The bioelectrical impedance analysis (BIA) international database: aims, scope, and call for data.

BACKGROUND: Bioelectrical impedance analysis (BIA) is a technique widely used for estimating body composition and health-related parameters. The technology is relatively simple, quick, and non-invasive, and is currently used globally in diverse settings, including private clinicians' offices, sports and health clubs, and hospitals, and across a spectrum of age, body weight, and disease states. BIA parameters can be used to estimate body composition (fat, fat-free mass, total-body water and its compartments). Moreover, raw measurements including resistance, reactance, phase angle, and impedance vector length can also be used to track health-related markers, including hydration and malnutrition, and disease-prognostic, athletic and general health status. Body composition shows profound variability in association with age, sex, race and ethnicity, geographic ancestry, lifestyle, and health status. To advance understanding of this variability, we propose to develop a large and diverse multi-country dataset of BIA raw measures and derived body components. The aim of this paper is to describe the 'BIA International Database' project and encourage researchers to join the consortium. METHODS: The Exercise and Health Laboratory of the Faculty of Human Kinetics, University of Lisbon has agreed to host the database using an online portal. At present, the database contains 277,922 measures from individuals ranging from 11 months to 102 years, along with additional data on these participants. CONCLUSION: The BIA International Database represents a key resource for research on body composition.

Appendicular Skeletal Muscle Mass Prediction in People Living With HIV: A Cross-sectional Study.

ABSTRACT: People living with HIV (PWH) experience an accelerated aging process. There is no anthropometric predictive model for appendicular skeletal muscle mass (ASM) in PWH. This study develops anthropometric models to predict and validate ASM measured by dual energy x-ray absorptiometry (DXA) in PWH; DXA scans were obtained for 125 PWH (male = 74; age >18 years) on antiretroviral therapy. Fat mass ratio was used for lipodystrophy diagnosis. A multiple stepwise linear regression considered ASM DXA as the dependent variable and validated by PRESS method. A high power of determination and low standard estimate error were found for ASM DXA -predicted (adjusted r2 = 0.84 to 0.87, standard estimate error = 1.7-1.6 kg) and high PRESS validation coefficients (Q 2PRESS = 0.84-0.86, S PRESS = 1.7-1.6 kg). The variables included were lipodystrophy diagnosis, medial calf circumference, sex, and total body weight. We present novel, reliable, and validated anthropometric models to predict ASM DXA in PWH.

Higher Body Mass Index Values Do Not Impact Physical Function and Lower-Extremity Muscle Strength Performance in Active Older Individuals.

This study examined the potential impact of BMI on physical function and lower-extremity muscle strength (leg extension and flexion peak torque) performance in active/trained older individuals. Sixty-four active/trained older individuals were enrolled, and later allocated to groups according to BMI categories (normal [≤ 24.9 kg/m2], overweight [25 to 29.9 kg/m2] and obese [≥ 30 kg/m2]). Sixty-four active/trained older individuals were enrolled, and later allocated to groups according to BMI categories (normal [≤ 24.9 kg/m2], overweight [25 to 29.9 kg/m2] and obese [≥ 30 kg/m2]). Assessments were conducted in two separate visits to the laboratory. In the first visit, participants underwent measures of height, body mass, and peak torque leg extension and flexion using an isokinetic dynamometer. On visit two, participants performed the 30-second Sit and Stand test (30SST), Timed Up and Go (TUG), and 6-minute Walk (6MW) tests. ANOVA one-way was used to analyze the data and significance was set at P < .05. One-way ANOVAs did not reveal significance differences among BMI categories for leg extension peak torque (F(2,61) = 1.11; P = 0.336), leg flexion peak torque (F(2,61) = 1.22; P = 0.303), 30SST (F(2,61) =1.28; P = 0.285), TUG (F(2,61) = 0.238; P = 0.789), and 6MW (F(2,61) = 2.52; P = 0.089)]. Our findings indicated that for older individuals who exercise regularly, physical function tests which mimic ordinary activities of daily living, are not impacted by BMI status. Thus, being physically active may counteract some of the negative effects of high BMI observed in the older adult population.

