M.Tech. (Food and Beverage Management) / Calcium is a nutrient of concern for adolescents due to the high Incidence of osteoporosis. The adolescent growth spurt combined with the vulnerability of females to osteoporosis suggests an urgent need to determine calcium requirements. The knowledge and intake of calcium, cereals and legume foods and the causes of osteoporosis amongst adolescent girls In a westernized South African society are yet to be elucidated. The aim of the study was to detennlne the knowledge and intake of calcium, cereals and osteoporosis in white adolescent girls in South Africa. Preliminary and main studies were undertaken on 282 female subjects between the ages of fifteen and seventeen years In sixteen schools. A seven-day weighed record, (WR) and food frequency questionnaires, (FFQ) were applied and anthropometrical data were collected from all participants, while blood samples and bone density measurements were performed on selected Subjects. Results revealed that 54% of the Subjects had calcium intakes below 800 mg per day (1200 mg AI). They were classified as the individuals at risk, while only 34% had adequate intakes of 800 mg/d and more. Results regarding the functions and knowledge of calcium showed that most subjects, (91%), were familiar with the sources of dairy calcium, but few could identify correct sources of non-dairy calcium. Most of the subjects, (58%), thought that calcium could be beneficial to their health and could prevent diseases such as breast cancer and high blood pressure.

La Organización Mundial de Salud ha clasificado la osteoporosis como el quinto problema de salud a nivel mundial donde la densidad de la masa ósea disminuye llevando a la mujer a ser propensa de fracturas, por ello es importante prevenir el desarrollo de esta enfermedad. Algunas medidas para la prevención de osteoporosis son una alimentación balanceada y rica en calcio, desarrollo de actividad física, no consumo de sustancias nocivas y un control médico periódico. Las docentes de enfermería no solo tienen como función esencial el enseñar, sino que además como seres humanos requieren realizar diversas actividades preventivas, promocionales para evitar enfermedades en este caso la osteoporosis, por lo que se formula la siguiente interrogante ¿Cuáles son las medidas de autocuidado para la prevención de osteoporosis que practican las docentes del Departamento Académico de Enfermería de la Universidad Nacional Mayor de San Marcos - 2014?, teniendo como objetivo principal determinar las medidas de autocuidado que practican las docentes para la prevención de osteoporosis. El tipo de estudio es descriptivo, la muestra fue 27 docentes, se utilizó un cuestionario como instrumento de recolección de datos, después del análisis se llegó a la siguiente conclusión: Las docentes del Departamento Académico de Enfermería no practican medidas para la prevención de osteoporosis en relación a la alimentación, actividad física, consumo de sustancias nocivas y control médico periódico, lo que pone en riesgo a padecer esta enfermedad. / Tesis

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A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Master of Medicine (MMed). Johannesburg 2017 / BACKGROUND: The aim of the study was to assess whether African subjects with fragility fractures were being identified for assessment for osteoporosis on presentation to the orthopaedic department at Chris Hani Baragwanath Academic Hospital (CHBAH) in Soweto. In addition, the recommendation for secondary prevention of disease for these subjects, was also assessed. METHOD: One hundred African subjects over the age of 50 years with fragility fractures were identified in the orthopaedic wards and clinics at CHBAH. These subjects were interviewed with two separate questionnaires addressing risk factors and education regarding osteoporosis, and whether further management was suggested. The first interview was conducted in June and July 2015. After 18 months, a follow up telephonic interview was conducted, in December 2016, with 37 of the original 100 subjects. RESULTS: Of the 100 subjects evaluated, 89 (89%) were asked at least one screening question. The most frequently asked question about risk factors for osteoporosis in the first interview, was regarding previous fractures and was asked of 61 (61%) of the 100 subjects. A further 37 (37%) of all subjects had been given advice regarding appropriate bone strengthening exercises to prevent osteoporosis. Only five subjects (5%) were asked to return for further assessment. The second interview showed that the most frequently asked question was regarding previous fractures in 24 (64.9%) of the 37 subjects and 18 (48.6%) of the 37 subjects had been advised to do bone strengthening exercises. Only two (5.4%) new subjects could confirm receiving a date to return for assessment. CONCLUSION: In this study, orthopaedic surgeons were proven to be inadequately assessing risk factors for osteoporosis and were infrequently referring patients for therapy. Orthopedic surgeons are often the only practitioners to see patients with fragility fractures and thus they have a crucial role in identifying and appropriately referring these patients for further investigations and medical management for osteoporosis. / MT2017

