The impact of anorexia nervosa and BMI polygenic risk on childhood growth: A 20-year longitudinal population-based study.

Growth deviating from the norm during childhood has been associated with anorexia nervosa (AN) and obesity later in life. In this study, we examined whether polygenic scores (PGSs) for AN and BMI are associated with growth trajectories spanning the first two decades of life. AN PGSs and BMI PGSs were calculated for participants of the Avon Longitudinal Study of Parents and Children (ALSPAC; n = 8,654). Using generalized (mixed) linear models, we associated PGSs with trajectories of weight, height, body mass index (BMI), fat mass index (FMI), lean mass index (LMI), and bone mineral density (BMD). Female participants with AN PGSs one standard deviation (SD) higher had, on average, 0.004% slower growth in BMI between the ages 6.5 and 24 years and a 0.4% slower gain in BMD between the ages 10 and 24 years. Higher BMI PGSs were associated with faster growth for BMI, FMI, LMI, BMD, and weight trajectories in both sexes throughout childhood. Female participants with both a high AN PGS and a low BMI PGS showed slower growth compared to those with both a low AN PGS and a low BMI PGS. We conclude that AN PGSs and BMI PGSs have detectable sex-specific effects on growth trajectories. Female participants with a high AN PGS and low BMI PGS likely constitute a high-risk group for AN, as their growth was slower compared to their peers with high PGSs on both traits. Further research is needed to better understand how the AN PGS and the BMI PGS co-influence growth during childhood and whether a high BMI PGS can mitigate the effects of a high AN PGS.

High-standard predictive equations for estimating body composition using bioelectrical impedance analysis: a systematic review.

The appropriate use of predictive equations in estimating body composition through bioelectrical impedance analysis (BIA) depends on the device used and the subject's age, geographical ancestry, healthy status, physical activity level and sex. However, the presence of many isolated predictive equations in the literature makes the correct choice challenging, since the user may not distinguish its appropriateness. Therefore, the present systematic review aimed to classify each predictive equation in accordance with the independent parameters used. Sixty-four studies published between 1988 and 2023 were identified through a systematic search of international electronic databases. We included studies providing predictive equations derived from criterion methods, such as multi-compartment models for fat, fat-free and lean soft mass, dilution techniques for total-body water and extracellular water, total-body potassium for body cell mass, and magnetic resonance imaging or computerized tomography for skeletal muscle mass. The studies were excluded if non-criterion methods were employed or if the developed predictive equations involved mixed populations without specific codes or variables in the regression model. A total of 106 predictive equations were retrieved; 86 predictive equations were based on foot-to-hand and 20 on segmental technology, with no equations used the hand-to-hand and leg-to-leg. Classifying the subject's characteristics, 19 were for underaged, 26 for adults, 19 for athletes, 26 for elderly and 16 for individuals with diseases, encompassing both sexes. Practitioners now have an updated list of predictive equations for assessing body composition using BIA. Researchers are encouraged to generate novel predictive equations for scenarios not covered by the current literature.Registration code in PROSPERO: CRD42023467894.

Association of musculoskeletal involvement with lung function and mortality in patients with idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a progressive disease associated with high mortality. Low muscle mass, frailty and sarcopenia lead to functional impairment that negatively impact quality of life and survival but are not used in clinical practice. We aimed to determine the association of Fat-free mass index (FFMI) and frailty with lung function, exercise tolerance and survival in patients with IPF. In this study, 70 patients with IPF underwent assessment of body composition, lung function, 6-min walk distance (6MWD) testing, hand grip strength, quality of life (QoL) assessment by St. George's Respiratory questionnaire (SGRQ) and frailty assessment using the SHARE-FI tool. FFMI was calculated using pectoralis muscle cross-sectional area (PM-CSA) on CT chest images and the lowest quartile defined reduced muscle mass. Sarcopenia was defined as low FFMI and handgrip strength. Regression analyses were conducted to determine predictive value of frailty, low FFMI and sarcopenia on clinical outcomes. The Cox proportional hazards model was used to analyze the impact of FFMI and frailty score on survival. The mean age was 70 years with moderate impairment in lung function (mean ppFVC 68.5%, ppDLCO 45.6%). Baseline forced vital capacity (p < 0.001), diffusion capacity of lung for carbon monoxide (p = < 0.01), 6WMD (p < 0.05) were significantly lower in frail patients compared to non-frail patients. BMI was found to closely correlate with FFMI (r = 0.79, p < 0.001), but not with frailty score (r = - 0.2, p = 0.07). Frailty was a significant predictor of FVC, DLCO, 6MWD, SGRQ scores when adjusted for age and gender. Muscle mass and sarcopenia were significant predictors of FVC, DLCO, but not 6MWD or QoL scores. Multivariate cox-proportional hazards ratio model adjusting for age and gender showed that frailty was significantly associated with increased mortality (HR = 2.6, 95% CI 1.1-6.1). Low FFMI (HR = 1.3, 95% CI 0.6-2.8), and sarcopenia (HR = 2.1, 95% CI 0.8-5.3), though associated with a trend to increased mortality, were not statistically significant. Frailty is associated with lower lung function and higher mortality in patients with IPF. Longitudinal evaluations are necessary to further determine the associations between low FFMI, sarcopenia and frailty with outcomes in IPF.

