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Purpose: Currently, body weight-based dosing of rifampicin is recommended. But lately, fat-free mass (FFM) was reported to be superior to body weight (BW). The present evaluation aimed to assess the influence of body mass-related covariates on rifampicin's pharmacokinetics (PK) parameters in more detail using non-linear mixed effects modeling (NLMEM). Methods: Twenty-four healthy Caucasian volunteers were enrolled in a bioequivalence study, each receiving a test and a reference tablet of 600 mg of rifampicin separated by a wash-out period of at least 9 days. Monolix version 2023R1 was used for NLMEM. Monte Carlo simulations (MCS) were performed to visualize the relationship of body size descriptors to the exposure to rifampicin. Results: A one-compartment model with nonlinear (Michaelis–Menten) elimination and zero-order absorption kinetics with a lag time best described the data. The covariate model including fat-free mass (FFM) on volume of distribution (V/F) and on maximum elimination rate (Vmax/F) lowered the objective function value (OFV) by 56.4. The second-best covariate model of sex on V/F and Vmax/F and BW on V/F reduced the OFV by 51.2. The decrease in unexplained inter-individual variability on Vmax/F in both covariate models was similar. For a given dose, MCS showed lower exposure to rifampicin with higher FFM and accordingly in males compared to females with the same BW and body height. Conclusion: Our results indicate that beyond BW, body composition as reflected by FFM could also be relevant for optimized dosing of rifampicin. This assumption needs to be studied further in patients treated with rifampicin. [ABSTRACT FROM AUTHOR]

Introduction: Bariatric surgery (BS) patients are advised to consume protein supplements to prevent fat-free mass (FFM) loss. However, limited research has explored the efficacy of diverse protein presentations on FFM preservation. This study assesses if short peptide-based (SPB) supplements surpass complex protein-based (CPB) supplements in reducing early FFM loss post-surgery. Methods: In this retrospective cohort study, 138 patients who underwent BS other than Roux-en-Y-gastric bypass (RYGB) between January 2021 and March 2021 at the Department of Bariatric Surgery of the Third People's Hospital of Chengdu were included for analysis. Patients were divided into two groups based on their consumption of protein supplements after surgery: SPB group and CPB group. Multiple linear regressions separated by sex were employed to examine the associations between SPB supplements and FFM loss and percentage of FFM (%FFM) loss, respectively. Results: Among participants, 69.6% were female, with a mean age of 33.3 years. In multiple linear regression analyses, SPB supplements were significantly and positively associated with a lower FFM loss in both female (ꞵ = − 1.14, P = 0.047) and male (ꞵ = − 2.36, P = 0.024), and were positively associated with a lower %FFM loss in both female (ꞵ = − 1.83) and male (ꞵ = − 2.26) but only significant in male (P = 0.049). Conclusion: SPB supplements may be more effective in preventing early FFM loss after BS, compared to CPB supplements, particularly among male patients. Therefore, SPB supplements may be recommended to patients undergoing BS. Further research is needed to validate these findings. [ABSTRACT FROM AUTHOR]

Background: Sarcopenic obesity may affect the health outcome of people with obesity after laparoscopic sleeve gastrectomy (LSG). To assess the impact of sarcopenic obesity (SO) on weight loss outcomes and improvement of quality of life after LSG. Materials and Methods: This observational study included patients who underwent LSG with SO (99 patients) or without SO (146 patients) from a single center. The primary endpoint was weight loss and disease-specific quality of life in patients with or without SO after the operation. Fat-free mass (FFM) and fat mass (FM) were calculated based on the L3-level images of preoperative CT scans. SO was diagnosed if FM/FFM ≥ 0.80. Results: Operative time and postoperative hospital stay days were longer in the SO group (p < 0.001). After LSG, weight, BMI, and EBMI were significantly lower in the NSO group than in the SO group (all P < 0.05), while %EWL and the number of patients with %EWL ≥ 100% were significantly lower in the SO group (both p < 0.05). The total BAROS scores of patients in the NSO group were higher than those in the SO group (p < 0.05). Additionally, the MA II questionnaire assessment showed a lower percentage of "very good" and "good" outcomes in the SO group (p < 0.05). Conclusions: Patients with SO take a slower rate, longer time to reach the ideal weight, and lower quality of life self-ratings than NSO patients after LSG. Thus, preoperative evaluation and tailoring rehabilitation guidance for people with SO should be accounted. [ABSTRACT FROM AUTHOR]

Aims: To assess body composition by means of BOD POD in the large cohort of Italian Olympic athletes of many sport disciplines (studied at the same time), and to provide possible reference values for body composition in elite athletes. Methods: 1556 elite athletes, who took part in the selection procedure for the 2016 Rio Olympic Games for the National Italian Olympic Committee (CONI), were retrospectively studied. Body composition was determined using air plethysmography-based BOD POD. Results: We observed that Fat Mass (FM) and Fat-free Mass (FFM) should be considered as two mutually independent domains in elite athletes. By performing Principal Component Analysis, we defined two independent main domains (respectively, representing FM and FFM), which presented different trends according to gender and static or dynamic exercise load. Lastly, we reported possible reference values for FM index and FFM index, respectively, representing the largest contributors to FM domain and FFM domain, and calculated as FM or FFM (kg)/height (m2). Conclusions: Our findings might provide a basis to optimize the practical approach to body composition in athletes, highlighting the importance of considering indicators of fat mass and lean mass "simultaneously" and not specularly, according to different sport disciplines as well. Moreover, these data might contribute to standardize reference values for body composition in elite athletes, with a view to potentially helping to monitor and guide training regimens, prevent related detrimental practices and plan cardiometabolic prevention and rehabilitation programs. [ABSTRACT FROM AUTHOR]

Reproducibility of body fat (BF) and fat-free mass (FFM) measurements obtained by two indirect methods (bioimpedance analysis (BIA) and ultrasound scanning (US)) was performed in a group of young adults. To evaluate reproducibility, the repeated body composition measurements obtained using an ABC-02 Medas bioimpedance analyzer and BodyMetrixTM ultrasound scanner were carried out in the group of adult men and women. The study indicates the reliability of both individual and group estimates, as well as high reproducibility of measurements obtained with BIA and US. Strong positive significant correlations were found between the body composition measurements obtained with an ABC-02 Medas and BodyMetrixTM, as well as between repeated measurements of each of the devices. The analysis carried out for the ABC-02 Medas and BodyMetrixTM devices indicates good reproducibility of BF and FFM measurements in young men and women. The highest reproducibility was shown for the results of FFM measurements. [ABSTRACT FROM AUTHOR]

Purpose: Large inter-individual variations in post-bariatric fat-free mass loss (FFML) are observed, which might relate to differences in protein intake and physical activity across patients. We performed repetitive assessments of protein intake and physical activity before and after banded Roux-en-Y gastric bypass surgery, and examined its relations to FFML during 6 months of follow-up. Materials and Methods: FFML (bio-impedance analyses), protein intake (24-h dietary recalls) and moderate-to-vigorous physical activity (MVPA; activPAL) were assessed in 28 patients (4 males, age 42 ± 12 years) before surgery and at 1-, 3- and 6-months post-surgery. Changes in protein intake and MVPA were evaluated with mixed model analysis, whereas associations with FFML were assessed by univariate regression analysis. Results: Six-month FFML was -7.3 ± 3.6 kg. Protein intake decreased from 80 ± 29 g/day (pre-surgery) to 45 ± 26 g/day (1 month post-surgery (P < 0.001)) and did not improve thereafter (51 ± 21 g/day; P > 0.05). Seven participants (25%) consumed ≥ 60 g protein/day at 6 months post-surgery. Participants performed 7394 ± 2420 steps/day in 54 ± 20 min/day of MVPA, which did not change from pre- to post-surgery (P > 0.05). A higher step count (B = -0.002; 95%CI = [-0.004 – 0.000]; P = 0.048) and higher level of MVPA (B = -0.29; 95%CI = [-0.54 – -0.03]; P = 0.018) were related to a lower FFML. Conclusion: A lower post-surgery FFML was attributable to higher MVPA levels but not protein intake. This may be due to the low total protein intake and the observation that only a minority of patients achieved a protein intake ≥ 60 g/day. Future studies should focus on interventions to increase post-bariatric protein intake and MVPA levels. [ABSTRACT FROM AUTHOR]

