Body fat, cardiovascular risk factors and polymorphism in the FTO gene: randomized clinical trial and different physical exercise for adolescents

Abstract Objective: To investigate the effects of different physical exercise programs and polymorphisms of the FTO (fat mass and obesity-associated gene) on body composition and cardiovascular risk factors in adolescents with overweight and obesity. Methods: A randomized, parallel, double-blind clinical trial consisting of the adolescent overweight from the state public network, in a simple representative random sample, who participated in an aerobic exercise or weight training intervention for 10 weeks. Anthropometry, body composition, biochemical markers, sexual maturation, and rs9939609 polymorphism in the FTO gene were assessed. 347 adolescents had their characterization of nutritional status. 72 individuals with overweight and obesity were invited to participate. 39 remained for the start of the program and were randomly allocated to both types of intervention. In the end, 26 subjects participated in the intervention programs, with 12 and 14 in the aerobic and weight training programs, respectively. Results: Heterozygous and homozygous bearers of risk allele A participating in the aerobic program showed improvements in glycemia (p = 0.002) and total cholesterol (p = 0.023) and a reduction in body fat mass (p = 0.041). The weight training program reduced glycemia in patients with the risk allele A (p = 0.027). Cameron's stage four sexual maturation participants were 2.1 times more likely to improve their body fat (CI = 1.31-3.39). Conclusion: Aerobic exercises produced exclusively a significant decrease in fat mass and total cholesterol in patients with risk allele A. Distinct physical exercise programs may cause diverse changes in risk variables related to the health of adolescents.

Body fat, cardiovascular risk factors and polymorphism in the FTO gene: randomized clinical trial and different physical exercise for adolescents.

OBJECTIVE: To investigate the effects of different physical exercise programs and polymorphisms of the FTO (fat mass and obesity-associated gene) on body composition and cardiovascular risk factors in adolescents with overweight and obesity. METHODS: A randomized, parallel, double-blind clinical trial consisting of the adolescent overweight from the state public network, in a simple representative random sample, who participated in an aerobic exercise or weight training intervention for 10 weeks. Anthropometry, body composition, biochemical markers, sexual maturation, and rs9939609 polymorphism in the FTO gene were assessed. 347 adolescents had their characterization of nutritional status. 72 individuals with overweight and obesity were invited to participate. 39 remained for the start of the program and were randomly allocated to both types of intervention. In the end, 26 subjects participated in the intervention programs, with 12 and 14 in the aerobic and weight training programs, respectively. RESULTS: Heterozygous and homozygous bearers of risk allele A participating in the aerobic program showed improvements in glycemia (p = 0.002) and total cholesterol (p = 0.023) and a reduction in body fat mass (p = 0.041). The weight training program reduced glycemia in patients with the risk allele A (p = 0.027). Cameron's stage four sexual maturation participants were 2.1 times more likely to improve their body fat (CI = 1.31-3.39). CONCLUSION: Aerobic exercises produced exclusively a significant decrease in fat mass and total cholesterol in patients with risk allele A. Distinct physical exercise programs may cause diverse changes in risk variables related to the health of adolescents.

Concordance of the Deuterium Dose to Mother Method and 24-Hour Recall to Measure Exclusive Breastfeeding at 6 Weeks Postnatally in Rural/Urban Setting in Jamaica.