Correlates of Body Composition in Children with Stunting: A Cross-sectional Study in Uganda.

BACKGROUND: Development of body composition (BC) may be disrupted in children with stunting. Such disruption may affect the later risk of excess adiposity and metabolic health, yet few studies have investigated correlates of BC in children with stunting. OBJECTIVES: We aimed to investigate nutritional status, infection and inflammation, breastfeeding behaviors, and other factors as correlates of BC in children with stunting. METHODS: Among Ugandan children with a height-for-age z-score <-2, BC was estimated using bioelectrical impedance analysis and compared with United Kingdom references. We used multiple linear regression analysis to identify correlates of fat mass (FM), fat-free mass (FFM), FM-index (FMI), and FFM index (FFMI) and height, adjusting for gender and age. RESULTS: In 750 children aged 1-5 y, FMI was 0.46 (95% confidence interval [CI]: 0.38, 0.54] and FFMI 0.18 [95% CI: 0.11, 0.26) z-scores lower than United Kingdom references. Elevated serum α1-acid glycoprotein was associated with 1.14 [0.76, 1.52] cm lower height, 0.50 [0.35, 0.65] kg/m2 less FFMI, and 0.48 [0.31, 0.66] kg/m2 greater FMI. Similar, weaker, associations for elevated serum C-reactive protein were detected. A positive malaria rapid test was associated with 0.64 [0.25, 1.02] cm shorter height, but 0.36 [0.18, 0.54] kg/m2 greater FMI. Anemia (according to hemoglobin) was associated with 0.20 [0.07, 0.33] kg less FFM in proportion to shorter height. Longer breastfeeding duration was associated with 0.03 [0.02, 0.04] kg greater FFM per month, in proportion to greater height. CONCLUSIONS: These children exhibited deficits in FM and FFM, proportionally to their stunted height, compared with United Kingdom references. Systemic inflammation correlated inversely with linear growth and FFM but positively with fatness, making it a possible target for intervention where fat-free tissue accretion is desirable. Longer breastfeeding may offer protection to lean linear growth, but findings for micronutrients were less clear. Longitudinal studies are warranted to support these findings. The study was registered at www.isrctn.com (Ref. ISRCTN13093195).

The effectiveness and sustainability of health outcomes from a holistic digital weight-loss service with concomitant initiation of tirzepatide: A pragmatic randomized controlled trial in the UK.