Purpose: Body composition can be estimated using anthropometric-based regression models, which are population-specific and should not be used interchangeably. However, the widespread availability of predictive equations in the literature makes selecting the most valid equations challenging. This systematic review compiles anthropometric-based predictive equations for estimating body mass components, focusing on those developed specifically for athletes using multicomponent models (i.e. separation of body mass into ≥ 3 components).Twenty-nine studies published between 2000 and 2024 were identified through a systematic search of international electronic databases (PubMed and Scopus). Studies using substandard procedures or developing predictive equations for non-athletic populations were excluded.A total of 40 equations were identified from the 29 studies. Of these, 36 were applicable to males and 17 to females. Twenty-six equations were developed to estimate fat mass, 10 for fat-free mass, three for appendicular lean soft tissue, and one for skeletal muscle mass. Thirteen equations were designed for mixed athletes, while others focused on specific contexts: soccer (n = 8); handball and rugby (n = 3 each); jockeys, swimming, and Gaelic football (n = 2 each); and futsal, padel, basketball, volleyball, American football, karate, and wheelchair athletes (n = 1 each).This review presented high-standards anthropometric-based predictive equations for assessing body composition in athletes and encourages the development of new equations for underrepresented sports in the current literature.Methods: Body composition can be estimated using anthropometric-based regression models, which are population-specific and should not be used interchangeably. However, the widespread availability of predictive equations in the literature makes selecting the most valid equations challenging. This systematic review compiles anthropometric-based predictive equations for estimating body mass components, focusing on those developed specifically for athletes using multicomponent models (i.e. separation of body mass into ≥ 3 components).Twenty-nine studies published between 2000 and 2024 were identified through a systematic search of international electronic databases (PubMed and Scopus). Studies using substandard procedures or developing predictive equations for non-athletic populations were excluded.A total of 40 equations were identified from the 29 studies. Of these, 36 were applicable to males and 17 to females. Twenty-six equations were developed to estimate fat mass, 10 for fat-free mass, three for appendicular lean soft tissue, and one for skeletal muscle mass. Thirteen equations were designed for mixed athletes, while others focused on specific contexts: soccer (n = 8); handball and rugby (n = 3 each); jockeys, swimming, and Gaelic football (n = 2 each); and futsal, padel, basketball, volleyball, American football, karate, and wheelchair athletes (n = 1 each).This review presented high-standards anthropometric-based predictive equations for assessing body composition in athletes and encourages the development of new equations for underrepresented sports in the current literature.Results: Body composition can be estimated using anthropometric-based regression models, which are population-specific and should not be used interchangeably. However, the widespread availability of predictive equations in the literature makes selecting the most valid equations challenging. This systematic review compiles anthropometric-based predictive equations for estimating body mass components, focusing on those developed specifically for athletes using multicomponent models (i.e. separation of body mass into ≥ 3 components).Twenty-nine studies published between 2000 and 2024 were identified through a systematic search of international electronic databases (PubMed and Scopus). Studies using substandard procedures or developing predictive equations for non-athletic populations were excluded.A total of 40 equations were identified from the 29 studies. Of these, 36 were applicable to males and 17 to females. Twenty-six equations were developed to estimate fat mass, 10 for fat-free mass, three for appendicular lean soft tissue, and one for skeletal muscle mass. Thirteen equations were designed for mixed athletes, while others focused on specific contexts: soccer (n = 8); handball and rugby (n = 3 each); jockeys, swimming, and Gaelic football (n = 2 each); and futsal, padel, basketball, volleyball, American football, karate, and wheelchair athletes (n = 1 each).This review presented high-standards anthropometric-based predictive equations for assessing body composition in athletes and encourages the development of new equations for underrepresented sports in the current literature.Conclusions: Body composition can be estimated using anthropometric-based regression models, which are population-specific and should not be used interchangeably. However, the widespread availability of predictive equations in the literature makes selecting the most valid equations challenging. This systematic review compiles anthropometric-based predictive equations for estimating body mass components, focusing on those developed specifically for athletes using multicomponent models (i.e. separation of body mass into ≥ 3 components).Twenty-nine studies published between 2000 and 2024 were identified through a systematic search of international electronic databases (PubMed and Scopus). Studies using substandard procedures or developing predictive equations for non-athletic populations were excluded.A total of 40 equations were identified from the 29 studies. Of these, 36 were applicable to males and 17 to females. Twenty-six equations were developed to estimate fat mass, 10 for fat-free mass, three for appendicular lean soft tissue, and one for skeletal muscle mass. Thirteen equations were designed for mixed athletes, while others focused on specific contexts: soccer (n = 8); handball and rugby (n = 3 each); jockeys, swimming, and Gaelic football (n = 2 each); and futsal, padel, basketball, volleyball, American football, karate, and wheelchair athletes (n = 1 each).This review presented high-standards anthropometric-based predictive equations for assessing body composition in athletes and encourages the development of new equations for underrepresented sports in the current literature.Graphical abstract: Body composition can be estimated using anthropometric-based regression models, which are population-specific and should not be used interchangeably. However, the widespread availability of predictive equations in the literature makes selecting the most valid equations challenging. This systematic review compiles anthropometric-based predictive equations for estimating body mass components, focusing on those developed specifically for athletes using multicomponent models (i.e. separation of body mass into ≥ 3 components).Twenty-nine studies published between 2000 and 2024 were identified through a systematic search of international electronic databases (PubMed and Scopus). Studies using substandard procedures or developing predictive equations for non-athletic populations were excluded.A total of 40 equations were identified from the 29 studies. Of these, 36 were applicable to males and 17 to females. Twenty-six equations were developed to estimate fat mass, 10 for fat-free mass, three for appendicular lean soft tissue, and one for skeletal muscle mass. Thirteen equations were designed for mixed athletes, while others focused on specific contexts: soccer (n = 8); handball and rugby (n = 3 each); jockeys, swimming, and Gaelic football (n = 2 each); and futsal, padel, basketball, volleyball, American football, karate, and wheelchair athletes (n = 1 each).This review presented high-standards anthropometric-based predictive equations for assessing body composition in athletes and encourages the development of new equations for underrepresented sports in the current literature. [ABSTRACT FROM AUTHOR]

Background: Centenarians often represent one of the best examples of aging successfully. However, the role of body composition or hydration status assessed with bioelectrical impedance analysis (BIA) is poorly explored in this population. Therefore, the aim of this systematic review was to better understand the use and the role of BIA for evaluating body composition and hydration status in centenarians. Methods: We conducted a systematic review of the literature up to the 1st of May, 2022 for published articles providing data on BIA to evaluate body composition parameters or hydration status in centenarians. Data were summarized descriptively because a meta-analysis was not possible due to the scarcity of available studies. Results: Among 2222 articles screened, four were eligible including 291 centenarians (mean age: 100.5 years) who were mainly women (88%). In one study, BIA overestimated fat-free mass and underestimated fat mass when compared to deuterium oxide dilution. Another study carried out in Italy including 14 centenarians found a significant correlation between BIA and fat-free mass evaluated using anthropometric tools. In one study, BIA showed a significant agreement with anthropometric measures of fat mass. In the same sample, sarcopenia and dehydration, evaluated with BIA, had a high prevalence. Conclusion: BIA may be used for assessing body composition in centenarians, but research is limited to a few studies suggesting the need of future research in this area. [ABSTRACT FROM AUTHOR]

Vitamin D insufficiency is a global health concern and low vitamin D status is regularly associated with reduced muscle mass and sarcopenia in observational research. Recent research using Mendelian randomization (MR) has highlighted the potentially causal positive effect of serum vitamin D (25(OH)D) on total, trunk and upper body appendicular fat-free mass (FFM). However, no such effect was found in lower body FFM, a result that mirrors the outcomes of some vitamin D intervention studies. Here we review the current literature on vitamin D, muscle mass and strength and discuss some potential mechanisms for the differing effects of vitamin D on upper and lower body FFM. In particular, differences in distribution of the vitamin D receptor as well as androgen receptors, in the upper and lower body musculature, will be discussed. [ABSTRACT FROM AUTHOR]

Purpose: Public health interventions to address stunting and wasting should be evaluated for possibly contributing to obesity risk. The present study tested the hypothesis that small-quantity lipid-based nutrient supplements (SQ-LNS) might increase fat deposition, and that additional zinc provided via SQ-LNS or in the form of dispersible tablets would increase fat-free mass (FFM) accretion. Methods: Using a two-stage, cluster-randomized trial design, 34 communities were randomly assigned to the intervention cohort (IC) or non-intervention cohort (NIC), and family compounds within the IC were randomly assigned to receive different amounts of zinc (0, 5 or 10 mg zinc) incorporated in SQ-LNS or 5 mg zinc in the form of dispersible tablets along with treatment for diarrhea, malaria and fever. Body composition was assessed in a subset of IC (n = 201) and NIC (n = 74) children at 9 and 18 months using the deuterium dilution method. A mixed linear model was used to examine average change in FFM and % fat mass (%FM) among intervention groups and by cohort. Results: Children in the IC had significantly greater change in FFM (Mean (95% Confidence Interval)) (1.57 (1.49, 1.64) kg) compared to the NIC (1.35 (1.23, 1.46) kg; p = 0.005). There were no significant differences in the change in %FM between the NIC and IC or among the intervention groups. Conclusion: SQ-LNS, along with morbidity treatment increased weight gain and FFM in young children from 9 to 18 months of age without increasing FM deposition. Additional zinc supplementation did not affect changes in FFM or %FM. Trial registration: The study was registered as a clinical trial with the US National Institute of Health (www.ClinicalTrials.gov; NCT00944281). [ABSTRACT FROM AUTHOR]

Purpose: Obesity is an independent risk factor for renal injury. A more favorable metabolic environment following weight loss may theoretically lead to improved renal function. We aimed to evaluate the evolution of renal function one year after sleeve gastrectomy in a large prospective cohort of patients with morbid obesity and assess the influence of fat-free mass (FFM) changes. Methods: We prospectively included obese patients admitted for sleeve gastrectomy between February 2014 and November 2016. We also included a historical observational cohort of patients undergoing sleeve gastrectomy between January 2013 and January 2014 who had FFM evaluation. Patients were systematically evaluated 1 year after surgery. The estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. The FFM was estimated by analyzing computerized tomography (CT) scan sections from CT systematically performed 2 days and 1 year after sleeve gastrectomy to detect surgery complications. Results: Five hundred sixty-three patients fulfilled the inclusion criteria. The mean age was 41.2 ± 0.5 years. The mean body mass index was 43.5 ± 0.3 kg/m2 and 20.4, 30.5, and 30.7% of the included patients had type 2 diabetes, hypertension, and dyslipidemia, respectively. One hundred fifteen patients were excluded and four hundred forty-eight patients were finally included in the analysis. The eGFR was significantly higher 1 year after sleeve gastrectomy than before surgery (87.8 ± 0.9 versus 86.1 ± 0.9, p < 0.01). There was no difference in terms of post-surgery FFM loss between patients with an improved eGFR and those without (6.7 ± 0.3 kg versus 6.8 ± 0.5 kg, p = 0.9). Furthermore, post-surgery changes in the eGFR did not correlate with the amount of FFM loss (r = 0.1, p = 0.18). Conclusion: Renal function assessed by eGFR is significantly improved at 1-year post-sleeve gastrectomy, independent of changes in skeletal muscle mass. [ABSTRACT FROM AUTHOR]

