The purpose of this study was to determine the validity and reliability of four methods of estimating body composition in 331 participants (177 boys, 154 girls) between 12-17 years of age. Percent body fat (%BF) was assessed once on one day using DEXA and twice using the sum of two skinfold (SF) and three bio-electrical impedance analysis (BIA) devices: OMRON hand-to-hand BIA, TANITA 521 foot-to-foot BIA, and TANITA 300A foot-to-foot BIA. The same assessments were repeated on 79 of the participants on a second day. DEXA was used as the criterion method of estimating %BF. The agreement between the estimates of %BF from the sum of two SF and the three BIA devices and DEXA was evaluated using linear regression and Bland-Altman analyses. Although the two analyses generally led to similar conclusions about each of the four prediction methods, the specific interpretations of each analysis varied because of the inherent differences in the analyses. In an attempt to determine if any of the four prediction methods were interchangeable with DEXA, the 95% confidence interval (CI) and prediction interval (PI) around the line-of-best-fit through the data are reported. The results of this study indicate that (a) all of the methods used in this study to estimate %BF were reliable within and between days, (b) the TANITA 300 BIA device performed poorly in both boys and girls and should not be used to assess body composition in children and adolescents, (c) none of the four prediction methods performed well in both boys and girls across the entire range of %BF values of the subjects in this study, (d) the sum of two SF, OMRON and TANITA 521 are acceptable for use in large population-based studies but are not recommended when the accurate assessment of body composition of an individual is critical, in which case (e) criterion methods of assessing body composition should be used.

IMPORTÂNCIA: Mudanças significativas na composição corporal ocorrem com o envelhecimento, havendo aumento progressivo da massa gorda e redução da massa magra. Este quadro está associado à perda de força e mobilidade, ao aumento da morbidade e mortalidade. Nos indivíduos diabéticos tipo 2, esta condição é agravada pelas alterações metabólicas impostas pela doença. OBJETIVO: Comparar as medidas da composição corporal de idosas diabéticas tipo 2 pelo método antropométrico e raio-x de dupla varredura (DEXA), e correlacioná-las à força de preensão da mão. MÉTODOS: Cinqüenta e três voluntárias de 60 a 70 anos, com índice de massa corporal (IMC, kg/m2) de 19 a 44, do Ambulatório de Diabetes do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo, foram avaliadas por: medidas antropométricas, raio-x de dupla varredura e força de preensão da mão. RESULTADOS: a) composição corporal antropometria x DEXA: não houve diferença estatística entre os métodos para as médias do peso, massa corporal magra, massa corporal gorda, porcentagem de gordura total e porcentagem de gordura do braço (P > 0,05). O peso, a massa corporal magra, a massa corporal gorda e o percentual de gordura total foram significativamente correlacionados pelos dois métodos. b) índices corporais x DEXA: o IMC, a circunferência do abdômen, a circunferência muscular do braço, a porcentagem de gordura do braço, a área muscular do braço, a área de gordura do braço, foram significativamente correlacionados, com os respectivos componentes do DEXA (P < 0,05); o índice abdômen/quadril não foi correlacionado ao DEXA. c) comparação entre diversos índices antropométricos: foram significativamente correlacionados (P < 0,05), o IMC e a circunferência do abdômen com a porcentagem de gordura total da antropometria; a circunferência muscular do braço com a massa corporal magra da antropometria. Não foram correlacionados o IAQ com o IMC e com a porcentagem de gordura total da antropometria. d) coeficiente de variação para medidas corporais do DEXA: variou de 0,3% a 9,6% entre os diferentes componentes corporais. e) teste de preensão de mão x variáveis associadas à massa muscular: foi correlacionado a variáveis antropométricas (P < 0,05), e não ao DEXA. CONCLUSÃO: Os dois métodos foram equivalentes para avaliação da composição corporal, sugerindo que a antropometria pode produzir um bom resultado de avaliação nestas idosas diabéticas. A força de preensão da mão teve correlação com a antropometria, mas não com as variáveis do DEXA. Portanto, estas medidas podem contribuir na avaliação do estado nutricional e de saúde em idosas diabéticas tipo 2 e ainda, acompanhar de maneira fácil e barata, a evolução de um tratamento. / IMPORTANCE: A significant change in corporal composition occurs with aging, with increase of fat mass and reduction lean mass. This situation is associated with loss of strength and mobility, and increase of morbidity and mortality. In diabetic type 2 individuals, this condition is aggravated by the metabolic alterations due to the illness. OBJECTIVE: To compare the measures of body composition of elderly women with diabetes type 2 through anthropometry and dual-energy x-ray absorptiometry (DEXA), and correlate findings to handgrip strength. METHODS: Fifty-three volunteers with age ranging from 60 to 70 years old, body mass index (BMI, kg/m2) 19 to 44 selected from the Diabetes Ambulatory of the Clinical Hospital of the School of Medicine of Ribeirão Preto, University of São paulo, were evaluated by: anthropometry, DEXA and handgrip strength. RESULTS: a) anthropometry x DEXA in body composition analyses: there were no statistical differences between the average of the weight, lean body mass, fat body mass, percentage of body fatness and percentage of fatness of the arm (P > 0,05). The weight, lean body mass, body fat mass and percentage of body fatness were significantly correlated. b) body indices x DEXA: BMI, abdomen circumference, muscle arm circumference, percentage of fatness of the arm, muscular area of the arm and area of fatness of the arm were significantly correlated with the respective components of the DEXA (P < 0,05); the waist/hip ratio (WHR) was not correlated with DEXA (P < 0,05): c) comparison between athropometric indices: the following variables were significantly correlated (P < 0,05): BMI and circumference of the abdomen with the percentage of body fatness of the anthropometry; muscular circumference of the arm with the lean body mass of the anthropometry. The WHR was not correlated with the IMC and with the percentage of body fatness of the anthropometry. d) coefficient of variation for corporal measures of the DEXA: varied from 0,3% to 9,6%. Handgrip strength was correlated to anthropometrics variables (P <0,05), but not with DEXA. CONCLUSIONS: The two approaches were equivalent for the assessment of body composition, suggesting that anthropometry can produce a good result in the evaluation of this population. The handgrip strength was correlated with anthropometry, but not with the variables of DEXA. Therefore, these measures can contribute to the assessment of the nutritional status in elderly diabetic type 2.

