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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.
31

Beta thalassemia-induced osteoporosis: evaluating current and novel therapeutic options

Khullar, Natasha 03 November 2016 (has links)
Osteopenia and/or Osteoporosis (OOS) is becoming an increasingly prevalent chronic disease among Beta Thalassemia Major (BTM) patients, especially now that life expectancy in these patients has considerably improved through regular blood transfusions and iron chelation therapy. With several, complex genetic and acquired factors involved in its pathogenesis, coupled with the heterogeneity in the clinical response of BTM patients to different pharmacological agents, OOS has proven to be particularly difficult to treat. The great majority of treatment options currently available are not curative, but instead are aimed towards managing the symptoms and progression of the disease in patients. General preventative measures, such as iron chelation therapy and hormonal replacement therapy (HRT), are instrumental aspects of the treatment plan; however, the incredible complexity of OOS necessitates an individualized, multidisciplinary approach to management, with a principal therapy that is safe and effective in patients, and that is accompanied by these other supportive measures. This review, through a comprehensive analysis of current literature, includes data from randomized, placebo-controlled trials, double blind and observational clinical studies, and suggests optimal therapeutic interventions for first-line management of OOS. It also addresses treatment options for BTM patients in whom resistance to the recommended first-line therapy develops, or who display secondary endocrine conditions contributing to OOS. In addition to providing a current synopsis of OOS management and the potential of emerging treatment options, this analysis highlights some of the limitations of traditional therapies. In this way, the paper effectively illustrates the current status of TM-induced OOS; it describes what is or isn’t working, as well as underscores the diagnostic and therapeutic challenges continually faced by patients, researchers and clinicians.
32

La masse osseuse de l'adolescent : effets de la composition corporelle, de la surcharge pondérale et d'un programme pluridisciplinaire d'entraînement en endurance / Bone mass in adolescents : effects of body composition, overweight and of an endurance training program

El Hage, Rawad 02 June 2009 (has links)
Les buts de cette thèse étaient d’explorer les effets de la composition corporelle, de la surcharge pondérale et d’un programme d'entraînement pluridisciplinaire en endurance sur le contenu minéral osseux (CMO) et la densité minérale osseuse (DMO) chez les adolescents. Au total 4 études ont été menées. La première étude avait comme but d’explorer la contribution relative de la masse maigre et de la masse grasse aux valeurs de DMO chez 35 filles et 65 garçons français. Celle-ci a montré que la masse grasse est un déterminant positif de la DMO chez les filles mais pas chez les garçons. En effet, la masse maigre était le meilleur déterminant de la DMO chez les garçons. La deuxième et la troisième étude avaient comme objectif d’étudier les effets de la surcharge pondérale sur le CMO et la DMO du corps entier, du rachis lombaire et de la hanche chez des adolescentes libanaises. Ces 2 études ont montré que la surcharge pondérale est accompagnée d’une augmentation des valeurs absolues de CMO et de DMO. Cependant, après ajustement par le poids, ces différences disparaissent. Dès lors, ces études suggèrent que la DMO des filles en surcharge pondérale soit bien adaptée à l’excès de poids. La quatrième étude a étudié les effets de 12 semaines d’entraînement en endurance sur le CMO et la DMO chez des adolescentes obèses, en surpoids et normo-pondérées. Cette étude a montré une augmentation des valeurs de DMO dans les 3 groupes alors que le CMO n’a augmenté que dans le groupe obèse. Cette étude confirme le rôle positif de l’exercice physique sur la DMO chez les adolescentes obèses et non obèses. / The aims of this thesis were to explore the effects of body composition, overweight and of an endurance training program on bone mineral content (BMC) and bone mineral density (BMD) in adolescents. 4 studies were undertaken to achieve this goal. The first study explored the relative importance of lean and fat mass on BMD in a group of adolescent girls and boys. This study showed that fat mass is a positive determinant of BMD in girls but not in boys. In fact, lean mass was the best positive determinant of BMD in boys. The studies 2 and 3 aimed at studying the effects of overweight on whole-body, lumbar spine and hip BMD in Lebanese adolescent girls. These studies showed that the crude values of BMC and BMD were higher in overweight girls compared to controls. However, there were no differences in BMC or BMD between the two groups after adjusting for weight. Therefore, these studies suggest that the BMD of the overweight girls adapts to the increased body weight. The last study explored the effects of 12 weeks of endurance training on BMC and BMD in obese, overweight and normal-weighted sedentary adolescent girls. The BMD increased in the three groups. However, the whole-body BMC increased only in the obese group. This study confirmed the positive effects of physical exercise on BMD in obese and non-obese adolescent girls.
33

