer n = 31, volleyball n = 16), measured by BIA and ADP on the same day. Paired t-tests, effect size using Cohen’s d, Pearson’s correlation, and Bland-Altman plots were used to compare percent body fat (%BF) and fat-free mass (FFM) measurements from BIA and ADP for the whole sample, and within sports. RESULTS: The sample included 61 female athletes ages 18-25 years (x̅ = 19.5 ± 1.4 years), with heights ranging from 160-190.5 cm (x̅ = 172.3 ± 8.9 cm), %BF measures ranging from 6.0-38.5% (x̅ = 21.3 ± 6.3%) for ADP and 13.4-36.0% for BIA (x̅ = 22.5 ± 4.7%) and FFM measures ranging from 36.2-69.3 kg (x̅ = 53.4 ± 6.8 kg) for ADP, and 38.8-63.8 kg for BIA (x̅ = 52.4 ± 5.8 kg). Overall, BIA and ADP had strong positive correlations for %BF (r = 0.67) and FFM (r = 0.891). BIA significantly underestimated FFM when compared to ADP (mean difference [MD] = -0.99 kg, p = 0.016, d = -0.32), while no significant difference was observed in %BF (MD = 1.17%, p = 0.056, d = 0.25). Linear regression on the Bland-Altman plots revealed small but significant negative trends for both %BF (β = -0.34, p = 0.004) and FFM (β = -0.166, p = 0.01) estimation by BIA in the total sample. This indicates possible proportional bias, in which BIA is more likely to overestimate %BF and FFM at low values, and underestimate %BF and FFM at high values. When comparing sports, BIA significantly overestimated %BF (MD = 5.42%, p = 0.001, d = 1.14) and underestimated FFM (MD = -3.71 kg, p = 0.001, d = -1.07) for basketball players and significantly underestimated %BF (MD = -2.06%, p = 0.04, d = -0.56) in volleyball players, when compared to ADP. No significant measurement differences were found in soccer players. CONCLUSIONS: BIA gives comparable body composition results to ADP for soccer players, but gives conflicting results regarding over and underestimation of %BF and FFM in basketball and volleyball players. Conflicting conclusions based on sport may indicate the need for specialized equations when extrapolating body composition measures using BIA for athletes at the higher and lower ends of the spectrum of %BF and FFM.

Obesity, dynapenia, and their combination: Implications for bone mineral density in Brazilian adults-the Pró-Saúde study.

This study aimed to evaluate bone mineral density (BMD) in the presence or absence of dynapenia or obesity in Brazilian adults. This is a cross-sectional study conducted in 502 adults (age: 33-81 y; 51% women) participating in the Pró-Saúde study, a cohort of civil servants at the university campuses in Rio de Janeiro, Brazil. Body composition and BMD were determined by dual energy x-ray absorptiometry. Handgrip strength was measured using a dynamometer. According to measures of handgrip strength (≤19 kg for women; ≤32 kg for men) and fat mass (>30% for men; >40% for women), participants were classified into four groups: non-obese non-dynapenic, obese non-dynapenic, non-obese dynapenic, and obese dynapenic. The association between BMD at each specific bone site and obesity, dynapenia, and their interaction was evaluated using a general linear model. The prevalence of dynapenic obesity was 14% in men and 15.2% in women. Dynapenia alone was not associated with BMD at any site in either men nor women. Obesity and dynapenia interacted to influence BMD in women (P < 0.05). Total body, lumbar spine, and femoral neck BMD were higher by 6.3%, 9.3%, and 10.4%, respectively, in dynapenic obese women compared with their non-obese counterparts (P < 0.05). In men, obesity, dynapenia, and their combination were not associated with BMD at any site. Our results suggest that dynapenia, obesity, and their combination may affect BMD in a sex-dependent manner. In the presence of dynapenia, fat mass appears to exert a protective effect on BMD in women, but not in men.