O objetivo deste estudo foi investigar os efeitos de dois programas de exercício físico na composição corporal de adolescentes obesos submetidos ao tratamento multidisciplinar e verificar qual programa de exercício físico foi mais eficaz para reduzir a gordura corporal e aumentar a massa magra nos dois gêneros. Foram selecionados 60 adolescentes obesos, sendo 36 do gênero feminino e 20 do gênero masculino, com índice de massa corporal (IMC) igual ou acima do percentil 95, na faixa etária de 15 a 19 anos. A amostra foi dividida em dois grupos: grupo aeróbio e grupo força. Os adolescentes foram submetidos a avaliação antropométrica, clínica, de composição corporal e da aptidão física. Além disso, receberam orientação para mudança no estilo de vida e consultas nutricional, psicológica e médica. As sessões de exercícios físicos ocorriam três vezes por semana, em dias alternados, com duração de 60 minutos. A composição corporal foi avaliada pela absortometria de duplo feixe de energia (DEXA) nos momentos inicial e final do estudo. A duração da intervenção foi de 12 semanas. Os principais resultados demonstraram que os grupos aeróbio e força apresentaram redução significante na massa corporal e no IMC e, quando analisados por gênero, verificou-se que no gênero feminino não houve diferença significante, enquanto que o gênero masculino apresentou redução significante no grupo força. Na massa magra observou-se aumento significante apenas no grupo força, tanto sem distinção de gênero quanto diferenciando por gênero. Os dois grupos apresentaram redução significante na massa de gordura, no percentual de gordura corporal total e no percentual de gordura de tronco tanto sem distinção de gênero quanto diferenciando por gênero. Verificou-se correlação positiva na redução do percentual de gordura de tronco com o percentual de gordura periférica. Concluiu-se que o treinamento de força foi mais efetivo para aumentar a massa magra e, levando em consideração a maior redução na variação percentual entre os momentos inicial e final, o grupo aeróbio foi mais efetivo para reduzir a massa de gordura e o grupo força para reduzir o percentual de gordura corporal total dos adolescentes obesos submetidos ao tratamento multidisciplinar de doze semanas. / The objective of this study was to investigate the effects of two physical exercises programs applied to obese adolescents submitted to multidisciplinary treatment in order to establish which program is more effective to reduce body fat and increase lean mass in both gender. 60 obese adolescents aged between 15 and 19 years were selected, comprising 36 girls and 20 boys with body mass index (BMI) equal to or above the 95th percentile. The sample was divided into two groups: aerobic and strength. The adolescents were submitted to anthropometric, clinical, body composition and physical fitness evaluation. In addition, they were oriented to change their lifestyle and received nutritional, psychological and medical assistance. 60 minute physical exercise sessions occurred three times a week on alternate days. Body composition was evaluated by dual-energy X-ray absorptiometry (DEXA) twice: at the beginning and at the end of the program. The program lasted for 12 weeks. The main results show that both aerobic and the strength groups had significant reduction of body weight and of the BMI, and when analyzed by gender, no significant difference was observed among girls of both groups, while boys of the strength groups had a significant reduction. Lean mass increased significantly in the strength group only. Participants of both physical training groups had significant reduction of their fat mass, percentage of total body fat and percentage of trunk fat. A positive correlation was established between the reduction in the percentage of trunk fat and the percentage of peripheral fat. In conclusion, strength training was more effective to increase lean mass. Considering the greater reduction in the percentage variation between the beginning and the end of the period, aerobic training was more effective to reduce the fat mass while strength training was more effective to reduce the percentage of total body fat of obese adolescents submitted to multidisciplinary treatment during twelve weeks.