Frequency of osteopenia and osteoporosis in men and women living with HIV/Aids: an observational study / Frequência de osteopenia e osteoporose em homens e mulheres vivendo com HIV/Aids: um estudo observacional

ABSTRACT: Aims: To identify the frequency in changes of bone metabolism, including below the average value for age, osteopenia, and osteoporosis, in people living with HIV/AIDS (PLWHA) and to compare the frequency of factors associated with bone mineral density (BMD) and body composition between sex. Methods: This observational study assessed 106 PLWHA (65 male) recruited from the University Hospital of Ribeirão Preto Medical School from 2013 to 2014. BMD was measured using Dual Energy X-ray Absorptiometry (DXA). Standard deviation values for Z- and T-score proposed by the International Society for Clinical Densitometry were adopted to classify participants below the average value for age, osteopenia, and osteoporosis. Qui-square and Fischer's exact tests were employed to compare males and females based on their factors associated with BMD reduction. Results: Fifty-two (49%) PLWHA presented at least one diagnosis for below the average value for age, osteopenia, and osteoporosis, being 37 (57%) and 15 (37%) male and female, respec-tively. Frequency of alcohol consumption was higher in males (n=20; 30.8%) than females (n=05; 12.2%) (p=0.028).Conclusions: A high rate of PLWHA showed changes in bone metabolism, with a higher frequency in males. The fre-quency of alcohol consumption was higher in males, and it may partially explain the possible causes of the increased rates of bone metabolism changes observed in this group. This information may help develop strategies for reducing the frequency of diagnosis for below the average value for age, osteopenia, osteoporosis improving quality of life in PLWHA. (AU)

RESUMO: Objetivos: Identificar a frequência de alterações no metabolismo ósseo, incluindo valores abaixo do estimado para idade, osteopenia e osteoporose, em pessoas vivendo com HIV/Aids (PVHA) e comparar a frequência de fatores associados à redução da densidade mineral óssea (DMO) e composição corporal entre sexos. Métodos: Estudo observacional que ava-liou 106 PVHA (65 do sexo masculino) recrutadas do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo entre os anos 2013 e 2014. A DMO foi medida utilizando a Absorciometria Radiológica de Dupla Energia (DXA). Valores de desvio padrão Z- e T- scores propostos pela Sociedade Internacional para Densitometria Clí-nica foram adotados para classificar os participantes em abaixo do valor estimado para idade, osteopenia e osteoporose. Os testes do qui-quadrado e exato de Fischer foram empregados na comparação entre os sexos baseado em seus respec-tivos fatores associados à redução da densidade mineral óssea. Resultados: Cinquenta e dois (49%) PVHA apresentaram ao menos um diagnóstico para abaixo do valor estimado para idade, osteopenia e osteoporose, sendo 37 (57%) do sexo masculino e 15 (37%) feminino. A frequência de consumo de álcool foi maior no sexo masculino (n=20; 30,8%) compara-do ao feminino (n=5; 12,2%) (p=0,028). Conclusões: Uma alta taxa de PVHA apresentaram alterações no metabolismo ósseo, com maior frequência no sexo masculino. A frequência no consumo de álcool foi maior no sexo masculino, podendo explicar parcialmente as possíveis causas para taxa aumentada de alterações no metabolismo ósseo observada nesse grupo. Essa informação pode contribuir no desenvolvimento de estratégias para redução da frequência do diagnóstico para valores abaixo do estimado para idade, osteopenia e osteoporose, melhorando a qualidade de vida em PVHA

Resistance training with blood flow restriction: Impact on the muscle strength and body composition in people living with HIV/AIDS.

The aim of the study was to compare the impact of 12-week resistance training with blood flow restriction (GRTBFR) versus, traditional resistance training (GTRT) and non-training on the muscle strength and body composition HIV/AIDS participants. Muscle strength was tested at baseline, and on the 6th, 21st and 36th training sessions, using maximal repetition test. Pre- and post-intervention body composition changes were measured by dual-energy X-ray absorptiometry. Resistance training was undertaken three times a week comprising bilateral elbow extension and flexion exercises, unilateral flexion and bilateral knee extension. Changes in strength and body composition (pre- and post-intervention) between groups were evaluated by mixed models of repeated measures, and by paired and unpaired comparisons, considering the Effect Size. All groups were similar at baseline for muscle strength and body composition. Post-intervention, the training groups showed similar, statistically significant increases in muscle strength (GRTBFR=25.7-57.4%; GTRT=24.5-52.3%) and skeletal muscle tissue (GRTBFR=8.4%; GTRT=8.3%). There was also a significant change in body fat (p=0.023-0.043), with significant effect sizes for strength and skeletal muscle tissue (0.41-2.27), respectively. These results suggest that both resistance training interventions promoted muscle hypertrophy, body fat reduction and positive impact on muscle strength in people living with HIV/AIDS. Resistance training with blood flow restriction proved to be an effective alternative to include patients with marked physical weakness, unable to engage in regular strength training programme.ClinicalTrials.gov identifier: NCT02783417.

Scaling left ventricular mass in adolescent female soccer players.

