Comparison of Methods for the Measurement of Body Composition in Overweight and Obese Brazilian Children and Adolescents before and after a Lifestyle Modification Program

Abstract

Aim: To compare the body composition of overweight children and adolescents by bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) before and after physical activity program. Methods: One hundred and eleven patients with mean age (SD) of 12 (1.9) participated in the study. We assessed the weight, height, waist circumference (WC), and body composition by DXA and BIA. Patients underwent a program of diet and physical activity (1 h 30 min/day, 3 times a week for 3 months) and were evaluated before and after this period. Results: Mean initial zBMI were 2.3 (0.5) and waist SDS 5.9 (1.8). Significant differences were observed when we compared the measurements taken by DXA and BIA, respectively: total body fat percentage (40 and 31.5) and fat-free mass (43.1 and 50.6 kg). Regarding the trunk fat by DXA, there was a positive correlation with the WC/height ratio (r = 0.65; p < 0.01). After the intervention period, we observed a reduction in the zBMI, waist SDS, and total body fat and increase of fat-free mass by DXA. BIA only detected reduction in fat. Conclusion: BIA underestimates the percentage of fat and overestimates fat-free mass in relation to DXA. There is positive correlation between trunk fat and the ratio WC/height. In addition, DXA detected changes in body composition induced by a short period of physical training, unlike BIA. © 2014 S. Karger AG, Basel

Neck circumference as a complementary measure to identify excess body weight in children aged 13-24 months

“…Traditionally, BMI has been used for identifying individuals with obesity; 12 although the accuracy of BMI varies according to the percentage body fat of the child. As an alternative to BMI, WC has been used as a proxy for body fat accumulation, 8,9 especially for screening purposes. 18 Nevertheless, WC can be affected by postprandial Table 4 Area under the curve (AUC), frequency (N), optimal cutoff points, sensitivities and specificities for neck circumference (NC) associated with excess body weight in three age groups of boys and girls.…”

“…7 Measures of waist circumference (WC) have been used to diagnose excess body weight and body fat accumulation. 8,9 More recently, neck circumference (NC) has been proposed by a number of authors as an effective, inexpensive and easily applied measure for evaluating upper body fat distribution 7,9-15 and thereby identifying children at risk of developing conditions related to central obesity. 16 An additional advantage of using NC as a proxy for upper body fat distribution is that it shows no variation in size throughout the day.…”

Concurrent and aerobic exercise training promote similar benefits in body composition and metabolic profiles in obese adolescents

“…The prevalence of obesity in pediatric population is increasing at an accelerated rate in many countries, and has become a major public health concern [ 1 ]. Childhood obesity is one of the main predictor factors of adult obesity [ 2 ], with a high risk that an obese adolescent has 80 % chance of becoming an obese adult [ 3 ].…”

Validity of Slaughter Equations and Bioelectrical Impedance Against Dual‐Energy X‐Ray Absorptiometry in Children

“…To our knowledge, no longitudinal studies have compared changes over time in body composition measurements, including these three methods together. Separately, some studies have evaluated BIA against DXA in children and adolescents with overweight or obesity , and we found only one study that included other SKF‐based equations against DXA in 38 children and adolescents with obesity . Overall, these studies had several limitations and found poor accuracy, although these methods seemed to be valid to monitor the direction of the change or to consider the evaluation at a group level rather than individually in BIA compared with DXA .…”

“…The proposed fat mass index (FMI) is less reported than other parameters in the literature , and there have been few validation studies that included height‐adjusted measures in children and/or adolescents . 3) There is little information about how accurate Slg‐Eq and BIA are in measuring changes in BFP and FMI over time when compared with DXA as a criterion method.…”