Avaliação do equilíbrio postural em mulheres na pós-menopausa e sua relação com a densidade mineral óssea /

Cangussu, Luciana Mendes. January 2011 (has links)
Resumo: Avaliar a associação entre o equilíbrio postural e a densidade mineral óssea (DMO) em mulheres na pós-menopausa e correlacionar com o risco de quedas. Realizou-se estudo de corte transversal com 225 mulheres, idade 45-75 anos, atendidas em Hospital Universitário. Incluíram-se mulheres em amenorréia >12 meses e idade ≥ 45 anos, com valores de DMO (coluna lombar e colo de fêmur) pelo DXA, dos últimos 12 meses. E se excluíram aquelas com doenças neurológicas ou musculoesqueléticas, história atual de vestibulopatias, déficit visual sem correção, obesidade grau III e usuárias de drogas que alterem o equilíbrio. As mulheres foram divididas segundo a DMO em > -2,0 DP (n=140) e ≤ -2 DP (n=85). Foram analisados o histórico de quedas (últimos 24 meses) e as características clínicas e antropométricas. O equilíbrio postural foi avaliado pela estabilometria (plataforma de força), teste de Romberg, alcance funcional e teste do agachamento. Para análise estatística foram empregados o Teste de Wilcoxon para variáveis quantitativas, o teste do Qui-Quadrado ou Exato de Fisher para variáveis categóricas e o método de regressão logística para o risco de quedas (Odds Ratio-OR). As pacientes com DMO > -2,0 DP eram mais jovens e com menor tempo de menopausa, assim como apresentavam maior IMC e circunferência da cintura quando comparadas aquelas com baixa DMO (≤ -2 DP) (p<0,05). Observou-se que 57,8% (130/225) das participantes relataram episódio de queda nos últimos dois anos, sem diferença significativa na distribuição percentual entre os grupos (p=0,055). Nos parâmetros estabilométricos e no alcance funcional não foram demonstradas diferenças na comparação entre os grupos (p>0,05). No teste de Romberg notou-se aumento progressivo da positividade à medida que aumentava a dificuldade do teste, sendo observada diferença significante entre os grupos apenas com ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: To analyze the association between postural balance and bone mineral density (BMD) in postmenopausal women and correlate it with risk for falls. A cross-sectional study was conducted on 225 women aged 45-75 years and cared for at a University Hospital. Women in amenorrhea >12 months and age ≥ 45 years, with BMD values (lumbar spine and femur neck) by DXA for the last 12 months, were included. Those with neurological or musculoskeletal disorders, current history of vestibulopathies, uncorrected visual deficit, level-III obesity or drug use that could affect balance were excluded. The women were divided, according to BMD, in > -2.0 DP (n=140) and ≤ -2 DP (n=85). Histories of falls (last 24 months) as well as clinical and anthropometric characteristics were evaluated. Postural balance was assessed by stabilometry (strength platform), Romberg's test, functional reach test and the crouching test. For statistical analysis, Wilcoxon's test was used for quantitative variables, the Chi-square or Fisher's exact test for categorical variables and the logistic regression method for fall risk (Odds Ratio-OR). Patients with BMD > -2.0 DP were younger and had been menopausal for a shorter period of time; they also showed higher BMI and larger waist circumference as compared to those with low BMD (≤ -2 DP) (p<0.05). It was observed that 57.8% (130/225) of the participants reported fall episodes in the last two years, without significant difference in the percent distribution between the groups (p=0.055). No differences were found in the comparison between the groups (p>0.05) for stabilometric parameters or functional reach test. Concerning Romberg's test, progressive positive increase was observed as the test difficulty increased, and significant difference between the groups was found only when the women kept their feet in a series and their eyes closed (p<0.05). When evaluating the ... (Complete abstract click electronic access below) / Orientador: Jorge Neto Nahás / Coorientador: Eliana Aguiar Petri Nahás / Banca: Fábio Lera Orsatti / Banca: Luciano de Melo Pompei / Mestre
34