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Objectives: This study aimed to investigate whether new potential risk factors (cognition, frailty, falls, social isolation/loneliness, and osteosarcopenia), not included in traditional fracture risk prediction models, are associated with fracture risk in community-dwelling older adults. Methods: Participants aged 65 years or older from the Canadian Longitudinal Study on Aging (CLSA) who completed the 2015 baseline and 2018 follow-up assessments were included. The outcome was self-reported fractures in the 12 months prior to both baseline and a three-year follow-up. Baseline predictor variables included cognition variables (memory, executive function, and psychomotor speed), frailty (assessed using the Rockwood Frailty Index), falls (assessed as occurrence at the 12 months prior to baseline), social isolation/loneliness (assessed using the CLSA-Social Isolation Index), and osteosarcopenia defined as a combination of osteopenia/osteoporosis (bone mineral density femoral neck T-score <-1) and sarcopenia (grip strength <35.5 kg for males and <16kg for females, as well as gait speed <0.8 m/s for both sexes). Findings: When considering cognition, frailty, and falls simultaneously, the frailty index was independently associated with fracture risk [adjusted odd ratio (OR) 1.44, 95% confidence interval (CI) 1.11-1.52 per each standard deviation (SD) increment in the frailty index]. The Social Isolation Index was associated with fracture risk (adjusted OR 1.13, 95% CI 1.01-1.27); however, this association was dependent on an interaction with depressive symptoms. In males, osteosarcopenia was associated with a 2.6-fold higher fracture risk compared to those with normal bone density without sarcopenia (adjusted OR 2.60, 95% CI 1.14-5.91). Conclusion: Frailty, social isolation/loneliness, and osteosarcopenia are associated with fracture risk in Canadian community-dwelling older adults aged 65 years or older. These new risk factors may be used in the future to develop better fracture prediction assessments. / Thesis / Doctor of Philosophy (PhD) / Several fracture risk prediction models use various risk factors, such as bone density, to predict fracture risk. However, many factors are not considered in these models that may be related to fractures. We explored the associations between new potential risk factors including cognition, frailty, falls, social isolation/loneliness, and osteosarcopenia; and fracture risk. When considering cognition, frailty, and falls together, we found that only frailty was associated with fracture risk. Social isolation/loneliness was also associated with fracture risk, but it depended on individuals’ depressive symptoms. Only in males, osteosarcopenia was associated with higher fracture risk compared with those with normal bone density and without sarcopenia. Frailty, social isolation/loneliness, and osteosarcopenia are associated with fracture risk in community-dwelling adults aged 65 years or older.

Tang, Xiaolin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 132-144). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