BACKGROUND: The aim of the study was to examine the contribution of chronological age (CA), skeletal maturation, training experience and concurrent body size descriptors, to inter-individual variance in left ventricular mass (LVM) among female adolescent soccer players. METHODS: The sample included 228 female soccer players 11.8-17.1 years. Training experience defined as years of participation in competitive soccer (range 2-9 years), was obtained by interview. Stature, body mass and skinfolds (triceps, medial calf) were measured. Fat mass was estimated; Fat-free mass was derived. LVM was assessed by echocardiography. Skeletal maturity status was as the difference of skeletal age (SA, Fels method) minus CA. RESULTS: Fat-free mass was the most prominent single predictor of LVM (R2 = 36.6%). It was associated with an allometric coefficient close to linearity (k = 0.924, 95%CI: 0.737 to 1.112). A significant multiplicative allometric model including body mass, fat-free mass, CA, training experience and skeletal maturity status was also obtained (R = 0.684; R2 = 46.2%). CONCLUSION: Stature has limitations as a valid size descriptor of LVM. Body mass, fat-free mass, training experience, CA, body mass and skeletal maturity status were relevant factors contributing to inter-individual variability in LVM.

Lipodystrophy diagnosis in people living with HIV/AIDS: prediction and validation of sex-specific anthropometric models.

BACKGROUND: Body composition alterations, or lipodystrophy, can lead to serious health problems in people living with HIV/AIDS (PLWHA). The objectives of this study are to predict and validate sex-specific anthropometric predictive models for the diagnosis of lipodystrophy in PLWHA. METHODS: A cross-sectional design was employed to recruit 106 PLWHA (men = 65 and women = 41) in Brazil during 2013-2014. They were evaluated using dual-energy X-ray absorptiometry, and 19 regions of body perimeters and 6 skinfold thicknesses were taken. Sex-specific predictive models for lipodystrophy diagnosis were developed through stepwise linear regression analysis. Cross-validations using predicted residual error sum of squares was performed to validate each predictive model. RESULTS: Results support the use of anthropometry for the diagnosis of lipodystrophy in men and women living with HIV/AIDS. A high power of determination with a small degree of error was observed for lipodystrophy diagnosis for men in model six (r2 = 0.77, SEE = 0.14, r2PRESS = 0.73, SEE PRESS = 0.15), that included ratio of skinfold thickness of subscapular to medial calf, skinfold thickness of thigh, body circumference of waist, formal education years, time of diagnosis to HIV months, and type of combined antiretroviral therapy (cART) (with protease inhibitor "WI/PI = 1" or without protease inhibitor "WO/PI = 0"); and model five for women (r2 = 0.78, SEE = 0.11, r2PRESS = 0.71, SEE PRESS = 0.12), that included skinfold thickness of thigh, skinfold thickness of subscapular, time of exposure to cART months, body circumference of chest, and race (Asian) ("Yes" for Asian race = 1; "No" = 0). CONCLUSIONS: The proposed anthropometric models advance the field of public health by facilitating early diagnosis and better management of lipodystrophy, a serious adverse health effect experienced by PLWHA.

Estimate of Resting Energy Expenditure by DXA in Boys of Different Nutritional Statuses

Abstract Aim: to estimate the resting energy expenditure (REE) of organ tissue components using Dual Energy x-ray Absorptiometry (DXA) in pubertal boys. The mass of components and REE were compared among groups of different nutritional statuses. Methods: a sample of 278 boys (13.7 ± 2.4 years old) was grouped according to BMI nutritional status for Brazilian children and adolescents1 such as Underweight (UW), Normal weight (NW), Overweight (OW), and Obese (OB). The REE of organ tissue components given by DXA was calculated using specific models for skeletal muscle tissue (SMT), adipose tissue (AT), bone tissue (BT) and residual tissue (RT) based on previous reports. The absolute and relative REE (REEDXA) of each component were statistically compared among groups. Results: No differences of total REEDXA were found among nutritional groups (F(3, 274)=0.071, p=0.976). When, however, specific REE was considered per component, differences were found for BT and REEBT between NW-OW (p=0.003) and NW-OB (p=0.048); in AT and REEAT for all the groups (p<0.001), except between UW-NW (p=1.000); in RT and REERT between NW-OB (p=0,022) and SMT and REESMT (p=0,039). Greater proportions of organ tissue of RT and high metabolic rates, were observed in the UW group (78.3%) in comparison to the OB group (60.7%). Conclusion: This approach provides a new opportunity to examine energy metabolism for individual differences of pediatric populations. It is an applicable strategy both to prescribe exercises and to administer diets to this population, as it reveals the magnitude of heat-producing body components.