O objetivo deste estudo foi investigar os efeitos de dois programas de exercício físico na composição corporal de adolescentes obesos submetidos ao tratamento multidisciplinar e verificar qual programa de exercício físico foi mais eficaz para reduzir a gordura corporal e aumentar a massa magra nos dois gêneros. Foram selecionados 60 adolescentes obesos, sendo 36 do gênero feminino e 20 do gênero masculino, com índice de massa corporal (IMC) igual ou acima do percentil 95, na faixa etária de 15 a 19 anos. A amostra foi dividida em dois grupos: grupo aeróbio e grupo força. Os adolescentes foram submetidos a avaliação antropométrica, clínica, de composição corporal e da aptidão física. Além disso, receberam orientação para mudança no estilo de vida e consultas nutricional, psicológica e médica. As sessões de exercícios físicos ocorriam três vezes por semana, em dias alternados, com duração de 60 minutos. A composição corporal foi avaliada pela absortometria de duplo feixe de energia (DEXA) nos momentos inicial e final do estudo. A duração da intervenção foi de 12 semanas. Os principais resultados demonstraram que os grupos aeróbio e força apresentaram redução significante na massa corporal e no IMC e, quando analisados por gênero, verificou-se que no gênero feminino não houve diferença significante, enquanto que o gênero masculino apresentou redução significante no grupo força. Na massa magra observou-se aumento significante apenas no grupo força, tanto sem distinção de gênero quanto diferenciando por gênero. Os dois grupos apresentaram redução significante na massa de gordura, no percentual de gordura corporal total e no percentual de gordura de tronco tanto sem distinção de gênero quanto diferenciando por gênero. Verificou-se correlação positiva na redução do percentual de gordura de tronco com o percentual de gordura periférica. Concluiu-se que o treinamento de força foi mais efetivo para aumentar a massa magra e, levando em consideração a maior redução na variação percentual entre os momentos inicial e final, o grupo aeróbio foi mais efetivo para reduzir a massa de gordura e o grupo força para reduzir o percentual de gordura corporal total dos adolescentes obesos submetidos ao tratamento multidisciplinar de doze semanas. / The objective of this study was to investigate the effects of two physical exercises programs applied to obese adolescents submitted to multidisciplinary treatment in order to establish which program is more effective to reduce body fat and increase lean mass in both gender. 60 obese adolescents aged between 15 and 19 years were selected, comprising 36 girls and 20 boys with body mass index (BMI) equal to or above the 95th percentile. The sample was divided into two groups: aerobic and strength. The adolescents were submitted to anthropometric, clinical, body composition and physical fitness evaluation. In addition, they were oriented to change their lifestyle and received nutritional, psychological and medical assistance. 60 minute physical exercise sessions occurred three times a week on alternate days. Body composition was evaluated by dual-energy X-ray absorptiometry (DEXA) twice: at the beginning and at the end of the program. The program lasted for 12 weeks. The main results show that both aerobic and the strength groups had significant reduction of body weight and of the BMI, and when analyzed by gender, no significant difference was observed among girls of both groups, while boys of the strength groups had a significant reduction. Lean mass increased significantly in the strength group only. Participants of both physical training groups had significant reduction of their fat mass, percentage of total body fat and percentage of trunk fat. A positive correlation was established between the reduction in the percentage of trunk fat and the percentage of peripheral fat. In conclusion, strength training was more effective to increase lean mass. Considering the greater reduction in the percentage variation between the beginning and the end of the period, aerobic training was more effective to reduce the fat mass while strength training was more effective to reduce the percentage of total body fat of obese adolescents submitted to multidisciplinary treatment during twelve weeks.

IMPORTÂNCIA: Mudanças significativas na composição corporal ocorrem com o envelhecimento, havendo aumento progressivo da massa gorda e redução da massa magra. Este quadro está associado à perda de força e mobilidade, ao aumento da morbidade e mortalidade. Nos indivíduos diabéticos tipo 2, esta condição é agravada pelas alterações metabólicas impostas pela doença. OBJETIVO: Comparar as medidas da composição corporal de idosas diabéticas tipo 2 pelo método antropométrico e raio-x de dupla varredura (DEXA), e correlacioná-las à força de preensão da mão. MÉTODOS: Cinqüenta e três voluntárias de 60 a 70 anos, com índice de massa corporal (IMC, kg/m2) de 19 a 44, do Ambulatório de Diabetes do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo, foram avaliadas por: medidas antropométricas, raio-x de dupla varredura e força de preensão da mão. RESULTADOS: a) composição corporal antropometria x DEXA: não houve diferença estatística entre os métodos para as médias do peso, massa corporal magra, massa corporal gorda, porcentagem de gordura total e porcentagem de gordura do braço (P > 0,05). O peso, a massa corporal magra, a massa corporal gorda e o percentual de gordura total foram significativamente correlacionados pelos dois