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1.
J Nutr Health Aging ; 27(2): 166-171, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36806871

RESUMO

OBJECTIVES: Malnutrition, particularly protein insufficiency, is common in institutionalised older adults and increases morbidity, mortality, and costs. We aimed to determine whether 12 months supplementation using high-protein foods (milk, cheese, yoghurt) prevents malnutrition in older adults. DESIGN: Cluster randomised control study. SETTING: Sixty Australian aged care facilities. PARTICIPANTS: Older adults living in aged care homes (n=654, mean age 86.7±7.2 years, 72% females). Intervention Facilities randomly allocated to a high-protein (n=30 intervention) or regular (n=30 controls) menu. MEASUREMENTS: Nutritional status assessed using the Mini Nutrition Assessment (MNA) tool and fasting morning blood samples (n=302) assayed for haemoglobin (Hb) and albumin. Food intake was monitored 3-monthly using visual plate waste assessment. Measurements at baseline and month 12 were analysed using random effects model accounting for clustering (facility), repeated measure and confounders. RESULTS: Addition of 11g of protein as 1.5 servings of high-protein foods daily preserved nutritional status that deteriorated in controls [MNA screen (-0.68, 95%CI: -1.03, -0.32, p<0.001) and total (-0.90, 95%CI: -1.45, -0.35, p=0.001) scores], resulting in group differences in MNA screen (0.62, 95%CI: 0.17, 1.06, p=0.007) and total (0.81, 95%CI: 0.11, 1.51, p=0.023) scores and group difference in Hb (3.60g/L, 95%CI: 0.18, 7.03, p=0.039), the net result of preservation with intervention (0.19g/L, 95%CI: -2.04, 2.42, p=0.896) and a decline in controls (-3.41g/L, 95%CI: -6.01, -0.82, p=0.010). No group differences were observed for serum albumin. CONCLUSION: Consumption of high-protein foods is a pragmatic approach to maintaining nutritional status in older adults in aged-care.


Assuntos
Desnutrição , Estado Nutricional , Idoso , Feminino , Humanos , Idoso de 80 Anos ou mais , Masculino , Austrália , Desnutrição/prevenção & controle , Avaliação Nutricional , Instituição de Longa Permanência para Idosos
2.
Osteoporos Int ; 33(1): 67-75, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34235548

RESUMO

In this study of 695 Australian older adults (aged ≥50 years), we found that men and women had a similar trajectory of health-related quality of life (HRQoL) recovery following fragility fracture at any skeletal site. These results provide us with critical knowledge that improves our understanding of health outcomes post-fracture. INTRODUCTION: Mortality is higher in men than that in women following a fragility fracture, but it is unclear whether recovery of patient-reported outcomes such as health-related quality of life (HRQoL) differs between sexes. This study aimed to identify sex differences in HRQoL recovery 12 months post-fracture. METHODS: Data were from the Australian arm of the International Costs and Utilities Related to Osteoporotic Fractures Study (AusICUROS). Participants recruited to AusICUROS were adults aged ≥50 years who sustained a fragility fracture. HRQoL was measured using the EQ-5D-3L at three time-points post-fracture: within 2 weeks (including pre-fracture recall) and at 4 and 12 months. Multivariate logistic regression analyses were undertaken, adjusting for confounders including age, education, income, and healthcare utilization post-fracture. RESULTS: Overall, 695 AusICUROS participants (536 women, 77.1%) were eligible for analysis with fractures at the hip (n = 150), distal forearm (n = 261), vertebrae (n = 61), humerus (n = 52), and other skeletal sites (n = 171). At the time of fracture, men were younger, reported a higher income, and were more likely to be employed, compared with women. For all fracture sites combined, there were no differences between men and women in recovery to pre-fracture HRQoL at 12-month follow-up (adjusted OR = 1.09; 95% CI: 0.75-1.61). When stratified by fracture site, no significant sex differences were seen for hip (OR = 1.02; 95% CI: 0.42-2.52), distal forearm (OR = 1.60; 95% CI: 0.68-3.78), vertebral (OR = 2.28; 95% CI: 0.61-8.48), humeral (OR = 1.62; 95% CI: 0.16-9.99), and other fractures (OR = 1.00; 95% CI: 0.44-2.26). CONCLUSION: Community-dwelling men and women who survived the 12 months following fragility fracture had a similar trajectory of HRQoL recovery at any skeletal site.