AIM: To measure the effectiveness and sustainability of the Juniper UK digital weight-loss service (DWLS), which delivers 6 months of personalized, proactive lifestyle coaching supplemented with tirzepatide to patients through a multidisciplinary team (MDT). METHODS: An observer-blinded randomized controlled trial (RCT) will be conducted on a cohort of non-diabetic patients of the Juniper DWLS in the UK. Participants in both the intervention and control groups will receive weekly subcutaneous injections of 2.5 mg tirzepatide for 4 weeks, uptitrating the dose to 5.0 mg from weeks 5 to 8, and by 2.5 mg every 4 weeks until reaching 15 mg in week 21, which they will maintain until the end of the intervention period at 6 months, when participants will be taken off the medication. The intervention group will receive personalized weeklylifestyle coaching with a focus on protein intake and resistance training for 6 months. Participants in the control group will attend a diet and exercise group counselling session at programme inception and will be sent a summary of the session's content at months 2 and 4. Aside from these events, health coaches will only interact with control group participants on a reactive basis. From month 6 to month 12, participants from both groups will no longer have access to their MDTs. The trial's co-primary endpoints include weight loss, fat-free to fat-mass ratio and composite strength measures at 12 months (6 months following the end of treatment), compared with baseline. Secondary endpoints include percentage change in weight, fat-free to fat-mass ratio, and composite strength from baseline to 6 months, side effect incidence, and change in cardiometabolic risk factors at 12 months. Quality of life and programme engagement represent the study's exploratory endpoints. RESULTS: A total of 688 participants enrolled in the study, with a mean age of 44.6 (± 11.4) years and a mean body mass index of 34.8 (± 7.5) kg/m2; 81.0% of participants are women, and 72.8% are of White ethnicity. More than three-quarters of participants have at least one co-morbidity, with dyslipidaemia (42.4%), hypertension (35.3%) and high cholesterol (31.8%) being the most prevalent conditions. CONCLUSIONS: This RCT will be the first to assess the effectiveness and sustainability of a real-world intensive, multidisciplinary DWLS, and it should highlight the potential of such a service for long-term obesity treatment compared with programmes that deliver standard health counselling.

Fat-free mass may play a dominant role in the association between systolic blood pressure and body composition in children and adolescents.

Systolic blood pressure (SBP) is significantly associated with body composition in children and adolescents. However, which one of the components of body composition is the dominant contributor to SBP in children and adolescents remains unclear. We, therefore, aimed to determine the dominant contributor to SBP among components of body composition in a large cohort of American children and adolescents derived from the National Health and Nutrition Examination Survey with cross-sectional analysis. In total, 13 618 children and adolescents (median age 13 years; 6107 girls) with available data on whole-body dual-emission X-ray absorptiometry measurements were included. Multiple linear regression showed that SBP was associated with higher total fat-free mass in boys (ß = 0·49, P < 0·001) and girls (ß = 0·47, P < 0·001) and with higher total fat mass only in boys (ß = 0·12, P < 0·001) after adjustment for covariates. When taking fat distribution into consideration, SBP was associated with higher trunk fat mass (boys: ß = 0·28, P < 0·001; girls: ß = 0·15, P < 0·001) but negatively associated with leg fat mass (Boys: ß = -0·14, P < 0·001; Girls: ß = -0·11, P < 0·001), in both boys and girls. Dominance analysis showed that total fat-free mass was the dominant contributor to SBP (boys: 49 %; girls: 55·3 %), followed by trunk fat mass (boys: 32·1 %; girls: 26·9 %); leg fat mass contributed the least to SBP in boys (18·9 %) and girls (17·8 %). Our findings indicated that total fat-free mass was not only associated with SBP but also the most dominant contributor to SBP variation in American children and adolescents.

Changes in alanine aminotransferase and body composition and metabolic factors among individuals receiving medical health checkups.

AIM: To examine the relationship between changes in alanine aminotransferase (ALT) and those in body composition and metabolic factors in participants receiving medical health checkups (4350 men [mean age 52.5 years] and 5398 women [mean age 50.5 years]) METHODS: We divided the participants into four types based on their ALT value at baseline and 1 year: A, ALT ≤30 (baseline) and ≤30 (1 year); B, ALT ≥31 (baseline) and ≤30 (1 year); C, ALT ≤30 (baseline) and ≥31 (1 year); and D, ALT ≥31 (baseline) and ≥31 (1 year). The change in each body composition-related parameter (waist circumference, fat mass, fat-free mass, fat mass to fat-free mass ratio, etc.) after 1-year was defined as Δ. RESULTS: The mean changes in waist circumference (cm) in the four types (A, B, C, and D) were -0.33, -1.54, 0.66, and -0.29 (overall p < 0.0001) in men, and -0.19, -0.90, 0.30, and 0.090 (overall p < 0.0001) in women. The mean changes in fat mass (kg) in the four types were -0.027, -0.86, 0.62, and 0.092 (overall p < 0.0001) in men, and 0.0067, -0.48, 0.39, and 0.063 (overall p < 0.0001) in women. The mean changes in fat-free mass (kg) in the four types were -0.028, -0.55, 0.42, and -0.034 (overall p < 0.0001) in men, and -0.0091, -0.34, 0.12, and -0.045 (overall p = 0.0012) in women. The mean changes in fat mass to fat-free mass ratio in the four types were -0.00042, -0.0120, 0.00837, and 0.00171 (overall p < 0.0001) in men, and -0.00013, -0.00817, 0.00730, and 0.00628 (overall p < 0.0001) in women. CONCLUSION: A decrease in ALT to ≤30 IU/L may be associated with improved body composition balance, but caution should be exercised for the decrease in muscle mass.