métodos. b) índices corporais x DEXA: o IMC, a circunferência do abdômen, a circunferência muscular do braço, a porcentagem de gordura do braço, a área muscular do braço, a área de gordura do braço, foram significativamente correlacionados, com os respectivos componentes do DEXA (P < 0,05); o índice abdômen/quadril não foi correlacionado ao DEXA. c) comparação entre diversos índices antropométricos: foram significativamente correlacionados (P < 0,05), o IMC e a circunferência do abdômen com a porcentagem de gordura total da antropometria; a circunferência muscular do braço com a massa corporal magra da antropometria. Não foram correlacionados o IAQ com o IMC e com a porcentagem de gordura total da antropometria. d) coeficiente de variação para medidas corporais do DEXA: variou de 0,3% a 9,6% entre os diferentes componentes corporais. e) teste de preensão de mão x variáveis associadas à massa muscular: foi correlacionado a variáveis antropométricas (P < 0,05), e não ao DEXA. CONCLUSÃO: Os dois métodos foram equivalentes para avaliação da composição corporal, sugerindo que a antropometria pode produzir um bom resultado de avaliação nestas idosas diabéticas. A força de preensão da mão teve correlação com a antropometria, mas não com as variáveis do DEXA. Portanto, estas medidas podem contribuir na avaliação do estado nutricional e de saúde em idosas diabéticas tipo 2 e ainda, acompanhar de maneira fácil e barata, a evolução de um tratamento. / IMPORTANCE: A significant change in corporal composition occurs with aging, with increase of fat mass and reduction lean mass. This situation is associated with loss of strength and mobility, and increase of morbidity and mortality. In diabetic type 2 individuals, this condition is aggravated by the metabolic alterations due to the illness. OBJECTIVE: To compare the measures of body composition of elderly women with diabetes type 2 through anthropometry and dual-energy x-ray absorptiometry (DEXA), and correlate findings to handgrip strength. METHODS: Fifty-three volunteers with age ranging from 60 to 70 years old, body mass index (BMI, kg/m2) 19 to 44 selected from the Diabetes Ambulatory of the Clinical Hospital of the School of Medicine of Ribeirão Preto, University of São paulo, were evaluated by: anthropometry, DEXA and handgrip strength. RESULTS: a) anthropometry x DEXA in body composition analyses: there were no statistical differences between the average of the weight, lean body mass, fat body mass, percentage of body fatness and percentage of fatness of the arm (P > 0,05). The weight, lean body mass, body fat mass and percentage of body fatness were significantly correlated. b) body indices x DEXA: BMI, abdomen circumference, muscle arm circumference, percentage of fatness of the arm, muscular area of the arm and area of fatness of the arm were significantly correlated with the respective components of the DEXA (P < 0,05); the waist/hip ratio (WHR) was not correlated with DEXA (P < 0,05): c) comparison between athropometric indices: the following variables were significantly correlated (P < 0,05): BMI and circumference of the abdomen with the percentage of body fatness of the anthropometry; muscular circumference of the arm with the lean body mass of the anthropometry. The WHR was not correlated with the IMC and with the percentage of body fatness of the anthropometry. d) coefficient of variation for corporal measures of the DEXA: varied from 0,3% to 9,6%. Handgrip strength was correlated to anthropometrics variables (P <0,05), but not with DEXA. CONCLUSIONS: The two approaches were equivalent for the assessment of body composition, suggesting that anthropometry can produce a good result in the evaluation of this population. The handgrip strength was correlated with anthropometry, but not with the variables of DEXA. Therefore, these measures can contribute to the assessment of the nutritional status in elderly diabetic type 2.

Die Dualenergie-Röntgenabsorptiometrie (DEXA, Dual Energy X-Ray Absorptiometry) ist ein in der Humanmedizin und Teilen der Veterinärmedizin etabliertes Verfahren zur Untersuchung der Knochenmineraldichte, des Knochenmineralgehaltes und der Körperzusammensetzung. Für das Pferd existieren bisher lediglich vereinzelte Studien zur Untersuchung des Knochens mittels der DEXA-Methode, welche allesamt auf nur sehr geringen Versuchstierzahlen beruhen. Ziel dieser Arbeit war es daher die DEXA-Methode für die Untersuchung am Pferd zu validieren. Hierfür wurden die Röhrbeine von 103 Schlachtpferden mittels des Densitometers PIXI LUNAR®, welches aus der Humanmedizin stammt und dort zur Untersuchung des Unterarmes dient, untersucht und die densitometrische Knochenmineraldichte (BMD) und der densitometrische Knochenmineralstoffgehalt (BMC) ermittelt. Als Messpunkt wurde standar-disiert die Mitte zwischen der Basis und dem Caput des Os metacarpale tertium bzw. des Os metatarsale tertium gewählt. Im Anschluss an die densitometrische Messung wurde als Referenzverfahren eine chemische Analyse durchgeführt, in welcher der Rohasche- sowie der Calcium- Phosphor- und Magnesiumgehalt der Röhrbeine bestimmt wurden. Die Angabe der Ergebnisse erfolgt als Median und 25-/75-Perzentil. Der Rohaschegehalt lag im Mittel über alle Röhrbeine bei 698 (69,1 - 70,3) g/kg TS. Für die Mineralstoffe konnten folgende Gehalte ermittelt werden: Calcium 265 (259 - 272) g/kg TS, Phosphor 123 (121 - 126) g/kg TS und Magnesium 2,40 (2,19 - 2,66) g/kg TS. Das Calcium-Phosphor-Verhältnis lag in einem Bereich