Introduktion: Benskörhet är vanligt förekommande och är ett tillstånd där skelettets funktion försämras. Minskad bentäthet påverkas av faktorer såsom kost, fysisk aktivitet, ålder och hormoner. Av alla som får en höftledsfraktur över 75 års ålder avlider 30% av patienterna inom ett år. Benskörhet bidrar till minskad styrka, muskelmassa och större risk för fler framtida frakturer. Syfte: Syftet med studien är att sammanställa och jämföra studier kring fysisk träning hos äldre (60+) och träningens effektivitet vid osteoporos eller osteopeni. Metod: Metoden genomfördes enligt avancerad sökning i Pubmed, CINAHL och Scopus där endast RCT studier inkluderades. Kvalitetsgranskningen skedde enligt PEDro-skalan. Resultat: Artikelsökningen gav 288 träffar, efter artikelsökningen återstod 12 st artiklar. Resultatet av BMD analyserades  i femur, ländrygg, underarm, underben och total body. Styrketräning, multikomponent träning och vibrationsträning har visat ökning av BMD i femur och ländrygg. Submaximal träning kombinerat med läkemedel ger effekt på BMD. Vibrationsträning ser en ökning av BMD i distala radius och tibia. Konklusion: Högintensiv träning, multikomponent träning och vibratorisk träning gav effekt på BMD. Vandring och aerobisk träning gav inte lika stor effekt på BMD. Däremot sågs att varierad träning minskar fallrisk och att komponenter såsom styrka, balans, aerobisk kapacitet och koordination är viktiga för ökad och bibehållen fysisk funktion samt för att förhindra fallrisk hos äldre. Fysioterapeuter och sjukvårdens samarbete är viktigt för att minska risken för frakturer hos äldre.

The objectives of this research were to evaluate non-invasive measures of bone mineral content (BMC) and bone mineral density (BMD) as rapid, on-farm tools to assess phosphorus (P) status in dairy cows. In addition, the effects of parity and stage of lactation on measures of BMC of the fused 3rd and 4th metacarpal bone and of caudal vertebrae 14 and 15 were assessed. The caudal vertebrae and right front metacarpal (sample pairs) were excised from 107 Holstein cull cows following slaughter. Parity, age, and days in milk (DIM) of the donor animal were obtained for 43 pairs of samples. Samples were grouped by parity (1, 2, 3, and >4) and stage of lactation (Stage 1 = < 90 DIM, Stage 2 = > 90 and < 150 DIM, Stage 3 = >150 and < 250 DIM and Stage 4 = > 250 DIM). Samples were analyzed for BMC and BMD with dual energy X-ray absorptiometry (DXA), BMC with radiographic photometry (RP), breaking strength with mechanical methods, and mineral content with chemical procedures. Estimates of BMC obtained with RP and DXA were poorly related to chemical measures of actual BMC and to measures of breaking strength. In caudal vertebrae 14 and 15, increasing stage of lactation decreased energy to peak load with the lowest values observed in late lactation. Stage of lactation had no effect on BMC measured chemically in the caudal vertebrae or metacarpal. Parity did not affect breaking strength of the metacarpal or caudal vertebrae or total ash or P content of any bone. Results indicated that imaging techniques are not useful measures of BMC in mature dairy cattle. / Master of Science

