Body composition in childhood: effects of normal growth and disease

Effect of treatment with growth hormone on body composition and metabolic profile of short children born small for gestational age

OBJECTIVE

To assess the effect of recombinant growth hormone (rGH) on body composition and metabolic profile of prepubertal short children born small for gestational age (SGA) before and after 18 months of treatment.

METHODS

It is a clinical, non-randomized, and paired study. Children born SGA, with birth weight and/or length <-2 standard deviations (SD) for gestational age and sex, prepubertal, born at full term, of both genders, with the indication for treatment with rGH were included. The intervention was performed with biosynthetic rGH at doses ranging from 0.03 to 0.05 mg/kg/day, administered subcutaneously, once a day at bedtime. Total lean mass (LM) and total fat mass (FM) were carried out using dual-energy X-ray absorptiometry (DXA), and the metabolic profile was assessed for insulin, glycemia, IGF-1 levels and lipid profile.

RESULTS

Twelve patients (nine girls, 8.17±2.39 y) were evaluated; three patients dropped out of the study. There was an increase of LM adjusted for length (LMI) (p=0.008), LMI standard deviation score (SDS) adjusted for age and sex (p=0.007), and total LM (p<0.001). The percentage of body fat (BF%) and abdominal fat (AF) remained unaltered in relation to the beginning of treatment. Among the metabolic variables, blood glucose remained within normal levels, and there was a reduction in the number of participants with altered cholesterol (p=0.023).

CONCLUSIONS

The effect of rGH treatment was higher on LM than in FM, with increased LM adjusted for length and standardized for age and sex. Glycemia remained within the normal limits, and there was a decreased number of children with total cholesterol above the recommended levels.

Effect of after-school physical activity on body composition in primary school children: The Slovak "PAD" project

Physical activity is associated with many physical and mental health benefits. This study aimed to investigate the effect of a 24-month after-school physical activity intervention on body composition in normal-weight children. Participating students (6-7 years of age at baseline) were divided by reason of their parental preference to intervention and control groups. Children in the intervention group (n = 20; 10 boys and 10 girls) followed an aerobic training program (two 60-min sessions per week), whereas children in the control group (n = 20; 10 boys and 10 girls) participated in the usual practice. Body composition characteristics were repeatedly measured by means of bioelectrical impedance method. At 2 years, finally, intervention boys had a smaller rise in BMI (mean difference, MD: -0.97 kg/m2 , p < 0.05), BMI z-score (-0.44, p < 0.09), body fat % (BF%) (-6.47%, p < 0.01), and fat mass index (FMI) (-1.32 kg/m2 , p < 0.001) than controls. In girls, however, the intervention program induced no significant differences (p > 0.9) in the measured variables compared to controls at the final follow-up (MD: -0.04 kg/m2 for BMI and -0.01 for BMI z-score). Changes in BF% and FMI in a positive direction occurred at 18 months (MD: -3.38%, p < 0.05 and -0.99 kg/m2 , p < 0.01, respectively), but did not persist over time (p > 0.07). In addition, no significant changes (p > 0.07) in the fat-free mass index were associated with the physical activity intervention in either boys or girls. In conclusion, compared to the controls, a long-term physical activity intervention in boys was associated with a significantly smaller rise in BMI and improvement of body composition by reducing both BF % and FMI. In girls, however, this intervention did not result in any statistically significant changes in body composition variables.

Body Composition Assessment in Mexican Children and Adolescents. Part 1: Comparisons between Skinfold-Thickness, Dual X-ray Absorptiometry, Air-Displacement Plethysmography, Deuterium Oxide Dilution, and Magnetic Resonance Imaging with the 4-C Model

The evaluation of body composition (BC) is relevant in the evaluation of children’s health-disease states. Different methods and devices are used to estimate BC. The availability of methods and the clinical condition of the patient usually defines the ideal approach to be used. In this cross-sectional study, we evaluate the accuracy of different methods to estimate BC in Mexican children and adolescents, using the 4-C model as the reference. In a sample of 288 Mexican children and adolescents, 4-C body composition assessment, skinfold-thickness (SF), dual-energy X-ray absorptiometry (DXA), air displacement plethysmography (ADP), and deuterium dilution (D₂O) were performed, along with MRI in a subsample (52 participants). The analysis of validity was performed by correlation analysis, linear regression, and the Bland–Altman method. All methods analyzed showed strong correlations for FM with 4-C values and between each other; however, DXA and MRI overestimated FM, whereas skinfolds and ADP under-estimated FM. Conclusion: The clinical assessment of BC by means of SF, ADP, DXA, MRI and D₂O correlated well with the 4-C model and between them, providing evidence of their clinical validity and utility. The results from different methods are not interchangeable. Preference between methods may depend on their availability and the specific clinical setting.

Associations of mothers' source of feeding information with longitudinal trajectories of sugar-sweetened beverage intake, 100% juice intake and adiposity in early childhood

BACKGROUND

There remains a need to understand how information sources can promote young children's healthy beverage consumption and prevent obesity.

OBJECTIVES

To examine associations of mothers' primary feeding information source with children's sugar-sweetened beverage (SSB) intake, 100% juice intake and adiposity between ages 3 and 7 years.

METHODS

We analyzed data from a prospective cohort study (n = 371 children; 13 visits). Mothers reported their primary feeding information source at baseline and completed child 3-day dietary records each visit. Child adiposity indicators were calculated from repeated height/weight measurements and dual-energy X-ray absorptiometry. Longitudinal models examined beverage intakes and adiposity over time by source.

RESULTS

Primary feeding information sources included doctors (48.2%), mothers (17.5%), grandmothers (13.5%), other healthcare professionals (11.3%) and other family/friends (9.4%). Children's juice intake with age differed by source (P interaction = 0.03), with steepest and slightest intake decreases in the doctor (-19.7% each year; 95% CI: -23.7%, -15.5%) and grandmother (-5.0%; -14.5%, 5.5%) subgroups, respectively. Children's SSB intake did not differ by source, but increased annually by 7.1% (4.5%, 9.8%) overall. The grandmother subgroup had the greatest child adiposity over time.

CONCLUSIONS

Mothers' primary feeding information source may have important, yet heterogeneous, influences on young children's beverage intakes and adiposity over time. Consistent evidence-based messages are likely needed.

Lean mass reference curves in adolescents using dual-energy x-ray absorptiometry (DXA)

The body composition phenotype of low lean mass (LM) has been associated with metabolic disorders and impaired physical functioning in the pediatric population. Abnormalities in body composition may be identified using reference curves; however, no reference data on LM is available for Brazilian adolescents. The purpose of this study was to present reference data, including percentile curves, of whole body LM, lean mass index (LMI), appendicular lean mass (ALM), and fat mass for Southern Brazilian adolescents. This was a cross-sectional study of adolescents aged 12–17 years from a southern region in Brazil, who had body composition assessed using dual energy x-ray absorptiometry (DXA). Percentile values and reference curves employing the Lambda, Mu and Sigma method (LMS) were computed for LM, LMI (lean mass/height²), ALM and fat mass. Data on 541 adolescents (68.6% boys) was included. Sex differences in growth trajectories were observed for absolute and adjusted LM, with boys presenting greater LM quantity with advancing ages than girls (66.9% and 17.4% difference between the ages of 12 and 17 for boys and girls, respectively). The values corresponding to the lowest percentile (3^rd) of LMI ranged between 10.63 to 13.93 kg/m² in boys and 11.13 to 12.03 kg/m² among girls aged 12–17 years. This study established the first LM, LMI, and ALM reference curves in Southern Brazilian adolescents, which can potentially be used in association with functional measures to identify LM abnormalities during growth.

