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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Avaliação da técnica de impedância bioelétrica na identificação das alterações da composição corporal em mulheres no período pós-parto / Assessment of body composition changes in women in the postpartum period by bioelectrical impedance

Ana Cristina Teixeira Santos 20 December 2013 (has links)
Este trabalho teve como objetivo verificar se a técnica de impedância bioelétrica (IB) identifica as modificações da composição corporal em mulheres no período pós-parto. Participaram do estudo 47 mulheres (≥ 18 anos), nas quais foram avaliadas massa livre de gordura (MLG), massa gorda (MG) e percentual de gordura corporal (%GC) pelos equipamentos IB_Tanita BC 533; IB_RJL 101 e por absorciometria de raio X de dupla energia (DXA). Todas as avaliações foram feitas no mesmo dia. Posteriormente, as mulheres foram categorizadas em dois grupos: com perda ponderal (n= 24) e com ganho ponderal (n= 22). Os valores médios das alterações da composição corporal (CC), foram comparados intra-métodos e em relação ao método padrão-ouro (DXA) através de teste T-pareado. A concordância entre as diferenças das alterações da CC obtidas pelas IB e DXA foi avaliada pelo método de Bland & Altman e pelo coeficiente de correlação intraclasse (CCI). A média  desvio padrão de idade foi de 26,7  5,2 anos e o tempo médio da captação no pós-parto para a primeira avaliação foi de 2,6  2,0 meses e 8,0  2,7 meses para a segunda avaliação. A média de massa corporal (MC) foi de 74,6  11,4 kg na primeira avaliação e 75,1  12,6 kg na segunda avaliação, correspondendo a um valor de índice de massa corporal (IMC) de 28,8  4,0 kg/m2 e 29,0  4,6 kg/m2, respectivamente. O %GC medido pela DXA foi de 40,1  4,9 % para a primeira avaliação e de 41,0  5,2 %, para a segunda avaliação, representando uma MG de 30,2  6,6 kg e de 30,9  8,0 kg, respectivamente. Ambas as IB subestimaram a alteração do % GC (-0,7 % para IB_Tanita e -1,1% para IB_RJL) e MG (-0,6 kg para IB_Tanita e -1,0 kg IB_RJL) em relação ao DXA. Por sua vez, as alterações de MLG foram superestimadas 0,8 kg pela IB_Tanita e 1,0 kg IB_RJL. Houve boa concordância (CCI ≥ 0,75) entre as alterações identificadas para MG pela IB_Tanita e por DXA e satisfatória pela IB_RJL. Dessa forma o presente estudo verificou um desempenho satisfatório da técnica de IB em identificar as alterações da MG gorda e que a IB_Tanita mostrou-se melhor que a IB_RJL na estimativa da alteração desse componente corporal nesse grupo de mulheres pós-parto. / The aim of the present study is to assure that the measurement of the bioelectrical impedance (IB) identifies the changes in the body composition of postpartum women. Forty-seven women (≥ 18 years of age) were enrolled in the study. Body composition (BC) - fat free mass (FFM), fat mass (FM) and percentage body fat (%BF) - was obtained by two IB devices (Tanita BC 533 and RJL 101) and DXA. All measurements were performed at the same day in two different postpartum moments. The women were categorized in two groups: with weight loss (WWL, n= 24) and with weight gain (WWG, n= 22). Pair T-test was used to compare mean difference values within methods and DXA. Bland & Altman plots and intraclass correlation coefficients (ICC) were used to evaluate the agreement between body composition changes obtained by both IB and DXA. The first and second visits for BC measurements occurred 2,6  2,0 months e 8,0  2,7 months after delivery, respectively. Mean ( SD) age was 26.7  5.2 years and body mass was 74.6  11.4 kg at the first visit and 75.1  12.6 kg at the second visit. Women were overweight in both visits (BMI= 28.8  4,0kg/m2 e 29.0  4.6 kg/m2). % BF measured by DXA at the first visit was 40.1  4.9% and at the second visit was 41.0  5.2% yielding on average a FM of 30.2  6,6 kg and 30,9  8,0 kg, respectively.. IB_Tantia yelded lower mean values for FFM and FM compare to DXA mean values, except for %BF. Both IB underestimated %BF (-0.7% for Tanita and -1.1% for RJL) and FM changes (-0.6 kg for Tanita and -1.0 for RJL) compared to DXA changes. On the other hand FFM changes were overestimated by Tanita (0,8 kg) and RJL (1,0 kg). There was a good agreement (CCI ≥ 0.75) between FM changes measured by IB_Tanita and DXA and a fair agreement for IB_RJL. Therefore the IB technique was able to identified FM changes, and IB_Tanita showed a better performance than IB_RJL on the estimation of FM changes in these postpartum women.
42