Background: Aging presents changes in muscle mass that may lead to sarcopenia. Identifying safe, quick, and accessible methods to assess muscle mass is imperative. Aims: The purpose of this investigation was to compare the assessments of appendicular skeletal muscle mass (ASMM), fat-free mass (FFM), and fat mass (FM) between bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA). Methods: Seventy-three healthy, community-dwelling, physically active males (n = 19) and females (n = 54) (BMI = 27.1 ± 4.3 kg m−2) between the ages of 55–85 years underwent total-body BIA and DXA. ASMM was estimated via BIA from a previously published regression equation while DXA ASMM was calculated as the sum of the measured total arm lean mass and total leg lean mass. Paired-samples t tests with a significance level of p < 0.05 were conducted, while agreement between the methods was assessed via Bland–Altman plots. Results: In comparison to DXA, the chosen BIA equation overestimated ASMM (21.61 ± 5.82 kg vs. 18.82 ± 4.81 kg) and FFM (49.57 ± 9.94 kg vs. 46.22 ± 10.11 kg) and underestimated FM (24.59 ± 8.28 kg vs. 27.13 ± 10.01 kg), all p < 0.001. Visual inspection of the Bland–Altman plots revealed wide limits of agreement. Female participants were more clustered around the mean than male participants. Discussion: The multifrequency BIA device and chosen ASMM estimation equation resulted in wide limits of agreement and significantly different comparisons to the reference method of DXA. Conclusion: Future research should continue to investigate and validate methodologies to screen older individuals for characteristics of aging-related diseases, such as sarcopenia. [ABSTRACT FROM AUTHOR]

Introduction/objectives: Gastrointestinal tract (GIT) involvement is frequently observed in systemic sclerosis (SSc) and may lead to nutritional impairment. The aim of the study was to assess the prevalence of symptoms related to GIT involvement and to analyze the possible association between gastrointestinal symptoms and low muscularity in SSc patients. Methods: Sixty-nine consecutive patients (60 females, median age 53 (IQR 43–63), body mass index (BMI) 23.2 (IQR 20.9–24.6) kg/m2) with diagnosis of SSc admitted to our Scleroderma Unit were enrolled. Clinical status, anthropometric data, and bioelectrical impedance (Inbody 770, USA) analysis-assessed Fat-Free Mass Index (FFMI) were recorded upon enrollment. UCLA questionnaire was used to quantify GIT involvement with seven specific scales. Results: Mean FFMI was 16.2 kg/m2 (IQR 15.2–17.6). The median UCLA total score was 0.53 (IQR 0.19–0.89). FFMI showed a significant negative correlation with UCLA total score (r = −0.29, p = 0.016) and UCLA distention/bloating (r = −0.35, p < 0.01). In 16 patients (23.1%), FFMI was reduced and UCLA distention/bloating was significantly higher (p = 0.039) in SSc patients with lower FFMI [1.75 (IQR 0.75–2.12) vs 0.75 (IQR 0.25–1.75)]. At multiple linear regression model, FFMI showed association with UCLA distention/bloating [beta coefficient − 0.315 (95% CI of beta coefficient: −0.591; −0.039), p = 0.026], BMI [beta coefficient 0.259 (95% CI of beta coefficient: 0.163; 0.355), p = 0.001], and disease duration [beta coefficient − 0.033 (95% CI of beta coefficient: −0.059; −0.007), p = 0.015]. Conclusions: In SSc, low FFMI is associated with symptoms related to GIT involvement, in particular with distension/bloating. Key Points • FFMI is associated with symptoms related to GIT involvement. • Low FFMI is associated with symptoms related to UCLA distention/bloating. • Malnutrition is not associated with symptoms related to GIT involvement. [ABSTRACT FROM AUTHOR]

Aims: Bariatric surgeries induce profound weight loss (decrease in body mass index, BMI), through a decrease in fat mass (FM) and to a much lesser degree of fat-free mass (FFM). Some reports indicate that the weight which is lost after gastric bypass (RYGB) and sleeve gastrectomy (SG) is at least partially regained 2 years after surgery. Here we compare changes in BMI and body composition induced by four bariatric procedures in a 5 years follow-up study. Methods: We analyzed retrospectively modifications in BMI, FM and FFM obtained through Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG), biliopancreatic diversion (BPD) and a long common limb revisional biliopancreatic diversion (reduction of the gastric pouch and long common limb; BPD + LCL−R). Patients were evaluated at baseline and yearly for 5 years. Of the whole cohort of 565 patients, a subset of 180 patients had all yearly evaluations, while the remaining had incomplete evaluations. Setting University Hospital. Results: In a total of 180 patients evaluated yearly for 5 years, decrease in BMI and FM up to 2 years was more rapid with RYGB and SG than BPD and BPD + LCL−R; with RYGB and SG both BMI and FM slightly increased in the years 3–5. At 5 years, the differences were not significant. When analysing the differences between 2 and 5 years, BPD + LCL−R showed a somewhat greater effect on BMI and FM than RYGB, BPD and SG. Superimposable results were obtained when the whole cohort of 565 patients with incomplete evaluation was considered. Conclusions: All surgeries were highly effective in reducing BMI and fat mass at around 2 years; with RYGB and SG both BMI and FM slightly increased in the years 3–5, while BPD and BPD + LCL−R showed a slight further decreases in the same time interval. [ABSTRACT FROM AUTHOR]

Purpose: Low serum vitamin D status has been associated with reduced muscle mass in observational studies although the relationship is controversial and a causal association cannot be determined from such observations. Two-sample Mendelian randomization (MR) was applied to assess the association between serum vitamin D (25(OH)D) and total, trunk, arm and leg fat-free mass (FFM). Methods: MR was implemented using summary-level data from the largest genome-wide association studies (GWAS) on vitamin D (n=73,699) and total, trunk, arm and leg FFM. Inverse variance weighted method (IVW) was used to estimate the causal estimates. Weighted median (WM)-based method, and MR-Egger, leave-one-out were applied as sensitivity analysis. Results: Genetically higher serum 25(OH)D levels had a positive effect on total (IVW = Beta: 0.042, p = 0.038), trunk (IVW = Beta: 0.045, p = 0.023) and arm (right arm IVW = Beta: 0.044, p = 0.002; left arm IVW = Beta: 0.05, p = 0.005) FFM. However, the association with leg FFM was not significant (right leg IVW = Beta: 0.03, p = 0.238; left leg IVW = Beta: 0.039, p = 0.100). The likelihood of heterogeneity and pleiotropy was determined to be low (statistically non-significant), and the observed associations were not driven by single SNPs. Furthermore, MR pleiotropy residual sum and outlier test did not highlight any outliers. Conclusions: Our results illustrate the potentially causal, positive effect of serum 25(OH)D concentration on total, trunk and upper body appendicular fat-free mass. [ABSTRACT FROM AUTHOR]

Purpose This study aimed to evaluate body composition changes and the determinants of fat-free mass loss (FFML) up to 3 years after sleeve gastrectomy (SG) and one-anastomosis gastric bypass (OAGB). Materials and Methods A prospective study was conducted on 3864 patients with severe obesity who underwent either SG (2746, 76.1% women, mean age: 39.2 ± 11.6 years, and BMI: 44.3 ± 5.6 kg/m2) or OAGB (1118, 82.2% women, age: 39.9 ± 10.7 years, BMI: 45.6 ± 6.3 kg/m2). Body composition parameters were measured by bioelectrical impedance analysis preoperatively and 1, 3, 6, 9, 12, 18, 24, and 36 months after surgery. Changes in body composition were assessed using the propensity matched generalized estimated equation (GEE) method. The determinants of fat-free mass loss/weight loss (FFML/WL%) were defined using a mixed-model GEE analysis. Results Means of FM, FFM, and FFML/WL% decreased significantly in both study groups (Ptrend < 0.001). Changes in BMI, EWL%, FM, and FFML/WL% were different between the two groups (Pbetween < 0.05). The results showed a better FFM preservation and a greater FM loss over time in the OAGB group compared to the SG group (Pinteraction < 0.05). FFML during the first 3 months was greater in the SG compared to the OAGB group (P < 0.001). SG surgery, higher preoperative BMI, and female gender were associated with greater FFML/WL%. Conclusion In the SG compared to the OAGB group, FFML was greater, especially early after the surgery, emphasizing the need for therapeutic interventions such as regular exercise programs and dietary intake modifications. [ABSTRACT FROM AUTHOR]

Purpose: As one of the major problems for the health sector, morbid obesity is associated with many hormonal dysfunctions, including thyroid hormone disorders. Few studies have been performed on improving subclinical and clinical hypothyroidism following bariatric surgery. Therefore, we designed and conducted this study to evaluate the effect of various types of bariatric surgery on thyroid hormone levels and to assess the change of levothyroxine requirement in these patients. Methods: The data of all patients who underwent either sleeve gastrectomy (SG) or one-anastomosis gastric bypass (OAGB) surgery in the 5 years from 2016 to 2020 at our hospital were analyzed retrospectively. Results: From 1486 patients (792 cases of SG and 694 cases of OAGB), 281 patients had preoperative abnormal thyroid function tests: subclinical hypothyroidism (102 patients) and clinical hypothyroidism (179 patients). The T4 level did not change significantly in any of the groups and subgroups. However, the TSH level at the end of the sixth month after SG and OAGB in both groups significantly lowered. Nevertheless, there is no significant difference between the effect of SG and OAGB surgical procedures on the rate of TSH and T4 alterations in both subclinical and clinical hypothyroid patients. In the sixth month after surgery, 49% of clinically hypothyroid patients in the SG group (n = 179) reduced or stopped taking the medication. Conclusion: Whereas bariatric surgery reduces TSH levels, it does not significantly alter T4 levels. Furthermore, there is no apparent difference between subclinical and clinical hypothyroidism and different types of bariatric surgery. [ABSTRACT FROM AUTHOR]