Relation between changes in weight parameters and height parameters in prepubertal children: daily weight gain and BMIi changes in relation to linear growth during nutritional rehabilitation of underweight children

Background: Early detection of abnormal weight loss or gain in childhood may be important for preventive purposes. Variable growth response to nutrition rehabilitation have been reported in children with failure to thrive (FTT) who do not have any chronic disease or systematic illness due to different clinical and nutritional approach in their management. Aim of the study: To analyze the association of different body mass index (BMI) and BMI- SDS, to linear growth (Ht-SDS) in different BMI categories of prepubertal children. In addition, we studied the effect of weight changes on linear growth in a randomly selected group of prepubertal underweight children who received nutritional rehabilitation (NR) for 9±2 months. Subjects and methods: 102 children, between 1 and 9 years, followed at the General Pediatric Clinic, between January 2017 to December 2017, because of abnormal weight gain (decreased or increased) which was not associated with any acute or chronic illness were included in the study. Anthropometric measurements included weigh, height, Ht-SDS, BMI, and BMI-SDS. Children BMI-SDS were categorized into 4 groups: Group 1: BMI-SDS <-2, group 2: BMI-SDS <-1 but >-2, group 3 BMI-SDS >-1 but <2, group 4 BMI-SDS >2. We also evaluated the effects of weight changes on linear growth in a randomly selected group of underweight children who received nutritional counselling and oral nutritional supplementation (n = 51) for 9±months. Results: HT-SDS in children of groups 1 and 2 (underweight and at risk of underweight children) was significantly lower than Ht-SDS of groups 3 and 4 (normal and overweight children). Ht-SDS in children of group 4 was significantly higher than the Ht-SDS of children in group 3. A significant linear correlation was found between BMI-SDS and Ht-SDS in these prepubertal children. Discussion: After nutritional rehabilitation for a year, 55% of underweight children increased their BMI-SDS and 43% increased their Ht-SDS. Children who had weight gain >7g/d, over the whole period of follow-up, (n =14) increased their BMI-SDS and Ht-SDS significantly after versus before NR. The BMI-SDS and Ht-SDS did not increase significantly in the group of children who had weight gain <7 g/day. 28 children out of 51 improved their BMI-SDS after nutritional rehabilitation (group A) and 23 did not have improvement in their BMI-SDS (Group B). Group A had higher weight gain per day versus group B. Height growth velocity was significantly higher in Group B (7.4±3.6 cm/yr) versus group A (5.7±2.8 cm/yr). Ht-SDS increased significantly in the group of patients who had lower Ht-SDS before NR. Children who had faster linear growth velocity, after nutritional rehabilitation, did not increase their BMI-SDS. Linear regression showed a significant correlation between BMI-SDS and Ht-SDS supporting the notion that proper nutrition and maintaining normal BMI-SDS is essential for adequate gain in height. Conclusion: It appears that calculating the weight gain per day, BMI-SDS and Ht-SDS are clinically useful parameters to detect the effect of weight gain on linear growth and to monitor the nutritional management. Daily weight gain was correlated significantly to height growth rate during nutritional rehabilitation. Based on our findings and literature reports, we suggest an algorithm for follow-up of underweight/ malnourished children based mainly on anthropometric assessment. (www.actabiomedica.it)

Percentage Body Fat is As a Good Indicator for Determining Adolescents Who Are Overweight or Obese: A Cross-Sectional Study in Vietnam

OBJECTIVES

To identify trends in percentage body fat (PBF) in adolescents to determine gender-specific classification thresholds for being overweight and obese.

METHODS

A cross-sectional study of 899 adolescents (11 to 14.5 years) from Hanoi and Nam Dinh was conducted in Vietnam. PBF, subcutaneous fat and percentage of lean mass were measured directly using OMRON HBF 375 scales to measure bioelectrical impedance.

RESULTS

PBF decreased in boys with increasing age (p < 0.001). The difference in PBF between boys and girls, significantly increased with age after 12.5 years (p < 0.001). There was a stronger correlation between PBF and fat content (Pearson's r = 0.860, p < 0.0001) than that between (BMI) and fat content (Pearson's r = 0.521, p < 0.0001). The prevalence of being overweight or obese in girls was similar when determined by PBF or BMI. Hanoi had higher rates of adolescents being overweight or obese compared with Nam Dinh.

CONCLUSION

PBF provides a more accurate body assessment for being overweight or obese in adolescents compared with BMI.

Analysis of bone mass and its relationship with body composition in school-aged children and adolescents based on stage of puberty and site specificity: A retrospective case-control study

The aim of this study was to better understand the relationship of bone mass with body composition based on different stages of puberty and to illuminate the contribution of site-specific fat mass and lean mass (FM and LM) compared with bone mass in school-aged children and adolescents in Chongqing, China.A total of 1179 healthy subjects of both sexes were recruited. Bone mineral content (BMC), bone mineral density (BMD), bone area, and both FM and LM were measured by dual-energy X-ray absorptiometry (DXA). The fat mass and lean mass indexes (FMI and LMI, respectively) were calculated as the FM (kg) and LM (kg) divided by the height in meters squared, respectively.Most of the bone mass indicators were significantly higher for postpubertal boys than for girls at the same stage (P < .001). The proportion of subjects with normal bone mass increased, while the proportion of subjects with osteopenia and osteoporosis decreased with increased body weight regardless of gender and puberty stage (P < .01). FM and LM were significantly positively related to bone mass regardless of gender and puberty stage (P < .0001). FMI and LMI were significantly positively related to bone mass in most conditions (P < .05 and P < .0001, respectively). Four components of the FM and LM were linearly and significantly associated with BMD and BMC for TB and TBHL. Among them, the head fat mass and head lean mass showed the greatest statistical contribution.In the process of assessing bone status, we recommend measuring fat and lean masses, including the fat and lean masses of the head.

Body Composition Percentiles in Urban South Indian Children and Adolescents

OBJECTIVE

This study aimed to generate age- and sex-specific percentiles for body composition indices in children and to assess the variability in these indices, in relation to BMI.

METHODS

Anthropometry and body fat were measured with the BOD POD (Cosmed; Rome, Italy) in 9,702 children from Bangalore, India. Smoothed percentile curves using the lambda-mu-sigma method were obtained for BMI, fat-free mass index (FFMI), fat mass index (FMI), and body fat percentage (% BF).

RESULTS

Percentile curves for % BF and FMI in boys increased from 6 to 12 years and declined from 13 years on, while in girls, it increased until 15 years. The FFMI percentile curves increased with age in both sexes. The mean FMI declined from 12 years on in boys, corresponding to a large increase in FFMI from that age, while in girls, both FMI and FFMI continued to increase. The 75th percentile of % BF and FMI had greater sensitivity to identify children with obesity.

CONCLUSIONS

This study developed smoothed percentile curves for body composition in Indian children and suggests FMI and FFMI as good indicators of growth in children.

Soy protein supplement intake for 12 months has no effect on sexual maturation and may improve nutritional status in pre-pubertal children

AIM

To evaluate the intake of a soy protein-based supplement (SPS) and its effects on the sexual maturation and nutritional status of prepubertal children who consumed it for a year.

METHODS

Healthy children (n = 51) were recruited and randomly assigned to consume the lunch fruit juice with (n = 29) or without (n = 22) addition of 45 g of a commercial soy protein-based supplement (SPS) over 12 months. Nutritional assessment including anthropometry (bodyweight, height, triceps skinfold thickness, mid-upper arm circumference), body mass index (BMI), upper arm muscle area, arm muscle circumference, upper arm area, upper arm fat area data were derived from measures using usual procedures; age and gender-specific percentiles were used as reference. Sexual maturation was measured by Tanner stage. Isoflavones were quantified using liquid chromatography and tandem mass spectrometry.

