Comparison of field methods to estimate fat mass in children

Equations based on anthropometric measurements for adipose tissue, body fat, or body density prediction in children and adolescents: a scoping review

PURPOSE

Assessing the body composition of children and adolescents is important to monitor their health status. Anthropometric measurements are feasible and less-expensive than other techniques for body composition assessment. This study aimed to systematically map anthropometric equations to predict adipose tissue, body fat, or density in children and adolescents, and to analyze methodological aspects of the development of anthropometric equations using skinfolds.

METHODS

A scoping review was carried out following the PRISMA-ScR criteria. The search was carried out in eight databases. The methodological structure protocol of this scoping review was retrospectively registered in the Open Science Framework ( https://osf.io/35uhc/ ).

RESULTS

We included 78 reports and 593 anthropometric equations. The samples consisted of healthy individuals, people with different diseases or disabilities, and athletes from different sports. Dual-energy X-ray absorptiometry (DXA) was the reference method most commonly used in developing equations. Triceps and subscapular skinfolds were the anthropometric measurements most frequently used as predictors in the equations. Age, stage of sexual maturation, and peak height velocity were used as complementary variables in the equations.

CONCLUSION

Our scoping review identified equations proposed for children and adolescents with a great diversity of characteristics. In many of the reports, important methodological aspects were not addressed, a factor that may be associated with equation bias.

LEVEL IV

Evidence obtained from multiple time series analysis such as case studies. (NB: dramatic results in uncontrolled trials might also be regarded as this type of evidence).

Ultrasound measurements of subcutaneous adipose tissue thickness show sexual dimorphism in children of three to five years of age

Aim

A standard approach to measure subcutaneous adipose tissue (SAT) using ultrasound has proved successful in adults, but has not been studied in children. This study addressed that gap in children aged three to five years.

Methods

In autumn 2016, 24 preschools in Southwest Germany, recruited via mail, agreed to take part in this study and 274 children (51.4% boys) with a mean age of 4.6 ± 0.7 years participated in measurements of SAT and anthropometry. Differences in measurements were explored between the sexes and anthropometric predictors of mean SAT thickness were identified. Intra‐observer reliability for ultrasound measurements of SAT was also assessed.

Results

The mean SAT thickness showed significant differences between the boys and girls (5.3 ± 2.0 and 6.3 ± 2.0 mm, respectively, p < 0.01). The children's body mass, height and sex explained 66% of the variance in the mean SAT thickness, as SAT was larger with a higher body mass, a smaller stature and in girls. Intra‐observer reliability resulted in an intra‐class correlation coefficient of 0.994 (p < 0.01) with a 95% confidence interval of 0.983–0.998.

Conclusion

Subcutaneous adipose tissue thickness differed between boys and girls with a mean age of 4.6 years. Intra‐observer reliability was excellent. This standardised approach enabled high‐precision measurements of SAT in a paediatric population.

Estimates of the energy deficit required to reverse the trend in childhood obesity in Australian schoolchildren

OBJECTIVES

To estimate: 1) daily energy deficit required to reduce the weight of overweight children to within normal range; 2) time required to reach normal weight for a proposed achievable (small) target energy deficit of 0.42 MJ/day; 3) impact that such an effect may have on prevalence of childhood overweight.

METHODS

Body mass index and fitness were measured in 31,424 Australian school children aged between 4.5 and 15 years. The daily energy deficit required to reduce weight to within normal range for the 7,747 (24.7%) overweight children was estimated. Further, for a proposed achievable target energy deficit of 0.42 MJ/day, the time required to reach normal weight was estimated.

RESULTS

About 18% of children were overweight and 6.6% obese; 69% were either sedentary or light active. If an energy deficit of 0.42 MJ/day could be achieved, 60% of overweight children would reach normal weight and the current prevalence of overweight of 24.7% (24.2%-25.1%) would be reduced to 9.2% (8.9%-9.6%) within about 15 months.

CONCLUSIONS

The prevalence of overweight in Australian school children could be reduced significantly within one year if even a small daily energy deficit could be achieved by children currently classified as overweight or obese.

Longitudinal changes in adiposity during adolescence: a population-based cohort

OBJECTIVE

We aimed to assess the trends in body mass index (BMI) and body fat percentage (BF%) from the age of 13 to 17 years and to evaluate how sociodemographic and behavioural characteristics at the age of 13  impact changes in BMI and BF%.