Fatty liver index and somatic composition in subjects receiving medical health checkup.

AIMS: To elucidate the relationship between fatty liver index (FLI) and somatic composition among health checkup recipients (4533 men and 4877 women). METHODS: Fat (F) index, fat-free (FF) index, and fat mass to fat-free mass (F-FF) ratio was measured by bioimpedance analysis. Skeletal muscle mass (SMM) loss was defined as FF index <18 kg/m2 in men and FF index <15 kg/m2 in women. The impact of FLI on the somatic composition (i.e., F index, FF index, and F-FF ratio) was retrospectively investigated. RESULTS: The median age in men and women was 54 and 52 years (p < 0.0001). The median body mass index in men and women was 23.4 and 21.1 kg/m2 (p < 0.0001). The prevalence of fatty liver on ultrasonography was 52.5% in men and 22.1% in women. The median FLI in men and women was 25.1 and 6.9 (p < 0.0001). Fatty liver index correlated significantly with F index (r > 0.5 in all analyses). In all analyses, the decreased SMM group had significantly lower FLI than the nondecreased SMM group. In receiver operating characteristic (ROC) curve analysis for the SMM decrease, in both genders, area under the ROCs of FLI were all over 0.80 (optimal cut-off point: 19.7 in men and 8.4 in women). The FLI correlated significantly with F-FF ratio (r > 0.5 in all analyses). CONCLUSION: The FLI can be a good indicator of not only fat mass but also FF mass and body composition balance in health checkup subjects. The FLI may not be just a marker of hepatic steatosis.

Assessment of body mass-related covariates for rifampicin pharmacokinetics in healthy Caucasian volunteers.

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.

Comparison of body mass index and fat mass index to classify body composition in adolescents-The EVA4YOU study.

The objectives of this study were to develop age- and sex-specific reference percentiles for fat mass index (FMI) and fat-free mass index (FFMI) in adolescents aged 14 to 19 years and to determine differences in overweight/obesity classification by FMI and body mass index (BMI). The EVA4YOU study is a single-center cross-sectional study conducted in western Austria. Cardiovascular risks including anthropometric measurements and bioelectrical impedance analysis were assessed in adolescents (mean age 17 years). FMI and FFMI were calculated as the ratio of fat mass (FM) and fat-free mass (FFM) to the square of height and compared to study population-specific BMI percentiles. One thousand four hundred twenty-two adolescents were included in the analysis. Girls had a significantly higher mean FM and FMI and a significantly lower mean FFM, FFMI (p < 0.001, each), and mean BMI (p = 0.020) than boys. Body composition classification by FMI and BMI percentiles shows a concordance for the < 75th and > 97th percentile, but a significant difference in percentile rank classifications between these two cut-off values (all p < 0.05). Based on FMI, 15.5% (221/1422) of the whole population and 29.4% (92/313) of those between the 75th and 97th percentiles are classified one category higher or lower than those assigned by BMI. CONCLUSION:  Classification of normal or pathologic body composition based on BMI and FMI shows good accordance in the clearly normal or pathologic range. In an intermediate range, FMI reclassifies categories based on BMI in more than a quarter of adolescents. Cut-off values to differentiate normal from pathologic FMI values on a biological basis are needed. TRIAL REGISTRATION: The study is registered at www. CLINICALTRIALS: gov  (Identifier: NCT04598685; Date of registration: October 22, 2020). WHAT IS KNOWN: • Chronic non-communicable diseases (NCDs) are the leading cause of morbidity and mortality globally, with major risk factors including unhealthy diets, harmful behaviors, and obesity. Obesity in children and adolescents is a key risk factor for later NCDs, which is commonly measured by Body Mass Index (BMI). • BMI can be misleading as it doesn't distinguish between fat mass (FM) and fat-free mass (FFM), leading to potential misclassification of obesity in children. Previous studies have already suggested the use of the Fat Mass Index (FMI) and Fat-Free Mass Index (FFMI) as a more accurate measures of body composition. WHAT IS NEW: • This study adds the first age- and sex-specific reference values for FMI and FFMI in Austrian adolescents using bioelectrical impedance analysis (BIA) as a safe and secure measurement method of a large representative cohort. • We found percentile misclassification between BMI and FMI when categorizing for obesity, especially in intermediate categories of body composition. Furthermore, when comparing the new reference values for FMI and FFMI to existing ones from the US, UK, and Germany we could show a good alignment within the European cohorts and major differences with American values, indicating and confirming the difference of FMI and FFMI for different populations of different ethnical background, living on different continents.