Sarcopenia em idosos: revisão, prevalência, concordância entre métodos diagnósticos e antropometria como proposta de rasatreamento / Sarcopenia in the elderly: review, prevalence, agreement between diagnostic methods and anthropometry as a screening proposition

Pagotto, Valéria 21 June 2013 (has links)
Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2014-12-01T16:58:26Z No. of bitstreams: 2 Tese - Valéria Pagotto - 2013.pdf: 1825466 bytes, checksum: f97e4cc29d226317b6a69fbcc4e88f19 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2014-12-04T14:32:55Z (GMT) No. of bitstreams: 2 Tese - Valéria Pagotto - 2013.pdf: 1825466 bytes, checksum: f97e4cc29d226317b6a69fbcc4e88f19 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-12-04T14:32:55Z (GMT). No. of bitstreams: 2 Tese - Valéria Pagotto - 2013.pdf: 1825466 bytes, checksum: f97e4cc29d226317b6a69fbcc4e88f19 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-06-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The aim of this study was to review methods and diagnostic criteria for sarcopenia available in the literature to estimate the prevalence and concordance between them, in a sample of elderly Goiânia, and propose anthropometry for screening sarcopenia. To review methods we used the recommendations for systematic review and meta-analysis of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. For other purposes, we used a subsample of 132 elderly Senior Project/ Goiânia, selected in proportion to the Sanitation Districts of Goiânia. The data were collected by staff previously trained and standardized. Sarcopenia was analyzed by mass and muscle strength. The mass mucular was estimated by dual X-ray absorptiometry (DEXA), bioelectrical impedance analysis (BIA) and anthropometry, and muscle strength through hand grip strength (FPP). Analyses were performed in STATA 12.0, comparison of means and proportions, estimation of prevalence and prevalence ratio, Kappa, calculation of sensitivity and specificity analysis and ROC (receiver operator characteristic) curve. The project was approved by the Ethics Committee of the Federal University of Goiás. In 28 prevalence studies reviewed were found three methods for the diagnosis of sarcopenia: DEXA BIA and anthropometry with significant variations in prevalence as sex and the method adopted. Applying the diagnostic criteria found in the subsample Elderly Project/ Goiânia, the prevalence of sarcopenia ranged from 60.6% to 8.3% for the criteria of muscle mass and 54.2% to 48.8% for the strength, increasing in age and is more prevalent in men by criteria of muscle mass and women by criteria muscle strength. There was good agreement between two diagnostic criteria using DEXA, and moderate to weak for others. Anthropometric measurements of the circumference of the calf (CP), midlearm circumference (MAMC) and brachial circumference (CB) have been proposed for screenig sarcopenia and all showed good sensitivity and specificity for the cutoff of DEXA, and the CP had the best performance. We conclude that there are different methods and criteria for diagnosis of sarcopenia and its aplicabillity both in elderly sample of Goiânia, as other results in different prevalence rates by sex and age. The only good agreement between the two methods indicates DEXA both the need for an operational definition and the need for early detection. Anthropometric measurements of CP, CMB and CB can be used for tracking and consequent prevention of adverse events in elderly health resulting from sarcopenia / O objetivo deste estudo foi revisar os métodos e critérios diagnósticos de sarcopenia disponíveis na literatura, estimar a prevalência e a concordância entre estes diferentes critérios em amostra de idosos de Goiânia e propor o método antropométrico como rastreamento da sarcopenia. Para revisão de métodos foram utilizadas as recomendações para comunicação de estudos de revisão sistemática e metanálise do Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. Para os demais objetivos utilizou-se subamostra de 132 idosos do Projeto Idosos/ Goiânia, selecionados de forma proporcional aos Distritos Sanitários de Goiânia. Os dados foram coletados por equipe previamente treinada e padronizada. A sarcopenia foi analisada segundo a massa e força muscular. A massa mucular foi estimada por meio da Absortometria por raio-X de dupla energia (DEXA), bioimpedância elétrica (BIA) e antropometria; e a força muscular por meio da Força de Preensão Palmar (FPP). As análises foram realizadas no STATA 12.0, por meio de testes para comparação de médias e proporções, estimativa da prevalência e razão de prevalência, teste Kappa, cálculo de sensibilidade e especificidade e análise de Curva Roc (receiver operator characteristic curve). O projeto foi aprovado pelo Comitê de Ética em Pesquisa da Universidade Federal de Goiás. Em 28 estudos de prevalência revisados, foram encontrados 3 métodos para diagnóstico de sarcopenia: DEXA, BIA e antropometria, com variações significantes na prevalência conforme o sexo e o método adotado. Aplicando os critérios diagnósticos encontrados na subamostra do Projeto Idosos/ Goiânia, a prevalência de sarcopenia variou de 60,6% a 8,3% para os critérios de massa muscular e de 54,2% a 48,8% para os de força, aumentando nas faixa etária, sendo mais prevalente em homens por critérios de massa muscular e em mulheres por critérios de força muscular. Observou-se boa concordância entre dois critérios diagnósticos utilizando DEXA, e moderada a fraca para os demais. As medidas antropométricas da Circunferência da Panturrilha (CP), Circunferência Muscular do Braço (CMB) e Circunferência Braquial (CB) foram propostas para rastreamento de sarcopenia e todas apresentaram boa sensibilidade e especificidade para os pontos de corte de DEXA, sendo que a CP teve o melhor desempenho. Conclui-se que existem diferentes métodos e critérios para diagnóstico da sarcopenia e a aplicabilidiade deles tanto na amostra de idosos de Goiânia, como em outras resulta em diferentes prevalências conforme sexo e faixa etária. A boa concordância entre apenas dois métodos de avaliação pela DEXA sinaliza tanto a necessidade de uma definição operacional como a necessidade de detecção precoce. As medidas antropométricas da CP, CMB e CB podem ser utilizadas para rastreamento e consequente prevenção de eventos adversos a saúde do idoso decorrente da sarcopenia.
43