INTRODUCTION: The 2030 health agenda for the United Nations Sustainable Development Goals promote exclusive breastfeeding (EBF) for the first 6 months of life as a central step towards ensuring the survival of infants. As Jamaica attempts to achieve this goal, monitoring the rates of EBF is desirable. Currently, EBF rate is measured by questionnaires which are subject to recall and social desirability biases. We determined the rate of EBF using the Deuterium-oxide dose-to-mother (DTM) method and 24-h recall. The concordance of both methods and urban-rural differences of EBF were evaluated. Additionally, the growth of infants who were exclusively breastfed was compared to the infants who were mixed-fed. METHODS: Sixty-one healthy mother-child pairs were followed from birth. EBF was measured at 6 weeks. Growth was determined using standard anthropometric measurements. Differences in means were assessed by independent t-test or ANOVA. The agreement between the DTM and 24-h recall method was assessed with the kappa statistic. Differences in anthropometry and location were determined using a repeated measure model approach. RESULTS: Thirty (49%) women exclusively breastfed their infants with mean breast milk intake of 1024.3 ± 256.9 g/day. There was moderate agreement between the methods (Agreement 69%, kappa 0.37, p = 0.002). Rural women (65%) were more likely to practice exclusive breastfeeding. There was no significant difference between the growth of the exclusively breastfed infant and mixed-fed infants. CONCLUSION: EBF rate was successfully measured using the DTM method. Women from urban settings are less likely to practice EBF. Further research may be needed to gain an in-depth understanding of the factors affecting breastfeeding practices in urban Jamaica.

An Animal Able To Tolerate D2 O.

It is possible to gain a deeper insight into the role of water in biology by using physicochemical variant molecules, such as deuterium oxide (D2 O); however, D2 O is toxic to multicellular organisms in high concentrations. By using a unique desiccation-rehydration process, we demonstrate that the anhydrobiotic nematode Panagrolaimus superbus is able to tolerate and proliferate in 99 % D2 O. Moreover, we analysed P. superbus' water-channel protein (aquaporin; AQP), which is associated with dehydration/rehydration, by comparing its primary structure and modelling its tertiary structure in silico. Our data evidence that P. superbus' AQP is an aquaglyceroporin, a class of water channel known to display a wider pore; this helps to explain the rapid and successful organismal influx of D2 O into this species. This is the first demonstration of an animal able to withstand high D2 O levels, thus paving a way for the investigation of the effects D2 O on higher levels of biological organization.

Nutritional status in children with cancer: comparison of deuterium oxide dilution with bioelectric impedance analysis and anthropometry / Estado nutricional em crianças com câncer: comparação entre diluição de deutério, impedância bioelétrica e antropometria

ABSTRACT Objective: To explore changes in the nutritional status of pediatric cancer patients before and after chemotherapy and evaluate the correlation between deuterium oxide dilution, bioelectric impedance analysis, and anthropometry for assessment of body composition. Methods: This study included 14 children (aged 5.6 to 13.6 years) and classified them as having hematologic or solid tumors. They had their body composition analyzed according to deuterium oxide, bioelectric impedance, and anthropometric measurements before the first chemotherapy cycle and after three and six months of therapy. Results: The patients in the hematologic tumor group had an increase in weight, height, body mass index, waist, hip, and arm circumference, subscapular skinfold thickness, and fat mass with the isotope dilution technique during chemotherapy. In the solid tumor group, the children showed a reduction in fat-free mass when assessed by bioimpedance analysis. We found a positive correlation between the triceps skinfold thickness and fat mass determined by bioimpedance analysis and deuterium oxide. The arm muscle circumference correlated with the fat-free mass estimated by bioimpedance analysis and deuterium oxide. Conclusions: Patients with hematologic tumors had an increase in body weight, height, and fat mass, which was not identified in the solid tumor group. The positive correlation between anthropometry (triceps skinfold thickness and arm muscle circumference), deuterium oxide dilution, and bioelectric impedance analysis shows the applicability of anthropometry in clinical practice.