RESULTS

Height, BMI/age, weight/age and height/age were significantly different (P < 0.05) at 12 months between girls in the control and intervention groups. Statistically significant differences between groups by gender (P < 0.05) were found in boys in the control group for the triceps skinfold thickness and fat area. Nutritional status was adequate according to the World Health Organization parameters. On average, 0.130 mg/kg body weight/day of isoflavones were consumed by children, which did not show significant differences in their sexual maturation.

CONCLUSION

Consumption of SPS for 12 months did not affect sexual maturation or the onset of puberty in prepubertal boys and girls; however, it may have induced an increase in height, BMI/age, height/age and weight/age of the girls, associated with variations in fat-free mass.

Stress Measured by Allostatic Load in Neurologically Impaired Children: The Importance of Nutritional Status

BACKGROUND

Allostatic load (AL) is the cumulative physiological wear and tear that results from repeated efforts to adapt to stressors over time. The life stress response is modified by nutritional status.

AIM

We estimated AL scores among neurologically impaired (NI) children; the association with malnutrition was also evaluated.

METHODS

Forty-one patients with severe disabilities were included. Data based on 15 biomarkers were used to create the AL score. A dichotomous outcome of high AL was defined for those who had ≥6 dysregulated components. Body mass index (BMI)-standard deviation score (SDS) <-2 or SDS ≥2 and biochemical markers (≥4) defined malnutrition.

RESULTS

High AL was noted in 17/41 of the whole sample (41.47%). Malnutrition occurred in 36.6% of the subjects. A significant correlation between high AL and malnutrition was observed (p = 0.01; ar ea under the receiver operating characteristic curve, 0.7457). High AL subjects had a significantly higher BMI (p = 0.009) and lower BMI-SDS (p = 0.003) than low AL subjects. AL score correlated with fat mass (p ≤ 0.01) and negatively correlated with fat-free mass (p ≤ 0.02).

CONCLUSION

In NI children, high AL was associated with malnutrition. Body composition is a better indicator than BMI of allostatic adjustments. AL estimation should be considered a measure of health risk and be used to promote quality of life in at-risk disabled populations.

Growth and Puberty in Obese Children and Implications of Body Composition

Childhood obesity is a major public health concern throughout the world. Nutrition, energy balance and hormones interplay in growth and pubertal development regulation. Frequently overweight and obese children are taller for their age and sex and tend to mature earlier than lean children. The increased leptin and sex hormone levels seen in obese children with excessive adiposity may be implicated in accelerated pubertal growth and accelerated epiphyseal growth plate maturation. Efforts to detect the impact of obesity in children are needed to prevent metabolic and cardiovascular disease in later life. This review aims to cover the process of growth in obese children and implications of body composition on growth and pubertal development and introduce the use of body composition charts in clinical practice.

Use of upper arm anthropometry, upper arm muscle area-by-height (UAMAH) and midupper- arm-circumference (MUAC)-for-height as indicators of body composition and nutritional status among children

Upper arm anthropometry has a potential role to provide useful estimations of body composition and nutritional status. Aims of the present cross-sectional study were to assess body composition and nutritional status of rural school-going children using upper arm anthropometric measures such as upper arm muscle area-by-height (UAMAH) and mid-upper arm circumference (MUAC) for-height. The present cross-sectional study was conducted among 1281 children of West Bengal, India (boys 619, girls 662) aged 5-12 years and selected using a stratified random sampling method. Anthropometric measurements of height, weight, MUAC and triceps skinfold (TSF) were recorded. Body composition and nutritional status were assessed using upper arm muscle area (UMA), upper arm fat area (UFA), UAMAH and MUAC-forheight. Age-sex-specific overall adiposity in TSF, UFA, arm fat index and upper-arm fat area estimates were higher among girls than boys (p<0.01), but UMA and upper-arm muscle area estimates were observed to be higher among boys than girls (p<0.05). High prevalence of undernutrition was found among both boys (53.15%) and girls (41.69%) using UAMAH (p<0.01). The overall prevalence of low MUAC-forheight was higher among boys (28.59%) than girls (25.68%) (p>0.05). Upper arm anthropometric measures, UAMAH and MUAC-for-height are useful for assessment of body composition and nutritional status among children.

Age- and Sex-Dependent Values of the Distribution of Body Composition Parameters Among Chinese Children Using the Hattori Chart

This study aimed to examine the relationship between the fat-free mass (FFM) and fat mass (FM) and between the fat-free mass index (FFMI) and fat mass index (FMI) in Chinese children using the Hattori chart and to compare the changing pattern with Korean counterparts. In this study, 1541 (764 girls) children and adolescents aged 5-19 yr were recruited from southern China. The subjects' body composition was measured using dual-energy X-ray absorptiometry. The relationship between FFM and FM and between FFMI and FMI were delineated using the Hattori chart. Between 5 and 12 yr, a concurrent increase in FFM and FM and in FFMI and FMI was found in both sexes. After 12 yr, the age-related changing patterns are generally characterized by a sharp increase in FM, with a relatively small increase in FFM for girls, and a sharp increase in FFM, with a relatively little fluctuation in FM for boys. The increase in weight and BMI with age for this stage is largely due to the increase in FFM and FFMI in boys and in both the FFM and FM and FFMI and FMI components in girls. Sex differences in the patterns of body composition were found in Chinese children and adolescents.

Relationships between the lean mass index and bone mass and reference values of muscular status in healthy Chinese children and adolescents

This study aimed to analyze the relationships between the lean mass index (LMI) and bone outcomes in Chinese children and adolescents using dual-energy X-ray absorptiometry (DXA) and to establish sex-specific reference percentile curves for the assessment of muscle status. A total of 1541 Chinese children and adolescents between the ages of 5 and 19 years were recruited from southern China. Body composition was measured by DXA (Lunar Prodigy) to acquire total body and total body less head (TBLH) measures. LMI was calculated as the LM (kg) divided by the height in meters squared. Strong sex gaps were observed after age 14 in total body LMI and appendicular LMI (p < 0.001). LM and LMI values continued to increase for boys up to age 14 compared to girls who plateaued after age 12. For each sex group, total body bone mineral content (BMC) and TBLH BMC were highly correlated with total body LMI and appendicular LMI (r = 0.856-0.916 in boys, and r = 0.651-0.804 in girls, p < 0.001). The appendicular LMI was more strongly associated with total body BMC and TBLH BMC than was total body LMI. The correlations between the BMC values and the LM measures were stronger than the fat mass results. We also present sex-specific percentile curves for LM-age and LMI-age relationships, which could be useful for identifying the LM deficits in this population.

Gender Difference in Body Fat for Healthy Chinese Children and Adolescents

BACKGROUND

This study aimed to establish gender-related differences and the percentile curves for total body fat mass percentage (Total FM%), trunk/appendicular fat mass ratio (TrAppFMR), and fat mass ratio as % fat trunk/% fat lower limb (TrLLFMR) in Chinese children and adolescents using dual-energy X-ray absorptiometry (DXA).

METHODS

Children (n = 1541; 764 girls) and adolescents aged 5 to 19 years were recruited from southern China. Total FM% and regional FM were measured by DXA. TrAppFMR values were calculated as trunk FM divided by appendicular FM, and TrLLFMR values were calculated as the ratio between the percentage of trunk FM and the percentage of lower limb FM.