Avaliação da confiabilidade e concordância de métodos de avaliação da composição corporal em mulheres no período reprodutivo / Evaluation of reliability and consistency of body composition assessment methods in women in reproductive period

Rafael Costa Silva 12 January 2016 (has links)
Objetivos: Avaliar a composição corporal através da medida das dobras cutâneas (DC) intra e inter observador em mulheres na fase reprodutiva. Estimar a confiabilidade de dois protocolos de medidas de dobras cutâneas com o método Absorciometria Radiológica de Dupla Energia (DEXA). Métodos: A amostra foi composta por 90 mulheres com faixa etária de 18 a 37 anos, com Índice de Massa Corporal entre 18 e <= 39,9 Kg/m². A reprodutibilidade dos métodos foram avaliados pelos coeficientes de correlação de concordância (CCC) e coeficiente de Saint Laurent e pelos limites de concordância e gráficos de Bland-Altman. Resultados: A comparação intra observador foi excelente (CCC = 0,99) para os valores das medidas de DC tricipital, supraíliaca, coxa, soma das dobras e percentual de gordura. O mesmo ocorreu na comparação inter observador (CCC = 0,99). As medidas das DC tricipital foram as que apresentaram maior CCC (0,98), seguido da medida da coxa (0,90), e a medida da DC da suprailíaca foi a menor (0,89). A soma das DC e o percentual de gordura tiveram valores de 0,95. Já os protocolos de medidas de DC comparados entre si e com o padrão ouro DEXA, obtiveram valores de concordância baixa (0,35). Conclusões: Nossos achados mostraram que a comparação intra e inter observador foi satisfatória, contribuindo para a reprodutibilidade das medidas de DC. Os protocolos de avaliação das DC não tiveram concordância quando comparados com a DEXA / Objectives: Assessing body composition by measuring the intra and inter observer skin folds in women in the reproductive phase and estimate the reliability of two protocols skinfold measures with radiographic absorptiometry method of dual energy absorptiometry (DEXA). Methods: The sample consisted of 170 women aged 18-37 years with body mass index between 18 and <= 39.9 kg / m². The reproducibility of methods and skinfold thickness were evaluated by the coefficient of concordance correlation (CCC) and coefficient of Saint Laurent and the limits of agreement and Bland-Altman. Results: Comparison intra observer was excellent with the same values of the CCC (0.99) for the measurements of skinfold thickness of the triceps, suprailiac, thigh and fat percentage. The same occurred in the comparison inter observer (CCC = 0.99). The measures of skinfold thickness of the triceps showed the greatest CCC (0.98), followed by thigh (0.90), and the suprailiac was the lowest (0.89). The sum of the measurements of skinfold thickness and the percentage of fat had CCC values of 0.95. Already the reliability of two protocols skinfold thickness measures compared with the gold standard DEXA method was low (CCC = 0.35). Conclusions: Our findings showed that compared intra and inter observer was satisfactory, contributing to the reproducibility of skin folds. Assessment protocols skinfold did not have agreement when compared with DEXA
44