von 2,14 - 2,18. Die Resultate der DEXA-Methode werden neben dem Mineralstoffgehalt auch vom Knochenumfang beeinflusst, so dass die folgenden Ergebnisse für die Vorder- und Hintergliedmaße (VGM, HGM) separat dargestellt werden: BMD: VGM 3,22 (2,80 - 3,65) g/cm², HGM 4,21 (3,76 - 4,65) g/cm²; BMC: VGM 26,5 (22,8 - 30,1) g, HGM 32,9 (29,0 - 36,3) g. Im Rahmen dieser Arbeit wurden Reproduzierbarkeitsstudien durchgeführt, bei denen für die BMD bei der Reproduzierbarkeit ohne Reposition Abweichungen in einem Bereich von 1,06 - 1,85 % und mit Reposition in einem Bereich von 3,51 - 4,48 % gefunden wurden. Für die BMC lag die Abweichung für die Reproduzierbarkeit ohne Reposition in einem Bereich von 1,28 - 2,79 % und mit Reposition schwankte sie zwischen 3,38 und 3,94 %. Um für den Einsatz der DEXA-Methode bei Verlaufsuntersuchungen den Einfluss der exakten Messlokalisation zu eruieren, wurden Messungen in einem Abstand von ein, zwei und drei Zentimetern proximal und distal des ursprünglichen Messpunktes vorgenommen. Die Ergeb-nisse dieser Studie wichen für die BMD um 3,53 - 9,16 % und für den BMC um 4,21 - 12,5 % von den Ergebnissen des zentralen Messpunktes in der Mitte der Diaphyse ab. Diese Abweichung liegt innerhalb der 25-/75-Perzentile der Messergebnisse des zentralen Messpunktes. Die Ergebnisse der vorliegenden Studie führen zu dem Schluss, dass es möglich ist die Knochenmineraldichte und den Knochenmineralgehalt des Röhrbeines des Pferdes mittels der DEXA-Methode zu ermitteln. Die guten Ergebnisse der Reproduzierbarkeitsstudien und der Abstandsmessungen vom zentralen Messpunkt legen die Durchführbarkeit am stehenden, sedierten Pferd nahe. Bei der DEXA-Methode wird ein Knochenabschnitt mit einem sehr hohen Kortikalisanteil erfasst, welcher auf Einflüsse, wie beispielsweise Training oder Ruhigstellung mit einer Veränderung des Knochenumfanges bei gleichbleibenden Mineralstoffkonzentrationen reagiert. Diese Eigenschaft führt zu einem geringen Zusammenhang zwischen der DEXA-Methode und der chemischen Analyse, so dass sich die Ergebnisse der beiden Messverfahren zwar gut in den Kontext anderer Studien einfügen, der direkte Vergleich der beiden Methoden jedoch nicht möglich ist. / DXA (dual energy X-ray absorptiometry) is an established method for the measurement of bone mineral density (BMD), bone mineral content (BMC) and whole body composition in human and partly in veterinary medicine. However, there are only a small number of studies that examine the bone in horses using DXA. All these studies are based on small samples. Therefore, the objective of this study was to validate the use of DXA for the measurement of BMD and BMC in the horse. In total the cannons of 103 horses were scanned ex vivo, using the PIXI LUNAR® densitometer. In human medicine this densitometer is used for the exami-nation of the forearm. The measuring point was the exact middle between basis and caput of the third metacarpal/metatarsal bone. In a second step the DXA measurements were complemented with a chemical analysis, analyzing the ash content, calcium, phosphorus and magnesium content of the bones. The results are presented as median and 25-/75-percentile. The average ash content of the cannon bones was 698 (691 - 703) g/kg DM. The average mineral content was measured in the following order: calcium 265 (259 - 272) g/kg DM, phosphorus 123 (121 - 126) g/kg DM und magnesium 2.44 (2.19 - 2.66) g/kg DM. The ratio of calcium to phosphorus ranged from 2.14 to 2.18. The DXA results are influenced not only by the bone´s mineral content, but also by its diameter. Because of this the results are separated into the results of the forelimb (fl) and the hindlimb (hl) which generates the following results: BMD: fl 3.22 (2.80 - 3.65) g/cm², hl 4.21 (3.76 - 4.65) g/cm²; BMC: fl 26.5 (22.8 - 30.1) g, hl 32.9 (29.0 - 36.3) g. Several robustness checks of the measurements were conducted. For the BMD measurements, the range of measurements diverged by 3.51-4.48 % for measurements with limb repositioning, and by 1.06-1.85 % for measurements without limb repositioning. For the BMC measurements, the range of measurements diverged by 3.38-3.94 % for measurements with limb repositioning, and by 1.28-2.79 for measurements without limb repositioning. To determine the importance of the exact bone position for follow-up investigations, measurements in a distance of one, two and three centimeters proximal and distal of the original measuring point were performed. The results of these measurements deviated from the result of the central measuring point at the centre of the diaphysis in a range of 3.53 – 9.16 % for BMD and a range of 4.21 – 12.5 % for BMC. This variation falls within the percentiles of the central measuring point. Overall, the results of this study indicate that DXA is useable for determining BMD and BMC at the third metacarpal/metatarsal bone of the horse. The high reproducibility of the results and the distance measurements suggest that DXA is suitable for measurements at the standing, tranquilized horse. However, the cannon bone is a bone with a high content of cortical bone. This means that the diameter of the bone changes as a result of training or immobilization, while the BMD and BMC remain unchanged by such influence. This leads to a weak correlation between the results from the DXA and chemical analyses. Thus, while these two types of analysis fit well into the context of prior studies, a direct comparison between these measurements is not possible.