Purpose: The primary objective of the study was to compare the implications of body composition on work volume, power outputs (peak, mean, and minimum), and relative drop load throughout 4 weeks of sprint interval training (SIT) in individuals living with and without obesity.Methods: Thirty-four participants living with (n = 16) and without (n = 18) obesity took part in 12 sessions of SIT over 4 weeks. SIT consisted of repeated 30-s Wingate with a drop load of 7.5% of the participant's body mass separated by 4 min of active recovery. Fat-free mass was estimated using a BOD POD. Work volume, drop load, and power output (peak, mean, and minimum) relative to body mass and fat-free mass were calculated using a Monark 874E Weight cycle ergometer.Results: Individuals living with obesity had a significantly larger drop load relative to fat-free mass (p < 0.001) and absolute drop load (p < 0.001) as well as a lower cycling cadence (p < 0.001) compared to individuals without obesity. No significant difference was observed in work volume (p = 0.167) as well as mean (p = 0.903), peak (p = 0.294), and minimum (p = 0.103) power relative to fat-free mass between groups.Conclusion: The findings suggest that individuals living with obesity work at a higher relative drop load when utilizing a percentage of body mass; however, a reduced cycling cadence results in similar total work volume throughout SIT. [ABSTRACT FROM AUTHOR]

Background: Powerlifting exercises are commonly performed by athletes and recreational trainers for increasing muscle strength. Increased performance for these exercises may promote beneficial outcomes, especially in terms of bone health. The aim of this study was to examine whether powerlifting exercise performance and muscle mass indices are associated with bone mineral density. Methods: Fifty-one males (median age 24.0 years) with resistance training experience (median 5.0 years) performed one-repetition maximum tests for the bench press, squat and deadlift. Muscle mass indices and bone mineral density were assessed via a whole-body dual energy X-ray absorptiometry (DEXA) scan. Stronger and weaker participants were directly compared for fat-free mass, lean mass and bone mineral density. Spearman rank-order correlation coefficient analyses were used to determine whether powerlifting exercise performance is related with muscle mass indices and bone mineral density. Results: Stronger participants had greater fat-free mass, appendicular lean mass, and bone density (p < 0.01). For all muscle mass indices (e.g., fat-free mass and appendicular lean mass) there were small to strong positive relationships found with bone mineral density (rs = 0.28–0.65; p < 0.05). Small to strong relationships were found between powerlifting exercise performance and bone mineral density for the majority of regions (rs = 0.29–0.65, p < 0.05). Powerlifting exercise performance was not related with leg bone mineral density. Conclusion: Focusing on improving powerlifting exercise performance and muscle mass appears to be beneficial for improving bone mineral density in young men. However, since this was a cross-sectional study causality cannot be established. [ABSTRACT FROM AUTHOR]

Summary: Peak bone mass is established during childhood. This study aimed to evaluate the associations of the components of overall body mass with areal bone mineral density Z-score in children. The findings of this study showed that children with greater overall body mass had higher aBMD Z-score. Purpose: Peak bone mass is established during childhood and adolescence. One of the important factors influencing predicted bone mass tracking in childhood and adolescence is alteration in the body composition during this growth period. This study aimed to evaluate the associations of the components of overall body mass with areal bone mineral density Z-score in children and adolescents. Methods: In this cross-sectional study, 478 healthy Iranian children and adolescents (237 girls and 241 boys) who had DXA measures participated. We evaluated the linearity of associations using generalized additive models. Results: Children's mean age was14 years with a range of 9–18 years, and 49.6% were girls. We found an increase in aBMD Z-score with increasing overall body mass (r = 0.25, p < 0.001). We observed this association with fat-free mass and total fat mass up to the 60th (~30 Kg) and 75th percentile (~12.5 Kg) [0.051 (95% CI, 0.027–0.075) increase in aBMD Z-score per 1 Kg increase in fat-free mass and 0.079 (95% CI, 0.044–0.114) increase in aBMD Z-score per 1 Kg increase in the total fat mass]. The correlation between Z-score of overall body mass and its components with aBMD Z-score was strongly positive. (P value < 0.001 for all) Conclusion: The findings of this study showed that children with greater overall body mass had higher aBMD Z-score. In addition, this study adds to a growing literature, suggesting that the relationship between body composition and BMD may be influenced by the pattern of fat and fat-free mass distribution in population. [ABSTRACT FROM AUTHOR]

Purpose: An influential covariate for pharmacokinetics is (body) size. Recently, the method of estimation of normal fat mass (NFM) has been advocated. Here, the relative contribution of fat mass, estimated as a fraction fat (Ffat), is used to explain differences in pharmacokinetic parameters. This concept is more and more applied. However, it remains unclear whether NFM can be reliably estimated in these typical studies. Methods: We performed an evaluation of the reliability of NFM estimation in a typical study size (n = 30), otherwise best-case scenario, by means of a pharmacokinetic simulation study. Several values of Ffat were investigated. Results: In a typical pharmacokinetic study, high imprecision was observed for NFM parameter estimates over a range of scenarios. For example, in a scenario where the true value of Ffat on clearance was 0.5, we found a 95% confidence interval of − 0.1 to 2.1, demonstrating a low precision. The implications for practice are that one could conclude that fat-free mass best describes the relationship of the pharmacokinetics with body size, while the true relationship was between fat-free mass and total body weight. Consequently, this could lead to incorrect extrapolation of pharmacokinetics to extreme body sizes. Conclusion: In typical pharmacokinetic studies, NFM should be used with caution because the Ffat estimates have low precision. The estimation of Ffat should always be preceded by careful study design evaluation before planning a study, to ensure that the design and sample size is sufficient to apply this potentially useful methodology. [ABSTRACT FROM AUTHOR]

Background: The Elipse™ intragastric balloon (EIGB) is a new swallowable balloon for weight loss (WL). Preserving metabolically active fat-free mass (FFM) and resting metabolic rate (RMR) during WL are crucial to maximize fat mass (FM) loss. After EIGB placement, a standard low-calorie diet (LCD) is generally prescribed. A low-calorie ketogenic diet (LCKD) has proven to be safe and effective in reducing FM while preserving FFM and RMR. Objective: To prospectively compare the effects on WL, FM, FFM, and RMR in two groups of patients who were randomized to two different diets: LCKD and a standard LCD after EIGB placement. Methods: WL, FM, FFM, and RMR were measured before EIGB and at 4 months in 48 patients who received either a LCKD (n = 24) or a standard LCD (n = 24). Compliance in following the prescribed diet was determined with food frequency questionnaires in all patients. The impact of LCKD and LCD on renal function was also evaluated. Results: The LCKD group showed a significantly lower decrease in FFM and RMR when compared with the LCD group (3.55 vs 14.3%, p < 0.001; 9.79 vs 11.4%, p < 0.001, respectively). FM decreased more significantly with LCKD compared to LCD (41.6 vs 33.1%, p = 0.0606). Compliance in following the prescribed diets, without negative impact on renal function, was found. Conclusion: Based on our findings, despite the small sample size, we were able to support the hypothesis that LCKD is associated with an increased FM loss while reducing the FFM loss and the RMR, without interfering with renal function after EIGB. [ABSTRACT FROM AUTHOR]

Aims: Conflicting results have been reported on the association of fat-free mass (FFM) and insulin resistance (IR). This study sought to test the association of FFM and IR by indexing FFM to avoid collinearity with fat mass. Methods: This cross-sectional study comprised 11,284 volunteers, aged 38–79 years. Body composition was assessed by multi-frequency bioelectrical impedance. FFM indexed to body surface area (FFMbsa) was calculated. IR and impaired glucose tolerance (IGT) were estimated with homeostatic model assessment of insulin resistance index (HOMA-IR) and 2-h oral glucose tolerance test (2h-OGTT), respectively. Results: Percent body fat decreased from the 1st to the 5th quintile of FFMbsa in both women (Eta2 = 0.166) and men (Eta2 = 0.133). In women, fasting insulin (Eta2 = 0.002), glucose (Eta2 = 0.006), and HOMA-IR (Eta2 = 0.007) increased slightly, but 2-h plasma glucose (2-h PG) was similar across the quintiles of FFMbsa. In men, fasting insulin and HOMA-IR were similar across the quintiles of FFMbsa, whereas fasting glucose increased slightly (Eta2 = 0.002) and 2-h PG decreased (Eta2 = 0.005) toward the highest quintile of FFMbsa. The higher the odds ratio for IR, the greater the FFMbsa in both sexes. Differently, FFMbsa did not affect the odds of IGT in women, while in men the odds ratio for IGT was lower in the 5th quintile compared with the 1st quintile of FFMbsa. Conclusions: Higher odds of IR associated with greater FFMbsa contrasted with lower odds of IGT associated with greater FFMbsa. IR may be misdiagnosed by HOMA-IR in adults with greater fat-free mass. [ABSTRACT FROM AUTHOR]

Background: Head and neck cancer patients have the second highest malnutrition prevalence, when compared with other oncological patients. They experience significant weight loss before diagnosis, during and after treatment, and even during the first year of follow-up. However, the prognostic value of weight loss depends on body mass index, and this may be associated with low skeletal muscle mass, masking its loss. Thus, weight loss itself poorly predicts outcome in head and neck cancer patients when compared with depleted skeletal muscle mass, illustrating the inadequacy of body mass index as an accurate method to reflect nutritional status. A synthesis is needed of the body composition changes occurring in head and neck cancer patients during treatment, as well as of the methods to assess it. Objective: The aim of this scoping review is to examine and map the body composition changes in head and neck cancer patients under oncological treatment with curative intent. A further objective is to determine which methods are used to assess body composition in these patients. Inclusion criteria: Types of participants: The current review considered head and neck cancer patients, aged 18 years or older. Concept: This scoping review considered all studies that focused on the body composition changes. Context: This scoping review considered the studies that evaluated the body composition changes in the context of treatment with curative intent. Surgical treatment approach was excluded to avoid excess heterogeneity in the data. Types of sources: This scoping review considered only published studies, with abstract available. Search strategy: A three-step search strategy was undertaken. This review was limited to studies published in English, Spanish, and Portuguese during 2000–2019. Data extraction: The data extracted included author(s)/year of publication, aims and purpose of the study, sample size, study design, type of treatment, measurement points and component(s) of body composition evaluated, body composition assessment methods, and main results/findings. Presentation of results: Head and neck cancer patients suffer from serious loss of lean body mass, skeletal muscle, or free fat mass, after treatment compared with baseline. Further, nutritional deterioration is evident and occurs up to 8–12 months after treatment. Bioelectrical impedance analysis is one of the body composition assessment tools that has the great advantage for being available on a regular basis for assessment of body composition in head and neck cancer patients. However, it cannot be recommended for clinical decision making until further validation. Conclusion: Head and neck cancer patients experience a significant depletion of lean body mass, fat-free mass, and skeletal muscle, accompanied by body fat mass, while undergoing (chemo)radiotherapy. This can be demonstrated either by triceps skinfold thickness, bioelectrical impedance analysis, dual-energy x-ray absorptiometry, or computed tomography. This loss has a remarkable impact on their survival, on their quality of life, and on the risk for post-operative complications and may result in a reduced response to cancer treatment. Thus, body composition assessment should become an integral component of the care of head and neck cancer patients, beyond weight and body mass index, and should be carried out at different times throughout treatment. [ABSTRACT FROM AUTHOR]