Body Fat Distribution, Overweight, and Cardiac Structures in School-Age Children: A Population-Based Cardiac Magnetic Resonance Imaging Study.

BackgroundAdiposity is associated with larger left ventricular mass in children and adults. The role of body fat distribution in these associations is not clear. We examined the associations of body fat distribution and overweight with cardiac measures obtained by cardiac magnetic resonance imaging in school‐age children.Methods and ResultsIn a population‐based cohort study including 2836 children, 10 years of age, we used anthropometric measures, dual‐energy X‐ray absorptiometry, and magnetic resonance imaging to collect information on body mass index, lean mass index, fat mass index, and abdominal visceral adipose tissue index. Indexes were standardized by height. Cardiac measures included right and left ventricular end‐diastolic volume, left ventricular mass, and mass‐to‐volume ratio as a marker for concentricity. All body fat measures were positively associated with right and left ventricular end‐diastolic volumes and left ventricular mass, with the strongest associations for lean mass index (all P<0.05). Obese children had a 1.12 standard deviation score (95% CI, 0.94–1.30) larger left ventricular mass and a 0.35 standard deviation score (95% CI, 0.14–0.57) higher left ventricular mass‐to‐volume ratio than normal weight children. Conditional on body mass index, higher lean mass index was associated with higher right and left ventricular end‐diastolic volume and left ventricular mass, whereas higher fat mass measures were inversely associated with these cardiac measures (all P<0.05).ConclusionsHigher childhood body mass index is associated with a larger right and left ventricular size. This association is influenced by higher lean mass. In childhood, lean mass may be a stronger determinant of heart growth than fat mass. Fat mass may influence cardiac structures at older ages.

Measuring fat mass in body equivalent materials using an RF resonant cavity.

Provide a proof of concept for the potential of using a novel RF resonant cavity device for accurately and repeatedly measuring fat and fat-free masses in phantom infants. Design, construct, and characterize an RF resonant cavity with dimensions compatible to holding an infant. The cavity was characterized using spherical phantoms of 0%fat, 50% fat, and 100% fat to empirically calibrate shifts in resonant frequency. The phantoms were constructed using emulsions of bovine lard, water, and dish soap inside spherical containers which do not interact with the electric field. The calibration phantoms were compared with a phantom of a test sample to assess the ability of the resonant cavity perturbation technique for measuring body composition. Phantoms of distinct %fat (0%, 50%, and 100%) were used to calibrate the resonant cavity for measuring body composition. The calibration phantoms were used to create calibration lines of unique %fat and were compared to a 475-mL sample of unknown %fat as a measure of how accurate the resonant cavity technique is for measuring body composition. A 475mL test sample was used to examine the robustness of the RCP technique. The sample was 25% fat and had a fat mass of ( )g. The measured fat mass from the RCP technique was g, or a 2% difference. The resonant cavity perturbation technique provides an accurate and repeatable measurement of fat mass in spherical phantoms and suggests the technology might be an effective obesity research tool for infants. Future studies will focus on extending the work to more complex anthropomorphic shapes.

Development and validation of prediction equations for the assessment of muscle or fat mass using anthropometric measurements, serum creatinine level, and lifestyle factors among Korean adults.