RESULTS

Total FM% peaks for boys were at approximately age 11 years and continued to increase for girls throughout adolescence. Median Total FM% at the age of 19 years was 15.53% and 28.06% for boys and girls, respectively. Median TrAppFMR and TrLLFMR increases were 61% and 81% from 5 to 19 years of age in boys compared with those in girls, 31% and 54%. The curves for median TrAppFMR and TrLLFMR in girls were relatively flat, with TrAppFMR and TrLLFMR remaining near 1.0 after 16 years of age, whereas in boys, median TrAppFMR and TrLLFMR increased with age until approximately 19 years.

CONCLUSIONS

Gender differences in the patterns of proportion and distribution of body fat were found. We present sex-specific percentile curves for Total FM%-age, TrAppFMR-age, and TrLLFMR-age relationships in this population.

Distribuição da gordura corporal em escolares: um estudo usando o método LMS

INTRODUÇÃO: A avaliação do sobrepeso e obesidade em populações ainda tem sido baseada predominantemente no índice de massa corporal, o qual tem sido considerado o indicador universal da adiposidade. OBJETIVO: Analisar a distribuição da gordura corporal de escolares de sete a 10 anos, por meio da construção de referenciais percentílicos das dobras cutâneas, utilizando os parâmetros LMS. MÉTODO: Os dados são relativos a uma amostra representativa de escolares de sete a 10 anos frequentando escolas públicas e privadas, que participaram de pesquisa mais ampla de prevalência do sobrepeso e obesidade, realizada em 2002, em Florianópolis (Santa Catarina, Brasil), e composta por 2.918 crianças. Para este estudo utilizaram-se os dados antropométricos de estatura, dobras cutâneas subescapular, suprailíaca, tricipital e panturrilha medial. O método LMS, que visa normalizar os dados que apresentam assimetria em sua distribuição, foi utilizado para analisar e comparar a distribuição das dobras por faixa etária e sexo. RESULTADOS: Ambos os sexos apresentaram valores maiores de gordura subcutânea na região do tríceps e da panturrilha, porém, no sexo masculino estes foram inferiores aos das meninas e com pouco incremento ao longo da faixa etária investigada. A dobra que apresentou maior incremento nos valores medianos foi a suprailíaca, para o sexo feminino, a qual alcançou valores próximos aos da dobra tricipital aos 10 anos de idade. CONCLUSÕES: O método LMS propicia a análise da distribuição dos valores das dobras cutâneas, as quais são importantes para avaliar a evolução da gordura corporal e o estado nutricional de crianças.

Fat and lean BMI reference curves in children and adolescents and their utility in identifying excess adiposity compared with BMI and percentage body fat

BACKGROUND

Body mass index (BMI) and percentage body fat (%BF) are widely used to assess adiposity. These indexes fail to account for independent contributions of fat mass (FM) and lean body mass (LBM) to body weight, which vary according to age, sex, pubertal status, and population ancestry in the pediatric population.

OBJECTIVE

The objective was to develop pediatric reference curves for fat mass index (FMI) and lean body mass index (LBMI) and evaluate the effects of population ancestry and LBM on measures of excess adiposity (BMI, %BF, and FMI).

DESIGN

Sex-specific FMI and LBMI reference curves relative to age for children and adolescents aged 8-20 y were generated from cross-sectional body-composition data measured by dual-energy X-ray absorptiometry from NHANES.

RESULTS

The mean LBMI z score was higher in blacks (males: 0.26; females: 0.45) than in whites (males: -0.07; females: -0.09) and Mexican Americans (males: 0.05; females: -0.09). The positive predictive value of overweight by BMI to identify excess adiposity defined by FMI was lower in blacks (males: 35.9%; females: 30.3%) than in whites (males: 65.4%; females: 52.2%) and Mexican Americans (males: 73.3%; females: 68.3%). Participants classified as having excess adiposity by FMI but normal adiposity by %BF had significantly higher BMI, LBMI, and height z scores than did those classified as having excess adiposity by %BF but normal adiposity by FMI.

CONCLUSIONS

Relative to FMI, the prevalence of excess adiposity is overestimated by BMI in blacks and underestimated by %BF in individuals with high LBM. The use of FMI and LBMI improves on the use of %BF and BMI by allowing for the independent assessment of FM and LBM.

Body fat percentile curves for Korean children and adolescents: a data from the Korea National Health and Nutrition Examination Survey 2009-2010

A valid assessment of obesity in children and adolescents is important due to significant change in body composition during growth. This study aimed to develop percentile curves of body fat and fat free mass using the Lambda, Mu, and Sigma method, and to examine the relationship among body mass index (BMI), fat mass and fat free mass in Korean children and adolescents, using the Korea National Health and Nutrition Examination Survey (KNHANES) 2009-2010. The study subjects were 834 for boys and 745 for girls aged between 10 and 18 yr. Fat mass and fat free mass were measured by dual-energy x-ray absorptiometry. The patterns of development in body fat percentage, fat mass and fat free mass differed for boys and girls, showing a decreased fat mass with an increased fat free mass in boys but gradual increases with age in girls. The considerable proportion of boys and girls with relatively normal fat mass appeared to be misclassified to be at risk of overweight based on the BMI criteria. Therefore, the information on the percentiles of body fat and fat free mass with their patterns would be helpful to complement assessment of overweight and obesity based on BMI for Korean children and adolescents.

Prediction equations for fat and fat-free body mass in adolescents, based on body circumferences

BACKGROUND

Fat mass (FM) and fat-free body mass (FFB) are important parameters for assessing nutritional status, since they are associated with higher prevalence of excess body fat and malnutrition worldwide.

AIM

To develop prediction equations for fat and fat-free body mass in adolescents using body circumferences.

SUBJECTS AND METHODS

This cross-sectional study included 218 adolescents (10-16 years) with normal weight as defined by body mass index. FM(Pred) and FFB(Pred) were estimated using stepwise multiple linear regression, considering age and body circumferences. Response variables, FM(BIA) and FFB(BIA) were estimated using bioelectric impedance analysis (BIA). The accuracy of the prediction equations was evaluated using the coefficient of determination (R(2)) and Akaike's Information Criterion (AIC).

RESULTS

The best prediction equations for males were FM(Pred) = -7.114 - 0.592(age) - 0.958(wrist)+0.191(hip)+0.295(abdomen); R(2) = 0.552; AIC = 416.04 and FFB(Pred) = - 52.180+1.913(age)+1.954(wrist)+1.635(forearm); R(2) = 0.869; AIC = 578.24. For females, the best equations were FM(Pred) = -17.580 - 0.678(wrist)+0.221(abdomen)+0.241(hip)+0.202(proximal thigh) - 0.228(calf); R(2) = 0.838; AIC = 415.36 and FFB(Pred) = -31.066+0.90(age)+1.090(wrist) - 0.139(abdomen)+0.326(hip)+0.632(calf); R(2) = 0.878; AIC = 512.48.

CONCLUSION

The equations developed to estimate fat body mass in females and fat-free body mass in both genders had high adjusted coefficients of determination and are therefore preferable to those derived using BIA.

Body composition abnormalities in long-term survivors of pediatric hematopoietic stem cell transplantation

OBJECTIVE

To quantify lean mass (LM) and fat mass (FM) in survivors of childhood allogeneic hematopoietic stem-cell transplantation (alloHSCT) compared with healthy reference participants and identify risk factors for body composition abnormalities.

STUDY DESIGN

Whole body LM and FM were measured with dual energy x-ray absorptiometry in 54 survivors (ages 5-25 years) and 894 healthy reference participants in a cross-sectional study. Multivariate regression models were used to compare sex- and race-specific Z-scores for LM for height (LM-Ht) and FM for height (FM-Ht) in survivors and reference participants and to identify correlates of LM-Ht and FM-Ht Z-scores in alloHSCT.