Purpose: Bariatric surgery generates a large weight loss. It is considered a successful surgery when 50% of the excess weight loss is reached. However, this measure does not include some variables that may have a direct impact on a patient's health, such as fat-free mass (FFM) or bone mass. Therefore, the aim of this study is to evaluate body composition and bone mass in patients undergoing one-anastomosis gastric bypass (OAGB). Methods: A prospective observational study was performed in patients undergoing OAGB. Body composition and bone mass were evaluated by bioelectrical impedance analysis at baseline (1 day prior to surgery), at 6 and 12 months after surgery. Results: A total of 94 patients (67% females and 33% males) were included in the study. The excess BMI loss at 6 and 12 months after surgery was 97.9 ± 20.1% and 110.2 ± 30.5% respectively. The FFM showed a reduction of 6.6 ± 4.8 kg (p < 0.01) 6 months after surgery and of 7.9 ± 4.9 kg (p < 0.01) at 12 months, meaning a decrease of 10.5 ± 7.3% and a 12.9 ± 6.6% respectively. The bone mass decrease was 10.1 ± 6.9% (p < 0.01) and 12.9 ± 6.5% (p < 0.01) at 12 months after OAGB. Conclusions: OAGB obtains a relevant weight loss in patients with morbid obesity, mainly, due to fat mass reductions. However, this procedure also provokes FFM and bone mass decreases, especially in females, but not significantly greater than other restrictive or mixed procedures. [ABSTRACT FROM AUTHOR]

Purpose: Fat-free mass (FFM) loss is a concerning aspect of bariatric surgery, but little is known about its time-course and factors related with excessive FFM loss. This study examined (i) the progress of FFM loss up to 3 years post-bariatric surgery and (ii) the prevalence and determinants of excessive FFM loss. Materials and Methods: A total of 3596 patients (20% males, 43.5 ± 11.1 years old, BMI = 44.2 ± 5.5 kg/m2) underwent sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) surgery. Bioelectrical impedance analysis was performed preoperatively and 3, 6, 9, 12, 18, 24 and 36 months post-surgery. Changes in body composition were assessed by mixed model analysis. Prevalence of excessive FFM loss (based on three different cutoff values: ≥ 25%, ≥ 30% and ≥ 35% FFM loss/weight loss (= %FFML/WL)) was estimated and its determinants were assessed by linear regression analysis. Results: Highest rates of FFM loss were found at 3 and 6 months post-surgery, reflecting 57% and 73% of peak FFM loss, respectively. Prevalence of excessive FFM loss ranged from 14 to 46% at 36 months post-surgery, with an older age (β = 0.14, 95%CI = 0.10–0.18, P <.001), being male (β = 3.99, 95%CI = 2.86–5.12, P <.001), higher BMI (β = 0.13, 95%CI = 0.05–0.20, P =.002) and SG (β = 2.56, 95%CI = 1.36–3.76, P <.001) as determinants for a greater %FFML/WL. Conclusion: Patients lost most FFM within 3 to 6 months post-surgery. Prevalence of excessive FFM loss was high, emphasizing the need for more vigorous approaches to counteract FFM loss. Furthermore, future studies should assess habitual physical activity and dietary intake shortly after surgery in relation to FFM loss. [ABSTRACT FROM AUTHOR]

Background: Although bariatric surgery can achieve sustained weight loss, there are major differences in the magnitude of weight change post-operatively. Reduced resting energy expenditure (REE) plays an important role in unsatisfactory weight loss effect by contributing to positive energy balance. Objectives: To identify pre- and post-surgical predictors related to satisfactory percent of total weight loss (%TWL) in Chinese individuals with obesity after laparoscopic sleeve gastrectomy (LSG). Methods: A retrospective cohort study was conducted in 97 ethnic Chinese with mean body mass index (BMI) of 37.2 kg/m2, focusing on body composition, anthropometric and metabolic energy expenditure parameters, and %TWL before and 6 months after LSG. Patients were divided post-operatively into those with or without satisfactory %TWL (%TWL ≥ 20%). Multiple stepwise logistic regression analysis was used to identify predictors. Results: Satisfactory %TWL was achieved in 53 (54.6%) patients 6 months after surgery. The univariate analysis of post-operative variables showed that patients with satisfactory %TWL had significantly higher resting energy expenditure/body weight (REE/BW) and lower respiratory quotient (RQ) than those who did not (P < 0.001). Multiple stepwise logistic regression analysis indicated that REE/BW and RQ were closely associated with satisfactory %TWL (P = 0.004, P = 0.023, respectively). %TWL was positively correlated with changes in BMI, percent of fat-free mass (FFM%), REE/BW, and RQ. Conclusions: Higher REE/BW and lower RQ resulting from LSG correlated with satisfactory %TWL in Chinese patients with obesity. The maintenance of FFM might be an important factor linking %TWL and REE/BW. [ABSTRACT FROM AUTHOR]

Purposes: To investigate longitudinally (1) the contribution of morphological covariates to explaining the development of maximum cardiac output ([Formula: see text] max) and maximum arteriovenous oxygen difference (a-vO2 diff max), (2) sex differences in [Formula: see text] max and a-vO2 diff max once age, maturity status, and morphological covariates have been controlled for, and, (3) the contribution of concurrent changes in morphological and cardiovascular covariates to explaining the sex-specific development of peak oxygen uptake ([Formula: see text]).Methods: Fifty-one (32 boys) 11-13-year-olds had their peak [Formula: see text], maximum heart rate (HR max), [Formula: see text] max, and a-vO2 diff max determined during treadmill running on three annual occasions. The data were analysed using multilevel allometric modelling.Results: There were no sex differences in HR max which was not significantly (p > 0.05) correlated with age, morphological variables, or peak [Formula: see text]. The best-fit models for [Formula: see text] max and a-vO2 diff max were with fat-free mass (FFM) as covariate with age, maturity status, and haemoglobin concentration not significant (p > 0.05). FFM was the dominant influence on the development of peak [Formula: see text]. With FFM controlled for, the introduction of either [Formula: see text] max or a-vO2 diff max to multilevel models of peak [Formula: see text] resulted in significant (p < 0.05) additional contributions to explaining the sex difference.Conclusions: (1) With FFM controlled for, there were no sex differences in [Formula: see text] max or a-vO2 diff max, (2) FFM was the dominant influence on the development of peak [Formula: see text], and (3) with FFM and either [Formula: see text] max or a-vO2 diff max controlled for, there remained an unresolved sex difference of ~ 4% in peak [Formula: see text]. [ABSTRACT FROM AUTHOR]

Introduction: Bariatric surgery–induced weight loss may reduce resting energy expenditure (REE) and fat-free mass (FFM) disproportionately thereby predisposing patients to weight regain and sarcopenia. Methods: We compared REE and body composition of African-American and Caucasian Roux-en-Y gastric bypass (RYGB) patients after surgery with a group of non-operated controls (CON). REE by indirect calorimetry; skeletal muscle (SM), trunk organs, and brain volumes by MRI; and FFM by DXA were measured at post-surgery visits and compared with CON (N = 84) using linear regression models that adjusted for relevant covariates. Ns in RYGB were 50, 42, and 30 for anthropometry and 39, 27, 17 for MRI body composition at years 1, 2, and 5 after surgery, respectively. Results: Regression models adjusted for age, weight, height, ethnicity, and sex showed REE differences (RYGB minus CON; mean ± s.e.): year 1 (43.2 ± 34 kcal/day, p = 0.20); year 2 (− 27.9 ± 37.3 kcal/day, p = 0.46); year 5 (114.6 ± 42.3 kcal/day, p = 0.008). Analysis of FFM components showed that RYGB had greater trunk organ mass (~ 0.4 kg) and less SM (~ 1.34 kg) than CON at each visit. REE models adjusted for FFM, SM, trunk organs, and brain mass showed no between-group differences in REE (− 15.9 ± 54.8 kcal/day, p = 0.8; − 46.9 ± 64.9 kcal/day, p = 0.47; 47.7 ± 83.0 kcal/day, p = 0.57, at years 1, 2, and 5, respectively). Conclusions: Post bariatric surgery patients maintain a larger mass of high–metabolic rate trunk organs than non-operated controls of similar anthropometrics. Interpreting REE changes after weight loss requires an accurate understanding of fat-free mass composition at both the organ and tissue levels. Clinical Trial Registration: Long-term Effects of Bariatric Surgery (LABS-2) NCT00465829 [ABSTRACT FROM AUTHOR]