Influence of anatomical location and FOV size on cone-beam computed tomography gray values = Análise da influência da localização anatômica e tamanho do FOV nos valores de cinza em imagens de tomografia computadorizada de feixe cônico / Análise da influência da localização anatômica e tamanho do FOV nos valores de cinza em imagens de tomografia computadorizada de feixe cônico

Oliveira, Matheus Lima de, 1984- 02 May 2013 (has links)
Orientador: Guilherme Monteiro Tosoni / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-21T22:12:50Z (GMT). No. of bitstreams: 1 Oliveira_MatheusLimade_D.pdf: 24389100 bytes, checksum: b2e18d1167061c00f8285f26e1f8d746 (MD5) Previous issue date: 2013 / Resumo: O objetivo deste estudo foi avaliar a influência da região anatômica e do tamanho do FOV (field of view) nos valores de cinza em imagens de tomografia computadorizada de feixe cônico (TCFC). Soluções homogêneas de fosfato de potássio dibásico (K2HPO4) foram preparadas em sete diferentes concentrações e armazenadas separadamente em tubos de polipropileno. Um phantom de uma cabeça humana teve seis dentes extraídos - um incisivo central um primeiro prémolar e um primeiro molar da maxila e da mandíbula - e substituídos por esses tubos, que foram escaneados separadamente pelos aparelhos NewTom 3G, NewTom 5G e 3D Accuitomo 170, sob diferentes tamanhos de FOV. Em cortes axiais, valores médios de cinza foram obtidos em cinco níveis diferentes dentro de cada tubo de polipropileno e a média foi calculada. Para cada aparelho, análise de regressão linear avaliou a relação entre os valores médios de cinza e a concentração de K2HPO4 em seis regiões anatômicas, sob os diferentes FOVs. Coeficiente de determinação (R2) foi calculado. Nos três aparelhos, a correlação linear entre os valores de cinza e as concentrações de K2HPO4 variou entre as regiões anatômicas e os tamanhos de FOV (0,93 < R2 < 0,99). Desse modo, pode se concluir que a relação entre os valores de cinza em imagens de TCFC e a densidade do objeto não é uniforme por todo o arco dentário e é influenciada pelo tamanho do FOV nos três aparelhos de TCFC testados. A comparação desses valores obtidos em diferentes regiões anatômicas e com diferentes tamanhos de FOV não é confiável / Abstract: The aim of this study was to evaluate the influence of anatomical location and FOV (field of view) size in CBCT numbers. Homogeneous solutions of dipotassium phosphate (K2HPO4) were prepared at seven different concentrations and stored separately in polypropylene tubes. Six teeth were extracted from a human head phantom - the upper and lower central incisors, first premolars and first molars - and replaced by the tubes, which were scanned separately by NewTom 3G, NewTom 5G and 3D Accuitomo 170 under different FOV sizes. In axial sections, CBCT numbers were obtained at five levels within each polypropylene tube, and the average was calculated. For each CBCT unit, linear regression analysis evaluated the relationship between CBCT numbers and the concentration of K2HPO4 in six anatomical regions, under different FOVs. Coefficient of determination (R2) was calculated. Linear correlation between CBCT numbers and concentrations of K2HPO4 ranged between anatomical regions and FOV sizes (0.93 < R2 <0.99). Thus, it can be concluded that the relationship between CBCT numbers and object density is not uniform throughout the dental arch, and is influenced by the FOV size on the three CBCT units tested in this study. The comparison of CBCT numbers from different anatomical regions and with different FOV sizes is unreliable / Doutorado / Radiologia Odontologica / Doutor em Radiologia Odontológica
45