SETTING

Porto, Portugal.

PARTICIPANTS

We evaluated 1451 adolescents in a community-based cohort.

OUTCOME MEASURES

BMI z-scores were calculated according to CDC references. BF% was assessed by bioelectrical impedance. Variables with a significant effect in adiposity changes were identified through linear regression models. In girls, estimates were controlled for duration of follow-up, parental education, baseline BMI z-score, age at menarche and the interaction term baseline BMI z-score×age at menarche; in boys, adjustments were performed for duration of follow-up, parental education, baseline BMI z-score and the interaction term baseline BMI z-score×duration of follow-up.

RESULTS

On average, BMI z-score decreased from the age of 13 to 17 years (mean difference -0.20, 95% CI -0.23 to -0.16 among girls and -0.15, 95% CI -0.19 to -0.11 among boys). Accordingly, 12.4% of girls and 13% of boys moved to a lower BMI category and 2.2% of girls and 5.5% of boys to a higher category. There were sex differences in the significant determinants of adiposity trends. Among girls, BMI z-score significantly decreased with baseline BMI z-score (β=-0.163, 95% CI -0.204 to -0.122) and significantly increased with age at menarche (β=0.078, 95% CI 0.050 to 0.107). Results were similar for BF%. Among boys, BMI z-score significantly increased with higher parental BMI, and BF% decreased among those who wished to look larger at the age of 13 (β=-1.367, 95% CI -2.174 to -0.560), compared with those who were satisfied with their image.

CONCLUSIONS

In adolescents, ageing resulted in a decrease in BMI z-scores and BF%. BMI and BF% at the age of 13 were the major determinants of the observed trends. Our results suggest that adolescence is a possible specific time window for intervention.

Anthropometric parameters in screening for excess of adiposity in Argentinian and Spanish adolescents: evaluation using receiver operating characteristic (ROC) methodology

BACKGROUND

Various anthropometric parameters have been proposed for defining overweight in adolescence, but few studies have evaluated their diagnostic accuracy in comparative terms, using samples from different regions.

AIM

To compare the performance of anthropometric parameters in determining the excess of adiposity in Argentinian and Spanish adolescents.

SUBJECTS AND METHODS

The sample is composed of 1781 Argentinian and 1350 Spanish subjects, aged 12-17 years. Excess adiposity was defined as percentage BF in the 90th percentile or higher. ROC curves established the validity of parameters to define excess adiposity.

RESULTS

Descriptive statistics showed differences between the Argentinian and Spanish samples. ROC curves indicate that all the parameters analysed had, in the Spanish and Argentinian samples, a positive and elevated association with excess of adiposity. The waist-to-height ratio had the highest value of the area under ROC curve (AUC), while conicity index and waist-to-hip ratio had the lowest.

CONCLUSIONS

Differences exist with respect to size and body composition between the Argentinian and Spanish samples. ROC curves reflect a general pattern of variation. Waist-to-hip ratio and conicity index are less desirable in the diagnosis of excess adiposity and the most desirable is waist-to-height ratio.

Sleep duration and adiposity during adolescence

BACKGROUND AND OBJECTIVE

The association between sleep and obesity has been described in different age groups. However, there are not sufficient data to clarify the inconsistent results reported in adolescents. Our objective was to study the associations between sleep duration and adiposity at 13 and at 17 years of age, with both cross-sectional and longitudinal approaches.

METHODS

We evaluated, as part of an urban population-based cohort (EPITeen), 1171 adolescents at both 13 and 17 years of age. Sleep duration was estimated by self-reported bedtimes and wake-up times. Age- and gender-specific BMI z scores were calculated based on Centers for Disease Control and Prevention references. Body fat percentage (BF%) was assessed by bioelectrical impedance. Regression coefficients (β) and respective 95% confidence intervals (CIs) were used to estimate the association between sleep and BMI z scores and BF%. Additionally, a cross-lagged analysis was performed to investigate the causal relations.