Comparison of Black and White Elderly Women on Muscle Mass Bone Mineral Density and Balance.

Jones, Tyanez 01 December 2001 (has links)
Few studies have compared balance between aging black (BW) and white women (WW) and examined its relationship to muscle mass and bone mineral density (BMD). Nineteen BW and 56 WW between 60-91 years participated. Upper and lower body strength, body composition, BMD, volitional and non-volitional control of dynamic balance, and physical activity ratings were assessed. There were no differences in strength between the groups. A trend was reported for total body BMD (p=0.07). WW exhibited better control of rapid volitional movements, in the limits of stability and rhythmic weight shift tests. The relationships of strength and muscle mass to BMD and balance were weak. Physical activity ratings were higher for WW than BW (p<.05). In conclusion, differences reported in the literature between BW and WW for risk of falling may be due to other variables not assessed in this study. Future studies should examine other factors that contribute to increased risk of falling.
35

The relationship between peak lean tissue velocity and peak bone mineral content velocity during the adolescent growth spurt

Helgason, Nial John 22 August 2005
It has been theorized that muscles generate more force on bone than body weight alone and therefore it is likely that muscle contraction drives and sustains bone adaptation (Frost 1999). Purpose: To investigate the relationship between the timing and tempo of peak growth velocities of lean tissue (LT) and bone mineral content (BMC) in boys and girls at three sites using data derived from individual growth curves. Methods: 72 boys and 70 girls were fitted with growth curves that had a distinguishable peak. Height and weight were measured for each participant and tissue assessment was performed annually using DXA. Factorial ANOVAs were completed to analyse data for differences in age, while forward regression analyses was used between LT and BMC. Results: The peak growth velocity for lean occurred significantly (P<0.05) earlier than the peak growth velocity for bone at all locations except the legs. There was a difference (P<0.001) between genders in the age of peak for both lean tissue and bone tissue at all locations with females peak growth occurring before that of males. When aligned by PHV a significant difference (P<0.05) in the timing of PBMCV was found between the arms and the legs with the peak in bone growth in the legs occurring significantly before peak bone growth in the arms. PLTV was independently associated with PBMCV at the arms (r2= .71, p<0.001), legs (r2= .53, p<0.001) and trunk (r2= .52, p<0.001). Conclusion: In conclusion, LT growth precedes BMC growth and after controlling for gender, size and maturity the magnitude of LT growth is associated with BMC growth. The findings of this study are in support the Muscle-bone Unit (Frost and Schoenau, 2000), which theorizes that localised muscle action is a driving force for bone growth. Future studies are needed to analyse bone strength as it relates to local muscle strength and usage while controlling for confounding variables.
36

Coffee Consumption in Relation to Osteoporosis and Fractures : Observational Studies in Men and Women