Effects of a single dose of rocuronium in patients with different body fat percentages: A randomised controlled trial.

The pharmacodynamics in patients with high body fat percentage might be similar to those in obese patients. This randomised controlled clinical trial observed the effects of rocuronium in patients with different percent body fats (PBFs). Fifty-four patients who underwent elective urological or pelvic surgery under general anaesthesia at Shanghai General Hospital were included in the present study; 51 patients were included for data analysis. Patients with normal PBF (<25%) were given a single dose of rocuronium calculated based on total body weight (N-TBW, control group). Patients with a higher PBF (≥25%) were given a single dose of rocuronium calculated based on total body weight (H-TBW). Patients with higher PBF and rocuronium were dosed based on fat-free mass (H-FFM). A train of four (TOF)-Watch acceleromyography monitor was used to measure the effects of the rocuronium. H-TBW (91.9 ± 28.8 s) had significantly shorter onset time than N-TBW and H-FFM (p = 0.003). H-TBW had significantly longer clinical duration time and pharmacological duration time than the other groups (p = 0.000 and 0.000, respectively); the TOF ratio0.25-0.9 time was significantly different among the three groups (p = 0.005). There were no significant differences in the recovery time (p = 0.103) or recovery index (p = 0.159) among the three groups. The effects of rocuronium dosed based on FFM in patients with high PBFs are similar to those in normal patients. A single dose of rocuronium calculated based on TBW might shorten the onset time, prolong the clinical and pharmacological duration times, and prolong the recovery time.

Comprehensive evaluation of body composition in a wide age range of Iranian adults using bioelectrical impedance analysis: Tehran Lipid and Glucose Study.

OBJECTIVE: To evaluate sex- and age-stratified body composition (BC) parameters in subjects with wide age range of 20-79 years. DESIGN: Cross-sectional. SETTING: Participants of Tehran Lipid and Glucose Study (TLGS). PARTICIPANTS: Two thousand nine hundred seventy participants met our inclusion criteria. They were divided into five age groups, and BC parameters were analysed based on sex and age using a bioelectrical impedance analyser (BIA). RESULT: The mean age of the participants was 42·1 ± 12·5 years, and 54 % of them were males. The mean BMI was 26·7 ± 3·7 kg/m2. Obesity indices were significantly higher in females (P < 0·001); however, skeletal muscle mass (SMM) and fat-free mass (FFM) were significantly higher in males (P < 0·001). Both SMM and FFM decreased significantly after the age of 50 years. Obesity indices significantly increased from the age group of 20-29 to 30-39 years in males and the age groups of 30-39 to 40-49 years and 40-49 to 50-59 years in females. The fat mass ratio (fat mass/SMM) showed two peaks in both sexes (after the ages of 30 and 50 years in males and 40 and 50 years in females). A strong correlation was found between BMI and percentage of body fat (r = 0·823 in females v. r = 0·768 in males). CONCLUSION: This is the first community-based study in the MENA region identifying sex- and age-stratified BC values using BIA. Our findings can be used as a reference for comparison in appropriate settings.

Glucose volume of distribution affects insulin sensitivity measured by intravenous glucose tolerance test.