Die Dualenergie-Röntgenabsorptiometrie (DEXA, Dual Energy X-Ray Absorptiometry) ist ein in der Humanmedizin und Teilen der Veterinärmedizin etabliertes Verfahren zur Untersuchung der Knochenmineraldichte, des Knochenmineralgehaltes und der Körperzusammensetzung. Für das Pferd existieren bisher lediglich vereinzelte Studien zur Untersuchung des Knochens mittels der DEXA-Methode, welche allesamt auf nur sehr geringen Versuchstierzahlen beruhen. Ziel dieser Arbeit war es daher die DEXA-Methode für die Untersuchung am Pferd zu validieren. Hierfür wurden die Röhrbeine von 103 Schlachtpferden mittels des Densitometers PIXI LUNAR®, welches aus der Humanmedizin stammt und dort zur Untersuchung des Unterarmes dient, untersucht und die densitometrische Knochenmineraldichte (BMD) und der densitometrische Knochenmineralstoffgehalt (BMC) ermittelt. Als Messpunkt wurde standar-disiert die Mitte zwischen der Basis und dem Caput des Os metacarpale tertium bzw. des Os metatarsale tertium gewählt. Im Anschluss an die densitometrische Messung wurde als Referenzverfahren eine chemische Analyse durchgeführt, in welcher der Rohasche- sowie der Calcium- Phosphor- und Magnesiumgehalt der Röhrbeine bestimmt wurden. Die Angabe der Ergebnisse erfolgt als Median und 25-/75-Perzentil. Der Rohaschegehalt lag im Mittel über alle Röhrbeine bei 698 (69,1 - 70,3) g/kg TS. Für die Mineralstoffe konnten folgende Gehalte ermittelt werden: Calcium 265 (259 - 272) g/kg TS, Phosphor 123 (121 - 126) g/kg TS und Magnesium 2,40 (2,19 - 2,66) g/kg TS. Das Calcium-Phosphor-Verhältnis lag in einem Bereich von 2,14 - 2,18. Die Resultate der DEXA-Methode werden neben dem Mineralstoffgehalt auch vom Knochenumfang beeinflusst, so dass die folgenden Ergebnisse für die Vorder- und Hintergliedmaße (VGM, HGM) separat dargestellt werden: BMD: VGM 3,22 (2,80 - 3,65) g/cm², HGM 4,21 (3,76 - 4,65) g/cm²; BMC: VGM 26,5 (22,8 - 30,1) g, HGM 32,9 (29,0 - 36,3) g. Im Rahmen dieser Arbeit wurden Reproduzierbarkeitsstudien durchgeführt, bei denen für die BMD bei der Reproduzierbarkeit ohne Reposition Abweichungen in einem Bereich von 1,06 - 1,85 % und mit Reposition in einem Bereich von 3,51 - 4,48 % gefunden wurden. Für die BMC lag die Abweichung für die Reproduzierbarkeit ohne Reposition in einem Bereich von 1,28 - 2,79 % und mit Reposition schwankte sie zwischen 3,38 und 3,94 %. Um für den Einsatz der DEXA-Methode bei Verlaufsuntersuchungen den Einfluss der exakten Messlokalisation zu eruieren, wurden Messungen in einem Abstand von ein, zwei und drei Zentimetern proximal und distal des ursprünglichen Messpunktes vorgenommen. Die Ergeb-nisse dieser Studie wichen für die BMD um 3,53 - 9,16 % und für den BMC um 4,21 - 12,5 % von den Ergebnissen des zentralen Messpunktes in der Mitte der Diaphyse ab. Diese Abweichung liegt innerhalb der 25-/75-Perzentile der Messergebnisse des zentralen Messpunktes. Die Ergebnisse der vorliegenden Studie führen zu dem Schluss, dass es möglich ist die Knochenmineraldichte und den Knochenmineralgehalt des Röhrbeines des Pferdes mittels der DEXA-Methode zu ermitteln. Die guten Ergebnisse der Reproduzierbarkeitsstudien und der Abstandsmessungen vom zentralen Messpunkt legen die Durchführbarkeit am stehenden, sedierten Pferd nahe. Bei der DEXA-Methode wird ein Knochenabschnitt mit einem sehr hohen Kortikalisanteil erfasst, welcher auf Einflüsse, wie beispielsweise Training oder Ruhigstellung mit einer Veränderung des Knochenumfanges bei gleichbleibenden Mineralstoffkonzentrationen reagiert. Diese Eigenschaft führt zu einem geringen Zusammenhang zwischen der DEXA-Methode und der chemischen Analyse, so dass sich die Ergebnisse der beiden Messverfahren zwar gut in den Kontext anderer Studien einfügen, der direkte Vergleich der beiden Methoden jedoch nicht möglich ist.:1 Einleitung 2 Literaturübersicht 2.1 Das Röhrbein des Pferdes 2.1.1 Knochenaufbau 2.1.2 Knochenzusammensetzung 2.1.3 Knochenbildung 2.1.4 Knochenumbau 2.1.5 Einfluss des Alters auf den Knochen 2.1.6 Unterschiede zwischen und innerhalb der Gliedmaßen 2.1.7 Einfluss des Geschlechtes auf den Knochen 2.1.8 Einfluss von Haltung auf den Knochen 2.1.9 Einfluss von Belastung/Training auf den Knochen 2.1.10 Einfluss der Ernährung auf den Knochen 2.2 DEXA-Methode 2.3 Einsatz der DEXA-Methode in der Humanmedizin 2.4 Nicht-medizinische Einsatzgebiete der DEXA-Methode 2.5 Einsatz der DEXA-Methode in der Veterinärmedizin 2.5.1 Anwendung der DEXA-Methode bei Maus und Ratte 2.5.2 Anwendung der DEXA-Methode beim Geflügel 2.5.3 Anwendung der DEXA-Methode bei Hund und Katze 2.5.4 Anwendung der DEXA-Methode beim Schwein 2.5.5 Anwendung der DEXA-Methode beim Rind 2.6 Einsatz der DEXA-Methode beim Pferd 2.7 Weitere Methoden der Osteodensitometrie 2.7.1 In-vivo-Methoden 2.7.2 In-vitro-Methoden 3 Tiere, Material und Methoden 3.1 Tiere und Material 3.1.1 Tiere 3.1.2 Probenentnahme und –aufbewahrung 3.2 Methoden 3.2.1 Physikalische Grundlagen der DEXA-Methode 3.2.2 Dichtebestimmung mittels DEXA 3.2.3 Chemische Knochenanalyse 3.3 Statistische Auswertung 3.4 Darstellung der Ergebnisse 4 Ergebnisse 4.1 Ergebnisse der chemischen Analyse 4.1.1 volumetrische Knochendichte, Rohasche-, Calcium-, Magnesium- und Phoshorgehalte im Gliedmaßenvergleich (Angabe in Median und 25-/75-Perzentil) 4.1.2 Einfluss des Alters auf den Rohasche-, Calcium-, Magnesium- und Phosphorgehalt im Röhrbein (Angabe in