Search

This study aimed to compare phase angle (PhA) and bioelectrical impedance vector analysis (BIVA) values between adult patients with congenital adrenal hyperplasia caused by 21-hydroxylase deficiency (CAH21OHD) and a control group. A total of 22 patients (15 women, 22.9 ± 3.7 years) were compared with 17 controls (11 women, 27.0 ± 2.5 years). Body composition was determined by dual-energy X-ray absorptiometry. Bioelectrical impedance was used to calculate PhA, and BIVA was performed using specific software. Student’s t-test and analysis of covariance were used to compare groups. Hedges’ G and partial n2 were calculated for the effect estimates. Hotelling’s t2 test was used to compare the mean impedance vectors between the groups. The Mahalanobis test was used to determine the distance between confidence ellipses. Patients with CAH21OHD had a higher fat mass percentage than that of the control group (both sexes). There was no significant difference in PhA values between groups (CAH21OHD vs. control) in females (6.9° vs. 6.3°, p = 0.092) and males (8.2° vs. 8.1°, p = 0.849), after adjusting for covariates (age and height). BIVA analysis showed a significant difference in the mean impedance vectors between the female groups (T2 = 15.9, D = 1.58, p = 0.003) owing to the higher reactance/height (Δ = 8.5; p < 0.001) of the patients. The PhA did not significantly differ between the groups. Female patients had significantly higher reactance values. However, further studies are needed to determine the usefulness of bioimpedance parameters in evaluating the hydration status and cellular integrity of patients with CAH21OHD.

The phase angle is used to evaluate nutritional status and is an indicator of cellular health. Cardiorespiratory fitness and body composition are strong indicators of health during adolescence. We aimed to evaluate if body composition and cardiorespiratory fitness have an association with phase angle among adolescents. 203 girls and 220 boys (12.8±1.3 years) were evaluated. Peak height velocity, percentage fat mass, fat-free mass, cardiorespiratory fitness, and phase angle measurements were collected. Linear regression adjusted by peak height velocity was used to verify if predictor variables were associated with phase angle among adolescents. Phase angle showed correlation with fat-free mass (girls: r=0.42 and boys: r=0.37); with percent fat mass (girls: r=0.23); and with cardiorespiratory fitness (boys: r=0.19). Linear regression showed that percentage fat mass (in girls) and cardiorespiratory fitness (in boys) had an effect of 11 and 17% in phase angle, respectively, while fat-free mass had an effect of 22 and 26% in phase angle for girls and boys, respectively. Changes in phase angle seem to be more associated with the percentage fat mass in girls, cardiorespiratory fitness in boys, and fat-free mass in both when controlled by peak height velocity.

Made available in DSpace on 2022-04-28T19:50:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-02-01 The military are selected on the basis of physical standards and are regularly involved in strong physical activities, also related to particular sports training. The aims of the study were to analyze the effect of a 7-month military training program on body composition variables and the suitability of specific ‘bioelectrical impedance vector analysis’ (spBIVA), compared to DXA, to detect the changes in body composition. A sample of 270 male Brazilian cadets (19.1 ± 1.1 years), com-posed of a group practicing military physical training routine only (MT = 155) and a group involved in a specific sport training (SMT = 115), were measured by body composition assessments (evaluated by means of DXA and spBIVA) at the beginning and the end of the military routine year. The effect of training on body composition was similar in SMT and MT groups, with an increase in LST. DXA and spBIVA were correlated, with specific resistance (Rsp) and reactance (Xcsp) positively related to fat mass (FM), FM%, LST, and lean soft tissue index (LSTI), and phase angle positively related to LST and LSTI. Body composition variations due to physical training were recognized by spBIVA: the increase in muscle mass was indicated by the phase angle and Xcsp increase, and the stability of FM% was consistent with the unchanged values of Rsp. Military training produced an increase in muscle mass, but no change in FM%, independently of the sample characteristics at baseline and the practice of additional sports. SpBIVA is a suitable technique for the assessment of body composition in military people. Skeletal Muscle Assessment Laboratory (LABSIM) School of Technology and Science São Paulo State University (UNESP), SP Growth and Development Laboratory Center for Investigation in Pediatrics (CIPED) School of Medical Sciences University of Campinas (UNICAMP), SP Department of Life and Environmental Sciences University of Cagliari Skeletal Muscle Assessment Laboratory (LABSIM) School of Technology and Science São Paulo State University (UNESP), SP

Patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH21OHD) have increased fat mass and metabolic alterations. The bioelectrical impedance phase angle (PhA) is an indicator of cellular integrity in several diseases. This study aimed to determine the influence of adiposity levels, sex, CAH21OHD, pubertal development, body composition, and treatment on the PhA of patients with CAH21OHD.Forty girls and 30 boys with CAH21OHD aged 15.3 ± 5.8 years were evaluated. Sexual maturation was assessed by a pediatrician. The PhA was assessed using bioelectrical impedance, percentage of fat mass (% FM), and lean soft tissue (LST) with dual-energy X-ray absorptiometry. Adiposity levels were compared using % FM tertiles and body mass index (BMI). Glucocorticoid dosage was converted using hydrocortisone dose equivalent (HDE).No differences were found in the PhA values among the clinical form (LST determined the PhA variations in girls and the postpubertal group. Age and BMI were determinants in boys and the pre- and pubertal groups, respectively.

This study aimed to examine associations between phase angle (PhA) and incident cardiovascular disease (CVD) morbidity and mortality in a healthy Danish subpopulation free of major chronic diseases.A random subset (n = 2601) of adult men and women born in 1922, 1932, 1942, and 1952 and examined in 1987 and 1988 were included, and followed over 24 y during which 643 men and 570 women developed CVD. Measures at baseline included age, weight, height, whole-body bioimpedance, from which PhA was calculated, and information on lifestyle, obtained by a self-administered questionnaire. The association between PhA and incident CVD was assessed by Cox proportional hazard model with age as the underlying time scale and with additional adjustment for covariates. To explore nonlinear associations, all results were presented using restricted cubic splines, with the median value of PhA as the reference.PhA was lower among women who later developed CVD than among women who did not (6.3 vs. 6.0; P0.001). The highest risk of CVD was observed at the 5th percentile (hazard ratio: 1.33; 95% confidence interval, 1.11-1.60). Among men, PhA was not significantly associated with risk of CVD (7.1 vs. 7.0; P = 0.246).Among apparently healthy Danish men and women, a lower PhA value was associated with a higher incidence of CVD over 24 y, also after adjusting for potential confounders, and particularly among women. These findings may encourage the future use of PhA as an additional index in predicting CVD. However, more studies are needed to confirm our results.

Objectives The model most suitable for estimating resting energy expenditure (REE) using dual-energy X-ray absorptiometry (DXA) metabolic maps is not known; moreover, the applicability in individuals with different body sizes also is uncertain. The aim of this study was to test the accuracy of REE estimation from models of DXA metabolic maps with four, five, and six tissue-organ components in young men, stratified by body size. Methods We studied 52 young men between the ages of 18 and 29 y. Participants were clustered to small (SW; n = 32) and large (LW; n = 20) weight, and small (SWH; n = 25) and large (LWH; n = 27) weight–height. REE was measured by indirect calorimetry (REE m ), and predicted from DXA metabolic maps with four (REE c1 ), five (REE c2 ) and six (REE c3 ) tissue-organ components. Results REE c1 , REE c2 , and REE c3 explained 54% ( P P P m variance in all participants, respectively. However, REE c2 showed mean difference between REE m ( P c3 showed trends in estimating the REE ( P c1 showed limits of agreement (95%) of −248.3 to 285.8 kcal/d, 18.7 ± 136.3 kcal/d of bias, and no trends in the Bland–Altman analysis. The relationship between all predicted models and measured REE decreased in LW and LWH. Conclusions REE c1 can be considered the best accurate model of REE estimation in Brazilian young men, providing the REE and metabolically active tissue-organ of four components. Caution should be exercised with the use of DXA metabolic maps in populations with greater weight and greater weight–height.

The optimum abbreviated period for measurement by indirect calorimetry (IC) to estimate the resting energy expenditure (REE), including the acclimation period, in healthy individuals has not been established. This study aimed to determine the acclimation time required to achieve the REE steady state during a 30-minute IC measurement and to define the optimum abbreviated measurement period in the steady state to estimate the REE in healthy young adults.Thirty-nine volunteers (27 men and 12 women; age, 18-31 years) were recruited. The REE was obtained by IC over 30 minutes. Friedman's test was used to compare the coefficient of variation (CV%) among all 5-minute intervals (REE5). To compare the REE values obtained during the first REE5 interval in the steady state with the REE average values of the subsequent measurements, Student paired t test, linear regression, and Bland-Altman test were used.The CV% of the first REE5 (mean ± standard deviation: 19.9% ± 13.2%) was significantly higher (P.0001) than that of all other REE5 (second REE5: 7.4% ± 3.8%; third: 7.8% ± 5.2%; fourth: 7.1% ± 3.9%; fifth: 8.0% ± 5.7%; sixth: 8.0% ± 4.5%). No significant difference was found between the second REE5 and the REE average values of the last 20 minutes. The second REE5 explained 90% of the REE average of the last 20 minutes, with the 95% limits of agreement by the Bland-Altman test ranging from -142.92 to 150.44 kcal/d.Ten minutes can be used as an abbreviated alternative for IC measurements in healthy young adults, and values of the first 5-minute interval should be discarded.