RESUMO Objetivo: Verificar mudanças no estado nutricional de crianças com câncer antes e após o tratamento quimioterápico e avaliar a correlação entre diluição de óxido de deutério, análise de impedância bioelétrica (BIA) e dados antropométricos. Métodos: Quatorze crianças (entre 5,6 e 13,6 anos de idade) foram incluídas e classificadas como tendo tumores hematológicos ou sólidos. A composição corporal foi medida pelo óxido de deutério, impedância bioelétrica e medidas antropométricas antes da primeira quimioterapia e após três e seis meses de terapia. Resultados: Os pacientes do grupo de tumores hematológicos aumentaram o peso, a estatura, o índice de massa corporal, a circunferência da cintura, quadril e braço, dobra cutânea subescapular e a massa gorda com a técnica de diluição isotópica durante o tratamento quimioterápico. No grupo de tumores sólidos, as crianças mostraram uma redução na massa magra quando avaliadas por análise de impedância. Houve uma correlação positiva entre a dobra cutânea tricipital e a massa gorda determinadas pela análise de impedância e pelo óxido de deutério. A circunferência muscular do braço correlacionou-se com a massa magra estimada pela análise de impedância e pelo óxido de deutério. Conclusões: Pacientes com tumores hematológicos tiveram aumento no peso corporal, estatura e massa gorda, o que não foi observado naqueles com tumores sólidos. A boa correlação entre a antropometria (dobra cutânea tricipital e circunferência muscular do braço), a diluição do óxido de deutério e a análise da impedância bioelétrica mostra a aplicabilidade da antropometria na prática clínica.

Energy and protein requirements for Nellore steers estimated with the deuterium oxide marker

The aim of this study was determine the energy and protein requirements for maintenance and gain of Nellore steers. Thirty six Nellore steers with an average weight and age of 359±13 kg and 20 months at the beginning of the trial were individually fed for 56. The steers were fed the same diet (76.43% TDN and 13.62% CP) in three levels of dry matter (DM) intake, ad libitum, 75 g DM/kg BW0.75 and 60 g DM/kg BW0.75. The initial and final body composition was estimated with the marker deuterium oxide that allowed repeated water estimate in the same animal. Deuterium in blood samples was analyzed by mass spectrometry. The effects of intake levels, comparison of intercept and slope among feeding level, and equations were evaluated by the analysis of variance, adopting P<0.05 as a significant level. The net energy for maintenance was 75 kcal/kg EBW 0.75 or 70 kcal/kg BW 0.75. The net energy for gain for steers with 350 to 450 kg weight was 5.1 to 6.1Mcal. The efficiency of energy utilization for maintenance, km, was 0.7492 and for weight gain, kg, was 0.3404. The metabolizable protein requirement for maintenance was 4.32 * BW0.75and the net protein for gain was estimated with the equation NPg= (254.68*EBWG) (29.38*RE). The technique of deuterium oxide marker used to estimate energy and protein requirement for maintenance and weight gain at Nellore steers confirm the hypothesis presented in NRC, that NEmis lower than the requirement for taurine cattle. On the other hand, the reverse was true for the NP requirement for maintenance and for weight gain. We consider that indirect method using D2O for estimate body composition in zebu cattle was suitable to determine nutrient requirements.(AU)

Effects of fructans and probiotics on the inhibition of Klebsiella oxytoca and the production of short-chain fatty acids assessed by NMR spectroscopy.

Generally, the selection of fructans prebiotics and probiotics for the formulation of a symbiotic has been based on arbitrary considerations and in vitro tests that fail to take into account competitiveness and other interactions with autochthonous members of the intestinal microbiota. However, such analyzes may be a valuable step in the development of the symbiotic. The present study, therefore, aims to investigate the effect of lactobacilli strains and fructans (prebiotic compounds) on the growth of the intestinal competitor Klebsiella oxytoca, and to assess the correlation with short-chain fatty acids production. The short-chain fatty acids formed in the fermentation of the probiotic/prebiotic combination were investigated using NMR spectroscopy, and the inhibitory activities were assessed by agar diffusion and co-culture methods. The results showed that Lactobacillus strains can inhibit K. oxytoca, and that this antagonism is influenced by the fructans source and probably associated with organic acid production.