RESULTS

In the cross-sectional analysis, at 13 years, sleep duration was inversely associated with BMI z score only in boys (β = -0.155, 95% CI: -0.267 to -0.043); at 17 years, a positive association was found among girls but was only significant for BF% (β = 0.510, 95% CI: 0.061-0.958). In the longitudinal approach, sleep duration at age 13 was inversely associated with BMI z score (β = -0.123, 95% CI: -0.233 to -0.012) and BF% (β = -0.731, 95% CI: -1.380 to -0.081) at 17 years only in boys. These significant associations disappeared after adjustment for adiposity at 13 years. These results were corroborated by those from cross-lagged analysis.

CONCLUSIONS

Our results showed an effect of sleep duration in adiposity at younger ages of adolescence and suggested gender differences in this association.

Caucasian children's fat mass: routine anthropometry v. air-displacement plethysmography

The present paper will use fat mass percentage (FM%) obtained via BOD POD® air-displacement plethysmography (FMADP%) to examine the relative validity of (1) anthropometric measurements/indices and (2) of FM% assessed with equations (FMeq%) based on skinfold thickness and bioelectrical impedance (BIA). In 480 Belgian children (aged 5–11 years) weight, height, skinfold thickness (triceps and subscapular), body circumferences (mid-upper arm, waist and hip), foot-to-foot BIA (Tanita®) and FMADP% were measured. Anthropometric measurements and calculated indices were compared with FMADP%. Next, published equations were used to calculate FMeq% using impedance (equations of Tanita®, Tyrrell, Shaefer and Deurenberg) or skinfold thickness (equations of Slaughter, Goran, Dezenberg and Deurenberg). Both indices and equations performed better in girls than in boys. For both sexes, the sum of skinfold thicknesses resulted in the highest correlation with FMADP%, followed by triceps skinfold, arm fat area and subscapular skinfold. In general, comparing FMeq% with FMADP% indicated mostly an age and sex effect, and an increasing underestimation but less dispersion with increasing FM%. The Tanita® impedance equation and the Deurenberg skinfold equation performed the best, although none of the used equations were interchangeable with FMADP%. In conclusion, the sum of triceps and subscapular skinfold thickness is recommended as marker of FM% in the absence of specialised technologies. Nevertheless, the higher workload, cost and survey management of an immobile device like the BOD POD® remains justified.

From sleep duration to childhood obesity--what are the pathways?

Sleep duration has been identified as risk factor for obesity already in children. Besides investigating the role of fat mass (FM), this study addressed the question whether endocrine mechanisms act as intermediates in the association between sleep duration and overweight/obesity. Within the framework of the IDEFICS study, the present research was conducted in 609 German resident children aged 2-9 years with information on fasting insulin, C-reactive protein and cortisol levels next to anthropometric measurements and parental questionnaires. Emphasising methodological aspects, an age-specific measure of sleep duration was derived to account for alteration in sleep duration during childhood/period of growth. Multivariate linear regression and quantile regression models confirmed an inverse relationship between sleep duration and measures of overweight/obesity. The estimate for the association of sleep duration and body mass index (BMI) was approximately halved after adjustment for FM, but remained significant. The strength of this association was also markedly attenuated when adjusting for insulin mainly for the upper BMI quantiles (Q80, β = -0.36 vs. β = -0.26; Q95, β = -0.87 vs. β = -0.47). Adjustment for cortisol and CrP did not yield this attenuation.

CONCLUSION

The inverse relationship between sleep duration and BMI is mainly explained by the association between sleep duration and FM. Insulin may explain part of this association, in particular at the upper tail of the BMI distribution.

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.

Air-displacement plethysmography for the measurement of body composition in children aged 6-48 months

INTRODUCTION

Air-displacement plethysmography (ADP) is an age-appropriate method for measuring relative fat mass (%FM) in children; however, the accuracy of this method has not been evaluated in children aged 5 y or younger.

RESULTS

Mean %FM values measured by ADP (17.9 ± 8.0%) and by total body water (TBW) (23.7 ± 6.3%) were significantly different (P < 0.001). Regression analysis of %FM by ADP vs. TBW provided a line of best fit with a slope of 0.089, r(2) = 0.013, and standard error of the estimate (SEE) = 6.3% FM (P = 0.40).

DISCUSSION

The error was related to child weight and %FM, but not to behaviors (movement or vocalizations) occurring during the test sequence. A large portion of the error was attributable to imprecision in measuring small volumes. As currently designed, ADP is not an accurate method for measuring %FM in young children. Further investigation of the sources of variability will provide insight into ways of improving the accuracy of this technology for this population.

