Search

Objectives: The aim of this study was to evaluate body composition variability assessed by bioimpedance in relation to nutritional status assessed by anthropometry in children and adolescents living in countries characterized by contrasting nutritional conditions., Methods: The sample was comprised of 8614 children (4245 males; 4369 females), aged 3 to 19 years, from Nepal (477 children), Uganda (488 children and adolescents), UK (297 children and adolescents) and US (7352 children and adolescents). Height-for-age (HAZ) and body mass index-for-age (BAZ) z-scores were calculated according to WHO growth references. Specific bioelectrical impedance vector analysis (BIVA) was used to evaluate body composition variability. In each population sample, the relationship of HAZ and BAZ with bioelectrical outcomes was analysed by confidence ellipses and cubic spline regression, controlling for sex and age., Results: The participants from Uganda and Nepal were more affected by undernutrition, and those from the US and UK by obesity. In all groups, phase angle and specific vector length were weakly associated with HAZ, with null or opposite relationships in the different samples, whereas they were positively associated with BAZ. The stronger association was between vector length, indicative of the relative content of fat mass, and BAZ in the UK and US samples. Confidence ellipses showed that the relationships are more strongly related to phase angle in Nepalese and Ugandan samples., Conclusions: Bioelectrical values were more strongly associated with BAZ than HAZ values in all population samples. Variability was more related to markers of muscle mass in Ugandan and Nepalese samples and to indicators of fat mass in UK and US samples. Specific BIVA can give information on the variability of body composition in malnourished individuals., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Body composition could help identify malnutrition in pediatric patients, but there is uncertainty over which techniques are most suitable and prevailing opinion that measurements are difficult to obtain in practice. This study examined the acceptability, practicality, reliability, and validity of different anthropometric and body composition measurements in patients with complex diagnoses in a tertiary pediatric hospital., Methods: A total of 152 children aged 5-18 years had weight, height, body mass index (BMI), mid-upper arm circumference (MUAC), 4-site skinfold thicknesses (SFT), bioelectrical impedance analysis (BIA), and dual-energy x-ray absorptiometry (DXA) assessed on admission and discharge. Acceptability was assessed in a continuous scale, practicality with number/percentage of successful measurements, reliability with intraclass correlation coefficients and coefficients of repeatability, and validity between "simpler" techniques and DXA with Bland-Altman analysis of agreement and Cohen kappa., Results: Techniques were overall acceptable. Measurements were successful in >50%, with patient refusal uncommon. Coefficients of repeatability were good (0.3 cm MUAC and height, 0.2 kg weight, and 1.0 mm SFTs). All techniques significantly overestimated DXA fat mass, but BMI and triceps SFT better identified abnormal fat mass (κ = 0.46 and 0.49). BIA fat-free mass was not significantly different from DXA, with substantial agreement between techniques (κ = 0.65)., Conclusion: Body composition by a range of techniques is acceptable, practical, and reliable in a diverse group of children with complex diagnoses. BIA seems a good alternative to DXA for assessing fat-free mass, triceps SFT, and BMI for fat mass but should be used with care as it could overestimate total fat mass in individuals., (© 2023 American Society for Parenteral and Enteral Nutrition.)

Background: Variability in body mass index (BMI) (kg/m 2 ) trajectories is associated with body composition and cardiometabolic markers in early childhood, but it is unknown how these associations track to later childhood., Objectives: We aimed to assess associations of BMI trajectories from 0 to 5 y with body composition and cardiometabolic markers at 10 y., Methods: In the Ethiopian infant anthropometry and body composition (iABC) birth cohort, we previously identified 4 distinct BMI trajectories from 0 to 5 y: stable low BMI (19.2%), normal BMI (48.8%), rapid growth to high BMI (17.9%), and slow growth to high BMI (14.1%). At 10 y, we obtained data from 320 children on anthropometry, body composition, abdominal subcutaneous and visceral fat, and cardiometabolic markers. Associations of BMI trajectories and 10-y outcomes were analyzed using multiple linear regression., Results: Compared with children with the normal BMI trajectory, those with rapid growth to high BMI had 1.7 cm (95% CI: 0.1, 3.3) larger waist circumference and those with slow growth to high had 0.63 kg/m 2 (95% CI: 0.09, 1.17) greater fat mass index and 0.19 cm (95% CI: 0.02, 0.37) greater abdominal subcutaneous fat, whereas those with stable low BMI had -0.28 kg/m 2 (95% CI: -0.59, 0.03) lower fat-free mass at 10 y. Although the confidence bands were wide and included the null value, children with rapid growth to high BMI trajectory had 48.6% (95% CI: -1.4, 123.8) higher C-peptide concentration and those with slow growth to high BMI had 29.8% (95% CI: -0.8, 69.8) higher insulin and 30.3% (95% CI: -1.1, 71.6) higher homeostasis model assessment of insulin resistance, whereas those with rapid growth to high BMI had -0.23 mmol/L (95% CI: -0.47, 0.02) lower total cholesterol concentration. The trajectories were not associated with abdominal visceral fat, blood pressure, glucose, and other lipids at 10 y., Conclusions: Children with rapid and slow growth to high BMI trajectories before 5 y tend to show higher measures of adiposity and higher concentrations of markers related to glucose metabolism at 10 y., Clinical Trial Registry: ISRCTN46718296 (https://www.isrctn.com/ISRCTN46718296)., (Copyright © 2024 American Society for Nutrition. All rights reserved.)

Background: Children with intestinal failure (IF) receiving long-term parenteral nutrition (PN) have altered body composition (BC), but data on BC changes from start of PN onwards are lacking., Objectives: We aimed to assess growth and BC in infants after neonatal intestinal surgery necessitating PN and at risk of IF, and to explore associations with clinical parameters., Methods: A prospective cohort study in infants after intestinal surgery. IF was defined as PN dependency for >60 d. SD scores (SDS) for anthropometry were calculated until 6-mo corrected age. In a subgroup, fat mass (FM) and fat-free mass (FFM) were measured with air-displacement plethysmography at 2- and 6-mo corrected age. SDS for length-adjusted FM index and FFM index were calculated. Associations between cumulative amount of PN and BC parameters were analyzed with linear mixed-effect models., Results: Ninety-five neonates were included (54% male, 35% born <32 wk) and 39 infants (41%) had IF. Studied infants had compromised anthropometric parameters during follow-up. At 6-mo corrected age, they remained smaller (median weight-for-age SDS -0.9 [IQR -1.5, 0.1], P < 0.001) than the normal population. In 57 infants, 93 BC measurements were performed. FM index SDS was lower than in healthy infants at 2- and 6-mo corrected age (-0.9 [-1.6, -0.3], P < 0.001 and -0.7 [-1.3, 0.1], P = 0.001, respectively), but FFM index SDS did not differ. A higher cumulative amount of PN predicted a higher FM index in female infants but lower FM index in male infants., Conclusions: In this cohort of infants receiving PN after intestinal surgery, compromised anthropometrics, decreased FM, and adequate FFM were observed during the first 6 mo. Male and female infants seemed to respond differently to PN when it comes to FM index. Continuing growth monitoring after the age of 6 mo is strongly recommended, and further research should explore the benefit of incorporating ongoing BC monitoring during follow-up., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.)