Selective Serotonin Reuptake Inhibitors and Bone mineral Density in a Population of U.S. Premenopausal Women May 2011 M.S., UNIVERSITY of Massachusetts Amherst Directed by: Professor Elizabeth R. Bertone-Johnson Low bone mineral density (BMD) in post-menopausal women is a risk factor for bone fractures and osteoporosis development. Prior studies in post-menopausal women have shown the use of antidepressant medications, specifically selective serotonin reuptake inhibitors (SSRIs) to be inversely related to BMD. However, the association has not been studied in pre-menopausal women. Current SSRI use is widespread with 8% of U.S. women age 18-44 reporting use. We evaluated the association between SSRIs and BMD and bone mineral content (BMC) cross-sectionally using data from the University of Massachusetts Vitamin D Status Study. SSRI use, diet, and lifestyle factors were assessed by questionnaire. BMD and BMC were measured using dual-energy x-ray absorptiometry (DEXA). The study included 256 women aged 18-30 (mean=21.6 years, SD=4.3 years). In this population, SSRI use was 5%, BMD values ranged from 0.97-1.38 g/cm2 (mean 1.16, SD 0.08), and BMC values ranged from 1833g to 3682g (mean 2541.5, SD=349.2). After adjustment for age, body mass index, and physical activity, mean BMD in the 13 users of SSRIs was 1.15g/cm2 (SD=0.06) compared to 1.16g/cm2 (SD=0.77) in the 243 non-users (p =0.66). After the same adjustments, mean BMC in the 13 users was 2467.1g (SD=285.0) compared to 2547.6g (SD=352.6) in the 243 non-users (p=0.94). Our findings do not support an inverse association between SSRI use and BMD or BMC. However, given the prevalence of SSRI use in young women and the potential for adverse effects on bone health, further study of this association is warranted.

No description available.

A obesidade encontra-se associada a uma série de alterações metabólicas que podem elevar o risco de doenças crônicas não-transmissíveis. Em contraste, o excesso de peso apresenta-se como um fator protetor para a ocorrência de fraturas e baixa densidade óssea. Considerando que a adolescência é um período crucial para aquisição da massa óssea e minimização do risco de osteoporose na maturidade e os efeitos da perda de peso sobre a massa óssea, neste estágio de vida, não são completamente elucidados, o presente estudo foi desenvolvido. Objetivou-se investigar os efeitos da perda de peso sobre a massa óssea e as alterações metabólicas em adolescentes obesos pós-púberes. Realizou-se a revisão bibliográfica sobre o tema e um estudo longitudinal contemplando um período de 9 meses de intervenção baseada em dieta hipocalórica e orientações nutricionais. Foram incluídos 55 adolescentes pós-púberes, 43 meninas, com média de idade de 16,6 (1,4) anos, com índice de massa corporal por idade superior ao percentil 95. Os participantes foram monitorados a cada três semanas por meio de avaliação antropométrica (aferição do peso, estatura e circunferência) e do consumo alimentar (recordatório alimentar de 24 horas). Realizaram-se avaliações da composição corporal e da densidade mineral óssea de corpo total por meio da DXA (dual energy X-ray absorptiometry), do consumo alimentar (registro alimentar de 3 dias) e de parâmetros metabólicos (colesterol total e frações, tricilgliceróis, glicemia de jejum, insulina, leptina e grelina) no início do estudo, após 3 meses e ao fim da intervenção. Verificou-se que 44,4 por cento dos participantes não apresentavam redução do peso. O grupo que respondeu à intervenção apresentou média de perda de peso de 6,2 (4,6) por cento ao fim do estudo. Neste grupo, houve significativa redução do consumo energético, de 2105,4 (537,6) Kcal/dia na primeira avaliação para 1738,8 (608,4) Kcal/dia ao fim do estudo. Observou-se incremento da atividade física entre os participantes e melhora dos parâmetros metabólicos entre adolescentes que perderam peso. / Obesity is associated with several metabolic changes that may increase the risk of chronic diseases. Body weight is recognized as a protective factor against fractures and lower bone density. Considering that adolescence is a crucial period for bone mass acquisition and osteoporosis risk reduction in maturity and the effects of weight loss on bone mass in this life stage are not completely elucidated, the present study was performed. The objective was to investigate the effects of weight loss as well the metabolic changes related to bone mass in post-puberal adolescents. Bibliographic review and a longitudinal study, with adolescents submitted to nutritional intervention based on hipocaloric diet and nutritional advice during 9 months, were realized. Fifty-five subjects, 43 girls, mean age of 16.6 (1.4) years, with body mass index by age superior than 95 percentile, were recruited. Subjects were monitored every three weeks with anthropometric (weight, height and circumferences) and dietary intake (24h food intake recall) evaluation. Body composition and total-body bone mineral density. (assessed by dual-energy X-ray absorptiometry), metabolic parameters (plasma lipids, glucose, insulin, leptin and ghrelin concentrations) and dietary intake (3-day food records) were evaluated at the baseline, after 3-months and at the end of the study. Sixteen participants thatcompleted the study did not lost weight. The group that adhered to intervention nutritional had mean weight loss of 6.2 (4.6) %. In this group, there was a significant decrease in energy intake, from 2105.4 (537.6) Kcal/day to 1738.8 (608.4) Kcal/day. Physical activity pratice increased between participants and there were metabolic parameters improvement in adolescents who lose weight. In these subjects, hypercholesterolemia and insulin resistance decreased, 7,9% and 27.2% (p<0.05) respectively, after 3 months of intervention. There was a significant increase of total bone mineral density and bone mineral content (BMC) in adolescents did not lost weight. Increased BMC and bone area was verified in participants that adhered to intervention nutritional. Bone parameters changes were associated with body fat alterations. The increment in bone mineral density even under weight loss showed no negative effect of bone mass. Dietary intake change and weight control contributed to metabolic parameters improvement of obese adolescents.