Median und 25-/75-Perzentil) 4.1.3 Einfluss der Rasse auf den Rohasche-, Calcium-, Magnesium- und Phosphorgehalt im Röhrbein (Angabe in Median und 25-/75-Perzentil) 4.1.4 Einfluss des Geschlechtes auf den Rohasche-, Calcium-, Magnesium- und Phosphorgehalt im Röhrbein (Angabe in Median und 25-/75-Perzentil) 4.2 Ergebnisse der DEXA-Methode 4.2.1 Abweichung vom zentralen Messpunkt 4.2.2 Reproduzierbarkeit 4.3 Vergleich der Densitometrie mit der chemischen Analyse 5 Diskussion 5.1 Kritik der Methoden 5.1.1 Versuchspferde 5.1.2 DEXA-Methode 5.2 Diskussion der Ergebnisse 5.3 Schlussbetrachtung 6 Zusammenfassung 7 Summary 8 Literaturverzeichnis 9 Tabellenanhang 10 Danksagung / DXA (dual energy X-ray absorptiometry) is an established method for the measurement of bone mineral density (BMD), bone mineral content (BMC) and whole body composition in human and partly in veterinary medicine. However, there are only a small number of studies that examine the bone in horses using DXA. All these studies are based on small samples. Therefore, the objective of this study was to validate the use of DXA for the measurement of BMD and BMC in the horse. In total the cannons of 103 horses were scanned ex vivo, using the PIXI LUNAR® densitometer. In human medicine this densitometer is used for the exami-nation of the forearm. The measuring point was the exact middle between basis and caput of the third metacarpal/metatarsal bone. In a second step the DXA measurements were complemented with a chemical analysis, analyzing the ash content, calcium, phosphorus and magnesium content of the bones. The results are presented as median and 25-/75-percentile. The average ash content of the cannon bones was 698 (691 - 703) g/kg DM. The average mineral content was measured in the following order: calcium 265 (259 - 272) g/kg DM, phosphorus 123 (121 - 126) g/kg DM und magnesium 2.44 (2.19 - 2.66) g/kg DM. The ratio of calcium to phosphorus ranged from 2.14 to 2.18. The DXA results are influenced not only by the bone´s mineral content, but also by its diameter. Because of this the results are separated into the results of the forelimb (fl) and the hindlimb (hl) which generates the following results: BMD: fl 3.22 (2.80 - 3.65) g/cm², hl 4.21 (3.76 - 4.65) g/cm²; BMC: fl 26.5 (22.8 - 30.1) g, hl 32.9 (29.0 - 36.3) g. Several robustness checks of the measurements were conducted. For the BMD measurements, the range of measurements diverged by 3.51-4.48 % for measurements with limb repositioning, and by 1.06-1.85 % for measurements without limb repositioning. For the BMC measurements, the range of measurements diverged by 3.38-3.94 % for measurements with limb repositioning, and by 1.28-2.79 for measurements without limb repositioning. To determine the importance of the exact bone position for follow-up investigations, measurements in a distance of one, two and three centimeters proximal and distal of the original measuring point were performed. The results of these measurements deviated from the result of the central measuring point at the centre of the diaphysis in a range of 3.53 – 9.16 % for BMD and a range of 4.21 – 12.5 % for BMC. This variation falls within the percentiles of the central measuring point. Overall, the results of this study indicate that DXA is useable for determining BMD and BMC at the third metacarpal/metatarsal bone of the horse. The high reproducibility of the results and the distance measurements suggest that DXA is suitable for measurements at the standing, tranquilized horse. However, the cannon bone is a bone with a high content of cortical bone. This means that the diameter of the bone changes as a result of training or immobilization, while the BMD and BMC remain unchanged by such influence. This leads to a weak correlation between the results from the DXA and chemical analyses. Thus, while these two types of analysis fit well into the context of prior studies, a direct comparison between these measurements is not possible.:1 Einleitung 2 Literaturübersicht 2.1 Das Röhrbein des Pferdes 2.1.1 Knochenaufbau 2.1.2 Knochenzusammensetzung 2.1.3 Knochenbildung 2.1.4 Knochenumbau 2.1.5 Einfluss des Alters auf den Knochen 2.1.6 Unterschiede zwischen und innerhalb der Gliedmaßen 2.1.7 Einfluss des Geschlechtes auf den Knochen 2.1.8 Einfluss von Haltung auf den Knochen 2.1.9 Einfluss von Belastung/Training auf den Knochen 2.1.10 Einfluss der Ernährung auf den Knochen 2.2 DEXA-Methode 2.3 Einsatz der DEXA-Methode in der Humanmedizin 2.4 Nicht-medizinische Einsatzgebiete der DEXA-Methode 2.5 Einsatz der DEXA-Methode in der Veterinärmedizin 2.5.1 Anwendung der DEXA-Methode bei Maus und Ratte 2.5.2 Anwendung der DEXA-Methode beim Geflügel 2.5.3 Anwendung der DEXA-Methode bei Hund und Katze 2.5.4 Anwendung der DEXA-Methode beim Schwein 2.5.5 Anwendung der DEXA-Methode beim Rind 2.6 Einsatz der DEXA-Methode beim Pferd 2.7 Weitere Methoden der Osteodensitometrie 2.7.1 In-vivo-Methoden 2.7.2 In-vitro-Methoden 3 Tiere, Material und Methoden 3.1 Tiere und Material 3.1.1 Tiere 3.1.2 Probenentnahme und –aufbewahrung 3.2 Methoden 3.2.1 Physikalische Grundlagen der DEXA-Methode 3.2.2 Dichtebestimmung mittels DEXA 3.2.3 Chemische Knochenanalyse 3.3 Statistische Auswertung 3.4 Darstellung der Ergebnisse 4 Ergebnisse 4.1 Ergebnisse der chemischen Analyse 4.1.1 volumetrische Knochendichte, Rohasche-, Calcium-, Magnesium- und