BACKGROUND/OBJECTIVESThe measurement of body composition, including muscle and fat mass, remains challenging in large epidemiological studies due to time constraint and cost when using accurate modalities. Therefore, this study aimed to develop and validate prediction equations according to sex to measure lean body mass (LBM), appendicular skeletal muscle mass (ASM), and body fat mass (BFM) using anthropometric measurement, serum creatinine level, and lifestyle factors as independent variables and dual-energy X-ray absorptiometry as the reference method.SUBJECTS/METHODSA sample of the Korean general adult population (men: 7,599; women: 10,009) from the Korean National Health and Nutrition Examination Survey 2008–2011 was included in this study. The participants were divided into the derivation and validation groups via a random number generator (with a ratio of 70:30). The prediction equations were developed using a series of multivariable linear regressions and validated using the Bland–Altman plot and intraclass correlation coefficient (ICC).RESULTSThe initial and practical equations that included age, height, weight, and waist circumference had a different predictive ability for LBM (men: R2 = 0.85, standard error of estimate [SEE] = 2.7 kg; women: R2 = 0.78, SEE = 2.2 kg), ASM (men: R2 = 0.81, SEE = 1.6 kg; women: R2 = 0.71, SEE = 1.2 kg), and BFM (men: R2 = 0.74, SEE = 2.7 kg; women: R2 = 0.83, SEE = 2.2 kg) according to sex. Compared with the first prediction equation, the addition of other factors, including serum creatinine level, physical activity, smoking status, and alcohol use, resulted in an R2 that is higher by 0.01 and SEE that is lower by 0.1.CONCLUSIONSAll equations had low bias, moderate agreement based on the Bland–Altman plot, and high ICC, and this result showed that these equations can be further applied to other epidemiologic studies.

Prevalence of Risk of Eating Disorders and its Association with Obesity and Fitness.

The university stage is a critical developmental period for young adults, where lifestyles can determine future health. A cross-sectional study including 481 college students was conducted, with the following objectives: 1) to examine the prevalence of risk of developing eating disorders in college students, 2) to assess differences in obesity and physical fitness in those with and without risk of eating disorders, and 3) to determine whether cardiorespiratory fitness, muscular fitness or fat mass were associated with the risk of eating disorders. We measured fat mass percentage (by densitometry), risk of feeding or eating disorders (by SCOFF questionnaire), cardiorespiratory fitness levels and a muscular fitness index. The prevalence of risk of eating disorders in women (32.4%) was higher than in men (17.4%) (p<0.001). In both sexes, higher obesity indicator mean values were observed among those who were at risk of eating disorders. Men participants without risk had higher cardiorespiratory fitness means than their at-risk peers [39.4 (8.3) vs. 32.4 (5.5), p<0.001)], and women showed differences only in the dynamometry/weight variable. In college students, it is necessary to promote healthy habits, including good levels of physical fitness, and to prevent excess body fat to effectively prevent eating disorders.

MON-LB107 Treat: A Randomized Controlled Trial Examining the Effects of Time Restricted Eating on Weight Loss and Metabolic Markers

Background: Studies indicate that time-restricted eating (TRE) can prevent weight gain and/or lead to weight loss [1,2]. The few human studies to date are small and/or non-randomized [3,4]. This is a prospective and randomized study in humans who are overweight and obese designed to determine if TRE leads to weight loss and to characterize the metabolic effects of TRE. Methods: 140 overweight and obese males and females with a body mass index between 27-43 kg/m2 were enrolled in the study. 100 participants completed the 12-week protocol. The study was conducted on a custom mobile study app on the Eureka Research Platform. Participants were given a Bluetooth weight scale to use daily, which was connected through the study app. Subjects were randomized to one of two eating plans and received daily reminders about their eating windows through the app. The control group was instructed to eat three structured meals per day. The TRE group was instructed to eat ad libitum from 12:00 pm until 8:00 pm and completely abstain from caloric intake from 8:00 pm until 12:00 pm the following day (16h fast:8h eat). Participants who lived within 60 miles of the study site were eligible to undergo extensive in-person metabolic testing. Results: Weight change in the TRE group was -1.3 kg compared to -0.6 kg in the control group (p=0.22). 46 (TRE n=22; control=24) of 50 participants who opted into the “in-person” visits completed all 4 visits. In that cohort, weight change in the TRE group was -1.62 kg compared to -0.57 kg in control (p=0.09). There were no significant differences in the changes in total fat mass, visceral or subcutaneous fat mass, waist or hip measurements, or resting metabolic rate. However, there was a trend towards reduced fat-free mass in the TRE group (-1.10kg) compared to controls (-0.35kg) (p=0.09). There was a significant change in the appendicular fat-free mass index of the TRE subjects compared to controls (p=0.011). This change in appendicular fat-free mass index was not associated with significant differences in strength measures. No changes were observed in plasma ketones, insulin, or glucose between treatment groups. Conclusion: These results indicate that TRE may lead to reductions in body weight in individuals who are overweight or obese. However, the majority of weight loss is attributed to reductions in fat-free mass rather than fat mass. Future analyses will determine if TRE leads to changes in metabolic blood markers or the plasma metabolome.

