Ethnic differences in body composition and anthropometric characteristics in Australian Caucasian and urban Indigenous children

Cardiometabolic Risk Markers for Aboriginal and Torres Strait Islander Children and Youths: A Systematic Review of Data Quality and Population Prevalence

Cardiovascular disease and type 2 diabetes mellitus are leading contributors to the health inequity experienced by Aboriginal and Torres Strait Islander peoples, and their antecedents can be identified from early childhood. We aimed to establish the quality of available data and the prevalence of cardiometabolic risk markers among Aboriginal and Torres Strait Islander children and youths (0-24-year-olds) to inform public health approaches. A systematic review of the peer-reviewed and grey literature was conducted between 1 January 2000-28 February 2021. Included studies reported population prevalence of cardiometabolic risks, including elevated blood pressure, obesity, central adiposity, dyslipidaemia, hyperglycaemia, and 'metabolic syndrome' for Aboriginal and Torres Strait Islander people aged 0-24 years. Fifteen studies provided population estimates. Data quality was limited by low response rates (10/15 studies) and suboptimal outcome measurements. Obesity is the most reported risk (13/15 studies). Aboriginal and Torres Strait Islander children have an excess risk of obesity from early childhood and prevalence increases with age: 32.1% of Aboriginal and Torres Strait Islander 18-24-year-olds had obesity and 50.8% had central adiposity. In a cohort of 486 9-14-year-olds in Darwin, 70% had ≥1 component of metabolic syndrome; 14% met the full criteria for the syndrome. The prevalence of cardiometabolic risk in Aboriginal and Torres Strait Islander young people is difficult to estimate due to limitations in measurement quality and sampling representativeness. Available data suggest that cardiometabolic risk markers are evident from early childhood. The establishment of national and state-level datasets and a core outcome set for cardiometabolic screening would provide opportunities for preventative action.

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).

Prevalence and characteristics of overweight and obesity in indigenous Australian children: A systematic review

Evidence-based profiling of obesity and overweight in Indigenous Australian children has been poor. This study systematically reviewed evidence of the prevalence and patterns of obesity/overweight, with respect to gender, age, remoteness, and birth weight, in Indigenous Australian children, 0-18 years (PROSPERO CRD42014007626). Study quality and risk of bias were assessed. Twenty-five publications (21 studies) met inclusion criteria, with large variations in prevalence for obesity or overweight (11 to 54%) reported. A high degree of heterogeneity in study design was observed, few studies (6/21) were representative of the target population, and few appropriately recruited Indigenous children (8/21). Variability in study design, conduct, and small sample sizes mean that it is not possible to derive a single estimate for prevalence although two high-quality studies indicate at least one in four Indigenous Australian children are overweight or obese. Four of six studies reporting on gender, found overweight/obesity higher in girls and eight studies reporting on overweight/obesity by age suggest prevalence increases with age with one high quality large national study reporting total overweight/obesity as 22.4% of children aged 2-4 years, 27.5% of those aged 5-9, 38.5% aged 10-14, and 36.3% aged 15-17. Three of four studies, reporting obesity/overweight by region, found lower rates for children living in more remote areas than urban areas.

Performance of Two Bioelectrical Impedance Analyses in the Diagnosis of Overweight and Obesity in Children and Adolescents: The FUPRECOL Study

This study aimed to determine thresholds for percentage of body fat (BF%) corresponding to the cut-off values for overweight/obesity as recommended by the International Obesity Task Force (IOTF), using two bioelectrical impedance analyzers (BIA), and described the likelihood of increased cardiometabolic risk in our cohort defined by the IOTF and BF% status. Participants included 1165 children and adolescents (54.9% girls) from Bogotá (Colombia). Body mass index (BMI) was calculated from height and weight. BF% of each youth was assessed first using the Tanita BC-418^® followed by a Tanita BF-689^®. The sensitivity and specificity of both devices and their ability to correctly classify children as overweight/obesity (≥2 standard deviation), as defined by IOTF, was investigated using receiver operating characteristic (ROC) by sex and age groups (9–11, 12–14, and 13–17 years old); Area under curve (AUC) values were also reported. For girls, the optimal BF% threshold for classifying into overweight/obesity was found to be between 25.2 and 28.5 (AUC = 0.91–0.97) and 23.9 to 26.6 (AUC = 0.90–0.99) for Tanita BC-418^® and Tanita BF-689^®, respectively. For boys, the optimal threshold was between 16.5 and 21.1 (AUC = 0.93–0.96) and 15.8 to 20.6 (AUC = 0.92–0.94) by Tanita BC-418^® and Tanita BF-689^®, respectively. All AUC values for ROC curves were statistically significant and there were no differences between AUC values measured by both BIA devices. The BF% values associated with the IOTF-recommended BMI cut-off for overweight/obesity may require age- and sex-specific threshold values in Colombian children and adolescents aged 9–17 years and could be used as a surrogate method to identify individuals at risk of excess adiposity.