Hallström, Helena January 2013 (has links)
During the past decades, the incidence of osteoporotic fractures has increased dramatically in the Western world. Consumption of coffee and intake of caffeine have in some studies been found to be associated with increased risk of osteoporotic fractures, but overall results from previous research are inconsistent. Despite weak evidence, some osteoporosis organisations recommend limiting daily coffee or caffeine intake. The primary aim of this thesis was to study the association between long-term consumption of coffee and bone mineral density (BMD), incidence of osteoporosis and fractures. A secondary aim was to study the relation between tea consumption and fracture risk. An increased risk of osteoporotic fractures in individuals who consumed ≥ 4 cups of coffee vs &lt; 1 cup coffee per day was demonstrated in a study of 31,257 Swedish middle-aged and elderly women (a part of the Swedish Mammography Cohort - SMC) when calcium intake was low (&lt; 700 mg/day). However, no higher risks of osteoporosis or fractures were observed in the full SMC with increasing coffee consumption. In the full SMC (n = 61,433) the follow-up was longer and the number of fractures was higher. Similarly, no statistically significant associations between consumption of coffee (≥ 4 cups of coffee vs &lt; 1 cup) and incidence of osteoporotic fractures were observed in the Cohort of Swedish Men (COSM), including 45,339 men. Calcium intake did not modify the results from the investigations performed in the full SMC or COSM. Nonetheless, a 2 - 4% lower BMD at measured sites was observed in men participating in the PIVUS cohort and in women from a sub-cohort of the SMC who consumed ≥ 4 cups of coffee vs &lt; 1 cup daily. Individuals with high coffee intake and rapid metabolism of caffeine had lower BMD at the femoral neck. No association between tea consumption and risk of fractures was found in the studies. In conclusion, the findings presented in this thesis demonstrate that high consumption of coffee may be associated with a modest decrease in BMD. However, there was no evidence of a substantially increased incidence of osteoporosis or fractures typically associated with osteoporosis.
37

Factors Affecting Bone Mineral Density in Elite Female Runners

Cartoon, Maureen E 29 July 2010 (has links)
Introduction: The benefits of regular exercise on skeletal health have been well-documented in terms of stimulation of bone accrual and bone maintenance. Medium-impact sports activities such as running have been demonstrated to exert site-specific enhancement of bone mass in the lower appendicular skeleton. However, elite female runners engaged in high intensity training and sports activity may also be at risk of amenorrhea and low bone mineral density (BMD) resulting from inadequate caloric intake. Purpose: To investigate the effect of intensive exercise and maintenance of adequate caloric intake on BMD in a group of elite female runners. Methods: This study represents a secondary assessment of existing data that were obtained between 1994 and 2009. Using dual-energy X-ray absorptiometry, a group of elite runners (n=11) in this study was screened in the Laboratory for Elite Athlete Performance at Georgia State University. This was a longitudinal study in which three sequential measurements of BMD, as well as fat and lean tissue body composition of each athlete took place. The average interval between measurements was 1.1 years and 2.6 years respectively. Regional BMD measurements for head, arms, legs, trunk, ribs, pelvis, and spine were assessed, as well as the value for total body BMD. The study participants also received dietary counseling emphasizing daily caloric balance and adequate calcium intake. Results: The average age of the runners increased from 24.59 (±4.41) to 28.14 (±5.94) years over the study. This was accompanied by an increase in body mass (54.98±3.54 to 56.11±4.07 kg), while height remained constant. The average body mass index (BMI) of the subjects increased from 19.34 to 19.71 kg/m2, largely due to an increase in total per cent body fat (13.97±2.96% to 16.01±4.28%). Average regional and total BMD values increased over the study period and increases were between 2 and 4%. A majority of subjects (n=7) had a BMI>19 kg/m2, while a sub-group of runners (n=4) had a BMI˂19 kg/m2. Mean trunk, pelvis and spine BMD parameters for the two BMI groups were significantly different (p˂0.05), with reduced BMD values in the lower BMI sub-group. The average T-scores associated with arm BMD were considerably lower than T-scores associated with leg BMD values in the runners. The average T-scores for leg BMD values were almost two standard deviations higher than leg BMD values for a reference population at peak bone mass. Two subjects were osteopenic, resulting in an 18% prevalence rate of osteopenia in the group of runners. Conclusions: The majority of elite runners in this study exhibited a positive trend in BMD parameters. This was reflected as increased total as well as regional BMD values. Increased body mass in addition to the activity of running positively contributed to bone mass via a weight-bearing effect. Increased adipose tissue may also have been a source of endocrine hormones such as estrogen and leptin, which exert a positive effect on bone accrual.
38