Phase Angle is Determined by Body Composition and Cardiorespiratory Fitness in Adolescents.

The phase angle is used to evaluate nutritional status and is an indicator of cellular health. Cardiorespiratory fitness and body composition are strong indicators of health during adolescence. We aimed to evaluate if body composition and cardiorespiratory fitness have an association with phase angle among adolescents. 203 girls and 220 boys (12.8±1.3 years) were evaluated. Peak height velocity, percentage fat mass, fat-free mass, cardiorespiratory fitness, and phase angle measurements were collected. Linear regression adjusted by peak height velocity was used to verify if predictor variables were associated with phase angle among adolescents. Phase angle showed correlation with fat-free mass (girls: r=0.42 and boys: r=0.37); with percent fat mass (girls: r=0.23); and with cardiorespiratory fitness (boys: r=0.19). Linear regression showed that percentage fat mass (in girls) and cardiorespiratory fitness (in boys) had an effect of 11 and 17% in phase angle, respectively, while fat-free mass had an effect of 22 and 26% in phase angle for girls and boys, respectively. Changes in phase angle seem to be more associated with the percentage fat mass in girls, cardiorespiratory fitness in boys, and fat-free mass in both when controlled by peak height velocity.

Evaluation of anthropometric measures for assessment of cardiometabolic risk in early childhood.

Waist-to-height ratio has been shown to be an important indicator of cardiometabolic risk. There are few studies evaluating this measure against existing measures of adiposity and cardiometabolic markers in early childhood. The objectives were: (i) to determine in young children the ability of waist-to-height ratio, BMI z-score, weight for length, and sum of skin fold thickness to predict cardiometabolic risk and (ii) to examine this association at ages 1, 3 and 5 years. Prospective cohort study. A university hospital in Toronto, Ontario. Infants at 1 (n 406), 3 (n 112) and 5 years of age (n 94) born to mothers with and without gestational diabetes mellitus. Weight for length and BMI z-score demonstrated the strongest correlations with biochemical measures compared to waist-to-height ratio, including leptin (at 5 years, weight for length z-score: ρ = 0·65, P < 0·001; BMI z-score: ρ = 0·67, P < 0·001) and measures of insulin resistance (at 3 years, weight for length z-score: ρ = 0·25, P = 0·02; BMI z-score: ρ = 0·24, P = 0·02). The magnitude of associations between anthropometric measures and biochemical measures strengthened over time. Weight for length and BMI z-scores were moderately correlated with overall measures of fat mass as measured by dual-energy X-ray absorptiometry (ρ = 0·65, P = 0·00; ρ = 0·61, P = 0·01). Waist-to-height ratio was not superior to existing measures in predicting cardiometabolic risk in young children. BMI z-score is a preferred measure of adiposity between birth and 5 years of age.

Nonalcoholic Fatty Liver Disease Is Associated With Low Skeletal Muscle Mass in Overweight/Obese Youths.