We estimate weight and BMI values based on height, chest circumference, and mid upper arm circumference measures of Swiss conscripts in the city of Zurich for each year between 1904 and 1932. Height, chest circumference, and mid upper arm circumference were measured each year from 1904 to 1951. Body weight is available from 1933 to 1951. We used prediction equations from the literature, and also developed our own equations, which we tested and validated on the dataset from 1933 to 1951. We used a representative sample of usually 19-year-old Swiss males (N = 88,792, coverage > 88 %). There was an increase in average height and chest circumference between 1904 and 1951. During both world wars, chest circumference, mid upper arm circumference, weight, and BMI decreased, while height stagnated. Overall mean weight and BMI increased from 1904 to 1951, but decreased during the Great Depression. After World War II, weight quickly returned to the pre-war and pre-Great Depression level, while BMI had not reached the 1933 level by 1951. Average weights of the lower and middle socioeconomic groups were catching up with average weight of the upper socioeconomic group from 1904 to 1951. The convergence in height is less pronounced. Finally, we show that it is possible to accurately predict mean weight and BMI from other anthropometric measurements. We suggest that our estimation approach could be replicated for other historical populations to obtain more information on how nutritional status changed over time., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Weight can be adjusted for height using the Benn parameter (kg/m B ), where B is the power that minimises the correlation with height. Aim: To investigate how the Benn parameter changes across age (10-65 years) and time (1956-2015) and differs between sexes. Subjects and methods: The sample comprised 49,717 individuals born in 1946, 1958, 1970 or 2001. Cross-sectional estimates of the Benn parameter were produced and cohort differences at ages 10/11 and 42/43 years were examined using linear regression. Multilevel modelling was used to develop trajectories showing how the Benn parameter changed over age from childhood to mid-adulthood in the three older cohorts. Results: The Benn parameter was closest to 2 in childhood but consistently lower across adulthood, particularly in females and the most recent cohort. At ages 10/11 years, the Benn parameter was greater than 3 in both sexes in the 2001 cohort but between 2.2 and 2.7 in the three older cohorts. This difference was estimated to be +0.67 (0.53, 0.81) in males and +0.53 (0.38, 0.68) in females, compared to the 1946 cohort, and was driven by a much higher weight SD in the 2001 cohort. Conversely, at ages 42/43 years, the Benn parameter was lowest in the 1970 cohort due to a slightly lower weight-height correlation. This difference was estimated to be -0.12 (-0.34, 0.10) in males and -0.15 (-0.42, 0.13) in females, compared to the 1946 cohort. Conclusions: Changes over time in the obesogenic environment appear to have firstly reduced the Benn parameter due to a lowering of the weight-height correlation but secondly and more drastically increased the Benn parameter due to increasing weight variation.

Background: Both impaired and accelerated postnatal growth have been associated with adult risks of obesity and cardiometabolic diseases, like type 2 diabetes and cardiovascular disease. However, the timing of the onset of cardiometabolic changes and the specific growth trajectories linking early growth with later disease risks are not well understood., Objectives: The aim of this study was to identify distinct trajectories of BMI growth from 0 to 5 y and examine their associations with body composition and markers of cardiometabolic risk at age 5 y., Methods: In a prospective birth cohort study of 453 healthy and term Ethiopian children with BMIs assessed a median of 9 times during follow-up, we identified subgroups of distinct BMI trajectories in early childhood using latent class trajectory modeling. Associations of the identified growth trajectories with cardiometabolic markers and body composition at 5 y were analyzed using multiple linear regression analyses in 4 adjustment models for each outcome., Results: We identified 4 heterogeneous BMI growth trajectories: stable low BMI (19.2%), normal BMI (48.8%), rapid catch-up to high BMI (17.9%), and slow catch-up to high BMI (14.1%). Compared with the normal BMI trajectory, children in the rapid catch-up to high BMI trajectory had higher triglycerides (TGs) (range of β-coefficients in Models 1-4: 19-21%), C-peptides (23-25%), fat masses (0.48-0.60 kg), and fat-free masses (0.50-0.77 kg) across the 4 adjustment models. Children in the stable low BMI trajectory had lower LDL cholesterol concentrations (0.14-0.17 mmol/L), HDL cholesterol concentrations (0.05-0.09 mmol/L), fat masses (0.60-0.64 kg), and fat-free masses (0.35-0.49 kg), but higher TGs (11-13%)., Conclusions: The development of obesity and cardiometabolic risks may be established already in early childhood; thus, our data provide a further basis for timely interventions targeted at young children from low-income countries with unfavorable growth patterns. The birth cohort was registered at ISRCTN as ISRCTN46718296., (Copyright © American Society for Nutrition 2019.)

Background: Most body composition techniques assume constant properties of fat free mass (FFM) (hydration and density) regardless of nutritional status, which may lead to biased values., Aim: To evaluate the interactive associations of age and body mass index (BMI) with hydration and density of FFM., Methods: Data from subjects aged between 4 and 22 years old from several studies conducted in London, UK were assessed. Hydration (H FFM ) and density (D FFM ) of FFM obtained from the four-component model in 936 and 905 individuals, respectively, were assessed. BMI was converted in to z-scores, and categorised into five groups using z-score cut-offs (thin, normal weight, overweight, obese, and severely obese). Linear regression models for H FFM and D FFM were developed using age, sex, and BMI group as predictors., Results: Nearly 30% of the variability in H FFM was explained by models including age and BMI groups, showing increasing H FFM values in heavier BMI groups. On the other hand, ∼40% of variability in D FFM was explained by age, sex, and BMI groups, with D FFM values decreasing in association with higher BMI group., Conclusion: Nutritional status should be considered when assessing body composition using two-component methods, and reference data for H FFM and D FFM is needed for higher BMI groups to avoid bias. Further research is needed to explain intra-individual variability in FFM properties.