RESULTS

Height Z-scores were significantly lower in alloHSCT survivors (P < .001) compared with reference participants; body mass index Z-scores did not differ (P = .13). Survivors had significantly lower mean LM-Ht Z-scores (-0.72; 95% CI, -1.02--0.42; P < .001) and greater FM-Ht Z-scores (1.10; 95% CI, 0.84-1.39; P < .001) compared with reference participants. LM-Ht Z-score deficits in alloHSCT survivors were larger (-1.26; 95% CI, -1.53--0.99; P < .001) after adjustment for FM-Ht Z-scores. Endocrinopathies and alloHSCT characteristics were not associated with LM-Ht or FM-Ht Z-scores.

CONCLUSION

Survivors of childhood alloHSCT have significant LM deficits and FM excess. Future studies should identify the mechanism and consequences of these abnormalities.

To what extent do weight gain and eating avidity during infancy predict later adiposity?

Objective

To determine the extent to which weight gain and eating behaviours in infancy predict later adiposity.

Design

Population-based, prospective, longitudinal birth cohort study. Weights collected in infancy were used to calculate Z-scores for weight gain to age 1 year conditional on birth weight (CWG). To avoid multiple significance tests, variables from the parent questionnaire completed at age 1 year describing eating avidity were combined using general linear modelling to create an infancy avidity score. Anthropometry, skinfold thicknesses and bioelectrical impedance data collected at age 7–8 years were combined using factor analysis, to create an adiposity index.

Setting

Gateshead, UK.

Subjects

Members of the Gateshead Millennium Study cohort with data at both time points (n 561).

Results

CWG in infancy significantly predicted adiposity at age 7 years, but related more strongly to length and lean mass. High adiposity (> 90th internal percentile) at age 7 years was significantly associated with high CWG (relative risk 2·76; 95 % CI 1·5, 5·1) in infancy, but less so with raised (> 74th internal percentile) eating avidity in infancy (relative risk 1·87; 95 % CI 0·9, 3·7). However, the majority of children with high weight gain (77·6 %) or avidity (85·5 %) in infancy did not go on to have high adiposity at age 7 years.

Conclusions

Rapid weight gain in infancy and the eating behaviours which relate to it do predict later adiposity, but are more strongly predictive of later stature and lean mass.

External cross-validation of bioelectrical impedance analysis for the assessment of body composition in Korean adults

Bioelectrical impedance analysis (BIA) models must be validated against a reference method in a representative population sample before they can be accepted as accurate and applicable. The purpose of this study was to compare the eight-electrode BIA method with DEXA as a reference method in the assessment of body composition in Korean adults and to investigate the predictive accuracy and applicability of the eight-electrode BIA model. A total of 174 apparently healthy adults participated. The study was designed as a cross-sectional study. FM, %fat, and FFM were estimated by an eight-electrode BIA model and were measured by DEXA. Correlations between BIA_%fat and DEXA_%fat were 0.956 for men and 0.960 for women with a total error of 2.1%fat in men and 2.3%fat in women. The mean difference between BIA_%fat and DEXA_%fat was small but significant (P < 0.05), which resulted in an overestimation of 1.2 ± 2.2%fat (95% CI: -3.2-6.2%fat) in men and an underestimation of -2.0 ± 2.4%fat (95% CI: -2.3-7.1%fat) in women. In the Bland-Altman analysis, the %fat of 86.3% of men was accurately estimated and the %fat of 66.0% of women was accurately estimated to within 3.5%fat. The BIA had good agreement for prediction of %fat in Korean adults. However, the eight-electrode BIA had small, but systemic, errors of %fat in the predictive accuracy for individual estimation. The total errors led to an overestimation of %fat in lean men and an underestimation of %fat in obese women.

UAE population reference standard charts for body mass index and skinfold thickness, at ages 0-18 years

AIMS

To determine a range of anthropometric measurements including skinfold thickness measurements in four different areas of the body, to construct population growth charts for body mass index (BMI), skinfolds, and to compare these with growth charts from other countries. One aim was also to validate body fat charts derived from skinfold thickness.

METHODS

A national cross-sectional growth survey of children, 0-18 years old, was conducted using multistage stratified random sampling. The sample size included at least 200 children in each age-sex group. Height, weight, biceps skinfold, triceps skinfold, subscapular skinfold, suprailiac skinfold, and mid-upper-arm circumference were measured in each child. We describe correlation, standard deviation scores relative to the other standards, and calculation of body density in the United Arab Emirates population. We determined whether any of the above is a good indicator of fatness in children.

RESULTS

BMI, upper-arm circumference, sum of four skinfolds, and percentage body fat charts were constructed using the LMS method of smoothing. BMI was very significantly correlated with sum of skinfold thicknesses, and mid-upper-arm circumference. Prevalence of obesity and overweight in ages 13-17 years was respectively 9.94% and 15.16% in females and 6.08% and 14.16% in males. Derived body fat charts were found not to be accurate.

CONCLUSION

A national BMI, upper-arm circumference, and sum of four skinfolds chart has been constructed that can be used as a reference standard for the United Arab Emirates. Sum of four skinfold thickness charts can be used as crude determinants of adiposity in children, but derived body fat charts were shown to be inaccurate.

Cystatin C, cardiometabolic risk, and body composition in severely obese children

The aim of this study was to assess the relationship between cystatin C (CysC), cardiometabolic risk factors (CMRFs), and body composition in severely obese children. We evaluated 117 children aged 7-14 years old. Seventy-nine of these were severely obese (body mass index z-score ranging from 2.1 to 8.4), and 38 were children with normal nutrition state. CysC was determined by immunonephelometry. CMRFs (glucose, insulin, high-density lipoprotein cholesterol, triglycerides, homocysteine, uric acid, alanine aminotransferase, and high-sensitivity C-reactive protein) were measured by standard biochemical methods. Blood pressure was evaluated at the clinical examination. Renal function was estimated using the glomerular filtration rate (eGFR) based upon creatinine levels, and body weight (Léger formula). Body composition was assessed by segmental bioelectrical impedance. Obese children at the highest tertile of CysC values were characterized by their aggregation of CMRFs. CysC concentration was associated with insulin resistance, alanine aminotransferase, uric acid, and homocysteine after adjusting for age, gender, and eGFR. CysC values were also correlated with the fat-free mass and specifically with skeletal muscle mass. CysC levels were correlated with CMRFs factors independently of renal function, and affected by skeletal muscle mass in severely obese children, although they are less influenced by this than is creatinine.

Comparison of changes in body composition during puberty development of obese and normal-weight children in China

OBJECTIVE

To compare the changes in body composition, including fat mass index (FMI) and fat free mass index (FFMI) during puberty development of obese and normal-weight children in China, and to explore the effect of age and gender on body composition.

METHODS

A total of 356 children at the age of 7-15 years were enrolled in this study. Body composition of 10 normal-weight and obese children in each age group was measured by dual-energy x-ray absorptiometry (DEXA). FFMI and FMI were calculated according to the following formula: FFMI (kg x m(-2)) = FFM(kg) / height2 (m2) and FMI (kg x m(-2)) = FM (kg) / height2 (m2).

RESULTS

The fat mass and fat free mass of obese children were significantly higher than those of normal-weight children (P < 0.05). The FMI and FFMI of obese children increased significantly with age and were higher than those of the same sex, gender, and age normal-weight children (P < 0.05).

CONCLUSION

The levels of fat mass, fat free mass, FMI, and FFMI are different in obese and normal-weight children, and gender effects are significant in boys having higher levels of these indicators than in girls. FFMI and FMI can be used as monitoring indexes in weight control of obese children.