Background: Recent studies in adult non-elderly and elderly individuals have reported a link between nonalcoholic fatty liver disease (NAFLD) and sarcopenia. Nonetheless, whether this relationship would be found outside these populations it is still unknown. Hence, we evaluated the relationship between NAFLD and skeletal muscle mass in children and adolescents with overweight/obesity.Methods: Two-hundred and thirty-four overweight/obese youths were enrolled. NAFLD was diagnosed by ultrasononography, after exclusion of infectious and metabolic disorders. Forty of the patients with NAFLD had also liver biopsy. Total and regional lean body mass and total fat mass measurements were obtained by dual-energy X-ray absorptiometry. The relative muscle mass (RMM) was defined as the percent of muscle mass (kg) relative to the sum of muscle and fat (kg) mass. Appendicular skeletal muscle mass (ASM) was calculated by the sum of muscle masses of the four limbs (kg), and expressed as percent of body weight.Results: Subjects were stratified according to tertiles of RMM. The prevalence of abdominal obesity, dyslipidemia, insulin resistance, metabolic syndrome, NAFLD as well as biopsy-proven nonalcoholic steatohepatitis (NASH) was significantly increased in the lowest tertile of RMM. After controlling for age, sex and Tanner stage, children in the lowest tertile of RMM had an increased risk for NAFLD (OR= 2.80, 95% CI=1.57–5.02) compared to those in the other two tertiles. This association persisted after additional adjustments for clinical and metabolic variables. Similarly, the risk of NAFLD in the lowest tertile of ASM/weight index was significantly higher compared to those in the other two tertiles after adjustment for the above confounders.Conclusions: This is the first study to establish an independent association between low muscle mass and NAFLD/NASH in overweight/obese youths. Considering the worldwide increase of pediatric obesity, measurements of muscle mass may serve as useful method of identifying among obese children those at high metabolic risk who may need intensive lifestyle interventions to prevent NAFLD and its progression.

Artificial Intelligence in the Evaluation of Body Composition.

Body composition entails the measurement of muscle and fat mass in the body and has been shown to impact clinical outcomes in various aspects of human health. As a result, the need is growing for reliable and efficient noninvasive tools to measure body composition. Traditional methods of estimating body composition, anthropomorphic measurements, dual-energy X-ray absorptiometry, and bioelectrical impedance, are limited in their application. Cross-sectional imaging remains the reference standard for body composition analysis and is accomplished through segmentation of computed tomography and magnetic resonance imaging studies. However, manual segmentation of images by an expert reader is labor intensive and time consuming, limiting its implementation in large-scale studies and in routine clinical practice. In this review, novel methods to automate the process of body composition measurement are discussed including the application of artificial intelligence and deep learning to tissue segmentation.

Metabolic reduction after long-duration flight is not related to fat-free mass loss or flight duration in a migratory passerine.

Migratory birds catabolize large quantities of protein during long flights, resulting in dramatic reductions in organ and muscle mass. One of the many hypotheses to explain this phenomenon is that decrease in lean mass is associated with reduced resting metabolism, saving energy after flight during refueling. However, the relationship between lean body mass and resting metabolic rate remains unclear. Furthermore, the coupling of lean mass with resting metabolic rate and with peak metabolic rate before and after long-duration flight have not previously been explored. We flew migratory yellow-rumped warblers (Setophaga coronata) in a wind tunnel under one of two humidity regimes to manipulate the rate of lean mass loss in flight, decoupling flight duration from total lean mass loss. Before and after long-duration flights, we measured resting and peak metabolism, and also measured fat mass and lean body mass using quantitative magnetic resonance. Flight duration ranged from 28 min to 600 min, and birds flying under dehydrating conditions lost more fat-free mass than those flying under humid conditions. After flight, there was a 14% reduction in resting metabolism but no change in peak metabolism. Interestingly, the reduction in resting metabolism was unrelated to flight duration or to change in fat-free body mass, indicating that protein metabolism in flight is unlikely to have evolved as an energy-saving measure to aid stopover refueling, but metabolic reduction itself is likely to be beneficial to migratory birds arriving in novel habitats.