Objective: National body fatness (BF) data for English South Asian and Black children use BMI, which provides inaccurate ethnic comparisons. BF levels and time trends in the English National Child Measurement Programme (NCMP) between 2007 and 2013 were assessed by using ethnic-specific adjusted BMI (aBMI) for South Asian and Black children., Methods: Analyses were based on 3,195,323 children aged 4 to 5 years and 2,962,673 children aged 10 to 11 years. aBMI values for South Asian and Black children (relating to BF as in White children) were derived independently. Mean aBMI levels and 5-year aBMI changes were obtained by using linear regression., Results: In the 2007-2008 NCMP, mean aBMIs in 10- to 11-year-old children (boys, girls) were higher in South Asian children (20.1, 19.9 kg/m 2 ) and Black girls, but not in Black boys (18.4, 19.2 kg/m 2 ) when compared with White children (18.6, 19.0 kg/m 2 ; all P < 0.001). Mean 5-year changes (boys, girls) were higher in South Asian children (0.16, 0.32 kg/m 2 per 5 y; both P < 0.001) and Black boys but not girls (0.13, 0.15 kg/m 2 per 5 y; P = 0.01, P = 0.41) compared with White children (0.02, 0.11 kg/m 2 per 5 y). Ethnic differences at 4 to 5 years were similar. Unadjusted BMI showed similar 5-year changes but different mean BMI patterns., Conclusions: BF levels were higher in South Asian children than in other groups in 2007 and diverged from those in White children until 2013, a pattern not apparent from unadjusted BMI data., (© 2017 The Authors. Obesity published by Wiley Periodicals, Inc. on behalf of The Obesity Society (TOS).)

Objectives: This study sets out to investigate the intergenerational associations between the body mass index (BMI) of parents and the body composition of their offspring., Methods: The cross-sectional data were analyzed for 511 parent-offspring trios from London and south-east England. The offspring were aged 5-21 years. Parental BMI was obtained by recall and offspring fat mass and lean mass were obtained using the four-component model. Multivariable regression analysis, with multiple imputation for missing paternal values was used. Sensitivity analyses for levels of non-paternity were conducted., Results: A positive association was seen between parental BMI and offspring BMI, fat mass index (FMI), and lean mass index (LMI). The mother's BMI was positively associated with the BMI, FMI, and LMI z-scores of both daughters and sons and of a similar magnitude for both sexes. The father's BMI showed similar associations to the mother's BMI, with his son's BMI, FMI, and LMI z-scores, but no association with his daughter. Sensitivity tests for non-paternity showed that maternal coefficients remained greater than paternal coefficients throughout but there was no statistical difference at greater levels of non-paternity., Conclusions: We found variable associations between parental BMI and offspring body composition. Associations were generally stronger for maternal than paternal BMI, and paternal associations appeared to differ between sons and daughters. In this cohort, the mother's BMI was statistically significantly associated with her child's body composition but the father's BMI was only associated with the body composition of his sons. Am. J. Hum. Biol. 28:524-533, 2016. © 2016 The Authors American Journal of Human Biology Published by Wiley Periodicals, Inc., (© 2016 The Authors American Journal of Human Biology Published by Wiley Periodicals, Inc.)

Background: Our aim was to systematically summarize the evidence on whether prenatal, birth and early life factors up to 6 years of age predict sedentary behavior in young people (≤18 years)., Methods: PRISMA guidelines were followed, and searches were conducted in PubMed, SPORTDiscus, EMBASE and Web of Science up to December 1, 2015. We included observational (non-intervention) and longitudinal studies, that reported data on the association between one or more of the potential predictors and objectively or subjectively measured sedentary behavior. Study quality was assessed using a formal checklist and data extraction was performed using standardized forms independently by two researchers., Results: More than 18,000 articles were screened, and 16 studies, examining 10 different predictors, were included. Study quality was variable (0.36-0.95). Two studies suggest that heritability and BMI in children aged 2-6 years were significant predictors of sedentary behavior later in life, while four and seven studies suggest no evidence for an association between gestational age, birth weight and sedentary behavior respectively. There was insufficient evidence whether other prenatal, birth and early life factors act as predictors of later sedentary behavior in young people., Conclusion: The results suggest that heritability and early childhood BMI may predict sedentary behavior in young people. However, small number of studies included and methodological limitations, including subjective and poorly validated sedentary behavior assessment, limits the conclusions., Trial Registration: The systematic review is registered in the International Prospective Register of Systematic Reviews, PROSPERO, 17.10.2014 ( CRD42014014156 ).

The long-term effects on bone health of nutritional status in adolescence are unclear. The impact of adolescent and current body mass on bone mass in young adulthood in rural India was assessed. Current lean mass was a more important determinant of bone mass than thinness during adolescence in this population., Purpose/introduction: Adolescence is a crucial period for skeletal growth. However, the long-term effects on bone health of nutritional status in adolescence, particularly in the context of nutritional transition, are unclear. The current manuscript assessed the impact of adolescent and current body size on bone mass in young adulthood in an Indian rural community that is undergoing rapid socioeconomic changes., Methods: The Andhra Pradesh Children and Parents Study is a prospective cohort study in Hyderabad, India. In 2003-2005, the study collected anthropometric and cardiovascular data on adolescents (mean age = 16 years old). The second and third waves of the study in 2009-2012 collected data on current anthropometric measures, areal bone mineral density (aBMD) in hip and lumbar spine (L1-L4) measured by dual-energy X-ray absorptiometry, and living standards of the trial participants who were now young adults (mean age = 22 years old)., Results: The median body mass index (BMI) of the 722 participants included in this analysis was 16.8 kg/m(2) during adolescence, while the median BMI as young adults was 19.3 kg/m(2). Lower aBMD during adulthood was associated with lower adolescent BMI (β (95 % confidence interval) for hip aBMD 0.017 (0.013 to 0.022) and LS aBMD 0.012 (0.008 to 0.016)). This association was attenuated upon adjustment for current fat and lean mass (β (95 % CI) for hip aBMD 0.00 (-0.005 to 0.005) and LS aBMD 0.005 (0.000 to 0.01)). There was clear evidence for positive associations between aBMDs and current lean mass., Conclusions: Current lean mass was a more important determinant of bone mass than thinness during adolescence in this population. Weight gain during late adolescence and young adulthood coupled with improvement in lean mass may help to mitigate any adverse effects that pre-adulthood undernutrition may have on bone mass accrual.