MR allows non-invasive means of evaluating the non-mineralized components of bone, particularly the bone marrow. This thesis focuses on potential changes occurring in bone marrow perfusion and marrow fat in osteoporosis, - changes which may improve our understanding of osteoporosis pathophysiology. We know from histology studies that as osteoporosis develops and bone tissue is lost, it is replaced by fat filling the vacated marrow space. MR allows non-invasive quantification of this fat component. Although fat content may be increasing, it is not known whether any change in fat composition occurs with osteoporosis i.e. does the type of fat within bone change. Epidemiological studies have indicated a link between arterial disease and osteoporosis. It is not known, however, whether any changes occur in bone perfusion in osteoporosis and how these may be related to increasing fat within the marrow. / The hypothesis to be tested is that: Advanced magnetic resonance (MR) techniques can be applied to investigate the non-mineralised components of bone tissue in osteoporosis thereby providing more information on bone physiology both in health and disease / This thesis is based on a series of eight studies designed to study the relationship between bone marrow perfusion, bone marrow fat content, bone marrow fat composition and bone mineral density. These studies showed that as bone mineral density decreased, bone marrow perfusion decreased. A strong reciprocal relationship was found between decreasing bone marrow perfusion and increasing marrow fat. The reduction in perfusion occurred only with bone and did not affect the extra-osseous tissues alongside bone with the same arterial supply. This indicates that the reduction in bone perfusion is not simply a reflection of a more generalized circulatory impairment in subjects with osteoporosis. This same effect is seen in both males and females and in the proximal femora as well as the spine. / In animal-based studies, we found that reduction in bone perfusion was apparent as little as two weeks after orchidectomy or oorphorectomy and closely paralleled features of impaired endothelial function as well as decreased bone mineral density and a hitherto unrecognized reduction in red marrow fraction within the medullary canal. Nitric oxide synthase, produced by the endothelium, is a potent stimulator of angiogenesis and osteoblastic activity. Mesenchymal stem cell differentiation may switch from osteoblastogenesis to adipocytogenesis under hypoxic conditions, while haematopoetic stem cells also supply endothelial stem cells. Potentially endothelial dysfunction, mesenchymal stem cell differentiation and haematopoetic stem cell maturation may be implemented in the development of osteoporosis. / In normal subjects, blood perfusion was markedly reduced in the femoral head compared to the femoral neck. In osteoporotic subjects, a further reduction in blood perfusion occurred in both areas. Overall perfusion indices reduced relatively more in the femoral neck than the femoral head region. These changes in bone perfusion help explain why subjects with osteoporosis have impaired healing of femoral neck fractures though do not seem to be at increased risk of avascular necrosis. At a micro-architectural level, reduced bone perfusion may also help explain the impaired healing of microfractures seen in subjects with osteoporosis, a feature likely to contribute to reduce bone strength, microfracture accumulation and eventually clinical insufficiency fracture. / Marrow fat was increased in subjects with osteoporosis. Our studies showed that percentage marrow fat content increased even allowing for the quantitative effect increased marrow fat has on the bone densitometry measurements. This effect was shown to be of negligible clinical significance. We found a strong reciprocal relationship between increasing fat and decreasing bone perfusion in both the proximal femur and vertebral body. Although fat content increased, very little difference in marrow fat composition was apparent between normal subjects and those with osteoporosis. We found no difference was apparent in either the N3/N6 marrow fat ratio or the spectrum of individual fatty acids in the marrow of subjects with either normal bone mineral density or osteoporosis. This suggests that alternation of marrow fat composition is not likely to be a direct contributory factor in osteoporosis. Also marrow fat increase was shown to be due to an increase in number rather than size of marrow fat cells. This suggests that marrow fat increases as a result of a switch in mesenchymal cell maturation to adipocytes rather than osteoblasts. / Below average perfusion indices in the acetabulum and adductor muscle is predictive of more pronounced bone loss at the femoral neck over the ensuing four years. Perfusion indices can also predict between fast and slow losers with a high sensitivity / To summarise, in the eight studies presented, it was shown that osteoporosis is associated with a significant reduction in bone perfusion and a reciprocal increase in marrow fat content though no change in marrow fat composition. Reduction in bone perfusion is most likely due to an accompanying reduction in functioning marrow fraction. Marrow fat increase is most likely the result of a switch in mesenchymal cell maturation to adipocytes rather than osteoblasts. The studies present in this thesis confirmed the initial hypothesis that “Advanced magnetic resonance techniques can be applied to investigate the non-mineralised components of bone tissue in osteoporosis thereby providing more information on bone physiology both in health and disease. / Griffith, James Frances. / "June 2009." / Thesis (M.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 227-250). / Appendix includes Chinese. / PREFACE AND DECLARATION --- p.1 / DEDICATION --- p.2 / ACKNOWLEDGEMENT --- p.3 / PRECIS --- p.4 / PUBLICATIONS AND PRESENTATIONS OF STUDIES RELATED TO THIS THESIS --- p.8 / INTRODUCTION --- p.16 / Chapter STUDY 1 --- What is the relationship between bone perfusion, marrow fat and bone mineral density? --- p.76 / Chapter STUDY 2 --- Vertebral marrow fat content, molecular diffusion, and perfusion indices in women with varying bone density, including osteoporosis: MR evaluation --- p.94 / Chapter STUDY 3 --- Could the results of Study 1 and Study 2 be spurious due to the effect of increasing marrow fat lowering BMD estimation by DEXA? --- p.111 / Chapter STUDY 4 --- Are the same changes in perfusion and marrow fat seen in the proximal femur as were seen in the lumbar spine (Study 1 & Study 2)? --- p.128 / Chapter STUDY 5 --- What is the reproducibility of MR perfusion studies and 1H spectroscopy of bone marrow? --- p.150 / Chapter STUDY 6 --- Marrow fat content increases but does the composition of marrow fat change in osteoporosis? --- p.159 / Chapter STUDY 7 --- Likely causes of reduced bone perfusion in osteoporosis: novel findings in an ovariectomy rat model --- p.180 / Chapter STUDY 8 --- Do perfusion indices or marrow fat content predict rate of bone loss? --- p.204 / SUMMARY --- p.222 / REFERENCES --- p.227 / ABBREVIATION LIST --- p.251 / APPENDIX --- p.253

Access to abstract permanently restricted to Ball State community only / Access to thesis permanently restricted to Ball State community only / School of Physical Education, Sport, and Exercise Science

Source: Dissertation Abstracts International, Volume: 69-07, Section: B, page: 4115. Advisers: Mary Ann Smith; Benoit de Crombrugghe. Includes bibliographical references.