Assuntos
Fraturas do Quadril , Fraturas por Osteoporose , Idoso , Austrália/epidemiologia , Feminino , Humanos , Vida Independente , Masculino , Qualidade de Vida , Caracteres Sexuais
3.
BMJ ; 375: n2364, 2021 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-34670754

RESUMO

OBJECTIVE: To assess the antifracture efficacy and safety of a nutritional intervention in institutionalised older adults replete in vitamin D but with mean intakes of 600 mg/day calcium and <1 g/kg body weight protein/day. DESIGN: Two year cluster randomised controlled trial. SETTING: 60 accredited residential aged care facilities in Australia housing predominantly ambulant residents. PARTICIPANTS: 7195 permanent residents (4920 (68%) female; mean age 86.0 (SD 8.2) years). INTERVENTION: Facilities were stratified by location and organisation, with 30 facilities randomised to provide residents with additional milk, yoghurt, and cheese that contained 562 (166) mg/day calcium and 12 (6) g/day protein achieving a total intake of 1142 (353) mg calcium/day and 69 (15) g/day protein (1.1 g/kg body weight). The 30 control facilities maintained their usual menus, with residents consuming 700 (247) mg/day calcium and 58 (14) g/day protein (0.9 g/kg body weight). MAIN OUTCOME MEASURES: Group differences in incidence of fractures, falls, and all cause mortality. RESULTS: Data from 27 intervention facilities and 29 control facilities were analysed. A total of 324 fractures (135 hip fractures), 4302 falls, and 1974 deaths were observed. The intervention was associated with risk reductions of 33% for all fractures (121 v 203; hazard ratio 0.67, 95% confidence interval 0.48 to 0.93; P=0.02), 46% for hip fractures (42 v 93; 0.54, 0.35 to 0.83; P=0.005), and 11% for falls (1879 v 2423; 0.89, 0.78 to 0.98; P=0.04). The risk reduction for hip fractures and falls achieved significance at five months (P=0.02) and three months (P=0.004), respectively. Mortality was unchanged (900 v 1074; hazard ratio 1.01, 0.43 to 3.08). CONCLUSIONS: Improving calcium and protein intakes by using dairy foods is a readily accessible intervention that reduces the risk of falls and fractures commonly occurring in aged care residents. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12613000228785.


Assuntos
Acidentes por Quedas/prevenção & controle , Cálcio da Dieta/uso terapêutico , Proteínas Alimentares/uso terapêutico , Fraturas do Quadril/prevenção & controle , Osteoporose/dietoterapia , Fraturas por Osteoporose/prevenção & controle , Idoso , Idoso de 80 Anos ou mais , Austrália/epidemiologia , Método Duplo-Cego , Feminino , Seguimentos , Fraturas do Quadril/epidemiologia , Fraturas do Quadril/etiologia , Instituição de Longa Permanência para Idosos , Humanos , Incidência , Estimativa de Kaplan-Meier , Masculino , Osteoporose/complicações , Fraturas por Osteoporose/epidemiologia , Fraturas por Osteoporose/etiologia , Modelos de Riscos Proporcionais , Estudos Prospectivos , Comportamento de Redução do Risco , Resultado do Tratamento
4.
Osteoporos Int ; 29(7): 1671-1674, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29619541

RESUMO

Two women presenting with fragility fractures during lactation had bone mineral density (BMD) reduced more greatly than usually associated with lactation. The first woman was 29 years old with a BMD T-score of - 3.2 SD at the spine and- 2.0 SD at the femoral neck. The second woman was 35 years old with a BMD T-score of - 4.5 SD at the spine and - 2.8 SD at the femoral neck. Both women had increased cortical porosity and reduced trabecular density. Investigation identified an elevated serum tryptase, and marrow biopsy confirmed the diagnosis of mastocytosis. Lactation causes bone loss, but the occurrence of fractures in the setting of severe deficits in BMD and microstructural deterioration signals the need to consider additional causes of bone loss.