Impact of Strength Training on Bone Mineral Density in Patients Infected With HIV Exhibiting Lipodystrophy.

This study aimed to evaluate the impact of strength training on bone mineral density (BMD) in individuals harboring HIV exhibiting lipodystrophy. The study included 20 subjects (16 men) aged 50.60 ± 6.40 years with reduced BMD, presenting positive serology for HIV, using highly active antiretroviral therapy, and performing no regular practice of physical exercise before being enrolled in the study. Bone mineral density levels were evaluated by dual-energy x-ray absorptiometry in the lumbar spine, femoral neck, and 1/3 radius, before and after 36 sessions (12 weeks) of strength training. Compared with pre-exercise period, the results showed increased BMD in lumbar spine (3.28%; p = 0.012), femoral neck (8.45%; p = 0.044), and 1/3 radius (5.41%; p = 0.035). This is the first study evaluating the impact of strength training in patients living with HIV and exhibiting lipodystrophy, showing an increased BMD in all the regions measured (lumbar spine, femoral neck, and 1/3 radius). This study showed the beneficial impact of the strength training on BMD increase in patients living with HIV as an effective and available approach to improve bone health.

Half-ironman induces changes in the kidney function of triathletes.

Long duration exercise may lead to the occurrence of urine abnormalities. Aiming to investigate the effects of triathlon training and competition on the renal function, twelve male triathletes (32.60 ± 5.10 years, 175.04 ± 6.67m, 71.83 ± 7.42Kg) were studied during the 12-week training protocol and after a Half Ironman. Urine was collected in M-1 - beginning of the training season, M-2 - before the competition and M-3 - after the half ironman. Urine pH was measured using reagent strips, density with a refractometer, proteinuria by Bradford assay, creatinine with a colorimetric assay and blood cells by microscopy. Data were analyzed using Shapiro-Wilk test, One-Way ANOVA and Tukey-Kramer test (p < 0,05). Changes were found after the competition in the protein (M-1= 7.41 ± 2.48; M-2= 7.57 ± 3.74; M-3= 86.10 ± 76.21 mg/mL), creatinine (M-1= 157.66 ± 41.59; M-2= 177.68 ± 44.46; M-3= 316.46 ± 132.86 mg/mL), erythrocytes (M-1= 1060.00 ± 0.30; M-2= 1142.86 ± 377.96; M-3= 52555.56 ± 58.65 units/mL) and leucocytes (M-1= 2375.00 ± 744.02; M-2= 2090.00 ± 0.50; M-3= 5000.00 ± 2738.60 units/mL) excretion when compared to the other collection times. These effects are probably due to the exercise-induced modifications in the glomerular membrane and endocrine variables such as anti diuretic hormone, catecholamines and aldosterone.

Performance of body fat and body mass index cutoffs in elevated blood pressure screening among male children and adolescents.

For percentage of body fat (%BF), there are no internationally accepted cutoffs. The primary function of body fat cutoffs should be to identify not only excessive body fatness, but also the increased risk of unhealthy outcomes, such as hypertension. The purpose of this study was to analyze the accuracy of different %BF and body mass index (BMI) cutoffs as screening measures for EBP in pediatric populations. It was a cross-sectional study with a sample of 358 male subjects from 8 to 18 years old. BP was measured by the oscilometric method, and body composition was measured by dual-energy X-ray absorptiometry (DXA). The accuracy of three reference tables used for body fat cutoffs was assessed. The three body fat reference tables were highly specific, but insensitive, for elevated BP screening. For elevated BP screening, all body fat cutoffs presented similar sensitivity (range=48.3-53.7%) and specificity (range=79.2-84.1%). The body fat cutoffs performed no better than BMI in screening of children and adolescents at risk of elevated BP (EBP). BMI seems a more attractive tool for this function, as it performed similarly and can be applied in large surveys and with lower costs.

The accuracy of national body fat cutoff levels in the prediction of elevated blood pressure among Brazilian male adolescents.

OBJECTIVE: To assess viability of the development of percentage body fat cutoffs based on blood pressure values in Brazilian adolescents. METHODS: A cross-sectional study was conducted with a sample of 358 male subjects from 8 to 18 years old. Blood pressure was measured by the oscilometric method, and body composition was measured by dual-energy X-ray absorptiometry (DXA). RESULTS: For the identification of elevated blood pressure, these nationally developed body fat cutoffs presented relative accuracy. The cutoffs were significantly associated with elevated blood pressure [odds ratio = 5.91 (95% confidence interval: 3.54-9.86)]. CONCLUSIONS: Development of national body fat cutoffs is viable, because presence of high accuracy is an indication of elevated blood pressure.