Pediatric body composition analysis with dual-energy X-ray absorptiometry

Pediatric applications of body composition analysis (BCA) have become of increased interest to pediatricians and other specialists. With the increasing prevalence of morbid obesity and with an increased awareness of anorexia nervosa, pediatric specialists are utilizing BCA data to help identify, treat, and prevent these conditions. Dual-energy X-ray absorptiometry (DXA) can be used to determine the fat mass (FM) and lean tissue mass (LTM), as well as bone mineral content (BMC). Among the readily available BCA techniques, DXA is the most widely used and it has the additional benefit of precisely quantifying regional FM and LTM. This review evaluates the strengths and limitations of DXA as a pediatric BCA method and considers the utilization of DXA to identify trends and variations in FM and LTM measurements in obese and anorexic children.

Pediatric body composition analysis with dual-energy X-ray absorptiometry

Pediatric applications of body composition analysis (BCA) have become of increased interest to pediatricians and other specialists. With the increasing prevalence of morbid obesity and with an increased awareness of anorexia nervosa, pediatric specialists are utilizing BCA data to help identify, treat, and prevent these conditions. Dual-energy X-ray absorptiometry (DXA) can be used to determine the fat mass (FM) and lean tissue mass (LTM), as well as bone mineral content (BMC). Among the readily available BCA techniques, DXA is the most widely used and it has the additional benefit of precisely quantifying regional FM and LTM. This review evaluates the strengths and limitations of DXA as a pediatric BCA method and considers the utilization of DXA to identify trends and variations in FM and LTM measurements in obese and anorexic children.

Cross-validation of bioelectrical impedance analysis for the assessment of body composition in a representative sample of 6- to 13-year-old children

BACKGROUND/OBJECTIVES

(1) To cross-validate tetra- (4-BIA) and octopolar (8-BIA) bioelectrical impedance analysis vs dual-energy X-ray absorptiometry (DXA) for the assessment of total and appendicular body composition and (2) to evaluate the accuracy of external 4-BIA algorithms for the prediction of total body composition, in a representative sample of Swiss children.

SUBJECTS/METHODS

A representative sample of 333 Swiss children aged 6-13 years from the Kinder-Sportstudie (KISS) (ISRCTN15360785). Whole-body fat-free mass (FFM) and appendicular lean tissue mass were measured with DXA. Body resistance (R) was measured at 50 kHz with 4-BIA and segmental body resistance at 5, 50, 250 and 500 kHz with 8-BIA. The resistance index (RI) was calculated as height(2)/R. Selection of predictors (gender, age, weight, RI4 and RI8) for BIA algorithms was performed using bootstrapped stepwise linear regression on 1000 samples. We calculated 95% confidence intervals (CI) of regression coefficients and measures of model fit using bootstrap analysis. Limits of agreement were used as measures of interchangeability of BIA with DXA.

RESULTS

8-BIA was more accurate than 4-BIA for the assessment of FFM (root mean square error (RMSE)=0.90 (95% CI 0.82-0.98) vs 1.12 kg (1.01-1.24); limits of agreement 1.80 to -1.80 kg vs 2.24 to -2.24 kg). 8-BIA also gave accurate estimates of appendicular body composition, with RMSE < or = 0.10 kg for arms and < or = 0.24 kg for legs. All external 4-BIA algorithms performed poorly with substantial negative proportional bias (r> or = 0.48, P<0.001).

CONCLUSIONS

In a representative sample of young Swiss children (1) 8-BIA was superior to 4-BIA for the prediction of FFM, (2) external 4-BIA algorithms gave biased predictions of FFM and (3) 8-BIA was an accurate predictor of segmental body composition.

Body mass index and body composition in relation to sexual maturation

AIM

To assess body mass index. (BMI) in relation to sexual maturation and verify how fat-free mass (FFM) and fat mass (FM) contribute to its increase.

METHODS

1,275 White adolescents (656 girls and 619 boys), aged 9 to 18 years, were evaluated according to Tanner stages. FFM and FM were calculated by triceps and subscapular skinfold measurements and leg-to-leg bioelectrical impedance. BMI-for-maturation was distributed into percentiles. Fat-free mass index (FFMI) and body fat mass index (BFMI) were calculated based on BMI 50t" ph percentile values.

RESULTS

During maturation, as BMI increases, girls gain FFMI (13.3 kg/m2 at B1 and 15.8 kg/m2 at B5) and BFMI (3.7 kg/m2 at B1 and 5.7 kg/m2 at B5)--proportionally more fat-- while boys gain FFMI (14.3 kg/m2 at G1 and 17.9 kg/m2 at G5) and lose BFMI (4.8 kg/m2 at G1 and 3.2 kg/m2 at G5).

CONCLUSION

These data suggest that FFMI and BFMI-for-maturation should be assessed in adolescents monitored for overweight and obesity.

Metabolic complications of HIV infection and its therapy in children

HIV infection has become a chronic disease in pediatric patients, with the potential for longer term survival and exposure to combination antiretroviral therapy for two decades longer than HIV-positive adults. However, body shape and metabolic abnormalities are frequently observed during antiretroviral therapy. These abnormalities have been poorly evaluated in HIV-infected children and their long-term consequences are not yet well assessed. This review summarizes our current understanding of the epidemiology, diagnosis and management of body shape abnormalities, dyslipidemia, disorders of glucose metabolism and vascular dysfunction in HIV-infected children and adolescents.

Objective assessment of childhood adherence to Canadian physical activity guidelines in relation to body composition

Low levels of childhood physical activity (PA) are a contributing factor to obesity. The objective of this study was to determine the adherence of children to PA guidelines in relation to body composition. Body fat (Slaughter equation) and body mass index (BMI) were determined during the school year (n = 251, ages 8-11 y). Daily energy expenditure (EE, kcal.kg-1.d-1) and activity time (AT, min.d-1) above moderate and vigorous intensity thresholds were assessed (accelerometry). Using EE criteria, 35.9% expended < 3.0 kcal.kg-1.d-1, 27.9% expended between 3.0 and 5.9 kcal.kg-1.d-1, 13.5% expended between 6.0 and 7.9 kcal.kg-1.d-1, and 22.9% expended >or= 8.0 kcal.kg-1.d-1. Using AT criteria, 52.2% accumulated < 30.0 min, 31.1% accumulated 30.0-59.9 min, 12.7% accumulated 60.0-89.9 min, and 4.0% accumulated >or=90.0 min of AT. The EE corresponding to accumulation of AT > 90 min was 14.8 kcal.kg-1.d-1. The AT corresponding to >or= 8 kcal.kg-1.d-1 was 73.0 min. Inverse relationships were observed between EE and body fat (p = 0.0004), BMI (p = 0.002), mass (p = 0.008), and fat mass index (FMI) (p = 0.001), as well as between AT and body fat (p = 0.001), BMI (p = 0.008), mass (p = 0.017), and FMI (p = 0.002). Controlling for BMI, FMI was inversely related to EE (p = 0.049) and AT (p = 0.039). Fat-free mass index and AT were positively related (p = 0.038). Physical activity had beneficial effects on body composition for children independent of BMI. The relationship between AT and daily EE guidelines was rationalized (60 min.d-1 with 8 kcal.kg-1.d-1) and demonstrated association with acceptable body composition. The 60 min.d-1 of moderate activity may be a more suitable initial target than 90 min.d-1, as so few children met the upper tiers of PA guidelines.

Development of bioelectrical impedance-derived indices of fat and fat-free mass for assessment of nutritional status in childhood

OBJECTIVES

(1) To develop a method of manipulating bioelectrical impedance (BIA) that gives indices of lean and fat adjusted for body size, using a large normative cohort of children. (2) To assess the discriminant validity of the method in a group of children likely to have abnormal body composition.