Energy and protein requirements for Nellore steers estimated with the deuterium oxide marker

The aim of this study was determine the energy and protein requirements for maintenance and gain of Nellore steers. Thirty six Nellore steers with an average weight and age of 359±13 kg and 20 months at the beginning of the trial were individually fed for 56. The steers were fed the same diet (76.43% TDN and 13.62% CP) in three levels of dry matter (DM) intake, ad libitum, 75 g DM/kg BW0.75 and 60 g DM/kg BW0.75. The initial and final body composition was estimated with the marker deuterium oxide that allowed repeated water estimate in the same animal. Deuterium in blood samples was analyzed by mass spectrometry. The effects of intake levels, comparison of intercept and slope among feeding level, and equations were evaluated by the analysis of variance, adopting P<0.05 as a significant level. The net energy for maintenance was 75 kcal/kg EBW 0.75 or 70 kcal/kg BW 0.75. The net energy for gain for steers with 350 to 450 kg weight was 5.1 to 6.1Mcal. The efficiency of energy utilization for maintenance, km, was 0.7492 and for weight gain, kg, was 0.3404. The metabolizable protein requirement for maintenance was 4.32 * BW0.75and the net protein for gain was estimated with the equation NPg= (254.68*EBWG) – (29.38*RE). The technique of deuterium oxide marker used to estimate energy and protein requirement for maintenance and weight gain at Nellore steers confirm the hypothesis presented in NRC, that NEmis lower than the requirement for taurine cattle. On the other hand, the reverse was true for the NP requirement for maintenance and for weight gain. We consider that indirect method using D2O for estimate body composition in zebu cattle was suitable to determine nutrient requirements.

Comparison of body composition analysis methods among centenary women: Seeking simpler methods.

OBJECTIVES: The aim of this study was to evaluate the most commonly used body composition tools in clinical practice, such as anthropometry and electrical bioimpedance, and compare it with deuterium oxide. METHODS: An exploratory cross-sectional study was conducted on women aged 100 years or above at home. Body composition was determined by measuring skinfolds (Jackson and Pollock and Durnin and Womersley equations), by bioimpedance, and by the deuterium oxide method. RESULTS: Body mass index values were lower than 22 kg/m2 in 64% of the subjects. When the various methods used were compared with deuterium oxide, there was better agreement for the determination of fat mass than lean mass. For fat mass, agreement was better when using bioimpedance (Lin's coefficient = 0.70), whereas for lean mass, agreement was better using the Durnin and Womersley equation (Lin's coefficient = 0.51). CONCLUSION: It is possible to use bioimpedance and skinfolds to evaluate fat mass and lean mass, respectively, in centenarians.

Evaluación antropométrica y composición corporal por medio de óxido de deuterio en escolares costarricenses / Anthropometric evaluation and body composition by means of deuterium oxide in Costa Rican schoolchildren

El objetivo del estudio fue determinar elestado nutricional de escolares costarricenses de seis a nueve años. Participaron 103 escolares (54 niños y 49 niñas) con un promedio de edad de 7,8 ± 0,9 años. Se evaluó peso, talla, talla sentado, circunferencia de cintura (CC), índice de masa corporal (IMC), índice córmico (IC) y relación cintura-talla (IC/T). Se utilizó el óxido de deuterio (D2O) para evaluar la composición corporal: % agua corporal total (% ACT), masa libre de grasa (MLG), masa grasa (MG) y % de grasa corporal (% GC). El sobrepeso/obesidad se determinó utilizando el IMC y el método de clasificación de McCarthy para % GC de acuerdo a sexo y edad. Los valores medios para niños y niñas fueron: peso (29,1 ± 7,2 vs 31,0 ± 6,7 kg), talla (124.7 ± 6.7 vs 127.5 ± 7.1 cm), talla sentado (64.4 ± 3.7 vs 65.6 ± 3.5 cm), IMC (18.5 ± 3.11 vs 18.9 ± 2.7 kg/m2), CC (62.1 ± 8.6 vs 63.8±7.8 cm), IC (51.6 ± 1.6 vs 51.5 ± 1.6), I.C/T (0.52 ± 0.1 vs 0.51 ± 0.1), % ACT (56.5 ± 5.7 vs 51.9 ± 4.5 %), MLG (21.0 ± 3.5 vs 20.5 ± 3.6 kg), MG (8.1 ± 4.2 vs 10.5 ± 3.6 kg), % GC (26.3 ± 7.3 vs 33.2 ± 5.7 %), respectivamente. La edad, talla, MG, % GC y % ACT fueron significativamente mayores (p<0.05) en las niñas. Los escolares presentan un crecimiento adecuado junto a una alta prevalencia de sobrepeso/obesida(AU)