AIM: To determine whether glucose volume of distribution (VdGLUCOSE ) affects the diagnosis of impaired insulin sensitivity (IS) when using an intravenous glucose tolerance test (IVGTT). METHODS: Individuals with distinct levels of IS underwent IVGTT after an overnight fast. The prediabetic group (Prediab; n = 33) differed from the healthy group (Healthy; n = 14) in their larger glycosylated hemoglobin (HbA1c of 5.9 ± 0.3 vs. 5.4 ± 0.1%; 41 ± 4 vs. 36 ± 1 mmol/mol; p < 0.001), percent body fat (37 ± 6 vs. 24 ± 3%; p < 0.001) and cardiovascular fitness level (VO2MAX 22 ± 5 vs. 44 ± 5 mL of O2 ·kg-1 ·min-1 ; p < 0.001). Ten minutes after intravenous infusion of the glucose bolus (i.e., 35 g in a 30% solution), VdGLUCOSE was assessed from the increases in plasma glucose concentration. IS was calculated during the next 50 min using the slope of glucose disappearance and the insulin time-response curve. RESULTS: VdGLUCOSE was higher in Healthy than in Prediab (230 ± 49 vs. 185 ± 21 mL·kg-1 ; p < 0.001). VdGLUCOSE was a strong predictor of IS (ß standardized coefficient 0.362; p = 0.004). VO2MAX was associated with VdGLUCOSE and IS (Pearson r = 0.582 and 0.704, respectively; p < 0.001). However, body fat was inversely associated with VdGLUCOSE and IS (r = -0.548 and -0.555, respectively; p < 0.001). CONCLUSIONS: Since fat mass is inversely related to VdGLUCOSE and in turn, VdGLUCOSE affects the calculations of IS, the IV glucose bolus dose should be calculated based on fat-free mass rather than body weight for a more accurate diagnosis of impaired IS.

Associations between 47 anthropometric markers derived from a body scanner and relative fat-free mass in a population-based study.

BACKGROUND: Low relative fat free mass (FFM) is associated with a greater risk of chronic diseases and mortality. Unfortunately, FFM is currently not being measured regularly to allow for individuals therapy. OBJECTIVE: One reason why FFM is not being used may be related to additional equipment and resources, thus we aimed to identify easily accessible anthropometric markers related with FFM. MATERIALS AND METHODS: We analyzed data of 1,593 individuals (784 women; 49.2%, age range 28-88 years) enrolled in the population-based Study of Health in Pomerania (SHIP-TREND 1). Forty-seven anthropometric markers were derived from a 3D optical body-scanner. FFM was assessed by bioelectrical impedance analysis (FFMBIA) or air displacement plethysmography (FFMADP). In sex-stratified linear regression models, FFM was regressed on anthropometric measurements adjusted for body height and age. Anthropometric markers were ranked according to the coefficient of determination (R2) derived from these regression models. RESULTS: Circumferences of high hip, belly, middle hip, waist and high waist showed the strongest inverse associations with FFM. These relations were stronger in females than in males. Associations of anthropometric markers with FFMAPD were greater compared to FFMBIA. CONCLUSION: Anthropometric measures were more strongly associated with FFMADP compared to FFMBIA. Anthropometric markers like circumferences of the high or middle hip, belly or waist may be appropriate surrogates for FFM to aid in individualized therapy. Given that the identified markers are representative of visceral adipose tissue, the connection between whole body strength as surrogate for FFM and fat mass should be explored in more detail.

Bioimpedance analysis of fat free mass and its subcomponents and relative associations with maximal oxygen consumption in facioscapulohumeral dystrophy.

PURPOSE: Fat free mass (FFM) is considered the metabolically active component of human body and is positively associated with maximal oxygen uptake ( VO 2 max ). However, FFM is composed of metabolically active and inactive subcomponents whose proportion can vary depending on body composition and clinical condition, possibly affecting such association. Although it is known that in facioscapulohumeral dystrophy (FSHD) peculiar changes in body composition occur, it is unclear whether there are alterations in FFM composition and, if so, whether such alterations affect the association towards VO 2 max compared to healthy subjects (HS). METHODS: To address this issue, 27 FSHD patients (mean age 37.3; 9 female) and 27 sex and age matched HS, underwent an assessment of VO 2 max by cardiopulmonary exercise tests (CPET) and body composition, with reference to FFM and its subcomponents, by bioimpedance analysis. RESULTS: In between-groups comparison, patients showed lower amounts of body cell mass (BCM) and intracellular water (ICW) which reflect in lower BCM/FFM ratio and higher extracellular to intracellular water ratio (ECW/ICW). Patients' VO 2 max was lower than HS and, even if with lower associative values than HS, correlated with FFM and BCM, while BCM/FFM and ECW/ICW ratios associations were observed only in HS. CONCLUSION: FSHD patients showed lower amount of BCM and ICW. BCM resulted as the parameter with the highest associative value with VO2max in both groups. Since VO 2 max is associated with functional ability in dystrophic patients, BCM, rather than FFM, could be an additional body composition-based clinical stratification factor.

The role of various physiological and bioelectrical parameters for estimating the weight status in infants and juveniles cohort from the Southern Cuba region: a machine learning study.