METHODS

This study examined the accuracy of an ADP system modified for young children (BOD POD; Life Measurement, Concord, CA) by comparing %FM results from ADP with those obtained from TBW by deuterium (D(2)O) dilution (reference method) in 72 children aged 6-48 mo.

Sleep duration and obesity in children: is the association dependent on age and choice of the outcome parameter?

STUDY OBJECTIVES

To assess the association between sleep duration in children and different markers of body fat by age and weight status.

DESIGN

Nation-wide health survey. Measurement of BMI and body fat percentage (KFA) calculated from weight, height, skin fold thickness, age, and sex. Sleep duration and potential confounding variables were assessed in a parent questionnaire.

SETTING

N/A.

PARTICIPANTS

7767 German resident children from 3 to 10 years of age.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Prolongation of sleep duration from the lowest to the highest percentile accounted for a similar mean decrease founding variables and did not show a systematic age dependency. The greatest effects of sleep duration were seen for the upper tails of the BMI and KFA distributions, which were about four as high as the lower tails.

CONCLUSIONS

The association between sleep duration and weight status is of similar size through ages 3 to 10 years. The sleep-associated changes in BMI are likely to be a consequence of higher body fat and primarily affect children whose BMI or KFA is already elevated. These findings favor hormonal pathways nurturing adipose tissue playing a key role in the underlying physiological mechanisms.

Dobras cutâneas e bioimpedância elétrica perna-perna na avaliação da composição corporal de crianças

OBJETIVO: Comparar os componentes da composição corporal, obtidos pela bioimpedância elétrica perna-perna e pela espessura das dobras cutâneas, em crianças. MÉTODOS: A composição corporal de 1 286 escolares (703 meninas e 538 meninos) entre 7 e 9 anos foi avaliada pelas dobras triciptal e subescapular e pela bioimpedância elétrica perna-perna (TANITA TBF-300ª). Para analisar a concordância entre o percentual de gordura corporal, a massa gorda e a massa magra obtidos pelos métodos, foram utilizados o coeficiente de correlação de Pearson (r) e o modelo de Bland-Altman. RESULTADOS: A correlação (r) foi alta e significante, respectivamente nas meninas e nos meninos, para o percentual de gordura corporal (0,77 e 0,89), para a massa gorda (0,93 e 0,94) e para a massa magra (0,92 e 0,89). O modelo de Bland-Altman também mostrou haver boa concordância entre os métodos, uma vez que poucos pontos, correspondentes às diferenças entre as medidas feitas pelos métodos, estavam fora do intervalo de confiança. CONCLUSÃO: Estes resultados demonstram que a técnica de bioimpedância elétrica perna-perna é comparável à técnica das dobras cutâneas para avaliar a composição corporal de escolares em estudos populacionais. Individualmente, a ampla variabilidade observada em algumas medidas sugere que a utilização da bioimpedância elétrica perna-perna ou das dobras cutâneas deve ser associada a outros indicadores na avaliação da composição corporal.

Effect of puberty on body composition

PURPOSE OF REVIEW

Here we examine the effect of puberty on components of human body composition, including adiposity (total body fat, percentage body fat and fat distribution), lean body mass and bone mineral content and density. New methods and longitudinal studies have expended our knowledge of these remarkable changes.

RECENT FINDINGS

Human differences in adiposity, fat free mass and bone mass reflect differences in endocrine status (particularly with respect to estrogens, androgens, growth hormone and IGF-1), genetic factors, ethnicity and the environment. During puberty, males gain greater amounts of fat free mass and skeletal mass, whereas females acquire significantly more fat mass. Both genders reach peak bone accretion during the pubertal years, though males develop a greater skeletal mass. Body proportions and fat distribution change during the pubertal years as well, with males assuming a more android body shape and females assuming a more gynecoid shape. Pubertal body composition may predict adult body composition and affects both pubertal timing and future health.

SUMMARY

Sexual dimorphism exists to a small degree at birth, but striking differences develop during the pubertal years. The development of this dimorphism in body composition is largely regulated by endocrine factors, with critical roles played by growth hormone and gonadal steroids. It is important for clinicians and researchers to know the normal changes in order to address pathologic findings in disease states.