Objective: To examine the body composition including fat patterning among 744 school going Chakma tribal and non- tribal Bengali girls (366 Chakma tribal and 378 Bengali girls), aged 6-12y from North, Unokoti, Dhalai and South District of Tripura.Methods: The subjects were selected using cluster-random sampling method. The anthropometric measurements of height, weight, triceps and subscapular skinfold were recorded. The body mass index (BMI) was also calculated. The measurements were used to estimate percent body fat (PBF) and fat-free mass (FFM) from skinfolds. Fat mass (FM) and FFM were each divided by height squared to produce the fat-mass index (FMI) and fat-free mass index (FFMI). Body composition was assessed using FM, FFM, FMI and FFMI.Results: Age-specific mean values of FM ranged from 2.65-6.75 kg (tribal) and 1.92-6.45 kg (non-tribal). Age-specific mean values of FFM ranged from 17.19-29.61 kg for tribals and 15.41-28.44 kg for non-tribals respectively. PBF of tribals was significantly (p < 0.01) higher (except 10 y) than non-tribals. FFM and PBF significantly (p < 0.01) related with all anthropometric variables.Conclusions: This study suggested a clear evidence of ethnic variation in fat patterning; Chakma tribal girls showing a greater subcutaneous adiposity in comparison with Bengali girls. These results are important for future investigations in clinical and epidemiological studies to identify the risk of lower or higher adiposity and body composition. [ABSTRACT FROM AUTHOR]

Background: A greater fat-free mass (FFM) is purported to be associated with protective effects on insulin resistance (IR). However, recent studies suggested negative associations between FFM and IR. Objectives: (1) To explore the direction of the association between FFM and IR in a large heterogeneous sample after controlling for confounding factors. (2) To determine cut off values of FFM associated with an increased risk of IR. Methods: Outcome variables were measured in 7044 individuals (48.6% women, 20–79 years; NHANES, 1999–2006): body composition [fat mass (FM), FFM and appendicular FFM (aFFM); DXA], FFM index [FFMI: FFM/height (kg/m2)], appendicular FFMI [aFFM/height (kg/m2)] and insulin resistance (HOMA-IR). Multivariate regression analyses were performed to determine the independent predictors of HOMA-IR in younger (20–49 years) and older (50–79 years) men and women. ROC analyses were used to determine FFM cut-offs to identify a higher risk of insulin resistance (HOMA-IR > 75th percentile). Results: aFFMI was an independent predictor of IR in younger (men: β = 0.21; women: β = 0.31; all p ≤ 0.001) and older (men: β = 0.11; women: β = 0.37; all p ≤ 0.001) individuals. Thresholds for aFFMI at which the risk of IR was significantly increased were 8.96 and 8.39 kg/m2 in younger and older men, and 7.22 and 6.64 kg/m2 in younger and older women, respectively. Conclusion: Independently of age, a greater aFFMI was an independent predictor of IR. These results suggest revisiting how we envision the link between FFM and IR and explore potential mechanisms. [ABSTRACT FROM AUTHOR]

Purposes: To investigate the development of peak oxygen uptake ([Formula: see text]) assessed on both a treadmill and a cycle ergometer in relation with sex and concurrent changes in age, body mass, fat-free mass (FFM), and maturity status and to evaluate currently proposed 'clinical red flags' or health-related cut-points for peak [Formula: see text].Methods: Multiplicative multilevel modelling, which enables the effects of variables to be partitioned concurrently within an allometric framework, was used to analyze the peak [Formula: see text]s of 138 (72 boys) students initially aged 11-14 years and tested on three annual occasions. Models were founded on 640 (340 from boys) determinations of peak [Formula: see text], supported by anthropometric measures and maturity status.Results: Mean peak [Formula: see text]s were 11-14% higher on a treadmill. The data did not meet the statistical assumptions underpinning ratio scaling of peak [Formula: see text] with body mass. With body mass appropriately controlled for boys' peak [Formula: see text]s were higher than girls' values and the difference increased with age. The development of peak [Formula: see text] was sex-specific, but within sex models were similar on both ergometers with FFM the dominant anthropometric factor.Conclusions: Data should not be pooled for analysis but data from either ergometer can be used independently to interpret the development of peak [Formula: see text] in youth. On both ergometers and in both sexes, FFM is the most powerful morphological influence on the development of peak [Formula: see text]. 'Clinical red flags' or health-related cut-points proposed without consideration of exercise mode and founded on peak [Formula: see text] in ratio with body mass are fallacious. [ABSTRACT FROM AUTHOR]

Introduction: Bariatric surgery has a significant influence on body composition (BC), which should be monitored. However, there is a need to recommend low-cost practical methods, with good estimation of BC for class III obese and/or bariatric patients.Objective: The aim of this study was to determine accuracy and agreement between BC assessed by direct segmental multifrequency bioelectrical impedance analysis (DSM-BIA) and doubly labeled water (DLW) as reference method.Material and Methods: Twenty class III obese women (age 29.3 ± 5.1 years; body mass index 44.8 ± 2.4 kg/m2) underwent Roux-en-Y gastric bypass surgery. BC (fat mass [FM], fat-free mass [FFM], and total body water [TBW]) was assessed by InBody 230 and DLW in the following periods: before and 6 and 12 months after surgery. Accuracy between the methods was evaluated by the bias and root mean square error. Pearson's correlation, concordance correlation coefficient (CCC), and Bland-Altman method were used to evaluate agreement between the methods.Results: Correlations were significant (p < 0.001) and CCC was good/excellent between both methods for the evaluation of FM (r = 0.84-0.92, CCC = 0.84-0.95), FFM (r = 0.73-0.90, CCC = 0.68-0.80), and TBW (r = 0.76-0.91, CCC = 0.72-0.81) before and after bariatric surgery. In addition, no significant bias was observed between DSM-BIA and DLW for FM (mean error [ME] = − 1.40 to 0.06 kg), FFM (ME = 0.91-1.86 kg), and TBW (ME = 0.71-1.24 kg) measurements.Conclusion: The DSM-BIA was able to estimate the BC of class III obese women submitted to bariatric surgery with values consistent with those of the DLW method. [ABSTRACT FROM AUTHOR]

Hospital malnutrition is a detrimental prognostic factor regarding hospital mortality, complications, and length of stay. However, the role of hospitalization itself on nutritional status has not been fully elucidated. We report the results of a secondary analysis from the dataset of a recent cross-sectional study at Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy. Data from patients evaluated at admission and discharge were collected and compared. One hundred thirty-nine patients were evaluated. Mean length of stay was 13.6 (± 7.7) days. Patients at risk of malnutrition, according to NRS-2002, were 75 (53.9%), while 63 (45.3%) were malnourished according to ESPEN Criteria. Compared to admission, at discharge, patients reported a significant decrease in Mid-Upper Arm Circumference (MUAC)-from 26.5 cm (± 3.6) to 25.9 cm (± 3.7) (p = 0.016), a reduction in Phase angle (PhA)-from 4.25° (± 1.20) to 4.01° (± 1.15) (p = 0.005), fat-free mass (FFM)-from 47.5 kg (± 9.19) to 44.9 kg (± 9.4) (p = 0.03) and fat-free mass index (FFMI)-from 16.9 kg/m2 (± 2.3) to 15.8 kg/m2 (± 2.7) (p = 0.04). Laboratory data showed a reduction of albumin-from 29.2 (± 5.7) to 28.0 (± 5.9) (p = 0.01) and Onodera's PNI- from 29.1 (± 5.6) to 27.6 kg (± 5.6) (p = 0.039). At the multivariate linear regression analysis, the variables significantly associated with a worsening of PhA at discharge are the PhA value at admission and the diagnosis of malnutrition according to ESPEN Criteria. Hospitalization leads to significative changes in nutritional status. A clinical concern should be raised about the quality of hospital food and meal times and on the need for a clinical nutritionist on the ward. [ABSTRACT FROM AUTHOR]

Purpose: Given the importance of physical activities for health outcomes, it is still unclear whether bariatric surgery per se and the standard care after surgery would result in an increase of physical activity level. This study aimed to determine physical activities preoperatively and at 6 and 12 months postoperatively among female patients who underwent bariatric surgery, and to investigate its relationship with body composition changes.Material and Methods: Thirty-four women who had Roux-Y gastric bypass (RYGB) surgery completed the study. Physical activity was measured objectively for 7 consecutive days by using an ActiGraph GT3X+ accelerometer. Body composition was estimated by using multifrequency bioimpedance analysis.Results: The percentage of time spent in moderate-to-vigorous physical activity (MVPA) changed significantly from preoperatively to 6 months postoperatively; however, no difference was observed at 12 months. No significant changes were detected for other physical activity variables. Multivariable regression analysis suggested that the percentage of time spent in sedentary activity was associated with fat-free mass loss at 6 months (β = − 0.323; 95% CI = − 0.649 to 0.003) and 12 months (β = − 0.510; 95% CI = − 0.867 to − 0.154) postoperatively.Conclusion: The overall MVPA increased at 6 months post-RYGB surgery; however, this change was not maintained at 12 months. Despite the considerable body mass loss postoperatively, most of the subjects were classified as being physically inactive and did not change their sedentary behavior. These findings indicate that female patients undergoing bariatric surgery should be encouraged to increase their physical activity level. [ABSTRACT FROM AUTHOR]

Background: Older adults experience age-related physiological changes that affect body weight and body composition. In general, nutrition and exercise have been identified as potent stimulators of protein synthesis in skeletal muscle. Milk proteins are excellent sources of all the essential amino acids and may represent an ideal protein source to promote muscle anabolism in older adults undergoing resistance training. However, several randomized control trials (RCTs) have yielded mixed results on the effects of milk proteins supplementation in combination with resistance training on body weight and composition.Methods: PubMed, Web of Science and Cochrane databases were searched for literature that evaluated the effects of milk proteins supplementation on body weight and composition among older adults (age ≥ 60 years) undergoing resistance training up to September 2016. A random-effects model was used to calculate the pooled estimates and 95% confidence intervals (CIs) of effect sizes.Results: The final analysis included 10 RCTs involving 574 participants (mean age range from 60 to 80.8 years). Overall, the combination of milk proteins supplementation and resistance training did not have significant effect on fat mass (0.30, 95% CI -0.25, 0.86 kg) or body weight (1.02, 95% CI: -0.01, 2.04 kg). However, a positive effect of milk proteins supplementation paired with resistance training on fat-free mass was observed (0.74, 95% CI 0.30, 1.17 kg). Greater fat-free mass gains were observed in studies that included more than 55 participants (0.73, 95% CI 0.30, 1.16 kg), and in studies that enrolled participants with aging-related medical conditions (1.60, 95% CI 0.92, 2.28 kg). There was no statistical evidence of publication bias among the studies.Conclusion: Our findings provide evidence that supplementation of milk protein, in combination with resistance training, is effective to elicit fat-free mass gain in older adults. [ABSTRACT FROM AUTHOR]