OBJECTIVE: The search for other indicators to assess the weight status of individuals is important as it may provide more accurate information and assist in personalized medicine.This work is aimed to develop a machine learning predictions of weigh status derived from bioimpedance measurements and other physical parameters of healthy infant juvenile cohort from the Southern Cuba Region, Santiago de Cuba. METHODS: The volunteers were selected between 2002 and 2008, ranging in age between 2 and 18 years old. In total, 393 female and male infant and juvenile individuals are studied. The bioimpedance parameters are obtained by measuring standard tetrapolar whole-body configuration. A classification model are performed, followed by a prediction of other bioparameters influencing the weight status. RESULTS: The results obtained from the classification model indicate that fat-free mass, reactance, and corrected resistance primarily influence the weight status of the studied population. Specifically, the regression model demonstrates that other bioparameters derived from impedance measurements can be highly accurate in estimating weight status. CONCLUSION: The classification and regression predictive models developed in this work are of the great importance for accessing to the weigh status with high accuracy of younger individuals at the Oncological Hospital in Santiago de Cuba, Cuba.

Big data-based reference centiles for body composition in Korean children and adolescents: a cross-sectional study.

BACKGROUND: The changes in body composition during puberty not only contribute to the differences in body composition between adult males and females but also have associations with growth problems and metabolic disorders, including obesity. Therefore, understanding the changes in body composition during the pubertal period and analyzing reference values based on race and gender are essential research resources. The objective of this study was to generate reference centiles for body composition on a monthly basis using an extensive dataset of body composition information from Korean children and adolescents. METHODS: A total of 88,069 measurements from 22,515 children (11,062 boys and 11,453 girls) aged 7-16 years using a bioelectrical impedance analysis were included in the study after performing a Z-score-based data management procedure. Height, weight, body fat mass (BFM), and fat-free mass (FFM) were measured and used to derive body fat percentage (BF%), body mass index (BMI), fat mass index (FMI), and fat-free mass index (FFMI). Sex- and age-specific centiles were estimated using generalized additive models for location, scale, and shape with the Box-Cox Cole and Green distribution (i.e., lambda-mu-sigma method). RESULTS: The sex- and age-related disparities in body composition were most pronounced when weight was partitioned into BFM and FFM. In boys, the FFM increased markedly during pubertal growth spurts, whereas BFM remained relatively stable. In girls, the BFM increased steadily, whereas the rate of FFM increased slowly. The BMI increased steadily with age in both sexes. However, when BMI was parsed into FMI and FFMI, it became clear that the FFMI increased substantially during pubertal growth in boys, whereas the FMI peaked around age 11 and then declined. Conversely, the FMI increased steadily in girls, albeit with a slowing rate in the increase of the FFMI beginning around age 12. CONCLUSIONS: This study produced age- and sex-specific reference percentiles for body composition indices in Korean children and adolescents using extensive biometric data.

Clinical Perspectives, Eligibility, and Success Criteria for Bariatric/Metabolic Surgery.

Obesity is a worldwide chronic, complex, and progressive disease that poses a challenge for physicians to pursue optimal therapeutic decision making. This chapter focuses on the definition of obesity, based on excessive fat accumulation, and thus underscores the importance of body composition, and the clinical tools used to diagnose it in the context of excess weight, metabolic alteration, and obesity-associated comorbidity development. Additionally, it addresses the indications for surgery that are currently applicable and the description of the different types of patients who could benefit the most from the surgical management of excessive body fat and its associated metabolic derangements and quality of life improvement. Furthermore, it also highlights plausible underlying mechanisms of action for the beneficial effects following bariatric/metabolic surgery.

Body composition and associated factors among 5-7-year-old children with moderate acute malnutrition in Jimma town in southwest Ethiopia: A comparative cross-sectional study.