DESIGN

Two prospective cohort studies.

SETTING

Normative data: Avon Longitudinal Study of Parents and Children (ALSPAC), population based cohort; proof of concept study: tertiary feeding clinic and special needs schools.

SUBJECTS

Normative data: 7576 children measured aged between 7.25 and 8.25 (mean 7.5) (s.d.=0.2) years; proof of concept study: 29 children with either major neurodisability or receiving artificial feeding, or both, mean age 7.6 (s.d.=2) years.

MEASURES

Leg-to-leg (Z (T)) and arm-to-leg (Z (B)) BIA, weight and height. Total body water (TBW) was estimated from the resistance index (RI=height(2)/Z), and fat-free mass was linearly related to TBW. Fat mass was obtained by subtracting fat-free mass from total weight. Fat-free mass was log-transformed and the reciprocal transform was taken for fat mass to satisfy parametric model assumptions. Lean and fat mass were then adjusted for height and age using multiple linear regression models. The resulting standardized residuals gave the lean index and fat index, respectively.

RESULTS

In the normative cohort, the lean index was higher and fat index lower in boys. The lean index rose steeply to the middle of the normal range of body mass index (BMI) and then slowly for higher BMI values, whereas the fat index rose linearly through and above the normal range. In the proof of concept study, the children as a group had low lean indices (mean (s.d.) -1.5 (1.7)) with average fat indices (+0.21 (2.0)) despite relatively low BMI standard deviation scores (-0.60 (2.3)), but for any given BMI, individual children had extremely wide ranges of fat indices. The lean index proved more stable and repeatable than BMI.

CONCLUSIONS

This clinical method of handling BIA reveals important variations in nutritional status that would not be detected using anthropometry alone. BIA used in this way would allow more accurate assessment of energy sufficiency in children with neurodisability and may provide a more valid identification of children at risk of underweight or obesity in field and clinical settings.

What use is the BMI?

The BMI is the best available tool for monitoring progress in the campaign against obesity

Do changes in body mass index percentile reflect changes in body composition in children? Data from the Fels Longitudinal Study

OBJECTIVE

Our aim was to examine the degree to which changes in BMI percentile reflect changes in body fat and lean body mass during childhood and how age and gender affect these relationships.

METHODS

This analysis used serial data on 494 white boys and girls who were aged 8 to 18 years and participating in the Fels Longitudinal Study (total 2319 observations). Total body fat (TBF), total body fat-free mass (FFM), and percentage of body fat (%BF) were determined by hydrodensitometry, and then BMI was partitioned into its fat and fat-free components: fat mass index (FMI) and FFM index (FFMI). We calculated predicted changes (Delta) in FMI, FFMI, and %BF for each 10-unit increase in BMI percentile using mixed-effects models.

RESULTS

FFMI had a linear relationship with BMI percentile, whereas FMI and %BF tended to increase dramatically only at higher BMI percentiles. Gender and age had significant effects on the relationship between BMI percentile and FFMI, FMI, and %BF. Predicted Delta%BF for boys 13 to 18 years of age was negative, suggesting loss of relative fatness for each 10-unit increase in BMI percentile.

CONCLUSIONS

In this longitudinal study of white children, FFMI consistently increased with BMI percentile, whereas FMI and %BF had more complicated relationships with BMI percentile depending on gender, age, and whether BMI percentile was high or low. Our results suggest that BMI percentile changes may not accurately reflect changes in adiposity in children over time, particularly among male adolescents and children of lower BMI.

Body-composition alterations consistent with cachexia in children and young adults with Crohn disease

BACKGROUND

Crohn disease (CD) in children is associated with low body mass index (BMI), poor growth, and delayed maturation; alterations in lean and fat mass, however, are poorly characterized.

OBJECTIVE

The objective was to quantify lean and fat mass in children and young adults with CD and in healthy control subjects, relative to height and pubertal maturation.

DESIGN

This cross-sectional study assessed whole-body lean and fat mass by using dual-energy X-ray absorptiometry in 104 subjects with CD and in 233 healthy control subjects aged 4-25 y. Linear regression was used to determine the effect of CD on body composition and to generate sex-specific SD scores (z scores) for lean and fat mass relative to height.

RESULTS

Subjects with CD had lower height-for-age and BMI-for-age z scores (P < 0.001 for both) than did control subjects. CD was associated with significant deficits in lean mass after adjustment for height, age, race, and Tanner stage (P = 0.003); deficits in fat mass were not observed. The mean (+/-SD) lean mass-for-height and fat mass-for-height z scores in the subjects with CD were -0.61 +/- 0.92 and -0.04 +/- 0.86, respectively. Within the control group, fat mass-for-height was positively correlated with lean mass-for height (r = 0.41, P < 0.0001); this association was absent in the subjects with CD.

CONCLUSIONS

Children and young adults with CD had significant deficits in lean mass but preserved fat mass, which is consistent with cachexia. Further research is needed to identify physical activity, nutritional, and antiinflammatory interventions to improve body composition in persons with CD.

Body-composition alterations consistent with cachexia in children and young adults with Crohn disease

BACKGROUND

Crohn disease (CD) in children is associated with low body mass index (BMI), poor growth, and delayed maturation; alterations in lean and fat mass, however, are poorly characterized.

OBJECTIVE

The objective was to quantify lean and fat mass in children and young adults with CD and in healthy control subjects, relative to height and pubertal maturation.

DESIGN

This cross-sectional study assessed whole-body lean and fat mass by using dual-energy X-ray absorptiometry in 104 subjects with CD and in 233 healthy control subjects aged 4-25 y. Linear regression was used to determine the effect of CD on body composition and to generate sex-specific SD scores (z scores) for lean and fat mass relative to height.

RESULTS

Subjects with CD had lower height-for-age and BMI-for-age z scores (P < 0.001 for both) than did control subjects. CD was associated with significant deficits in lean mass after adjustment for height, age, race, and Tanner stage (P = 0.003); deficits in fat mass were not observed. The mean (+/-SD) lean mass-for-height and fat mass-for-height z scores in the subjects with CD were -0.61 +/- 0.92 and -0.04 +/- 0.86, respectively. Within the control group, fat mass-for-height was positively correlated with lean mass-for height (r = 0.41, P < 0.0001); this association was absent in the subjects with CD.

CONCLUSIONS

Children and young adults with CD had significant deficits in lean mass but preserved fat mass, which is consistent with cachexia. Further research is needed to identify physical activity, nutritional, and antiinflammatory interventions to improve body composition in persons with CD.

Sustained rise in triacylglycerol synthesis and increased epididymal fat mass when rats cease voluntary wheel running

Four-week-old, Fischer-Brown Norway F1-generation male rats were given access to voluntary running wheels for 21 days, and then the wheels were locked for 5 (WL5), 10 (WL10), 29 (WL29), or 53 (WL53) hours. Two other groups (SED5 and SED10) had no access to voluntary running wheels and were killed at the same time as WL5 and WL10, respectively. Absolute and relative epididymal fat mass, mean cell volume, and amount of lipid per cell increased in WL53 relative to all other groups, with no change in cell number. C/EBPalpha protein levels in epididymal fat were 30% greater in SED5 than in WL5. The rate of triacylglycerol synthesis in epididymal fat was 4.2-fold greater in SED5 than in WL5, increased 14-fold between WLS and WL10, and was 79% lower in SED10 than in WL10. Triacylglycerol synthesis remained at this elevated level (at least 3.5-fold greater than SED5) through WL53. Thus, the rapid increase in epididymal fat mass with the cessation of voluntary wheel running is associated with a prolonged overshoot in epididymal fat triacylglycerol synthesis. Moreover, rats without running wheels had a 9.4% lower body mass after 21 days than those with running wheels. The individual mass of seven different muscles from the hindlimb, upper forelimb, and back were each lower in animals without running wheels, suggesting that physical activity in rapidly growing rats may be requisite for optimal muscle development.

