Can Adipose Tissue Influence the Evaluation of Thermographic Images in Adolescents?

Infrared thermography (IRT) is a technology easy to use for clinical purposes as a pre-diagnostic tool for many health conditions. However, the analysis process of a thermographic image needs to be meticulous to make an appropriate decision. The adipose tissue is considered a potential influence factor in the skin temperature (Tsk) values obtained by IRT. This study aimed to verify the influence of body fat percentage (%BF) on Tsk measured by IRT in male adolescents. A total of 100 adolescents (16.79 ± 0.97 years old and body mass index of 18.41 ± 2.32 kg/m²) was divided into two groups through the results of a dual-energy X-ray absorptiometry analysis: obese (n = 50, %BF 30.21 ± 3.79) and non-obese (n = 50, %BF 11.33 ± 3.08). Thermograms were obtained by a FLIR T420 infrared camera and analyzed by ThermoHuman® software version 2.12, subdividing the body into seven regions of interest (ROI). The results showed that obese adolescents presented lower mean Tsk values than the non-obese for all ROIs (p < 0.05), with emphasis on the global Tsk (0.91 °C) and anterior (1.28 °C) and posterior trunk (1.18 °C), with "very large" effect size values. A negative correlation was observed in all the ROI (p < 0.01), mainly in the anterior (r = -0.71, p < 0.001) and posterior trunk (r = -0.65, p < 0.001). Tables of thermal normality were proposed for different ROIs according to the classification of obesity. In conclusion, the %BF affects the registered Tsk values in male Brazilian adolescents assessed by IRT.

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).

Prediction of body fat in adolescents: validity of the methods relative fat mass, body adiposity index and body fat index.

OBJECTIVE: To verify the validity of anthropometric methods body adiposity index (BAI), relative fat mass (RFM) and body fat index (BFI) to estimate body fat percentage (%BF) in adolescents. METHODS: A cross-sectional study was carried out with 420 Brazilian adolescents aged 15-19 years, stratified by age (< 18 years, n = 356; ≥ 18 years, n = 64) and sex (boys, n = 216; girls, n = 204). The Anthropometric measurements height, body weight, hip circumference and waist circumference were collected to calculate the %BF by BAI, RFM, BFI methods. Subsequently, %BF was measured by dual emission X-ray absorptiometry (DXA), adopted as a reference method. In the statistical analysis of the data, the Pearson correlation test and the paired t test between %BF obtained by the equations and by the DXA were performed. The method validation criterion was that 68% of individuals should be within an acceptable error range of ± 3.5% of BF and Cohen's Kappa index ≥ 0.61. Additionally, the Bland-Altman graphical analysis was performed. RESULTS: All methods showed a high correlation with DXA. For the Kappa index, only the RFM reached the criterion in the total sample (0.67) and in the sample < 18 years (0.68). None of the methods reached the criterion of 68% of the sample within the error range of ± 3.5% of BF. CONCLUSION: The BAI, RFM and BFI equations were not valid for predicting BF in the studied sample according to the criteria adopted regardless of sex or age. LEVEL OF EVIDENCE: Level V, cross-sectional descriptive study.

Validity of the estimated body fat percentage by bioimpedance and skinfolds in middle-aged and elderly women / Validez del porcentaje de grasa corporal estimado por bioimpedancia y pliegues cutáneos en mujeres de mediana edad y ancianas

Objectives: Verify the validity of electrical bioimpedance (BIA) and the skinfold method in estimating the percentage ofbody fat (% BF) in middle-aged and elderly women, using dual emission X-ray absorptiometry (DXA) as a reference method.Material and methods: The sample consisted of 106 volunteers (middle age, n = 58 [51.3 ± 4.9 years] and elderly, n = 48[67.2 ± 5.8 years]). The volunteers were submitted to anthropometric assessments and the % BF was subsequently calculatedusing the Jackson and Pollock 7 skinfold protocol (7SF). The % BF was also measured using BIA and DXA. Pearson’s correlation,Bland and Altman method, effect size and repeated-measure t-test were used to test the hypotheses.Results: Although there is a moderate positive relationship between the methods evaluated for middle-aged women (DXAvs 7SF, r = 0.67; DXA vs BIA, r = 0.62) and moderate to strong for the elderly (DXA vs 7SF, r = 0.57; DXA vs BIA, r = 0.75) (p ≤ 0.05in all analyzes), the agreement between the methods was weak (limits of agreement > ± 3.5%). Additionally, when assessingthe % BF mean using each method within the groups, it was observed that there was no significant difference between theestimates only between DXA and Pollock 7SF in the elderly group.Conclusion: Therefore, both the 7SF method and the BIA are not valid for estimating body fat in the sample evaluated. It isnecessary to develop equations for specific skinfolds to estimate the % BF of middle-aged and elderly women and reviewthe equations used by the BIA.(AU)

Objetivo: Verificar la validez de la bioimpedancia eléctrica (BIA) y el método del pliegue cutáneo en la estimación delporcentaje de grasa corporal (% GC) en mujeres de mediana edad y ancianas, mediante la doble emisión de rayos X (DXA )como método de referencia.Material y método: La muestra estuvo formada por 106 voluntarias (mediana edad, n = 58 [51,3 ± 4,9 años] y ancianas, n= 48 [67,2 ± 5,8 años]). Las voluntarias fueron sometidas a evaluaciones antropométricas y, posteriormente, se calculó el %GC utilizando el protocolo de pliegues cutáneos Jackson y Pollock 7 (7PC). El% de GC también se midió usando BIA y DXA.La correlación de Pearson, el método de Bland y Altman, el tamaño del efecto y la prueba t de medida repetida se utilizaronpara probar las hipótesis.Resultados: Aunque existe una relación positiva moderada entre los métodos evaluados para mujeres de mediana edad (DXAvs 7PC, r = 0,67; DXA vs BIA, r = 0,62) y moderada a fuerte para las ancianas (DXA vs 7PC, r = 0,57 ; DXA vs BIA, r = 0,75) (p ≤ 0,05en todos los análisis), la concordancia entre los métodos fue débil (límites de acuerdo > ± 3,5%). Además, al evaluar la mediade % GC usando cada método dentro de los grupos, se observó que no hubo diferencia significativa entre las estimacionessolo entre DXA y Pollock 7PC en el grupo de ancianas.Conclusiones: Por tanto, tanto el método 7PC como el BIA no son válidos para estimar la grasa corporal en la muestra eva-luada. Es necesario desarrollar ecuaciones para pliegues cutáneos específicos para estimar el % GC de mujeres de medianaedad y ancianas y revisar las ecuaciones utilizadas por el BIA.(AU)