Acute malnutrition affects not only the growth and development but also the body composition of children. However, its specific effects have not yet been characterized. This study aims to compare the body composition of 5-7-year-old children with moderate acute malnutrition (MAM) to that of their well-nourished (WN) peers and identify associated factors. A school-based comparative cross-sectional study was conducted from June to July 2022 in Jimma town, southwest Ethiopia. The study participants were selected from eight kindergartens and eight primary schools using a simple random sampling technique based on the proportional allocation of the sample to the size of the population in the respective school. Descriptive statistics and multivariable linear regression analyses were used to assess the mean differences and associations between variables and isolate independent predictors of body composition, respectively. The statistical significance was determined using ß-coefficients with 95% confidence intervals and a p value of ≤ 0.05. Data were captured from 388 (194 MAM and 194 WN) children with a response rate of 97.9%. The mean fat-free mass of WN children was significantly higher compared with those with MAM (p < 0.001). The mean (SD) of fat mass of MAM children was 4.23 ± 0.72 kg, 4.36 ± 0.88 kg and 4.08 ± 0.89 kg for 5, 6 and 7-year-olds, respectively. For WN children, the mean (SD) of fat mass was 4.92 ± 0.88 kg for 5 years old, 5.64 ± 1.01 kg for 6 years old and 5.75 ± 1.26 kg for 7 years old (p < 0.001). On the multivariable linear regression analysis after controlling for background variables, WN children exhibited 1.51 times higher fat-free mass compared with MAM children (ß = 1.51, p = 0.003). A unit increase in age of the study participants was associated with a 1.37 increment in fat-free mass (ß = 1.37, p < 0.001). WN children had 1.07 times higher fat mass compared with children with MAM (ß = 1.07, p < 0.001). A unit increase in the age of the child resulted in 0.15 times increment in fat mass (ß = 0.15, p = 0.020), and being female was associated with a 0.37 increase in fat mass (ß = 0.37, p < 0.001). The results showed that the mean fat mass and fat-free mass were significantly lower among moderately acute malnourished children than in WN children showing the loss of both body compartments due to malnutrition. The body mass index for age, age of the child and sex of the child were significantly linked to both fat-free mass and fat mass.

Irradiation dose to the swallowing apparatus impacts nutritional status in head and neck cancer patients-results from the prospective randomized HEADNUT trial.

PURPOSE: To investigate the influence of radiation dose to the swallowing muscles on the nutritional status in patients with head and neck cancer undergoing primary or adjuvant (chemo)radiotherapy (C)RT. METHODS: Between 2018 and 2020, 61 patients were prospectively randomized into the so-called HEADNUT trial (head and neck cancer patients undergoing nutritional intervention). Follow-up was continued until 2022. Contouring of the swallowing apparatus included the superior (scm), middle (mcm), and inferior constrictor muscle (icm), the cricopharyngeal muscle (cphm), and the esophageal inlet. Nutritional status was assessed by bioelectrical impedance analysis (BIA) at the beginning and the end of radiotherapy. The posttherapeutic nutritional status was evaluated by the BIA-derived fat-free mass index (FFMI; kg/m2). Malnutrition was assumed at FFMI values of < 15 (women) and < 17 (men) kg/m2. To find differences between dosimetric parameters in well- and malnourished patients, Mann-Whitney U test was used. To model the association between malnutrition and its potentially influencing variables, several logistic regression models were built. RESULTS: The following parameters differed between well- and malnourished patients at the end of therapy: icm Dmean, V40Gy (%), V50Gy (%), and V60Gy (%), and sphm V40Gy (%). After entering these parameters into a multivariable logistic regression model (dosimetric model), icm Dmean (b = -0.12; Exp(b) = 0.88; 95% CI: 0.78-1.0; p = 0.06) and icm V40Gy (%; b = 0.06; Exp(b) = 1.07; 95% CI: 1-1.13; p = 0.04) proved to be independent dosimetric predictors of malnutrition. We only determined the cut-off value for predicting malnutrition for icm V40Gy (%) since it was the only parameter which met p < 0.05. The optimal cut-off value for the predictor V40Gy (%) based on the Youden Index was 85.6%. Another logistic regression model (dosimetric-clinical model) consisted of icm V40 (%) and the clinical parameters tumor localization, malnutrition before RT, gender, and combined chemotherapy. It was confirmed that both icm V40% (b = -1.9; Exp(b) = -2.7; 95% CI: 0.01-0.8; p = 0.03) and malnutrition at baseline (b = -1.9; Exp(b) = 4.4; 95% CI: 8.4-816.6; p = 0.0002) were independent predictors of subsequent malnutrition the end of RT. CONCLUSION: Establishment of a normal nutritional status before the start of RT and adherence to dose constraints for the swallowing apparatus may prevent malnutrition in head and neck cancer patients at the end of therapy. Specifically, we suggest an icm V40Gy (%) of more than 86% to be predictive for nutritional complications.