<p>Osteoporosis is a major health care problem, by reason of its devastating consequences, in particular hip fractures. Worldwide it has been estimated that the incidence of hip fracture will increase to more than 6 million per year by 2050 compared to 1.7 million per year in 1990. Osteoporosis can be caused by various factors namely, genetic, lifestyle and environmental factors, and since the rising incidence of its consequences is not fully explained by the growing age of the population, there is an urgent need to identify individual causal factors of this condition. </p><p>The present research has focused on aluminium, one potential environmental factor of importance for bone disease, and its possible relation to osteoporosis, since it is known to cause osteoporosis-like bone disease and has been associated with induction of progressive central nervous system diseases.</p><p>Aluminium is the third most common element in the earth’s crust and the most abundant metal (8%). It is widely utilized industrially and it is also naturally present in many foods. Although aluminium is ubiquitous in the human environment, evolution has not given it an essential biological function.</p><p>The aluminium content of bone was measured by inductively coupled mass spectrometry in a large group of patients suffering from hip fractures, high energy fractures and osteoarthrosis. An exponential increase in aluminium content of bone with age was found (p=0.0004). However, no significant association of aluminium in bone with occurrence of hip fracture or dementia could be found, and no indirect evidence was obtained, e.g. through bone mineral density or biomechanical properties, that aluminium is involved in the pathogenesis of osteoporosis. Although we accumulate aluminium in bone throughout our lives, and there are experimental suggestions that aluminium induces premature cell death, the body content of this metal does not seem to influence the overall mortality risk. </p>

Osteoporosis is a major health care problem, by reason of its devastating consequences, in particular hip fractures. Worldwide it has been estimated that the incidence of hip fracture will increase to more than 6 million per year by 2050 compared to 1.7 million per year in 1990. Osteoporosis can be caused by various factors namely, genetic, lifestyle and environmental factors, and since the rising incidence of its consequences is not fully explained by the growing age of the population, there is an urgent need to identify individual causal factors of this condition. The present research has focused on aluminium, one potential environmental factor of importance for bone disease, and its possible relation to osteoporosis, since it is known to cause osteoporosis-like bone disease and has been associated with induction of progressive central nervous system diseases. Aluminium is the third most common element in the earth’s crust and the most abundant metal (8%). It is widely utilized industrially and it is also naturally present in many foods. Although aluminium is ubiquitous in the human environment, evolution has not given it an essential biological function. The aluminium content of bone was measured by inductively coupled mass spectrometry in a large group of patients suffering from hip fractures, high energy fractures and osteoarthrosis. An exponential increase in aluminium content of bone with age was found (p=0.0004). However, no significant association of aluminium in bone with occurrence of hip fracture or dementia could be found, and no indirect evidence was obtained, e.g. through bone mineral density or biomechanical properties, that aluminium is involved in the pathogenesis of osteoporosis. Although we accumulate aluminium in bone throughout our lives, and there are experimental suggestions that aluminium induces premature cell death, the body content of this metal does not seem to influence the overall mortality risk.

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.