Estimation du risque de fracture ostéoporotique du rachis thoraco-lombaire par un modèle en élément finis personnalisé / Thoraco-lumbar vertebral osteoporotic fracture risk estimation with a patient specific finite element model

Travert, Christophe 18 December 2012 (has links)
L'ostéoporose est une maladie du squelette caractérisée par une perte de la qualité osseuse qui entraîne un risque de fracture accru, notamment au niveau vertébral. Des modèles en éléments finis basés sur la tomodensitométrie permettent d'estimer la résistance vertébrale, et donc le risque de fracture, mais leur utilisation en routine clinique est limitée par le coût et l'irradiation engendrée par la tomodensitométrie. L'estimation la résistance vertébrale à partir d'un modèle en éléments finis basés sur l'imagerie basse dose, telle que l'absorptiométrie biphotonique à rayons X, ou la stéréo-radiographie EOS en double énergie, permettrait une utilisation en routine clinique. Cette thèse contribue au développement de la modélisation à partir de l'imagerie basse dose pour la prédiction du risque de fracture. Un modèle en éléments finis de résistance vertébrale y est évalué par rapport à un modèle basé sur la tomodensitométrie, et une étude de sensibilité identifie les facteurs importants du modèle sont analysés. Des méthodes de maillage hexaédrique morpho-réalistes à partir de la reconstruction 3D, et d'estimation de la distribution de densité à partir d'image 2D de densité y sont développées. De plus, profitant des possibilités du système EOS qui permet de radiographier le patient de la tête aux pieds, une méthode préliminaire est proposée pour estimer l'effort exercé sur les vertèbres in vivo. Nous espérons que nos méthodes pourront être utilisées très prochainement in vivo, et contribuer à l'estimation du risque de fracture ostéoporotique, et à la prise en charge des patients à risque de fracture. / Osteoporosis is a bone disease which decreases bone quantity and quality, and increases fracture risk, notably at the vertebral level. CT-scan-based finite element models allow predicting vertebral strength, and thus fracture risk, but their use in routine clinical practice is limited by the cost and accessibility of CT-scan. However, vertebral strength prediction from a finite element model based on low dose images, such as dual X-ray absorptiometry or EOS stereo-radiography in dual energy, would allow a wider use. This PhD thesis contributes to develop fracture risk estimation by such a model. The low dose approach is evaluated in comparison to CT-based finite element model, and a sensitivity study is performed to identify the most important parameters of the model. Hexahedral morpho-realistic meshing techniques from 3D reconstruction and estimation methods for the 3D bone mineral density distribution from low dose images are developed and evaluated. Moreover, taking advantage of EOS system's possibility to take full body radiographs in standing position, a preliminary method is proposed to estimate the load applied to vertebra in vivo. We hope those methods will be used soon in vivo, and will contribute to estimating osteoporotic fracture risk estimation in clinical situations.
46

Kostní denzita u osob po poškození míchy / Bone density in persons after spinal cord injury

Starková, Kateřina January 2021 (has links)
Title: Bone density in people after spinal cord injury Objective: The purpose of this paper is to determine the levels of bone mineral density in people following a spinal cord injury. The levels are measured using a DXA device and the results are subsequently evaluated. Methods: The thesis is composed of eight independent case studies. A non-standardized 14 open and closed question survey was used for quantifying purposes. Answering the questions was a necessary prerequisite for participation in the survey. The measured results of bone density and body composition were used for data analysis, together with the survey, in comparison with other studies. Results: Eight probands (four women and four men) participated in the research. Based on the obtained data, we can state that all probands (n=8) record a decrease in bone mineral density to the level of Osteopenia. Better bone mineral density measurements have not been confirmed in individuals with lower spinal cord lesions. Probands who regularly engaged in sports and daily training before spinal injuries have better results in densitometric measurements. Furthermore, it can be confirmed that probands with a past compression fracture have worse measurement results than probands without a past fracture. However, due to the low number of measured...
47