Background: In 2005, it was estimated that hypertension affected 26.4% of the adult population worldwide. By 2025, it is predicted that it will affect about 60% of adults, a total of 1.56 billion. Both pre- and postnatal growth patterns have been associated with later blood pressure (BP), but in contrasting directions. These inconsistent associations of growth during different developmental periods merit elucidation. We tested a theoretical model treating birth weight as a marker of homeostatic metabolic capacity, and childhood height, lean mass and fat mass as independent indices of metabolic load. We predicted that decreased capacity and increased load would be independently associated with increased BP., Methods and Findings: Data from the ALSPAC cohort on growth from birth to 7 years, and body composition by dual-energy X-ray absorptiometry and BP at 9 years, were analysed (n = 6579). Data were expressed as standard deviation scores (SDS) or standardised regression residuals (SRR). BP was independently and positively associated with each of height, lean mass and fat mass. In a joint model systolic BP was positively associated with conditional weight velocity [males 0.40 (95%CI: 0.37-0.44) & females 0.44 (95%CI: 0.40-0.47) SDS/SRR], but not birth weight [0.00 (95%CI: -0.03-0.04) & 0.03 (95%CI: -0.01-0.07) SDS/SDS]. Adjusting for height, lean mass and fat mass, the association of systolic BP and conditional weight velocity attenuated [0.00(95%CI: -0.09-0.08) & -0.06(95%CI: -0.14-0.03) SDS/SRR], whereas that with birth weight became negative [-0.10 (95%CI: -0.14-0.06) & -0.09 (95%CI: -0.13-0.05) SDS/SDS]. Similar results were obtained for diastolic BP and pulse pressure., Conclusions: Consistent with our theoretical model, high metabolic load relative to metabolic capacity is associated with increased BP. Our data demonstrate the contribution of different growth and body composition components to BP variance, and clarify the developmental aetiology of hypertension.

Objectives: Childhood obesity is associated with an increased risk of atherosclerosis, which can be mediated by an increase in angiogenesis and inflammation. The objective was to investigate the association between body mass index (BMI) and circulating biomarkers of angiogenesis, inflammation, and cardiac dysfunction in children and adolescents., Methods: The Genetic Park Study is a highly inclusive survey conducted in three isolated villages of southern Italy. One hundred fifty-one children and adolescents (age range 5-17 y, 45% male) were included and categorized as obese (BMI z-score ≥ 1.64, n = 38) or non-obese (n = 113). Metabolic and cardiovascular biomarkers included glucose, triacylglycerol, total cholesterol, high-density lipoprotein, vascular endothelial growth factor (VEGF), placental growth factor, soluble feline sarcoma virus (fms)-like tyrosine kinase-1, highly sensitive C reactive protein (hs-CRP), highly sensitive troponin T (hs-TnT), and N-terminal prohormone brain natriuretic peptide (NT-proBNP)., Results: Obese subjects had higher levels of triacylglycerol (P = 0.03) and hs-CRP (P = 0.02) after adjustment for age and gender. Circulating levels of VEGF were directly associated with BMI z-score (r = 0.22, P = 0.007) and hs-CRP (r = 0.33, P < 0.001). BMI z-score was not associated with biomarkers of cardiac dysfunction (hs-TnT and NT-proBNP)., Conclusion: Increasing BMI was associated with plasma levels hs-CRP and VEGF, which are involved in the initiation and progression of atherosclerosis. The lack of association between BMI and markers of cardiac damage (hs-TnT) or ventricular volume overload (NT-proBNP) suggest that atherosclerotic risk may still at a preclinical stage in this population of obese but otherwise healthy young individuals. Collectively, this suite of biomarkers could provide mechanistic insights into the physiopathologic progression of cardiovascular risk associated with childhood obesity., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: Birth order has been associated with early growth variability and subsequent increased adiposity, but the consequent effects of increased fat mass on metabolic risk during adulthood have not been assessed. We aimed to quantify the metabolic risk in young adulthood of being first-born relative to those born second or subsequently., Methodology and Principal Findings: Body composition and metabolic risk were assessed in 2,249 men, aged 17-19 years, from a birth cohort in southern Brazil. Metabolic risk was assessed using a composite z-score integrating standardized measurements of blood pressure, total cholesterol, high density lipoprotein, triglycerides and fat mass. First-borns had lower birth weight z-score (Δ = -0.25, 95%CI -0.35, -0.15,p<0.001) but showed greater weight gain during infancy (change in weight z-score from birth to 20 months: Δ = 0.39, 95%CI 0.28-0.50, p<0.0001) and had greater mean height (Δ = 1.2 cm, 95%CI: 0.7-1.6, p<0.0001) and weight (Δ = 0.34 kg, 95%CI: 0.13-0.55, p<0.002) at 43 months. This greater weight and height tracked into early adulthood, with first-borns being significantly taller, heavier and with significantly higher fat mass than later-borns. The metabolic risk z-score was significantly higher in first-borns., Conclusions/significance: First-born status is associated with significantly elevated adiposity and metabolic risk in young adult men in Brazil. Our results, linking cardiovascular risk with life history variables, suggest that metabolic risk may be associated with the worldwide trend to smaller family size and it may interact with changes in behavioural or environmental risk factors.

Context: Waist circumference may offer improved diagnosis of obesity in youth compared with body mass index (BMI), but empirical evidence is limited., Objective: To compare the ability of BMI percentile using UK reference data and waist circumference percentile using UK reference data to diagnose high fat mass in English children., Design and Methods: In 7,722 9-10-year-olds (3,809 boys, 3,913 girls) sensitivity and specificity were calculated and receiver operator characteristic (ROC) analyses undertaken to determine the diagnostic accuracy of BMI and waist circumference z-scores to define high fat mass measured by dual energy x-ray absorptiometry (DXA). High fat mass was defined as being in the top decile of fatness for each sex (359 boys and 367 girls)., Results: The area under the ROC curve was slightly higher for BMI percentile (0.92 in boys, 95% CI: 0.91 -0.93; 0.94 in girls, 95% CI: 0.93-0.95) than waist circumference percentile (0.89 in boys, 95% CI: 0.86-0.91; 0.81 in girls, 95% CI: 0.73-0.90). Specificity of BMI percentile was slightly but significantly higher than that of waist circumference percentile for both sexes (p<0.05 in each case)., Conclusions: The present study suggests that waist circumference percentile has no advantage over BMI percentile for the diagnosis of high fat mass in children.

Background: Previous studies reported inconsistent associations between breastfeeding and body mass index (BMI; in kg/m2). Associations with body fatness are unknown., Objective: We investigated the association of breastfeeding with fatness measured by dual-energy X-ray absorptiometry., Design: The prospective cohort study involved 4325 singletons with measurements at 9-10 y of age to assess the main outcomes of BMI and total and trunk fat masses., Results: Prevalence of any breastfeeding was 82%. In crude analyses, breastfeeding was inversely associated with total fat mass [% change per category increase (4 categories)] in breastfeeding duration (-4.4%; 95% CI: -3.1%, -5.6%) and trunk fat mass (-0.5%; 95% CI: -1.1%, 0.1%); the odds of adiposity were measured by total [odds ratio (OR): 0.81; 95% CI: 0.75, 0.88] and trunk (OR: 0.78; 95% CI: 0.71, 0.84) fat masses in the top decile. In adjusted models, the inverse association of breastfeeding with mean total fat mass was attenuated by 59% (% change per category increase in breastfeeding duration: -1.8%; 95% CI: -0.5%, -3.1%), but associations with trunk fat mass (% change per category increase in breastfeeding duration: -0.6%; 95% CI: 0.0%, -1.3%) and the ORs for total (0.76; 95% CI: 0.69, 0.84) and trunk (0.74; 95% CI: 0.67, 0.81) fat masses in the top decile were little altered. Children breastfed >or=6 mo had the lowest odds of total fat mass in the top decile (OR: 0.45; 95% CI: 0.33, 0.62). In multivariate models, there was little evidence that breastfeeding was associated with mean or threshold values of BMI., Conclusions: The protective association of breastfeeding with mean total fat mass was attenuated somewhat after adjustment for confounders, which indicated that confounding may explain this association. Breastfeeding may protect against obesity if maintained for >or=6 mo.