FAT MASS IS NEGATIVELY ASSOCIATED WITH MUSCLE STRENGTH AND JUMP TEST PERFORMANCE

It is known that maintenance of muscle mass cannot prevent loss of muscle strength in older adults. Recent evidence suggests that fat mass can weaken the relationship between muscle mass and functional performance. No information exists if fat mass can independently affect muscle strength and jump test performance in middle-aged and older adults. To assess the independent relationships between fat mass, leg muscle mass, lower extremity muscle strength, and jump test performance in adults, 55-75 years of age. Cross-sectional. University laboratory. Fifty-nine older adults (men, n = 27, age = 64.8 ± 6.5 years; women, n = 32, age = 62.5 ± 5.1 years) participated in this study. Dual energy X-ray absorptiometry was used to measure fat mass and leg muscle mass. An average of 3 maximal countermovement jumps was used to calculate jump power and jump height. Two leg press and hip abduction strength were assessed by 1-repetition maximum testing. Stepwise sequential regression analysis of fat mass and leg muscle mass versus jump test performance and measures of muscle strength after adjusting for age, height, and physical activity revealed that fat mass was negatively associated with jump height (p = 0.047, rpartial = -0.410) in men. In women, fat mass was negatively associated with jump height (p = 0.003, rpartial = -0.538), leg press (p = 0.002, rpartial = -0.544), and hip abduction strength (p < 0.001, rpartial = -0.661). Leg muscle mass was positively associated with jump power in women (p = 0.047, rpartial = 0.372) only. Fat mass has an independent negative relationship with jump test performance in middle-aged and older men and women. This has clinical implications for rehabilitating neuromuscular performance in middle-aged and older adults.

Correlation between adiponectin, chemerin, vascular endothelial growth factor and epicardial fat volume in patients with coronary artery disease.

Epicardial fat, a local visceral fat depot surrounded by visceral pericardial sac, surrounds the coronary arteries for most of their course and may contribute to the development of coronary atherosclerosis by local production of inflammatory cytokines. Some studies on non-invasive measurement of epicardial fat mass have shown that epicardial fat mass is associated with the increased incidence of coronary artery disease (CAD), onset and progression of coronary plaque, mainly including major adverse cardiovascular events, myocardial ischemia, and atrial fibrillation. In the present study the correlation of adiponectin, chemerin, and vascular endothelial growth factor (VEGF) with the epicardial fat volume in patients with coronary artery disease was explored, and the risk factors for vascular remodeling of CAD patients were analyzed. A total of 50 CAD patients, treated in Chongzuo People's Hospital from August 2017 to September 2018, were enrolled as the observation group, and further 50 healthy individuals, who underwent physical examinations in the hospital at the same period, were enrolled as the control group. RT-qPCR was adopted to detect the expression levels of adiponectin, chemerin and VEGF in the two groups, a 64-slice dual-source CT to detect epicardial fat volume, and Pearson's correlation to analyze adiponectin, chemerin, VEGF and epicardial fat volume. Logistic regression analysis was performed to analyze the risk factors for vascular remodeling in CAD patients, and a receiver operating characteristic (ROC) curve analysis was used to analyze the value of indexes with multifactorial significance in vascular remodeling. The observation group showed obviously larger epicardial fat volume than the control group (P<0.001), lower adiponectin expression than the control group (P<0.001), and higher chemerin and VEGF expression than the control group (P<0.001). In the observation group, adiponectin expression decreased with the increase of epicardial fat volume (P<0.001), while the expression of chemerin and VEGF increased with the increase of epicardial fat volume (P<0.001). Remodeling occurred in 27 of the 50 patients. ROC curve analysis showed that the areas under the curves of adiponectin, chemerin, VEGF and epicardial fat volume were 0.697, 0.652, 0.696 and 0.689, respectively. Epicardial fat volume, adiponectin, chemerin and VEGF are independent risk factors for vascular remodeling and the expression of adiponectin, chemerin and VEGF can reflect epicardial fat volume.

Children and Adolescents' Anthropometrics Body Composition from 3-D Optical Surface Scans.