Background: Concerns for the possibility of an excessive loss of fat-free mass (FFM) and resting metabolic rate (RMR) after bariatric surgery, such as Roux-en-Y gastric bypass (RYGB) and duodenal switch (BPD/DS), have been raised. Objectives: This study aims to examine body composition and RMR in patients after RYGB and BPD/DS and in non-operated controls. Methods: Body composition and RMR were studied with Bod Pod and indirect calorimetry in weight-stable RYGB ( n = 15) and BPD/DS patients ( n = 12) and compared with non-operated controls ( n = 17). All patients were 30-55 years old and weight stable with BMI 28-35 kg/m. Results: FFM% was 58% (RYGB), 61% (BPD/DS), and 58% (controls). Body composition did not differ after RYGB and BPD/DS compared to controls, despite 27 and 40% total body weight loss, respectively. No difference in RMR or RMR/FFM was observed (1539, 1617, and 1490 kcal/24 h; and 28.9, 28.4, and 28.8 kcal/24 h/kg). Conclusion: Weight-stable patients with BMI 28-35 kg/m after RYGB and BPD/DS have a body composition and RMR similar to that of non-operated individuals within the same BMI interval. [ABSTRACT FROM AUTHOR]

Background: We recently showed that an 8-week preoperative protein-enriched diet (PED) is associated with significant reductions in body weight and fat mass (FM) without significant loss of fat-free mass (FFM) in morbidly obese patients scheduled for laparoscopic sleeve gastrectomy (LSG). Objectives: The objective of this study is to evaluate the impact of PED vs a normal protein diet (NPD) on total weight loss (TWL), FM, FFM, and resting metabolic rate (RMR) in patients after LSG. Methods: Before LSG and at 3, 6, and 12 months after, we prospectively measured and compared total body weight (TBW), FM, FFM, and RMR in 60 male patients who received either a NPD ( n = 30) with protein intake 1.0 g/kg of ideal body weight, or a PED ( n = 30) with protein intake 2.0 g/kg of ideal body weight. Compliance in following the prescribed diet was determined with food frequency questionnaires in all patients. The impact of NPD and PED on renal function was also evaluated. Results: Despite non-significant variation in total body weight (TBW), FM decreased more significantly ( p < 0.01) with the PED compared to the NPD. In addition, the PED group showed a significantly ( p < 0.01) lower decrease in FFM and RMR when compared with the NPD group. Both groups showed high compliance in following the prescribed diets, without negative impact on renal function. Conclusion: PED is more effective than NPD in determining FM loss and is associated with a lower decrease in FFM and RMR, without interfering with renal function in male patients after LSG. [ABSTRACT FROM AUTHOR]

Summary: The age-related loss of skeletal muscle and function are risk factors for osteoporosis and fractures. We found that higher adherence to the Mediterranean diet score was significantly associated with greater fat-free mass and leg explosive power suggesting a role for the Mediterranean Diet in prevention of loss of muscle outcomes. Introduction: The loss of skeletal muscle mass, strength, and function with age are contributing risk factors for the onset of sarcopenia, frailty, osteoporosis, fractures, and mortality. Nutrition may affect the progression and trajectory of these changes in skeletal muscle but the role of the micronutrient-rich Mediterranean diet (MD) has hardly been investigated in relation to these muscle outcomes. Methods: We examined associations between the MD score (MDS) and FFM% (fat-free mass / weight × 100), FFMI (fat-free mass/height), hand grip strength, and leg explosive power (LEP, watts/kg) in a cross-sectional study in 2570 women aged 18-79 years from the TwinsUK study. Measurements of body composition were made using dual-energy X-ray absorptiometry and dietary intake assessed by a food frequency questionnaire. FFM%, FFMI, grip strength, and LEP were compared across quartiles of the MDS after adjustment for covariates, with CRP measured in a subgroup ( n = 1658). Results: Higher adherence to the MDS was positively associated with measurements of muscle outcomes, with significant differences of 1.7 % for FFM% and 9.6 % for LEP ( P trend <0.001), comparing extreme quartiles of intake, but not with grip strength or CRP concentrations. Conclusions: For the first time in a northern European population, we have observed significant positive associations between the MDS and FFM% and LEP in healthy women that are potentially clinically relevant, independent of the factors known to influence muscle outcomes. Our findings emphasize the potential role for overall diet quality based on the MD in the prevention of age-related loss of skeletal muscle outcomes. [ABSTRACT FROM AUTHOR]

Dietary patterns have been linked to obesity in adults, however, not much is known about this association in early childhood. We examined associations of different types of dietary patterns in 1-year-old children with body composition at school age in 2026 children participating in a population-based cohort study. Dietary intake at the age of 1 year was assessed with a food-frequency questionnaire. At the children's age of 6 years we measured their body composition with dual-energy X-ray absorptiometry and we calculated body mass index, fat mass index (FMI), and fat-free mass index (FFMI). Three dietary pattern approaches were used: (1) An a priori-defined diet quality score; (2) dietary patterns based on variation in food intake, derived from principal-component-analysis (PCA); and (3) dietary patterns based on variations in FMI and FFMI, derived with reduced-rank-regression (RRR). Both the a priori-defined diet score and a 'Health-conscious' PCA-pattern were characterized by a high intake of fruit, vegetables, grains, and vegetable oils, and, after adjustment for confounders, children with higher adherence to these patterns had a higher FFMI at 6 years [0.19 SD (95 % CI 0.08;0.30) per SD increase in diet score], but had no different FMI. One of the two RRR-patterns was also positively associated with FFMI and was characterized by intake of whole grains, pasta and rice, and vegetable oils. Our results suggest that different a priori- and a posteriori-derived health-conscious dietary patterns in early childhood are associated with a higher fat-free mass, but not with fat mass, in later childhood. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare whole-body and segmental body composition variables of trained Brazilian table tennis players, according to different performance levels and gender. Sixty-four table tennis players (45 male and 19 female) were distributed in three groups according to performance level: international level players (ILP; 12 male; 8 female), national level players (NLP; 14 male; 6 female) and regional level players (RLP; 19 male; 5 female). The anthropometry measurements and body composition analysis were performed using Dual energy X-ray absorptiometry. Male players demonstrated higher fat-free mass (FFM), and lower fat mass (FM) and body fat percentage (%BF, p < 0.05) compared to female players in all competitive levels, however, non-significant differences were found between whole-body composition and performance level. In the comparison between the dominant and non-dominant arms, FFM, fat-free soft tissue mass (FFSTM) and bone mineral density (BMD) were higher in the dominant arm ( p < 0.05) compared to the non-dominant arm in all competitive levels, however, the male ILP group presented lower FFM and FFSTM in the dominant arm compared to the NLP, while the female ILP group presented higher BMD compared to the NLP and RLP. In conclusion, male table tennis players presented higher FFM and lower FM and %BF than female players and the dominant arm presented higher FFM and BMD than the non-dominant, possibly due to the mechanical impact-load imposed by time of table tennis practice. [ABSTRACT FROM AUTHOR]

The study of body composition can be used to verify one's state of fitness and the effectiveness of a training program. The aim of the study is to present the integration of this method for total and segmental assessment of body composition. 59 elite soccer players (aged 22.47 ± 5.58 years, height 1.81 ± 0.08 m) were enrolled for the study. Before the season and after 50 days of training, a body composition assessment was carried out. For the measurement of fat mass, folds of skin in 8 different regions were used. To evaluate cell mass and hydration status, bioimpedance with both whole-body and vector methods was used. The localized evaluation was performed by assessing bioelectrical values of the quadriceps, hamstrings and calf. Data before and after 50 days of soccer training were compared ( t test for paired data). The values of body composition were within the normal range for the sample. After 50 days of training, there was a significant increase in BMI mainly dependent on extracellular water. The fat did not undergo quantitative changes but only a change in distribution occurs. Lower limb muscles showed an increase in the amount of water more significant than the total body assessment. An integration of fat and fat-free mass in athletes allows us to determine different adaptations to training methods. The assessment of body segments under more stress by physical training provides more specific information than the total body assessment in athletes. This method could evaluate a peripheral status of hydration and cellular mass. [ABSTRACT FROM AUTHOR]

The causes of weight loss in Huntington's disease (HD) are not entirely clear. The aim was to identify risk factors that are associated with a loss of metabolically active tissues, i.e. fat-free mass. A consecutive cohort of non-diabetic HD participants (manifest HD, n = 43; CAG: mean 43.6.0 ± 3.6; preHD, n = 10; CAG: mean 41.4 ± 1.4) and 36 healthy controls was recruited. Twenty-five HD participants were early-stage HD (UHDRS Total Functional Capacity [TFC] stages I and II), 12 mid-stage HD (TFC stage III), and 6 participants were in late-stage HD (TFC stages IV and V). Food intake, basic metabolic rate and glucose homeostasis were assessed. In addition, fat-free mass was determined using bioelectric impedance analysis, and leptin, insulin and ghrelin as key metabolic regulators. Sex ratio and age were similar in HD participants (71 % women; age 50.6 ± 10.9) and controls (66 % women; age 46.4 ± 14.5). Body mass index (BMI) was lower in HD participants than controls (median 24.1 vs. 25.9, p = 0.04). However, fat-free mass and basic metabolic rate were not statistically different between groups and showed no association with disease burden. In controls and HD participants, leptin was the most important predictor of fat-free mass. While BMI was lower in HD participants, fat-free mass was similar to controls with leptin as its most important predictor. Leptin levels and fat-free mass measurements using bioelectric impedance analysis may be good screening tools to identify HD patients at risk for weight loss. [ABSTRACT FROM AUTHOR]