The Interplay Between Sex, Ethnicity, and Adipose Tissue Characteristics

The obesity epidemic in the USA affects disproportionately women and the ethnic minorities. On the other hand, female sex is traditionally associated with a favorable fat distribution preferentially in the subcutaneous depots of the lower body and with improved endocrine and metabolic function of the adipose tissue. However, these data are derived from predominantly non-Hispanic white populations. This review discusses fat distribution patterns in women of diverse ethnic backgrounds, together with data on the release of adipokines from adipose tissue in these populations. Very little information is available on how the metabolic function of the adipocyte differs depending on ethnicity. Thus, it becomes clear that future clinical and translational research should explicitly discuss and take into account the sex and ethnic background of the populations studied.

Predicting percentage body fat through waist-to-height ratio (WtHR) in Spanish schoolchildren

OBJECTIVE

To analyse the association between waist-to-height ratio (WtHR) and body fat and to develop predictive adiposity equations that will simplify the diagnosis of obesity in the paediatric age group.

DESIGN

Cross-sectional study conducted in Spain during 2007 and 2008. Anthropometric dimensions were taken according to the International Biology Program. The children were classified as underweight, normal weight, overweight or obese according to national standards of percentage body fat (%BF). WtHR differences among nutritional status categories were evaluated using ANOVA. Correlation analysis and regression analysis were carried out using WtHR as a predictor variable for %BF. A t test was applied to the results obtained by the regression model and by the Siri equation. The degree of agreement between both methods was evaluated by estimating the intra-class correlation coefficient.

SETTING

Elementary and secondary schools in Madrid (Spain).

SUBJECTS

Girls (n 1158) and boys (n 1161) from 6 to 14 years old.

RESULTS

WtHR differed significantly (P < 0.001) depending on nutritional status category. This index was correlated (P < 0.001) with all adiposity indicators. The mean %BF values estimated by the regression model (boys: %BF = 106.50 × WtHR - 28.36; girls: %BF = 89.73 × WtHR - 15.40) did not differ from those obtained by the Siri equation. The intra-class correlation coefficient (0.85 in boys, 0.79 in girls) showed a high degree of concordance between both methods.

CONCLUSIONS

WtHR proved to be an effective method for predicting relative adiposity in 6-14-year-olds. The developed equations can help to simplify the diagnosis of obesity in schoolchildren.

Anthropometric estimates of total and regional body fat in children aged 6-17 years

AIM

To develop prediction equations for total and regional (trunk, abdominal, arms and legs) body fat using surface anthropometric measures in children aged 6-17 years.

METHODS

This was a cross-sectional correlation study of 70 Caucasian children aged 6-17 years recruited from a larger randomly sampled population-based study. The independent variables included age, mass, height, body mass index, waist and hip girth, and skinfold thicknesses at eight sites. Subscapular/triceps skinfold ratio was also calculated and entered as an independent variable. The dependent variables were total body percentage fat, and fat mass for total body, trunk, abdominal region of interest, arms and legs measured using dual-energy X-ray absorptiometry (DXA). Partial least squares regression was used to determine the best predictive equation for fat percentage or fat mass in each body region in each sex.

RESULTS

Sex-specific prediction equations were developed with high coefficients of determination (r(2)), ranging from 0.869 to 0.936 in boys and from 0.900 to 0.979 in girls, absolute bias was low, and limits of agreement were narrow.

CONCLUSION

Equations were developed, which were able to predict total and regional body fat of Caucasian children aged 6-17 years using surface anthropometric measurements with high predictive accuracy.

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.

Assessment of obesity in children and adolescents: synthesis of recent systematic reviews and clinical guidelines

This review summarises recent systematic reviews and evidence-based guidelines that deal with the issue of how best to diagnose or define obesity in children and adolescents. A recent systematic review showed that parents typically fail to recognise obesity in their children and adolescents, and a good deal of other evidence suggests that health professionals under-diagnose obesity in children and adolescents when using informal methods based on observation. There is therefore a need for practical, objective, methods that both identify the fattest children and adolescents adequately, and identify those who are at greatest risk of the 'co-morbidities' of obesity. A large body of consistent evidence shows that a high body mass index (BMI) for age and sex identifies the fattest children adequately, with low-moderate false negative rate and a low false positive rate. Furthermore, children and adolescents at high BMI for age are at much greater risk of the co-morbidities of obesity. A recent systematic review found that the use of BMI for age with national reference data and cut-off points (such as the 95th percentile to define obesity) was superior to the Cole-International Obesity Task Force international approach for defining obesity based on BMI for age. The same systematic review also found no evidence that use of waist circumference for age improved the diagnosis of obesity, or the cardio-metabolic co-morbidities of obesity, in children and adolescents. Recent systematic reviews are therefore supportive of current guidelines that recommend percentile-based cut-offs relative to national reference data to (e.g. BMI at or above the 95th or 98th percentile in the UK) to define obesity for clinical applications in children and adolescents.