Background: Human body shape is a rich source of information about health and the risk of disease. Measuring anthropometry manually is time-consuming, however, and only a few indexes of shape (eg, body girths and their ratios) are used regularly in clinical practice or epidemiology, both of which still rely primarily on body mass index (BMI). Three-dimensional (3-D) body scanning provides high-quality digital information about shape., Objectives: The objectives of the study were to investigate the relation of shape and BMI and to examine associations between age, sex, and shape., Design: In a cross-sectional study of 9617 adults (45% male) aged 16-91 y who were participating in the UK National Sizing Survey, body girths and their ratios were obtained with the use of a 3-D body scan. Data on weight and height were also obtained., Results: BMI was significantly associated with chest and waist in men and with hips and bust in women. In early adulthood, the sexes differed significantly in shape; however, these differences declined with age. Whereas male shape remained highly stable through adulthood, upper body girths, particularly waist, increased in women, but thigh decreased. After adjustment for other girths, waist was significantly and inversely associated with height, particularly in men. Waist varied widely in both sexes for a given BMI value., Conclusions: Relations between BMI and shape differed significantly between the sexes, particularly in association with age. The inverse association between height and waist in men suggests either a genetic contribution or a link between early growth pattern and predisposition to obesity. The 3-D scans offer a novel approach for epidemiologic research into associations between body shape and health risks and outcomes.

The consequences for adolescent health due to early life exposure to natural disasters combined with war are not known. We collected data from adolescents aged 12-13 years in Sri Lanka whose mothers were pregnant during the Indian Ocean tsunami in 2004 in a tsunami-affected region (n = 22), conflict-affected region (n = 35), conflict-plus-tsunami-affected region (n = 29), or controls in areas unaffected by either (n = 24). Adjusted body mass index (BMI)-for-age z-scores were 1.3, 1.0 and 2.0 for conflict, tsunami, and conflict-plus-tsunami, respectively, compared with the control group. Greater skinfold thickness and higher diastolic blood pressure were found in adolescents born in the conflict zone but no differences were found in height, head circumference, and waist circumference, or blood results, with the exception of serum insulin. Being born after a natural disaster or during conflict was associated with increased BMI and body fat during adolescent, which are associated with longer-term risk of noncommunicable disease. [ABSTRACT FROM AUTHOR]

Objective: There is growing evidence that childhood malnutrition is associated with non-communicable diseases (NCD) in adulthood and that body composition mediates some of this association. This review aims to determine if childhood body composition can be used to predict later-life cardiometabolic NCD and which measures of body composition predicts future NCD. Design: Electronic databases were searched for articles where: children aged under 5 years had body composition measured; cardiometabolic health outcomes were measured a minimum of 10 years later. Setting: The databases Embase, Medline and Global Health were searched through July 2020. Participants: Children aged under 5 years with a follow-up of minimum 10 years. Results: Twenty-nine studies met the inclusion criteria. Though a poor proxy measure of body composition, body mass index (BMI) was commonly reported (n 28, 97 %). 25 % of these studies included an additional measure (ponderal index or skinfold thickness). Few studies adjusted for current body size (n 11, 39 %). Conclusions: Many studies reported that low infant BMI and high childhood BMI were associated with an increased risk of NCD-related outcomes in later life but no conclusions can be made about the exact timing of child malnutrition and consequent impact on NCD. Because studies focussed on BMI rather than direct measures of body composition, nothing can be said about which measures of body composition in childhood are most useful. Future research on child nutrition and long-term outcomes is urgently needed and should include validated body composition assessments as well as standard anthropometric and BMI measurements. [ABSTRACT FROM AUTHOR]

Background Most authorities define childhood overweight/obesity as a BMI exceeding the same high centile cutoff at all ages, but it seems unlikely that true obesity prevalence (excess body fat) is constant throughout childhood. Objectives We investigated how fat mass (FM) and lean mass (LM), adjusted for height, relate to BMI and each other across childhood, using a uniquely large database of body composition measures, estimated using gold standard methods. Methods Cross-sectional and cohort data were collated from representative samples of healthy children aged 6 wk to 20 y and children attending obesity clinics aged 7–16 y. Body composition was measured by deuterium dilution up to age 4 y, and by either deuterium or the criterion 4-component model from 4 to 20 y. FM and LM were expressed, respectively, as fat mass index (FMI; FM/height2) and lean mass index (LMI; LM/height2). Results There were 2367 measurements of weight, height, and body composition from 1953 individuals. Before age 6 y, the variability in FMI, LMI, and BMI was much less than after; FMI was low (mainly <8 kg/m2) and FMI and LMI were weakly negatively correlated. From mid-childhood, upper limits for both BMI and FMI rose, but FMI in children with BMI <91st centile still rarely exceeded 8. With increasing age, the correlation of FMI with LMI rose to 0.5–0.7, driven mainly by children with a high FMI also having a high LMI. Conclusions Raised fat levels are much less common at younger than older ages, and young children with a high BMI centile have lower FMI than older children with the same BMI centile. Current BMI centile cutoffs thus overdiagnose obesity in younger groups. More stringent cutoffs are required for children aged <6 y, matching the WHO recommendation for 0–5 y. [ABSTRACT FROM AUTHOR]

Objective. Prediction of body composition from bioimpedance spectroscopy (BIS) measurements using mixture theory-based biophysical modelling invokes a factor (K B) to account for differing body geometry (or proportions) between individuals. To date, a single constant value is commonly used. The aim of this study was to investigate variation in K B across individuals and to develop a procedure for estimating an individualized K B value. Approach. Publicly available body dimension data, primarily from the garment industry, were used to calculate K B values for individuals of varying body sizes across the life-span. The 3D surface relationship between weight, height and K B, was determined and used to create look-up tables to enable estimation of K B in individuals based on height and weight. The utility of the proposed method was assessed by comparing fat-free mass predictions from BIS using either a constant K B value or the individualized value. Results. Computed K B values were well fitted to height and weight by a 3D surface (R 2Â =Â 0.988). Body composition was predicted more accurately compared to reference methods when using individualized K B than a constant value in infants and children but improvement in prediction was less in adults particularly those with high body mass index. Significance. Prediction of body composition from BIS and mixture theory is improved by using an individualized body proportion factor in those of small body habitus, e.g. children. Improvement is small in adults or non-existent in those of large body size. Further improvements may be possible by incorporating a factor to account for trunk size, i.e. waist circumference. [ABSTRACT FROM AUTHOR]