The aim of the study was to determine the nutritional status of Costa Rican schoolchildren from six to nine years old. Participants were 103 schoolchildren (54 boys and 49 girls) with an average age of 7.8 ± 0.9. Each participant was assessed for weight, height, sitting height, waist circumference (WC), body mass index (BMI), cormic index (CI), and waist-height ratio (WHtR). Deuterium oxide dilution (D2O) was used to assess body composition; total body water % (TBW%), fat-free mass (FFM), fat mass (FM), and body fat % (BF %). Overweight/obesity was determined by the use of BMI and McCarthy's classification scheme for BF % in terms of sex and age. Mean values for boys and girls were: age (7.6 ± 0.9 vs 8.0 ± 1.0 years), weight (29.1 ± 7.2 vs 31.0 ± 6.7 kg), height (124.7 ± 6.7 vs 127.5 ± 7.1 cm), sitting height (64.4 ± 3.7 vs 65.6 ± 3.5 cm), BMI (18.5 ± 3.11 vs 18.9 ± 2.7 kg/m2), WC (62.1 ± 8.6 vs 63.8 ± 7.8 cm), CI (51.6 ± 1.6 vs 51.5 ± 1.6), WHtR (0.52 ± 0.1 vs 0.51 ± 0.1), TBW % (56.5 ± 5.7 vs 51.9 ± 4.5 %), FFM (21.0 ± 3.5 vs 20.5 ± 3.6 kg), FM (8.1 ± 4.2 vs 10.5 ± 3.6 kg), BF% (26.3 ± 7.3 vs 33.2 ± 5.7 %), respectively. Age, height, FM, BF %, and TBW % were significantly higher (p<0.05) in girls. Schoolchildren show adequate growth along with high prevalence of overweight/ obesity(AU)

Effects of obesity, energy restriction and neutering on the faecal microbiota of cats.

Surveys report that 25-57 % of cats are overweight or obese. The most evinced cause is neutering. Weight loss often fails; thus, new strategies are needed. Obesity has been associated with altered gut bacterial populations and increases in microbial dietary energy extraction, body weight and adiposity. This study aimed to determine whether alterations in intestinal bacteria were associated with obesity, energy restriction and neutering by characterising faecal microbiota using 16S rRNA gene sequencing in eight lean intact, eight lean neutered and eight obese neutered cats before and after 6 weeks of energy restriction. Lean neutered cats had a bacterial profile similar to obese rodents and humans, with a greater abundance (P<0·05) of Firmicutes and lower abundance (P<0·05) of Bacteroidetes compared with the other groups. The greater abundance of Firmicutes in lean neutered cats was due to a bloom in Peptostreptococcaceae. Obese cats had an 18 % reduction in fat mass after energy restriction (P<0·05). Energy reduction was concurrent with significant shifts in two low-abundance bacterial genera and trends in four additional genera. The greatest change was a reduction in the Firmicutes genus, Sarcina, from 4·54 to 0·65 % abundance after energy restriction. The short duration of energy restriction may explain why few bacterial changes were observed in the obese cats. Additional work is needed to understand how neutering, obesity and weight loss are related to changes in feline microbiota and how these microbial shifts affect host physiology.

Dilución isotópica con deuterio para determinar ingesta de leche humana y composición corporal materna / Deuterium-oxide turnover technique to assess breast milk intake and maternal body composition / Diluição isotópica com deutério para determinar a ingestão de leite humano e a composição corporal materna