OBJECTIVES The aim of this study was to evaluate the association between phase angle, body composition, and blood glucose changes in healthy young males after 6 months of physical training. METHODS Volunteers, 98 healthy males (18.8 ± 0.5 years), had 6 months of progressive physical training (5 days a week, 90 minutes a day). Resistance, reactance, and phase angle were obtained by bioelectrical impedance analysis, body composition (fat mass, bone mineral content [BMC], and lean soft tissue [LST]) by dual-energy X-ray absorptiometry, and blood glucose by reflectance photometry. Measurements were made at rest and in a fasted state, both before and after the training period. RESULTS Phase angle, reactance, BMC, and LST significantly increased (0.6°, 3.8 Ω, 0.1 kg, and 1.9 kg, respectively; P

Background/objectives Impaired inhibitory control has been associated with obesity, high blood pressure and lack of physical fitness. These impairments are thought to be related to decreased cognitive control over excessive food consumption and may start in childhood. However, previous studies in children have examined inhibitory control deficits using general (non-food-specific) tasks and relied on body mass index, which does not distinguish the amount of fat mass. As fat mass, hypertension and physical fitness have been shown to play a role in cognition, the aim of this study was to investigate the relationship between these variables and food specific inhibitory control in children. Subjects/methods Children's (n = 48; Age 10.7 ± 0.6 years) general characteristics, fat mass, cardiorespiratory fitness, blood pressure and performance on a food-specific inhibitory control task (Go/No-go) were measured across two sessions. Results Fat mass and sex were associated with inhibitory control performance, while no associations were found for cardiorespiratory fitness, blood pressure and other potential confounding variables (i.e. age, pubertal timing, body mass index, waist-to-hip ratio, scholar test performance and heart rate). Linear regression analyses showed that only fat mass predicted poorer food-specific inhibitory control (β = 0.36; ΔR2 = 0.04; p Conclusion These findings suggest that fat mass is an independent predictor of inhibitory control for food in children.

To analyze the association between a 34-week military training on body composition, physical fitness and compensatory changes in resting energy expenditure (REE) recognized as adaptive thermogenesis (AT). We also explored if regional body composition changes were related to AT.Twenty-nine male army cadets, aged 17 to 22 years were tested at baseline (T0) and after 34-weeks military training (T1). Physical training was performed 5 days/week during 90 minutes/day. Measurements included body composition by dual-energy x-ray absorptiometry; physical fitness by 3000-m running, pull-up, 50-m freestyle swimming, push-up and sit-up tests; REE measured by indirect calorimetry (REEm) and predicted from fat-free mass (FFM), fat mass (FM) and ethnicity at T0 (REEp). %AT was calculated using values at T1: 100(REEm/REEp-1); and AT (kcal/day) as %AT/100 multiplied by baseline REEm.Physical training was associated with increases of lean soft tissue (LST) (∆1.2±1.3 kg), FM (∆1.4±1.3 kg), FFM (∆1.2±1.3 kg) and physical fitness (P0.01), but no REE changes (∆59.6±168.9 kcal/day) and AT were observed (P0.05). Though a large variability was found, AT was partially explained by trunk LST (r2=0.17, P=0.027). Individuals showing a higher AT response demonstrated a higher trunk LST increase (∆0.8±0.7 kg, P0.05).The military training increased LST, FM, FFM and physical fitness. Though no mean changes in AT occurred, a large individual variability was observed with some participants increasing REE beyond the expected body composition changes, suggesting a spendthrift phenotype. Changes of trunk LST may play an important role in the AT response observed in these individuals.