This study aimed to explore the accuracy and precision of three-dimensional optical (3DO) whole-body scanning for automated anthropometry and estimating total and regional body composition. Healthy children and adolescents (n = 181, ages 5-17 years) were recruited for the Shape Up! Kids study. Each participant underwent whole-body dual-energy x-ray absorptiometry and 3DO scans; multisite conventional tape measurements served as the anthropometric criterion measure. 3DO body shape was described using automated body circumference, length, and volume measures. 3DO estimates were compared with criterion measures using simple linear regression by the stepwise selection method. Of the 181 participants, 112 were used for the training set, 49 were used for the test set, and 20 were excluded for technical reasons. 3DO body composition estimates were strongly associated with dual-energy x-ray absorptiometry measures for percent body fat, fat mass, and fat-free mass (R2 : 0.83, 0.96, and 0.98, respectively). 3DO provided reliable measurements of fat mass (coefficient of variation, 3.30; root mean square error [RMSE], 0.53), fat-free mass (coefficient of variation, 1.34; RMSE, 0.53 kg), and percent body fat (RMSE = 1.2%). 3DO surface scanning provides accurate and precise anthropometric and body composition estimates in children and adolescents with high precision. 3DO is a safe, accessible, and practical method for evaluating body shape and composition in research and clinical settings.

Sex Differences in Resting Metabolic Rate Among Athletes.

Jagim, AR, Camic, CL, Askow, A, Luedke, J, Erickson, J, Kerksick, CM, Jones, MT, and Oliver, JM. Sex differences in resting metabolic rate among athletes. J Strength Cond Res 33(11): 3008-3014, 2019-The purpose of this study was to compare differences in resting metabolic rate (RMR) between sexes in Division III National Collegiate Athletic Association (NCAA) collegiate athletes and to identify predictors of RMR. Sixty-eight male (M) (age: 20.1 ± 1.5 years; height: 181.8 ± 5.9 cm; body mass (BM): 93.7 ± 16.3 kg; and body fat%: 16.3 ± 8.6%) and 48 female (F) athletes (age: 19.4 ± 1.3 years; height: 166.5 ± 6.0 cm; BM: 63.4 ± 12.7 kg; and body fat%: 21.5 ± 6.3%) participated in a single day of testing, which included determination of RMR using indirect calorimetry and air displacement plethysmography to measure fat mass and fat-free mass (FFM). An independent-samples t-test was used to compare differences in body composition and RMR between sexes, and regression analysis was used to identify predictors of RMR. Men had a significantly higher absolute RMR (M: 2,481 ± 209 vs. F: 1,553 ± 193 kcals·d; p < 0.001), but when adjusted for BM (M: 25.6 ± 8.3 vs. F: 25.9 ± 2.5 kcals·kg BM per day; p = 0.82) and FFM (M: 31.1 ± 10.6 vs. F: 33.6 ± 3.8 kcals·kg FFM per day; p = 0.12), these differences became nonsignificant. Regression analysis indicated that BM in both men (β = 0.73) and women (β = 0.88) was the strongest predictor of RMR. The results of the current study indicate minimal differences in RMR between sexes among athletic populations when adjusted for BM and FFM. In the current group of athletes, BM seems to account for the largest variability in RMR.

Disparity in Adiposity among Adults with Normal Body Mass Index and Waist-to-Height Ratio.

SummaryBody mass index (BMI) is commonly used to define obesity. However, concerns about its accuracy in predicting adiposity have been raised. The feasibility of using BMI as well as waist-height ratio (WHtR) in assessing adiposity was examined in relation to a more direct measurement of percent body fat (%BF). We analyzed the relation between dual-energy X-ray absorptiometry (DXA)-measured fat mass and BMI and WHtR using the US 1999–2004 National Health and Nutrition Examination Survey (NHANES) data. A considerable proportion of subjects in the healthy BMI range 20–25 were found to have excess adiposity, including 33.1% of males and 51.9% of females. The use of WHtR also supports the notion of normal-weight central obesity (NWCO), which increases with age. These findings have important implications not only for clinical practice but also for many comparative studies where control subjects are usually selected based on age, sex, and BMI.