Cardiovascular Risk Factors, Body Composition, Fitness Levels and Quality of Life in Overweight and Obese 8-17 Year Olds

Martino, Sharon Ann 01 January 2010 (has links)
Purpose. To evaluate the effect of Fit Kids for Life (FKFL), a multi-disciplinary exercise and nutrition intervention, on body composition, fitness levels, cardiovascular risk factors and quality of life among overweight and obese children. Subjects. Forty-eight overweight or obese children (BMI ≥ 85th percentile), ages 8-17, were matched by age and BMI and then randomized into an exercise or wait list control group. The groups were similar at baseline for age, gender and ethnicity (p>.05). Method. The exercise group trained for 60 minutes, two times per week for 10 weeks, then performed a 10 week home program. After 10 weeks of waiting to start, the control group began the 10 week exercise program followed by a 10 week home program. Body composition (dual energy X-ray absorptiometry), fitness measures, quality of life, and cardiovascular risk factors were assessed at baseline, at completion of the 10 week intervention and following the 10 week home program. Results. Body composition improved over time in both groups with significant changes in % body fat and % lean tissue noted between baseline and twenty weeks (p<.05). Fitness measures improved and changes were maintained or increased during the home program phase. Cardiovascular risk factors remained unchanged between groups and across time, with the exception of systolic blood pressure which increased at 10 weeks. The physical domain of the Impact of Quality of Life scale significantly improved following completion of the program (p<.05). Conclusions.Overweight and obese children who completed the 10 week FKFL program improved their body composition and fitness levels. The beneficial changes were sustained or improved following an additional 10 week home program. Recommendations. Overweight and obese children can benefit from a 10 week multidisciplinary exercise and nutrition program. The use of body composition methods and fitness measures may be better indicators of program effectiveness.
48

Benchmarking the Quality of Medical Care of Childhood-Onset SLE

Zaal, Ahmad 04 September 2015 (has links)
No description available.
49

Body Composition and Nutrition Trends in Club Triathlon Members

Appleton, Elizabeth Allyn 24 August 2018 (has links)
No description available.
50

Reliability and Validity of Body Composition and Bone Mineral Density Measurements by DXA

Zack, Melissa Kareen 18 April 2002 (has links)
Dual energy X-ray absorptiometry (DXA) has been well established in both clinical and research settings for measurement of bone mineral density (BMD), and is becoming more widely utilized for assessment of body composition. Reliability and validity are essential factors in both applications of this technique; however, neither have been confirmed for the QDR-4500A DXA at Virginia Tech. Therefore, measurements of the whole body (WB), lumbar spine (LS), total proximal femur (TPF) and total forearm (TF) were made in a group of young-adult males and females at two time-points, 5-7 days apart. Significant differences were not found in BMD (g/cm2) at these body sites with repeated measurements by DXA. Furthermore, measures of percent body fat (%BF), lean body mass (LBM), and fat mass (FM) by DXA were reliable. Validity of %BF by DXA was assessed from comparison to single-frequency bioelectrical impedance analysis (BIA). Significant differences were not found in measures of %BF by DXA and BIA. A second study investigated the reliability and validity of the QDR-4500A DXA in measurements of distal tibia (DT) BMD. Significant differences were not found between repeated measurements. Validity was established by a significant correlation between WB BMD and DT BMD. A third study examined the influence of navel jewelry on the accuracy of LS DXA measurements. Repeated measurements with a spine phantom revealed that both a navel ring and a barbell produced significantly greater measures of LS BMD compared to the spine phantom alone. Manual correction of navel jewelry did not eliminate BMD inaccuracies. Data from these studies confirmed that the QDR-4500A DXA at Virginia Tech was a reliable and valid device in measurement of WB, LS, TPF, TF and DT BMD, as well as %BF, LBM, and FM. In addition, effects of navel jewelry on LS BMD have been recognized. Further studies investigating the reliability and validity of DT BMD measures as well as effects of different types, gauges, and shapes of body jewelry on BMD measures in human subjects are warranted. / Master of Science

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