Introduction Bioelectrical impedance analysis (BIA) is a practical and rapid method for making a longitudinal analysis of changes in body composition. However, most BIA validation studies have been performed in a clinical population and only at one moment, or point in time (cross-sectional study). The aim of this study is to investigate the accuracy of predictive equations based on BIA with regard to the changes in fat-free mass (FFM) in Brazilian male army cadets after 7 mo of military training. The values used were determined using dual-energy X-ray absorptiometry (DXA) as a reference method. Materials and Methods The study included 310 male Brazilian Army cadets (aged 17-24 yr). FFM was measured using eight general predictive BIA equations, with one equation specifically applied to this population sample, and the values were compared with results obtained using DXA. The student's t-test, adjusted coefficient of determination (R2), standard error of estimation (SEE), Lin's approach, and the Bland-Altman test were used to determine the accuracy of the predictive BIA equations used to estimate FFM in this population and between the two moments (pre- and post-moment). Results The FFM measured using the nine predictive BIA equations, and determined using DXA at the post-moment, showed a significant increase when compared with the pre-moment (p < 0.05). All nine predictive BIA equations were able to detect FFM changes in the army cadets between the two moments in a very similar way to the reference method (DXA). However, only the one BIA equation specific to this population showed no significant differences in the FFM estimation between DXA at pre- and post-moment of military routine. All predictive BIA equations showed large limits of agreement using the Bland-Altman approach. Conclusion The eight general predictive BIA equations used in this study were not found to be valid for analyzing the FFM changes in the Brazilian male army cadets, after a period of approximately 7 mo of military training. Although the BIA equation specific to this population is dependent on the amount of FFM, it appears to be a good alternative to DXA for assessing FFM in Brazilian male army cadets.

Objective: To determine the accuracy of two international Body Mass Index (BMI) cut-offs for classifying obesity compared to the percentage of fat mass (%FM) assessed by Dual-Energy X-ray Absorptiometry (DXA) in a Chilean sample of children and adolescents; Material and Methods: The subjects studied included 280 children and adolescents (125 girls and 155 boys) aged 8 to 17 years. Weight and height were measured. The BMI was calculated. Two international references (IOFT and WHO) were used as cut-off points. The %FM was assessed by DXA. The receiver operating characteristic (ROC) curve was used to assess the performance of BMI in detecting obesity on the basis of %FM; Results: A high correlation was observed between the %FM measured by the DXA and the Z-scores of IOTF and WHO scores in the Chilean adolescents separated by sex (r = 0.78–0.80). Differences occurred in both references (IOFT and WHO) in relation to the criteria (p < 0.001). Both references demonstrated a good ability to predict sensitivity (between 84% and 93%) and specificity (between 83% and 88%) in both sexes of children and adolescents; Conclusions: A high correlation was observed between the Z-score of the BMI with the percentage of fat determined by the DXA. Despite this, the classifications using the different BMI cut-off points showed discrepancies. This suggests that the cut-off points selected to predict obesity in this sample should be viewed with caution.

Background: Bioelectrical Impedance Analysis (BIA) is a fast, practical, non-invasive, and frequently used method for fat-free mass (FFM) estimation. The aims of this study were to validate predictive equations of BIA to FFM estimation in Army cadets and to develop and validate a specific BIA equation for this population. Methods: A total of 396 males, Brazilian Army cadets, aged 17–24 years were included. The study used eight published predictive BIA equations, a specific equation in FFM estimation, and dual-energy X-ray absorptiometry (DXA) as a reference method. Student’s t-test (for paired sample), linear regression analysis, and Bland–Altman method were used to test the validity of the BIA equations. Results: Predictive BIA equations showed significant differences in FFM compared to DXA (p < 0.05) and large limits of agreement by Bland–Altman. Predictive BIA equations explained 68% to 88% of FFM variance. Specific BIA equations showed no significant differences in FFM, compared to DXA values. Conclusion: Published BIA predictive equations showed poor accuracy in this sample. The specific BIA equations, developed in this study, demonstrated validity for this sample, although should be used with caution in samples with a large range of FFM.

The aim of this study was to systematically review studies on intervention programs involving physical activity promotion and/or nutritional education to reduce health-related risk factors (overweight/obesity and metabolic profilealterations) in Brazilian adolescent students. A search was performed in the following electronic databases: Medline (PubMed), Lilacs, Embase, Scielo and Capes Thesis Database. A total of 1,568 studies were identified, of which 21 full papers were analyzed and 5 were included in the systematic review. The majority of the studies involved physical activity practice combined with nutritional education in Brazilian adolescent students and all interventions showed positive effect on reducing health-related risk factors among Brazilian adolescents.It was concluded that all studies included in this review showed positive alterations in health-related risk factors after interventions, reinforcing the importance of intervention programs to promote a healthier lifestyle and reduce health-related risk factors in adolescents.