The relationship between peak lean tissue velocity and peak bone mineral content velocity during the adolescent growth spurt

Helgason, Nial John 22 August 2005 (has links)
It has been theorized that muscles generate more force on bone than body weight alone and therefore it is likely that muscle contraction drives and sustains bone adaptation (Frost 1999). Purpose: To investigate the relationship between the timing and tempo of peak growth velocities of lean tissue (LT) and bone mineral content (BMC) in boys and girls at three sites using data derived from individual growth curves. Methods: 72 boys and 70 girls were fitted with growth curves that had a distinguishable peak. Height and weight were measured for each participant and tissue assessment was performed annually using DXA. Factorial ANOVAs were completed to analyse data for differences in age, while forward regression analyses was used between LT and BMC. Results: The peak growth velocity for lean occurred significantly (P<0.05) earlier than the peak growth velocity for bone at all locations except the legs. There was a difference (P<0.001) between genders in the age of peak for both lean tissue and bone tissue at all locations with females peak growth occurring before that of males. When aligned by PHV a significant difference (P<0.05) in the timing of PBMCV was found between the arms and the legs with the peak in bone growth in the legs occurring significantly before peak bone growth in the arms. PLTV was independently associated with PBMCV at the arms (r2= .71, p<0.001), legs (r2= .53, p<0.001) and trunk (r2= .52, p<0.001). Conclusion: In conclusion, LT growth precedes BMC growth and after controlling for gender, size and maturity the magnitude of LT growth is associated with BMC growth. The findings of this study are in support the Muscle-bone Unit (Frost and Schoenau, 2000), which theorizes that localised muscle action is a driving force for bone growth. Future studies are needed to analyse bone strength as it relates to local muscle strength and usage while controlling for confounding variables.
39

Risk factors for osteoporotic fractures in Black South African men : a case control study / Martha Ettrusia Leach

Leach, Martha Ettrusia January 2003 (has links)
The main focus of bone loss and Osteoporosis (OP) research has been limited almost entirely to women, but OP has become increasingly common in older men and the impact of hip fracture on mortality may actually be greater in men. OP is a major cause of morbidity and mortality in developed countries, at a cost that currently exceeds $10 billion per year in the United States (US) alone. Osteoporotic fractures affect 50 % of women and 20-30% of white men and 4% of black men over the age of 50 years. These statistics may even increase because of increasing life expectancy. Few studies focusing on Blacks have been published to date and very little is known regarding the bone health and the aetiology and prevalence of OP and fractures among older South African blacks. From the above information it is clear that OP is of considerable clinical and economic importance. Without information on the patterns and determinants of bone loss, the formulation of rational prevention and treatment strategies in these groups is not possible. The aim of the study described in this thesis was to investigate the influence of the dietary factors (iron, vitamin C, and protein) and lifestyle factors (alcohol and tobacco smoking) on osteoporotic fractures and bone mineral density in older South African black men using a case-control study design. Sixteen black male patients with fractures of the proximal femur, the proximal humerus or the distal radius and who conformed to the inclusion and exclusion criteria were included in the study. An equal amount of age-matched (K? years), apparently healthy black men with no previous fracture (of the proximal femur and humerus and distal radius), were recruited as a control group. Dual energy X-ray absorptiometry (DEXA) was used for the measurement of the lumbar vertebrae and the proximal femur (hip). Questionnaires were used to gather demographic and medical information, data on physical activity and dietary intakes. Anthropometric measurements and blood samples were taken. Appropriate biochemical analyses were done with standard methods. Both the cases and controls were osteoporotic according to the mean lumbar spine BMD determined in both groups. The BMD was only marginally lower in the cases than in the controls and therefore not statistically significant. The mean tobacco pack years of the cases (13.29) [95% CI: 4.44; 22.141 were almost double that of the controls (7.43) [1.83; 13.031 but it was not statistically significant (p=0.55). Tobacco pack years were negatively associated with BMD of the lumbar spine (p=0.008) even after controlling for possible confounding SUMMARY factors (p=0.001). Malnutrition, as indicated by the low dietary intakes of energy, protein, vitamin C, iron and low BMI, could play a role in the lower bone mineral density (BMD) observed in the cases. The mean protein intakes of the cases (56.1 19) [46.49; 65.741 were very low compared to the recommended 639 per day. This low protein intake was also significantly less compared to the controls (739) [58.28; 88.311. lron intake tended to be lower in the cases compared to the controls (p=0.09). lron intake was not associated with BMD, however, in the stepwise regression analysis; iron intake came out as a possible predictor of BMD of both the lumbar spine and hip, although it was not statistically significant. The BMI was c 19 kg/m2 in 50% of the cases and the controls. S-GGT, a marker of alcohol intake, was significantly increased in the cases with a mean value of 65.88ulL opposed to the 36.33UIL in the control group. S-GGT was the most important predictor of BMD in both the hip and the lumbar spine. There was a significant statistical correlation between lumbar spine BMD (p=0.04); hip BMD (p=0.02) and s-GGT. In conclusion it can be said that malnutrition played a vital role in the low BMD aggravated by the use of tobacco from a young age and alcohol in excessive amounts over weekends. From the results of this study it can be recommended that any intervention programme should focus on alcohol abuse, tobacco smoking and improvement in nutritional status. Children should be encouraged not to smoke and be educated on the detrimental effects of alcohol. It is important to address dietary risk factors associated with OP, namely to increase the overall nutrition of the South African black male with low cost protein and calcium products. Vitamin C enhances iron absorption and may be beneficial for bone collagen. The increased intake thereof by using seasonal fruit can therefore be recommended. / Thesis (M.Sc. (Dietetics))--North-West University, Potchefstroom Campus, 2004.
40