El objetivo del trabajo fue describir la aplicación de la técnica de dilución isotópica con deuterio de dosis a la madre para determinar la ingesta de leche materna y la composición corporal de las madres, en distintos tipos de lactancia. El método analítico se aplicó en cuatro casos modelo de pares madre-lactante en los cuales las madres recibieron una dosis oral de agua deuterada, recolectándose 6 muestras de saliva de ambos durante 15 días. El enriquecimiento de deuterio se determinó en un espectrómetro FTIR-Shimadzu-Affinity obteniéndose la ingesta de leche materna (ILM) y de agua de otras fuentes (Fd). Se observó una variación del enriquecimiento de deuterio en la saliva del lactante, asociada al tipo de lactancia recibida, siendo mayor en el caso de lactancia materna exclusiva (LME). Asimismo, a medida que aumentó Fd, disminuyó ILM. Además, fueron determinadas el agua corporal, la masa libre de grasa y la masa grasa materna. La transferencia de las habilidades técnicas y del conocimiento a través de metodologías innovadoras para determinar la ingesta de leche materna es de utilidad como herramienta de evaluación de la alimentación del lactante y para investigar en qué medida la lactancia natural es reemplazada por la ingesta de otros alimentos. Mejorar la estimación de la LME contribuye al conocimiento de la recomendación de OMS y UNICEF de mantener la misma hasta el sexto mes de vida.

The aim of this study was to describe the application of the dose-to-the-mother deuterium-oxide turnover technique to determine the breast milk intake and body composition of mothers in different types of breastfeeding. This analytical method was performed in four mother-infant pairs at 4 months from birth. Mothers received an oral dose of deuterated water, collecting 6 samples of saliva from mother and baby during a period of 15 days. Deuterium enrichment was determined in a Shimadzu FTIR-spectrometer-Affinity to obtain the intake of breast milk and water from non-breast milk sources. In this study, a variation of the enrichment of deuterium in the saliva of the infant was observed, being higher when the infant was exclusively breastfed. As non-breast milk water increased, the intake of human milk decreased. Furthermore, maternal total body water, fat free mass and fat mass were determined. To improve technical skills and knowledge through innovative methods of breast milk measurement can be useful as an assessment tool for evaluating infant feeding and investigating the extent to which breast milk is being replaced by the consumption of other foods in order to estimate exclusive breastfeeding in the future. This would contribute to the knowledge of maintaining breastfeeding until the sixth month of life, as it is recommended by WHO and UNICEF.

O objetivo deste estudo foi descrever a aplicação da técnica de diluição isotópica com deutério de dose à mãe para determinar a ingestão de leite materno e a composição corporal das mães, em diferentes tipos de aleitamento. O método analítico foi aplicado em quatro casos modelo de pares mães-lactante nos quais as mães receberam uma dose oral de água deuterada, coletando-se 6 amostras de saliva de ambos (mães e lactantes) durante 15 días. O enriquecimento de deutério foi determinado em um espectrômetro FTIR-Shimadzu-Affinity, sendo obtida a ingestão de leite materno (ILM) e de água proveniente de outras fontes (Fd). Observou-se uma variação do enriquecimento de deutério na saliva do lactante, associada ao tipo de aleitamento recebido, sendo maior no caso de aleitamento materno exclusivo (AME). Também, na medida que aumentou Fd, diminuiu ILM. Além disso, a água corporal, a massa livre de gordura y a massa gorda materna foram determinadas. A transferência das habilidades técnicas e do conhecimento através de metodologias inovadoras para determinar a ingestão de leite materno é de utilidade como ferramenta de avaliação da alimentação do lactante e para investigar em que medida o aleitamento natural é substituído pela ingestão de outros alimentos. Melhorar a avaliação do AME contribui ao conhecimento da recomendação da OMS e UNICEF de manter a mesma até o sexto mês de vida.

'Dose-to-Mother' Deuterium Oxide Dilution Technique: An Accurate Strategy to Measure Vitamin A Intake in Breastfed Infants.