Trajectory of Lean Body Mass Assessed Using the Modified Creatinine Index and Mortality in Hemodialysis Patients

Although a declining body mass index (BMI) is associated with higher mortality in patients on hemodialysis, BMI cannot distinguish lean body mass from fat mass. It remains unclear whether changes over time in lean body mass are associated with mortality. We examined the prognostic significance of changes in the modified creatinine index, a proxy for lean body mass. Retrospective cohort study. Outpatients (n=349; mean age, 67.4 years; 60% men) undergoing maintenance hemodialysis 3 times a week at a treatment center. Modified creatinine index and BMI trajectories over a 1-year period. All-cause mortality. We calculated the percentage of change in modified creatinine index and BMI over a 1-year period. Patients were categorized according to change in modified creatinine index/BMI: no decline (≥0%) or decline (<0%). Kaplan-Meier and Cox proportional hazard analyses were performed to examine whether modified creatinine index and BMI trajectories were associated with mortality. During follow-up (median, 1,157 days), 79 patients died. Decreasing modified creatinine index (HR, 1.31; 95% CI, 1.11-1.54) and BMI (HR, 1.25; 95% CI, 1.01-1.54) over time, measured as continuous variables and expressed per 1-standard deviation decrease, were independently associated with higher risk for all-cause mortality. The decline in modified creatinine index/no decline in BMI group (HR, 2.14; 95% CI, 1.04-4.45) and the decline in modified creatinine index/decline in BMI group(HR, 3.05; 95% CI, 1.58-5.90) had higher rates of mortality compared to the no decline in modified creatinine index/decline in BMI group. The absence of a direct measure of lean body and fat mass and limited generalizability to non-Japanese hemodialysis populations. The modified creatinine index trajectory is independently associated with mortality and provides additional prognostic information to the BMI trajectory in patients on hemodialysis.

Body Composition Comparison of Upper- and Underclass Reserve Officers' Training Corps Cadets.

INTRODUCTION: Body composition (BC) measurements are used to determine qualification for enlistment and to ensure active members are meeting standards. Although there is extensive research on BC in active-duty military, very few have examined ROTC cadets. The purpose of this study was to identify and quantify differences in BC between freshman/sophomore [underclass (UND)] and junior/senior [upperclass (UPP)] ROTC cadets by using bioelectrical impedance spectroscopy (BIS).METHODS: UND (N = 21) and UPP (N = 15) Air Force ROTC cadets volunteered for this study. BIS was used to measure fat mass percentage (FM%), fat free mass percentage (FFM%), total body water percentage (TBW%), extracellular fluid percentage (ECF%), and intracellular fluid percentage (ICF%). Separate one-way ANOVAs were run between UND and UPP for all dependent variables with a Bonferroni correction factor. Additionally, a Pearson correlation between abdominal circumference (AC) and FM% was conducted.RESULTS: No significant differences were observed between the UND and UPP groups' BMI. However, significant differences were observed for ECF%, ICF%, TBW%, FFM%, and FM% in which the UPP had a higher TBW%, ICF%, FFM%, and a lower ECF% and FM% compared to the UND.CONCLUSIONS: This study observed significant differences in BC across class ranks in ROTC cadets. Findings from this study suggest that due to an increased exposure to ROTC training, UPP cadets have a more ideal body composition (FFM% and FM%) when compared to UND cadets.Johnson QR, Mackey CS, Muddle TD, Smith DB, DeFreitas JM. Body composition comparison of upper- and underclass Reserve Officers Training Corps cadets. Aerosp Med Hum Perform. 2019; 90(9):813-818.