An Investigation of the Associations among Recovery, Key Illness Characteristics and Bone Mineral Density in Women with a History of Anorexia Nervosa

Waugh, Esther J. 23 February 2010 (has links)
Background: Reduced bone mineral density (BMD) is an established complication of anorexia nervosa (AN). There is inconclusive evidence as to whether this reduction in bone mass is permanent or can be reversed with recovery from AN. The objectives of this study were to: i. determine the extent of reversal of skeletal deficits with recovery from AN, and the duration of recovery required for complete reversal, if this occurred; and, ii. evaluate the effect of key illness characteristics on BMD. Methods: Women (aged 17-40 years) who had previously received inpatient treatment for AN at one of two hospital-based programs were selected for this cross-sectional study; 514 healthy premenopausal women recruited from the community served as a control group. A detailed lifetime illness history was obtained by a Life History Calendar interview. BMD was measured by dual-energy X-ray absorptiometry (DXA) at the spine, hip and total body. Low BMD was defined as a weight and age-matched standard deviation (Z-score) of ≤ -1.5 at one or more skeletal sites. Participants were considered recovered if they had maintained a body mass index ≥ 18.5 kg/m2 and resumed regular menstruation for ≥ 1 year. Results: Of 190 AN participants, 77 were considered recovered and 113 were ill. The prevalence of low BMD was 11.7% in the recovered group, 47.3% in the ill group and 6.8% in the control group. The odds of low BMD in the recovered participants was significantly lower than in the ill participants (odds ratio [OR] = 0.17, 95% CI 0.07, 0.36, p<0.0001) and was not significantly different from the controls (OR = 1.81, 95% CI 0.79, 3.78, p=0.15). Duration of illness was associated with low BMD (OR = 1.16, 95% CI 1.08, 1.25, p<0.0001) and was negatively associated with the odds of AN recovery. Normal mean BMD values at each skeletal site were observed in women recovered ≥ 3 years. Conclusion: The results emphasize the importance of early and sustained AN recovery for the prevention and treatment of low bone mass in this population and may offer motivation for AN patients to make positive behavioural changes leading to successful, long-term recovery.

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