A obesidade encontra-se associada a uma série de alterações metabólicas que podem elevar o risco de doenças crônicas não-transmissíveis. Em contraste, o excesso de peso apresenta-se como um fator protetor para a ocorrência de fraturas e baixa densidade óssea. Considerando que a adolescência é um período crucial para aquisição da massa óssea e minimização do risco de osteoporose na maturidade e os efeitos da perda de peso sobre a massa óssea, neste estágio de vida, não são completamente elucidados, o presente estudo foi desenvolvido. Objetivou-se investigar os efeitos da perda de peso sobre a massa óssea e as alterações metabólicas em adolescentes obesos pós-púberes. Realizou-se a revisão bibliográfica sobre o tema e um estudo longitudinal contemplando um período de 9 meses de intervenção baseada em dieta hipocalórica e orientações nutricionais. Foram incluídos 55 adolescentes pós-púberes, 43 meninas, com média de idade de 16,6 (1,4) anos, com índice de massa corporal por idade superior ao percentil 95. Os participantes foram monitorados a cada três semanas por meio de avaliação antropométrica (aferição do peso, estatura e circunferência) e do consumo alimentar (recordatório alimentar de 24 horas). Realizaram-se avaliações da composição corporal e da densidade mineral óssea de corpo total por meio da DXA (dual energy X-ray absorptiometry), do consumo alimentar (registro alimentar de 3 dias) e de parâmetros metabólicos (colesterol total e frações, tricilgliceróis, glicemia de jejum, insulina, leptina e grelina) no início do estudo, após 3 meses e ao fim da intervenção. Verificou-se que 44,4 por cento dos participantes não apresentavam redução do peso. O grupo que respondeu à intervenção apresentou média de perda de peso de 6,2 (4,6) por cento ao fim do estudo. Neste grupo, houve significativa redução do consumo energético, de 2105,4 (537,6) Kcal/dia na primeira avaliação para 1738,8 (608,4) Kcal/dia ao fim do estudo. Observou-se incremento da atividade física entre os participantes e melhora dos parâmetros metabólicos entre adolescentes que perderam peso. / Obesity is associated with several metabolic changes that may increase the risk of chronic diseases. Body weight is recognized as a protective factor against fractures and lower bone density. Considering that adolescence is a crucial period for bone mass acquisition and osteoporosis risk reduction in maturity and the effects of weight loss on bone mass in this life stage are not completely elucidated, the present study was performed. The objective was to investigate the effects of weight loss as well the metabolic changes related to bone mass in post-puberal adolescents. Bibliographic review and a longitudinal study, with adolescents submitted to nutritional intervention based on hipocaloric diet and nutritional advice during 9 months, were realized. Fifty-five subjects, 43 girls, mean age of 16.6 (1.4) years, with body mass index by age superior than 95 percentile, were recruited. Subjects were monitored every three weeks with anthropometric (weight, height and circumferences) and dietary intake (24h food intake recall) evaluation. Body composition and total-body bone mineral density. (assessed by dual-energy X-ray absorptiometry), metabolic parameters (plasma lipids, glucose, insulin, leptin and ghrelin concentrations) and dietary intake (3-day food records) were evaluated at the baseline, after 3-months and at the end of the study. Sixteen participants thatcompleted the study did not lost weight. The group that adhered to intervention nutritional had mean weight loss of 6.2 (4.6) %. In this group, there was a significant decrease in energy intake, from 2105.4 (537.6) Kcal/day to 1738.8 (608.4) Kcal/day. Physical activity pratice increased between participants and there were metabolic parameters improvement in adolescents who lose weight. In these subjects, hypercholesterolemia and insulin resistance decreased, 7,9% and 27.2% (p<0.05) respectively, after 3 months of intervention. There was a significant increase of total bone mineral density and bone mineral content (BMC) in adolescents did not lost weight. Increased BMC and bone area was verified in participants that adhered to intervention nutritional. Bone parameters changes were associated with body fat alterations. The increment in bone mineral density even under weight loss showed no negative effect of bone mass. Dietary intake change and weight control contributed to metabolic parameters improvement of obese adolescents.

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