Group and Individual Agreement between Field and Dual X-Ray Absorptiometry–Based Body Composition Techniques in Children from Standard Schools and a Sports Academy

Body composition estimation in children and adolescents by bioelectrical impedance analysis: A systematic review

BACKGROUND

Bioelectrical impedance analysis (BIA) has commonly been used to assess the body composition of children and adolescents. BIA validation studies have found distinct correlation values with reference methods.

OBJECTIVES

To assess the reproducibility, correlation and mean differences in body composition estimated by BIA and reference methods, we systematically reviewed the literature in the pediatric population.

METHOD

The search for articles was conducted in March 2016 and was limited to articles published from 2005 to 2015 in the PubMed, Embase, EBSCO, Web of Science, Scopus and SciELO databases. Two reviewers independently performed data selection and extraction of studies that investigated the BIA validity, responsiveness, reliability and/or measurement error (reproducibility) to estimate body composition in children and adolescents with an average age ≤ 18 years.

RESULTS

The search produced 48 articles. Almost perfect reproducibility was found in the body fat percentage estimated by BIA, and there was almost perfect correlation between the BIA ratings and reference methods for fat mass and fat-free mass. Regarding component estimates, BIA underestimated the fat mass in both sexes.

CONCLUSIONS

The body fat percentage estimated by BIA exhibited almost perfect reproducibility. The fat mass and fat-free mass estimated by BIA correlated almost perfectly with the reference methods in both sexes. BIA underestimated the fat mass in both sexes.

Reliability, Validity, and Diagnostic Value of a Pediatric Bioelectrical Impedance Analysis Scale

BACKGROUND

Accurate body composition assessment is critical to identify children who are overfat or obese. Unlike BMI measures, bioelectrical impedance analysis (BIA) differentiates between lean and fat mass. However, bioelectrical impedance analysis has historically had questionable reliability and validity in children. The aim of this study was to determine the reliability, validity, and diagnostic value of a portable BIA scale (Tanita BF-689; Tanita Corporation, Tokyo, Japan) designed specifically for use within the pediatric population.

METHODS

Fifty-five children (males = 26; females = 29) had percent body fat (%BF) assessed twice using BIA and once using dual-energy X-ray absorptiometry (DEXA). Intraclass correlation coefficients (ICCs) were calculated for reliability. Mean difference and limits of agreement were calculated for convergent validity. Sensitivity/specificity for healthy, overfat, and obese classification were assessed.

RESULTS

Test-retest ICC was 0.999 (0.999, 0.999). The ICC comparing BIA and DEXA for %BF was 0.788 (-0.167, 0.942). Mean difference between BIA and DEXA was -6.75% (limits of agreement = -0.04%; -13.46%). No gender or proportional bias was observed. Sensitivity/specificity for healthy, overfat, and obese classification were 0.67/0.65, 0.22/0.78, and 0.43/1.0, respectively.

CONCLUSIONS

The Tanita BF-689 demonstrates excellent test-retest reliability, moderately strong absolute agreement with DEXA, and high specificity for overfat and obese classification. Compared to DEXA, the BF-689 is an accurate, portable, and efficient means of assessing %BF in elementary school children.

High prevalence of vitamin D insufficiency/deficiency in Dutch multi-ethnic obese children

Vitamin D insufficiency/deficiency is common among non-white children; however, little is known about the prevalence of vitamin D insufficiency/deficiency in non-white obese children living in the Netherlands. Therefore, a retrospective analysis was performed on data from multi-ethnic Dutch children and adolescents 6–18 years who visited the obesity outpatient clinic in 2012–2013. We performed anthropometric measurements, oral glucose tolerance test, and measured 25(OH)D and lipid levels. Vitamin D insufficiency was defined as 25(OH)D levels 37.5- <50 nmol/L and vitamin D deficiency as 25(OH)D <37.5 nmol/L. In total, data from 387 children were obtained (mean age 11.6 years, 41.1 % boys, 10.3 % Dutch native, 25.6 % Turkish, 24.5 % Moroccan, 7.5 % African Surinamese, and 7.0 % West African). The median 25(OH)D level was 34 (range 12–105) nmol/L. In total, 17.8 % were vitamin D sufficient, 24.5 % with vitamin D insufficiency, and 57.6 % with vitamin D deficiency. Obese ethnic children showed the highest (87.5 %) and normal weight white children showed the lowest (20.0 %) prevalence of vitamin D insufficiency/deficiency . Conclusion: Vitamin D insufficiency and deficiency is extremely prevalent in treatment-seeking obese ethnic children. However, there was no evidence of an effect of vitamin D status on various components of the metabolic syndrome in our cohort.

A comparison study of portable foot-to-foot bioelectrical impedance scale to measure body fat percentage in Asian adults and children

Objective. To compare the measurements of body fat percentage (BF%) using the foot-to-foot bioelectrical impedance analysis (FTF-BIA) with the direct segmental multifrequency BIA (DSM-BIA). Methods. There were 36 men and 52 women (37.1 ± 14.3 years) with 57% Malays, 30% Chinese, and 13% Indian. For children, there were 45 boys and 26 girls (11.5 ± 2.5 years) with 52% Malay, 15% Chinese, and 33% Indian. Results. Mean height for men was 168.4 cm, 11 cm taller than women. Men were 10 kg heavier than women at 70 kg. BF% in women was 32% and 33% whereas BF% in men was 23% and 25% when measured using FTF-BIA and DSM-BIA, respectively. In children, BF% measured with FTF-BIA and DSM-BIA was 49% and 46%, respectively. The correlations were significant for men (r = 0.92, SEE = 2.80), women (r = 0.91, SEE = 3.31), boys (r = 0.95, SEE = 5.44), and girls (r = 0.96, SEE = 5.27). The BF% in underweight/normal (r = 0.92, SEE = 2.47) and that in overweight/obese adults (r = 0.89, SEE = 3.61) were strongly correlated. The correlations were significant in normal/underweight (r = 0.94, SEE = 3.78) and obese/overweight children (r = 0.83, SEE = 6.49). All ethnic groups showed significant correlation with BF%. Malay adults (r = 0.92, SEE = 3.27) and children (r = 0.94, SEE = 0.88) showed significant mean differences in BF%. Conclusion. The FTF-BIA showed higher accuracy for all normal/underweight and Chinese group with acceptable overestimation in children and underestimation in adults. Caution should be taken when interpreting BF% depending on gender, BMI, and ethnicity.