Objective: On average, boys grow faster than girls in early life but appear more susceptible to undernutrition. We investigated sex differences in early child growth, and whether maternal nutritional status and diet differed by offspring sex during and after pregnancy in an undernourished population. Methods: We analyzed longitudinal data from a cluster‐randomized trial from plains Nepal, stratifying results by child or gestational age. Children's outcomes (0–20 months) were weight, length, and head circumference and their z‐scores relative to WHO reference data in 2‐monthly intervals (n range: 24837 to 25 946). Maternal outcomes were mid‐upper arm circumference (MUAC), and body mass index (BMI) during pregnancy (12–40 weeks) (n = 5550 and n = 5519) and postpartum (n = 15 710 and n = 15 356), and diet in pregnancy. We fitted unadjusted and adjusted mixed‐effects linear and logistic regression models comparing boys with girls. Results: Boys were larger than girls, however relative to their sex‐specific reference they had lower length and head circumference z‐scores from birth to 12 months, but higher weight‐for‐length z‐scores from 0 to 6 months. Mothers of sons had higher MUAC and BMI around 36 weeks gestation but no other differences in pregnancy diets or pregnancy/postpartum maternal anthropometry were detected. Larger sex differences in children's size in the food supplementation study arm suggest that food restriction in pregnancy may limit fetal growth of boys more than girls. Conclusions: Generally, mothers' anthropometry and dietary intake do not differ according to offspring sex. As boys are consistently larger, we expect that poor maternal nutritional status may compromise their growth more than girls. Copyright © 2021 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Background: Childhood overweight and obesity is a global health problem that continues to worsen in many low- and middle-income countries. Low-cost measurements for monitoring overweight and relative metabolic risk, such as neck circumference (NC), should be evaluated in different populations and age groups. Aim: To test associations of NC and BMI with cardiometabolic parameters in 5-8-year-old Brazilian children. Methods: This cross-sectional study carried out from 2004–2006 measured height, weight and NC by anthropometry, and estimated fat and fat-free mass by bioelectrical impedance. Cardiometabolic risk factors assessed were systolic and diastolic blood pressure, high- and low-density lipoprotein cholesterol, triglycerides, and homeostatic model assessment of insulin resistance (HOMA). Associations of NC and BMI with cardiometabolic risk factors were tested using multiple regression and precision-recall plot analysis. Results: Analyses included 371 children (52% female). NC associated positively with BMI, fat mass, and fat-free mass, and with systolic blood pressure and HOMA following adjustment for age in sex-stratified multiple regression models. However, the latter relationships largely disappeared following adjustment for BMI. Area under the curve for NC or BMI in association with systolic blood pressure or HOMA >90th percentile was low in the pooled sample, indicating poor classifier performance. Conclusions: NC and BMI demonstrated similar associations with cardiometabolic risk factors, although NC mostly did not correlate with risk factors independently of BMI. In contrast to previous studies, NC was a poor classifier of cardiometabolic risk factors in children. The association of NC with both fat and fat-free mass may aid in explaining its poor performance. [ABSTRACT FROM AUTHOR]

Background Better tools are needed to diagnose and identify children at risk of clinical malnutrition. Objectives We aimed to compare body composition (BC) and malnutrition screening tools (MSTs) for detecting malnutrition on admission; and examine their ability to predict adverse clinical outcomes [increased length of stay (LOS) and complications] in complex pediatric patients. Methods This was a prospective study in children 5–18 y old admitted to a tertiary pediatric hospital (n  = 152). MSTs [Pediatric Yorkhill Malnutrition Score (PYMS), Screening Tool for the Assessment of Malnutrition in Pediatrics (STAMP), and Screening Tool for Risk of Impaired Nutritional Status and Growth (STRONGkids)] were completed on admission. Weight, height, and BC [fat mass (FM) and lean mass (LM) by DXA] were measured (n  = 118). Anthropometry/BC and MSTs were compared with each other and with clinical outcomes. Results Subjects were significantly shorter with low LM compared to reference data. Depending on the diagnostic criteria used, 3%–17% were classified as malnourished. Agreement between BC/anthropometric parameters and MSTs was poor. STAMP and STRONGkids identified children with low weight, LM, and height. PYMS, and to a lesser degree STRONGkids, identified children with increased LOS, as did LM compared with weight or height. Patients with complications had lower mean ± SD LM SD scores (−1.38 ± 1.03 compared with −0.74 ± 1.40, P  < 0.05). In multivariable models, PYMS high risk and low LM were independent predictors of increased LOS (OR: 3.76; 95% CI: 1.36, 10.35 and OR: 3.69; 95% CI: 1.24, 10.98, respectively). BMI did not predict increased LOS or complications. Conclusions LM appears better than weight and height for predicting adverse clinical outcomes in this population. BMI was a poor diagnostic parameter. MSTs performed differently in associations to BC/anthropometry and clinical outcomes. PYMS and LM provided complementary information regarding LOS. Studies on specific patient populations may further clarify the use of these tools and measurements. [ABSTRACT FROM AUTHOR]

Background: Children with intestinal failure (IF) are at risk of growth failure, but little information about body composition is available. Our aim was to assess body composition using air displacement plethysmography (ADP) and relate it to clinical and growth parameters.Methods: In this prospective descriptive observational 2-center cohort study, children aged 2-18 years receiving home parenteral nutrition (PN) for ≥6 months underwent ADP measurement. Fat mass index (FMI) and fat-free mass index (FFMI) standard deviation scores (SDSs) were calculated to normalize for small body size.Results: Twenty-one out of 22 children, median age 7.4 years, underwent successful ADP measurement after a median PN duration of 5.5 years. They were significantly lighter (median weight for age SDS -0.71, P = 0.004) and shorter (median height for age SDS -1.55, P < 0.001) than the normal population mean; 52% were growing below target height range. They had low FFMI (median SDS -1.53, P < 0.001) and high FMI (median SDS 0.80, P = 0.002). Weight for height and body mass index (BMI) were significantly associated with FFMI and BMI with FMI, but children with the same weight and height showed different body composition. In 13 patients with 1-year follow-up, growth and body composition did not change significantly.Conclusion: Children with IF receiving long-term PN show lower FFM and higher FM than healthy children. Additionally, children with similar routine growth parameters showed different body composition. Further studies should evaluate the effect of a patient-tailored approach including physical activity and nutrition advice based on body composition. [ABSTRACT FROM AUTHOR]