Phoshorgehalte im Gliedmaßenvergleich (Angabe in Median und 25-/75-Perzentil) 4.1.2 Einfluss des Alters auf den Rohasche-, Calcium-, Magnesium- und Phosphorgehalt im Röhrbein (Angabe in Median und 25-/75-Perzentil) 4.1.3 Einfluss der Rasse auf den Rohasche-, Calcium-, Magnesium- und Phosphorgehalt im Röhrbein (Angabe in Median und 25-/75-Perzentil) 4.1.4 Einfluss des Geschlechtes auf den Rohasche-, Calcium-, Magnesium- und Phosphorgehalt im Röhrbein (Angabe in Median und 25-/75-Perzentil) 4.2 Ergebnisse der DEXA-Methode 4.2.1 Abweichung vom zentralen Messpunkt 4.2.2 Reproduzierbarkeit 4.3 Vergleich der Densitometrie mit der chemischen Analyse 5 Diskussion 5.1 Kritik der Methoden 5.1.1 Versuchspferde 5.1.2 DEXA-Methode 5.2 Diskussion der Ergebnisse 5.3 Schlussbetrachtung 6 Zusammenfassung 7 Summary 8 Literaturverzeichnis 9 Tabellenanhang 10 Danksagung

Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biological and Medical Sciences Student: Barbora Malinová Supervisor of Diploma thesis: PharmDr. Miroslav Kovařík Ph.D. Title of diploma thesis: Densitometric determination of body composition in patients with chronic obstructive pulmonary disease Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in 2004 according to the WHO Global Burden of Disease Project and its morbidity and mortality worldwide is still increasing. Besides the lung function impairment, there are often described changes in body composition in COPD patients e.g. the skeletal muscle protein loss. The main aim of the study was determining the body composition by DEXA in patients diagnosed with COPD and comparing them with physiological values or studies dealing with this issue. On each patient was performed one examination, patients were coming after twelve-hour fasting. Average age was 66 ± 8 years. The amount of fat-free mass was not reduced. There was not therefore a loss of muscle tissue due to COPD. When evaluating total fat, we find that men have more fat than normal levels. This is also indicated by BMI that has been in the majority in the range of overweight and obesity. We did not confirm the link between COPD...

The purpose of this thesis project was to determine the precision error of dual-energy x-ray absorptiometry (DXA) derived bone mineral density (BMD) at regions of interest (ROI) that are clinically relevant to persons with spinal cord injury (SCI), and secondarily to compare the precision error between a group of persons who are able-bodied and a group of persons with chronic SCI. Over 2 visits, four DXA scans at sites of the distal femur, proximal tibia, and calcaneus were completed in 10 persons who are able-bodied and 10 persons with chronic SCI. Using forearm sub region analysis, we measured the BMD and calculated the precision error for a total of 7 ROI at these sites. Despite a lower BMD at every ROI in the group of persons with chronic SCI compared to the group of persons who are able-bodied (range, 33 – 56%), the relative precision error was similar between groups. However, there was a trend for greater precision error in persons with SCI at a whole bone ROI of the distal femur (RMS-CV of 8.40% vs. 5.63%) and a ROI of the posterior calcaneus body (RMS-CV of 3.52% vs. 1.78%) when compared to persons who are able-bodied. Further, the ROI of the posterior calcaneus body appeared to have a lower precision error in persons who are able-bodied (RMS-CV, 1.78%) than the distal femur and proximal tibia (RMS-CV range 3.26 – 5.63%). The results from this study suggest that the precision error of DXA derived BMD is similar between persons with SCI and persons who are able-bodied, and that the posterior calcaneus body may be a more precise site than the distal femur and proximal tibia.

The purpose of this study was to investigate differences among the percent body fat (%BF) values of Turkish sedentary male and female university students measured by dual-energy x-ray absorptiometry (DEXA), skinfold (SKF), ultrasound (US) and hand to hand bioelectrical impedance analysis (BIA). Two hundred eight Turkish university students (one hundred four males and one hundred four females) aged between 18 to 26 years old participants participated in this study voluntarily. %BF assessment was performed by the SKF, US, BIA and DEXA methods. Differences among DEXA, SKF, US and BIA were examined by applying a series of paired-t test. Multiple regression analyses were conducted to developed regression equations to predict %BF from SKF and US measurements. Results demonstrated that there were significant differences between DEXA and SKF, US, and BIA measurements for males and females. The mean %BF derived from DEXA was significantly (p&lt / .001) greater than those of SKF, US and BIA for males and females. Multiple regression analyses showed that SKF and US measurement of subcutaneous fat at three-sites gave the best prediction to %BF for male and female separately. The multiple correlations using three sites simultaneously for men and women were r=0.92, SEE=2.4 and r=0.91, SEE=2.8 for SKF and r=0.93, SEE=2.3 and r=0.90, SEE=3.0 for US, respectively. In summary, with the new regression equation US appears to be a reliable, portable, and non-invasive tool which can be used by any field investigator on obese or thin individuals. Finally, new regression equations developed do not seem to be superior to those reported using calipers.