Background: A wide variety of functions has been attributed to ghrelin, a peptide hormone secreted in the stomach. The objective of the study was to assess the association of ghrelin concentrations with body composition among Iranian children. Methods: In this study, blood samples of 57 boys and 54 girls aged 6-10 were collected to measure ghrelin levels. Fat mass (FM) and fat-free mass (FFM) were examined by body composition analyzer. Actigraph GT3X was administered to assess children's physical activity and sleep. Data were analyzed using linear regression models. Results: All measured parameters did not differ between genders except for sleep time which was higher and sleep efficacy which was lower in boys compared with girls. None of the FM and FFM indices studied in boys was significantly associated with ghrelin levels. In girls, however, ghrelin concentrations were significantly associated with FM ( β = 0.04, P = 0.01), fat mass index ( β = 0.07, P = 0.008), and fat-free mass index ( β = 0.08, P = 0.04) and near-significantly associated with FFM ( β = 0.03, P = 0.09) after adjusting for age, physical activity, sleep, and dietary intake. Conclusion: Girls with higher ghrelin levels were more likely to have increased total FM and FFM. Conversely, body composition was not associated with ghrelin levels in boys. Consequently, ghrelin may influence the gender-related differences of body composition during childhood in girls. But, further study is needed to confirm our findings. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the influence of fat-free adipose tissue mass (FFAT) on association between dual-energy X-ray absorptiometry (DXA)-derived lean soft tissue mass and skeletal muscle mass (TMM). Forty-one middle-aged and older women were recruited for this study. Percent body fat, total and appendicular fat mass (tFM and aFM, respectively), and total and appendicular lean soft tissue mass (tLM and aLM, respectively) were measured using a DXA. FFAT was calculated based on the methods of a previous study. TMM was estimated from the ultrasound-derived prediction equation. The subjects were separated into three groups based on DXA-determined percent fat: low (n = 12, <25 %), middle (n = 15, ≥25 and <35 %), and high (n = 14, ≥35 %). DXA-derived aLM was greater in high than in middle or low, although ultrasound-estimated TMM was similar among the three groups. There was a strong correlation between aLM and TMM (r = 0.905, p < 0.001). The difference between aLM and TMM was correlated (p < 0.001) with aFM (r = 0.599) and tFM (r = 0.587). After adjusting for FFAT, aLM minus appendicular FFAT was similar among the three groups. aLM minus appendicular FFAT was strongly associated with TMM (r = 0.912, p < 0.001). Our results suggest that DXA-derived aLM accurately predicts TMM when subjects have moderate or lower adipose tissue mass. However, FFAT may falsely inflate the DXA-derived aLM measurement in individuals with a relatively high amount of adipose tissue mass (>35 % of body fat). Therefore, in this population, it is advisable to use DXA-derived aLM minus FFAT when evaluating age-related loss of skeletal muscle mass. [ABSTRACT FROM AUTHOR]

Purpose: This study tested the hypothesis that hypoxia exacerbates reductions in body mass observed during unloading. Methods: To discern the separate and combined effects of simulated microgravity and hypoxia, 11 healthy males underwent three 21-day campaigns in a counterbalanced fashion: (1) normoxic bed rest (NBR; FO = 0.209; PO = 133.1 ± 0.3); (2) hypoxic ambulatory confinement (HAMB; FO = 0.141 ± 0.004; PO = 90.0 ± 0.4; ~4,000 m); and (3) hypoxic bed rest (HBR; FO = 0.141 ± 0.004; PO = 90.0 ± 0.4). The same dietary menu was applied in all campaigns. Targeted energy intakes were estimated individually using the Harris-Benedict equation taking into account whether the subjects were bedridden or ambulatory. Body mass and water balance were assessed throughout the campaigns. Whole body and regional body composition was determined before and after the campaigns using dual-energy X-ray absorptiometry. Before and during the campaigns, indirect calorimetry and visual analogue scores were employed to assess the resting energy expenditure (REE) and perceived appetite sensations, respectively. Results: Energy intakes were lower than targeted in all campaigns (NBR: −5 %; HAMB: −14 %; HBR: −6 %; P < 0.01). Body mass significantly decreased following all campaigns (NBR: −3 %; HAMB: −4 %; HBR: −5 %; P < 0.01). While fat mass was not significantly altered, the whole body fat free mass was reduced (NBR: −4 %; HAMB: −5 %; HBR: −5 %; P < 0.01), secondary to lower limb fat-free mass reduction. Water balance was comparable between the campaigns. No changes were observed in REE and perceived appetite. Conclusions: Exposure to simulated altitude of ~4,000 m does not seem to worsen the whole body mass and fat-free mass reductions or alter resting energy expenditure and appetite during a 21-day simulated microgravity. [ABSTRACT FROM AUTHOR]

Background: Bioelectrical impedance (BIA) represents a simple, inexpensive and non-invasive method that is often used to assess fat-mass (FM) and fat-free mass (FFM) in large population-based cohorts. Objective: The aim of this study was to describe the reference ranges and examine the influence of age and gender on FM, FFM and skeletal muscle mass (SMM) as well as height-adjusted estimates of FM [fat mass index (FMI)], FFM [fat-free mass index (FFMI)] and SMM [SMM index (SMI)] in a national, population-based cohort of Australian adults. Design and Participants: The analytical sample included a total of 8,582 adults aged 25-91 years of Europid origin with complete data involved in the cross-sectional 1999-2000 Australian, Diabetes, Obesity and Lifestyle (AusDiab) Study. Measurements: Bioelectrical impedance analysis was used to examine components of body composition. Demographic information was derived from a household interview. Results: For both genders, FFM, SMM and SMI decreased linearly from the age of 25 years, with the exception that in men SMI was not related to age and FFM peaked at age 38 years before declining thereafter. The relative loss from peak values to ≥75 years in FFM (6-8%) and SMM (11-15%) was similar between men and women. For FM and FMI, there was a curvilinear relationship with age in both genders, but peak values were detected 6-7 years later in women with a similar relative loss thereafter. For FFMI there was no change with age in men and a modest increase in women. Conclusion: In Australian adults there is heterogeneity in the age of onset, pattern and magnitude of changes in the different measures of muscle and fat mass derived from BIA, but overall the age-related losses were similar between men and women. [ABSTRACT FROM AUTHOR]

Background: The Czech Republic lacks body composition data for women. Therefore, the purpose of the study was to analyze body composition [body fat mass (BFM), fat-free mass (FFM), body fat percentage (%BFM) and visceral adipose tissue (VAT)] and to evaluate the changes that occur with aging in women aged 18-89 years. We also analyzed anthropometric characteristics of study participants and developed age-specific percentile curves for body composition parameters. Methods: A cross-sectional, non-randomized study was conducted with a sample of 1,970 apparently healthy Czech women. Body composition was measured using a direct segmental multi-frequency bioelectrical impedance analysis (BSM-BIA). Results: The mean BFM was 19.7 ± 8.9 kg, and BFM reached its peak in women over 70, at 27.6 ± 8.8 kg. There was a strong correlation between BFM and age ( r = 0.61; r = 0.37). Fifty percent of the women in the study had a BFM between 13.0 and 25.0 kg. The %BFM ( r = 0.69; r = 0.47) and VAT ( r = 0.88; r = 0.77) were also significantly associated with age. The reference range for %BFM was 22.0-35.6 % (25th-75th percentile). The mean FFM was 45.8 ± 5.5 kg, and FFM decreased with age ( r = −0.27; r = 0.07). Conclusions: The results presented in this study showed a statistically significant increase in BFM, %BFM and VFA as age increased, and the values reached their peak in women over 70. Even when FFM decreased slightly with age, body weight increased because of the increase in BFM. [ABSTRACT FROM AUTHOR]

Background: Laparoscopic Roux-en-Y gastric bypass (LRYGBP) is currently the most common bariatric procedure and results in a substantial weight loss and recovery from obesity-related comorbidities, both of which are maintained in the long term. However, besides the desired loss of fat mass, LRYGBP is also followed by the loss of fat-free mass (FFM). We aimed to determine the factors associated with the loss of ≥20 % of the initial FFM 1 year after LRYGBP in a prospective series of 115 Caucasian, premenopausal women. Methods: Anthropometrics, body composition (bioelectrical impedance analysis), resting energy expenditure (REE) (indirect calorimetry), inflammation, insulin resistance, and lipid disturbances were determined before and 1 year after LRYGBP. Results: The mean loss of initial FFM was 15.3 ± 13.8 %. 1 year after LRYGBP, 81 women lost <20 % (<20 % FFM group) and 35 lost ≥20 % (≥20 % FFM group) of the initial FFM. Before surgery, the FFM, weight, BMI, excess BMI, brachial circumference, waist circumference, and REE were significantly higher in the ≥20 % FFM group while inflammation, insulin resistance, and lipid disturbances were comparable between the two groups. 1 year after LRYGBP, the FFM, weight, BMI, excess BMI, brachial circumference, waist circumference, and REE decreased significantly and were comparable between the two groups. Inflammation, insulin resistance, and lipid disturbances improved comparably between the two groups after surgery. The only variable associated with the loss of ≥20 % of the initial FFM in the multivariable analysis was the presence of more FFM before surgery (67.0 ± 9.9 vs. 53.5 ± 6.7 kg). Conclusions: One year after LRYGBP the loss of ≥20 % of the initial FFM occurred mainly in women with more FFM before surgery and resulted in the same body composition of women who lost <20 % of the initial FFM. [ABSTRACT FROM AUTHOR]