Body mass prediction from the skeleton most commonly employs femoral head diameter (FHD). However, theoretical predictions and empirical data suggest the relationship between mass and FHD is strongest in young adults, that bone dimensions reflect lean mass better than body or fat mass and that other femoral measurements may be superior. Here, we generate prediction equations for body mass and its components using femoral head, neck and proximal shaft diameters and body composition data derived from dual-energy x-ray absorptiometry (DXA) scans of young adults (n = 155, 77 females and 78 males, mean age 22.7 ± 1.3 years) from the Andhra Pradesh Children and Parents Study, Hyderabad, India. Sex-specific regression of log-transformed data on femoral measurements predicted lean mass with smaller standard errors of estimate (SEEs) than body mass (12–14% and 16–17% respectively), while none of the femoral measurements were significant predictors of fat mass. Subtrochanteric mediolateral shaft diameter gave lower SEEs for lean mass in both sexes and for body mass in males than FHD, while FHD was a better predictor of body mass in women. Our results provide further evidence that lean mass is more closely related to proximal femur dimensions than body or fat mass and that proximal shaft diameter is a better predictor than FHD of lean but not always body mass. The mechanisms underlying these relationships have implications for selecting the most appropriate measurement and reference sample for estimating body or lean mass, which also depend on the question under investigation. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: Stature estimation from the skeleton is a classic anthropological problem, and recent years have seen the proliferation of population‐specific regression equations. Many rely on the anatomical reconstruction of stature from archaeological skeletons to derive regression equations based on long bone lengths, but this requires a collection with very good preservation. In some regions, for example, South Asia, typical environmental conditions preclude the sufficient preservation of skeletal remains. Large‐scale epidemiological studies that include medical imaging of the skeleton by techniques such as dual‐energy X‐ray absorptiometry (DXA) offer new potential datasets for developing such equations. Materials and methods: We derived estimation equations based on known height and bone lengths measured from DXA scans from the Andhra Pradesh Children and Parents Study (Hyderabad, India). Given debates on the most appropriate regression model to use, multiple methods were compared, and the performance of the equations was tested on a published skeletal dataset of individuals with known stature. Results: The equations have standard errors of estimates and prediction errors similar to those derived using anatomical reconstruction or from cadaveric datasets. As measured by the number of significant differences between true and estimated stature, and the prediction errors, the new equations perform as well as, and generally better than, published equations commonly used on South Asian skeletons or based on Indian cadaveric datasets. Conclusions: This study demonstrates the utility of DXA scans as a data source for developing stature estimation equations and offer a new set of equations for use with South Asian datasets. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: Estimating body mass from skeletal dimensions is widely practiced, but methods for estimating its components (lean and fat mass) are poorly developed. The ability to estimate these characteristics would offer new insights into the evolution of body composition and its variation relative to past and present health. This study investigates the potential of long bone cross‐sectional properties as predictors of body, lean, and fat mass. Materials and Methods: Humerus, femur and tibia midshaft cross‐sectional properties were measured by peripheral quantitative computed tomography in sample of young adult women (n = 105) characterized by a range of activity levels. Body composition was estimated from bioimpedance analysis. Results: Lean mass correlated most strongly with both upper and lower limb bone properties (r values up to 0.74), while fat mass showed weak correlations (r ≤ 0.29). Estimation equations generated from tibial midshaft properties indicated that lean mass could be estimated relatively reliably, with some improvement using logged data and including bone length in the models (minimum standard error of estimate = 8.9%). Body mass prediction was less reliable and fat mass only poorly predicted (standard errors of estimate ≥11.9% and >33%, respectively). Discussion: Lean mass can be predicted more reliably than body mass from limb bone cross‐sectional properties. The results highlight the potential for studying evolutionary trends in lean mass from skeletal remains, and have implications for understanding the relationship between bone morphology and body mass or composition. [ABSTRACT FROM AUTHOR]

Background: We have previously shown that fat-free mass (FFM) at birth is associated with height at 2 y of age in Ethiopian children. However, to our knowledge, the relation between changes in body composition during early infancy and later linear growth has not been studied.Objective: This study examined the associations of early infancy fat mass (FM) and FFM accretion with linear growth from 1 to 5 y of age in Ethiopian children.Methods: In the infant Anthropometry and Body Composition (iABC) study, a prospective cohort study was carried out in children in Jimma, Ethiopia, followed from birth to 5 y of age. FM and FFM were measured ≤6 times from birth to 6 mo by using air-displacement plethysmography. Linear mixed-effects models were used to identify associations between standardized FM and FFM accretion rates during early infancy and linear growth from 1 to 5 y of age. Standardized accretion rates were obtained by dividing FM and FFM accretion by their respective SD.Results: FFM accretion from 0 to 6 mo of age was positively associated with length at 1 y (β = 0.64; 95% CI: 0.19, 1.09; P = 0.005) and linear growth from 1 to 5 y (β = 0.63; 95% CI: 0.19, 1.07; P = 0.005). The strongest association with FFM accretion was observed at 1 y. The association with linear growth from 1 to 5 y was mainly engendered by the 1-y association. FM accretion from 0 to 4 mo was positively associated with linear growth from 1 to 5 y (β = 0.45; 95% CI: 0.02, 0.88; P = 0.038) in the fully adjusted model.Conclusions: In Ethiopian children, FFM accretion was associated with linear growth at 1 y and no clear additional longitudinal effect from 1 to 5 y was observed. FM accretion showed a weak association from 1 to 5 y. This trial was registered at www.controlled-trials.com as ISRCTN46718296. [ABSTRACT FROM AUTHOR]

ObjectiveFat mass (FM) and fat-free mass (FFM) are frequently measured to define body composition phenotypes. The load–capacity model integrates the effects of both FM and FFM to improve disease-risk prediction. We aimed to derive age-, gender- and BMI-specific reference curves of load–capacity model indices in an adult population (≥18 years).DesignCross-sectional study. Dual-energy X-ray absorptiometry was used to measure FM, FFM, appendicular skeletal muscle mass (ASM) and truncal fat mass (TrFM). Two metabolic load–capacity indices were calculated: ratio of FM (kg) to FFM (kg) and ratio of TrFM (kg) to ASM (kg). Age-standardised reference curves, stratified by gender and BMI (<25·0 kg/m2, 25·0–29·9 kg/m2, ≥30·0 kg/m2), were constructed using an LMS approach. Percentiles of the reference curves were 5th, 15th, 25th, 50th, 75th, 85th and 95th.SettingSecondary analysis of data from the 1999–2004 National Health and Nutrition Examination Survey (NHANES).SubjectsThe population included 6580 females and 6656 males.ResultsThe unweighted proportions of obesity in males and females were 25·5 % and 34·7 %, respectively. The average values of both FM:FFM and TrFM:ASM were greater in female and obese subjects. Gender and BMI influenced the shape of the association of age with FM:FFM and TrFM:ASM, as a curvilinear relationship was observed in female and obese subjects. Menopause appeared to modify the steepness of the reference curves of both indices.ConclusionsThis is a novel risk-stratification approach integrating the effects of high adiposity and low muscle mass which may be particularly useful to identify cases of sarcopenic obesity and improve disease-risk prediction. [ABSTRACT FROM AUTHOR]