Body composition in children with galactosaemia

Body composition in classical galactosaemia has not been studied. Patients with classical galactosaemia, an inherited disorder of galactose metabolism caused by deficiency of galactose-1-phosphate uridyltransferase (GALT, EC 2.7.7.10), might be at risk for an abnormal body composition because of intrinsic factors related to galactosaemia and/or diet-related factors. The aim of this study was to evaluate the body composition of children with classical galactosaemia. The studied population was a previously reported group of classical galactosaemia patients (13 male and 27 female, ages 3-17 years) with decreased height, weight, weight-for-height and insulin-like growth factor-I (IGF-I) Z-scores. Body composition data were obtained by dual-energy X-ray absorptiometry (DXA). In order to correct for height, fat mass (FM) and lean tissue mass (LTM) were divided by squared height. Mid-parental target height Z-scores were assessed and compared to actual height Z-scores. Linear and multiple regression analysis were done to investigate the relationship between body composition and IGF-I, dietary intake and growth data. We found decreased height Z-scores when compared to mid-parental target height Z-scores. Mean scores for FM and LTM (both adjusted for height) were decreased. LTM (adjusted for height) and height Z-score were correlated with IGF-I Z-score. FM (adjusted for height) was correlated with soy intake. No correlation was found between soy intake and IGF-I Z-score. In this limited group of patients, height is decreased and body composition is abnormal. The decreased levels of IGF-I and/or soy nutrition might play a role in these findings.

The relation of childhood BMI to adult adiposity: the Bogalusa Heart Study

OBJECTIVE

Although many studies have found that childhood levels of body mass index (BMI; kg/m(2)) are associated with adult levels, it has been reported that childhood BMI is not associated with adult adiposity. We further examined these longitudinal associations.

DESIGN

Cohort study based on examinations between 1973 and 1996.

SETTING

Bogalusa, Louisiana.

PARTICIPANTS

Children (2610; ages 2-17 years old) who were followed to ages 18 to 37 years; the mean follow-up was 17.6 years.

MAIN OUTCOME MEASURES

BMI-for-age and triceps skinfold thickness (SF) were measured in childhood. Subscapular and triceps SFs were measured among adults, and the mean SF was used as an adiposity index. Adult obesity was defined as a BMI >or= 30 kg/m(2) and adult overfat as a mean SF in the upper (gender-specific) quartile.

RESULTS

Childhood levels of both BMI and triceps SF were associated with adult levels of BMI and adiposity. The magnitude of these longitudinal associations increased with childhood age, but the BMI levels of even the youngest (ages 2-5 years) children were moderately associated (r = 0.33-0.41) with adult adiposity. Overweight (BMI-for-age >or= 95th centile) 2- to 5-year-olds were >4 times as likely to become overfat adults (15 of 23 [65%]), as were children with a BMI < 50th centile (30 of 201 [15%]). Even after accounting for the triceps SF of children, BMI-for-age provided additional information on adult adiposity.

CONCLUSIONS

Childhood BMI is associated with adult adiposity, but it is possible that the magnitude of this association depends on the relative fatness of children.

Comparison of multifrequency bioelectrical impedance analysis with dual-energy X-ray absorptiometry for assessment of percentage body fat in a large, healthy population

BACKGROUND

Bioelectrical impedance analysis (BIA) is widely used in clinics and research to measure body composition. However, the results of BIA validation with reference methods are contradictory, and few data are available on the influence of adiposity on the measurement of body composition by BIA.

OBJECTIVE

The goal was to determine the effects of sex and adiposity on the difference in percentage body fat (%BF) predicted by BIA compared with dual-energy X-ray absorptiometry (DXA).

DESIGN

A total of 591 healthy subjects were recruited in Newfoundland and Labrador. %BF was predicted by using BIA and was compared with that measured by DXA. Methods agreement was assessed by Pearson's correlation and Bland and Altman analysis. Differences in %BF among groups based on sex and adiposity were analyzed by using one-factor analysis of variance with Bonferroni correction.

RESULTS

Correlations between BIA and DXA were 0.88 for the whole population, 0.78 for men, and 0.85 for women. The mean %BF determined by BIA (32.89 +/- 8.00%) was significantly lower than that measured by DXA (34.72 +/- 8.66%). The cutoffs were sex specific. BIA overestimated %BF by 3.03% and 4.40% when %BF was <15% in men and <25% in women, respectively, and underestimated %BF by 4.32% and 2.71% when %BF was >25% in men and >33% in women, respectively.

CONCLUSIONS

BIA is a good alternative for estimating %BF when subjects are within a normal body fat range. BIA tends to overestimate %BF in lean subjects and underestimate %BF in obese subjects.

Relation of BMI to fat and fat-free mass among children and adolescents

OBJECTIVE

Although the body mass index (BMI, kg/m2) is widely used as a surrogate measure of adiposity, it is a measure of excess weight, rather than excess body fat, relative to height. We examined the relation of BMI to levels of fat mass and fat-free mass among healthy 5- to 18-y-olds.

METHODS AND PROCEDURES

Dual-energy X-ray absorptiometry was used to measure fat and fat-free mass among 1196 subjects. These measures were standardized for height by calculating the fat mass index (FMI, fat mass/ht2) and the fat-free mass index (FFMI, fat-free mass/ht2).

RESULTS

The variability in FFMI was about 50% of that in FMI, and the accuracy of BMI as a measure of adiposity varied greatly according to the degree of fatness. Among children with a BMI-for-age > or =85th P, BMI levels were strongly associated with FMI (r=0.85-0.96 across sex-age categories). In contrast, among children with a BMI-for-age <50th P, levels of BMI were more strongly associated with FFMI (r=0.56-0.83) than with FMI (r=0.22-0.65). The relation of BMI to fat mass was markedly nonlinear, and substantial differences in fat mass were seen only at BMI levels > or =85th P.

DISCUSSION

BMI levels among children should be interpreted with caution. Although a high BMI-for-age is a good indicator of excess fat mass, BMI differences among thinner children can be largely due to fat-free mass.

The relationship between socio-economic status and physical activity patterns in South African children

AIM

To examine: (1) the associations between socio-economic status, physical activity, anthropometric and body composition variables in South African children; (2) the influence maternal characteristics have on children's physical activity levels; and (3) associations between television watching, activity level and body composition.

METHODS

In 381 South African children, physical activity and socio-economic status were assessed via structured retrospective interview using validated questionnaires. An asset indicator score was calculated as a proxy measure of socio-economic status and used to divide children into quartiles.

RESULTS

Children falling into the highest socio-economic status quartile had mothers with the highest educational levels, generally came from dual parent homes, were highly physically active, watched less television, weighed more and had greater lean tissue than children in lower quartiles. A greater percentage of children living in dual parent homes and with mothers of a higher educational status were highly active compared with children living in single parent homes and with mothers of a lower educational status. We found greater levels of lean mass with increased activity level after controlling for television watching time and fat mass. There were high levels of low activity and high television watching time among lower socio-economic status groups. There were significant racial differences in patterns of activity. White children were found to be more active than black children, more likely to participate in physical education classes at school and watched less television than black children.

CONCLUSION

Physical activity levels and socio-economic variables are closely related in this population of South African children.