In Mexico, infants (0-2 years old) show the highest prevalence of vitamin A deficiency (VAD), measured by serum retinol concentrations. Thus, we consider that low vitamin A (VA) intake through breast milk (BM) combined with poor weaning practices are the main factors that contribute to VAD in this group. We combined the assessment of VA status in lactating women using BM retinol and a stable isotope 'dose-to-mother' technique to measure BM production in women from urban and agricultural areas. Infants' mean BM intake was 758 ± 185 mL, and no difference was observed between both areas (p = 0.067). Mean BM retinol concentration was 1.09 µmol/L, which was significantly lower for the agricultural area (p = 0.028). Based on BM retinol concentration, 57% of women were VAD; although this prevalence fell to 16% when based on fat content. Regardless of the VA biomarker used here, infants from the urban and agricultural areas cover only 66% and 49% of their dietary adequate intake from BM, respectively (p = 0.054). Our data indicate that VAD is still a public health concern in Mexico. Adopting both methods to assess VA transfer from the mother to the breastfed child offers an innovative approach towards the nutritional assessment of vulnerable groups.

Applications of deuterium oxide in human health.

The main aim goal of this review was to gather information about recent publications related to deuterium oxide (D2O), and its use as a scientific tool related to human health. Searches were made in electronic databases Pubmed, Scielo, Lilacs, Medline and Cochrane. Moreover, the following patent databases were consulted: EPO (Espacenet patent search), USPTO (United States Patent and Trademark Office) and Google Patents, which cover researches worldwide related to innovations using D2O.

Assessment of total body water and its compartments in elite judo athletes: comparison of bioelectrical impedance spectroscopy with dilution techniques.

Bioelectrical impedance spectroscopy (BIS) is an inexpensive and non-invasive technique to measure total body water (TBW), extracellular water (ECW), and intracellular water (ICW). The purpose of this study was to validate TBW, ECW and ICW assessed by BIS, using dilution techniques as the reference method (REF) in elite judo athletes. Thirty-two Portuguese elite male judo athletes were evaluated during a period of weight stability. TBW, ECW and ICW were assessed by BIS (Xitron 4000). Deuterium and bromide dilution techniques were used as the criterion method for measuring TBW and ECW, while ICW was calculated as the difference between the two. BIS explained 96%, 77% and 94% of the total variability from REFs for TBW, ECW and ICW, respectively. BIS also demonstrated high precision (ρ ≥ 0.88) and accuracy (Cb = 0.98), with a minimum concordance coefficient correlation of 0.87 for ECW. The mean bias demonstrated that BIS slightly overestimated the REF in 1.1 kg (2.3%), 0.3 kg (1.6%) and 0.8 kg (2.7%) for TBW, ECW and ICW, respectively. The 95% limits of agreement ranged from -1.2 to 3.3 kg in TBW, from -1.8 to 2.4 kg in ECW and from -1.0 to 2.6 kg in ICW. A non-significant trend was found between the difference and the mean of reference and alternative methods. These findings highlight the efficacy of BIS as a valid non-biased tool for the assessment of TBW and its compartments in elite male judo athletes, during a period of weight stability.

Body composition measures of obese adolescents by the deuterium oxide dilution method and by bioelectrical impedance

The objectives of the present study were to describe and compare the body composition variables determined by bioelectrical impedance (BIA) and the deuterium dilution method (DDM), to identify possible correlations and agreement between the two methods, and to construct a linear regression model including anthropometric measures. Obese adolescents were evaluated by anthropometric measures, and body composition was assessed by BIA and DDM. Forty obese adolescents were included in the study. Comparison of the mean values for the following variables: fat body mass (FM; kg), fat-free mass (FFM; kg), and total body water (TBW; percent) determined by DDM and by BIA revealed significant differences. BIA overestimated FFM and TBW and underestimated FM. When compared with data provided by DDM, the BIA data presented a significant correlation with FFM (r = 0.89; P < 0.001), FM (r = 0.93; P < 0.001) and TBW (r = 0.62; P < 0.001). The Bland-Altman plot showed no agreement for FFM, FM or TBW between data provided by BIA and DDM. The linear regression models proposed in our study with respect to FFM, FM, and TBW were well adjusted. FFM obtained by DDM = 0.842 x FFM obtained by BIA. FM obtained by DDM = 0.855 x FM obtained by BIA + 0.152 x weight (kg). TBW obtained by DDM = 0.813 x TBW obtained by BIA. The body composition results of obese adolescents determined by DDM can be predicted by using the measures provided by BIA through a regression equation.