Measures of nutritional status are often used as markers of health, at both individual- and population-level. Different measures of nutritional status – such as height or weight, for example, – may have different associations with health outcomes because they reflect both current nutritional status and the accumulation of past health experiences, but the weighting of past and present experiences differs between different measures. Here, we present an analysis of a longitudinal dataset, collected between 1950 and 1974 in four Gambian villages, to investigate whether three different measures – height, body mass index (BMI) or haemoglobin level – are associated with adult mortality. We interpret these different measures as indicators of different types of physical 'capital' that vary in their liquidity. Adult height represents 'illiquid' capital, indicative of nutritional status in the past, during different periods of development. BMI, determined both by past childhood experiences and recent nutrition and health exposures, represents capital of intermediate 'liquidity'. Haemoglobin represents 'liquid' capital, determined largely by recent environmental exposures. We find, not unexpectedly, that the more 'liquid' measures of capital show clearer associations with adult mortality: for haemoglobin there is a negative relationship with mortality risk for both sexes: BMI is also broadly negatively related to mortality risk for both men and women, though overweight individuals suffer a slightly increased risk of death. For men, there is no relationship between the 'illiquid' measure of height and adult mortality; but for women, there is a U-shaped relationship, with women of average height having the lowest mortality. [ABSTRACT FROM AUTHOR]

Background: Undernutrition and physical inactivity are both associated with lower bone mass. Objective: This study aimed to investigate the combined effects of early-life undernutrition and urbanized lifestyles in later life on bone mass accrual in young adults from a rural community in India that is undergoing rapid socioeconomic development. Design: This was a prospective cohort study of participants of the Hyderabad Nutrition Trial (1987-1990), which offered balanced protein-calorie supplementation to pregnant women and preschool children younger than 6 y in the intervention villages. The 2009-2010 follow-up study collected data on current anthropometric measures, bone mineral density (BMD) measured by dual-energy X-ray absorptiometry, blood samples, diet, physical activity, and living standards of the trial participants (n = 1446, aged 18-23 y). Results: Participants were generally lean and had low BMD [mean hip BMD: 0.83 (women), 0.95 (men) g/cm²; lumbar spine: 0.86 (women), 0.93 (men) g/cm²]. In models adjusted for current risk factors, no strong evidence of a positive association was found between BMD and early-life supplementation. On the other hand, current lean mass and weight-bearing physical activity were positively associated with BMD. No strong evidence of an association was found between BMD and current serum 25-hydroxyvitamin D or dietary intake of calcium, protein, or calories. Conclusions: Current lean mass and weight-bearing physical activity were more important determinants of bone mass than was early-life undernutrition in this population. In transitional rural communities from low-income countries, promotion of physical activity may help to mitigate any potential adverse effects of early nutritional disadvantage. [ABSTRACT FROM AUTHOR]

Background: Abnormal body compositions such as high adiposity (HA), low muscle mass (LM), or a combination of the 2 [high adiposity with low muscle mass (HA-LM)] are relevant phenotypes, but data on their prevalence and impact on health are still limited. This is largely because of a lack of a consensus definition for these conditions. Of particular interest is the HA-LM phenotype, also termed "sarcopenic obesity," which may confer greater health risk. Objective: We propose a new approach for operationalizing abnormal body-composition phenotypes in a representative adult population. Design: Whole-body dual-energy X-ray absorptiometry data obtained from the 1999-2004 NHANES were analyzed for 13,236 subjects aged ≥18 y (maximum weight and height of 136 kg and 1.96 m, respectively). Sex- and body mass index (BMI)-specific decile groups of appendicular skeletal muscle index (ASMI; kg/m²) and fat mass index (FMI; kg/m²) were developed. Cutoffs for HA and LM were incorporated into a diagnostic framework to characterize 4 specific body-composition phenotypes--low adiposity with high muscle mass, high adiposity with high muscle mass, low adiposity with low muscle mass, and HA-LM--and a subclassification of the phenotypes into classes I, II, and III. Results: Abnormal phenotypes were prevalent across the age spectrum and BMI categories. The association between ASMI or FMI and age was modified by sex and BMI. The prevalence of HA-LM in the whole sample was 10.3% in women and 15.2% in men. The prevalence of all subclasses of HA-LM in obese women and men was 14.7% and 22.9%, respectively. HA-LM class III was more prevalent in obese men (2.3%) than in obese women (0.3%). Conclusions: We developed sex- and BMI-specific reference curves to harmonize the classification of body-composition phenotypes. The application of this classification will be particularly useful in the identification of cases of sarcopenic obesity. The association of these phenotypes with metabolic deregulation and increased disease risk awaits verification. [ABSTRACT FROM AUTHOR]

Lean body mass (LBM) and muscle mass remain difficult to quantify in large epidemiological studies due to the unavailability of inexpensive methods. We therefore developed anthropometric prediction equations to estimate the LBM and appendicular lean soft tissue (ALST) using dual-energy X-ray absorptiometry (DXA) as a reference method. Healthy volunteers (n = 2,220; 36% women; age 18-79 yr), representing a wide range of body mass index (14-44 kg/m2), participated in this study. Their LBM, including ALST, was assessed by DXA along with anthropometric measurements. The sample was divided into prediction (60%) and validation (40%) sets. In the prediction set, a number of prediction models were constructed using DXA-measured LBM and ALST estimates as dependent variables and a combination of anthropometric indices as independent variables. These equations were cross-validated in the validation set. Simple equations using age, height, and weight explained >90% variation in the LBM and ALST in both men and women. Additional variables (hip and limb circumferences and sum of skinfold thicknesses) increased the explained variation by 5-8% in the fully adjusted models predicting LBM and ALST. More complex equations using all of the above anthropometric variables could predict the DXA-measured LBM and ALST accurately, as indicated by low standard error of the estimate (LBM: 1.47 kg and 1.63 kg for men and women, respectively), as well as good agreement by Bland-Altman analyses (Bland JM, Altman D. Lancet 1: 307-310, 1986). These equations could be a valuable tool in large epidemiological studies assessing these body compartments in Indians and other population groups with similar body composition. [ABSTRACT FROM AUTHOR]