Assuntos
Lactação/fisiologia , Mastocitose Sistêmica/complicações , Fraturas por Osteoporose/etiologia , Adulto , Densidade Óssea/fisiologia , Feminino , Colo do Fêmur/fisiopatologia , Humanos , Vértebras Lombares/fisiopatologia , Fraturas por Osteoporose/fisiopatologia , Fraturas da Coluna Vertebral/etiologia , Fraturas da Coluna Vertebral/fisiopatologia
5.
Osteoporos Int ; 27(2): 821-5, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26458389

RESUMO

We report that a postmenopausal woman with osteoporosis developed bilateral incomplete atypical femoral fractures (AFFs) after seven years of bisphosphonate therapy. Cessation of the bisphosphonate and treatment with teriparatide was associated with near complete radiological resolution of the AFFs. After 12 months without treatment, denosumab was commenced to prevent structural deterioration. Six months later she developed recurrent bilateral AFFs. This case highlights the management dilemma in patients with ongoing bone loss but prone to stress fractures associated with antiresorptive therapy. Stopping the antiresorptive is recommended but structural decay will recur predisposing to fragility fractures. If the antiresorptive is continued, bone material composition will be further compromised predisposing to atypical fractures. Teriparatide may assist healing of stress fractures and improvement in bone matrix composition. Later antiresosrptive therapy to preserve bone microstructure may compromise material composition.


Assuntos
Conservadores da Densidade Óssea/efeitos adversos , Denosumab/efeitos adversos , Fraturas do Fêmur/induzido quimicamente , Fraturas de Estresse/induzido quimicamente , Teriparatida/uso terapêutico , Idoso de 80 Anos ou mais , Conservadores da Densidade Óssea/uso terapêutico , Denosumab/uso terapêutico , Difosfonatos/efeitos adversos , Difosfonatos/uso terapêutico , Substituição de Medicamentos , Feminino , Fraturas do Fêmur/diagnóstico por imagem , Fraturas de Estresse/diagnóstico por imagem , Humanos , Osteoporose Pós-Menopausa/tratamento farmacológico , Radiografia , Recidiva
7.
Osteoporos Int ; 27(2): 653-63, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26259649

RESUMO

UNLABELLED: We tested whether GPRC6A, the putative receptor of undercarboxylated osteocalcin (ucOC), is present in mouse muscle and whether ucOC increases insulin sensitivity following ex vivo muscle contraction. GPPRC6A is expressed in mouse muscle and in the mouse myotubes from a cell line. ucOC potentiated the effect of ex vivo contraction on insulin sensitivity. INTRODUCTION: Acute exercise increases skeletal muscle insulin sensitivity. In humans, exercise increases circulating ucOC, a hormone that increases insulin sensitivity in rodents. We tested whether GPRC6A, the putative receptor of ucOC, is present in mouse muscle and whether recombinant ucOC increases insulin sensitivity in both C2C12 myotubes and whole mouse muscle following ex vivo muscle contraction. METHODS: Glucose uptake was examined in C2C12 myotubes that express GPRC6A following treatment with insulin alone or with insulin and increasing ucOC concentrations (0.3, 3, 10 and 30 ng/ml). In addition, glucose uptake, phosphorylated (p-)AKT and p-AS160 were examined ex vivo in extensor digitorum longus (EDL) dissected from C57BL/6J wild-type mice, at rest, following insulin alone, after muscle contraction followed by insulin and after muscle contraction followed by recombinant ucOC then insulin exposure. RESULTS: We observed protein expression of the likely receptor for ucOC, GPRC6A, in whole muscle sections and differentiated mouse myotubes. We observed reduced GPRC6A expression following siRNA transfection. ucOC significantly increased insulin-stimulated glucose uptake dose-dependently up to 10 ng/ml, in differentiated mouse C2C12 myotubes. Insulin increased EDL glucose uptake (∼30 %, p < 0.05) and p-AKT and p-AKT/AKT compared with rest (all p < 0.05). Contraction prior to insulin increased muscle glucose uptake (∼25 %, p < 0.05), p-AKT, p-AKT/AKT, p-AS160 and p-AS160/AS160 compared with contraction alone (all p < 0.05). ucOC after contraction increased insulin-stimulated muscle glucose uptake (∼12 % p < 0.05) and p-AS160 (<0.05) more than contraction plus insulin alone but without effect on p-AKT. In the absence of insulin and/or of contraction, ucOC had no significant effect on muscle glucose uptake. CONCLUSIONS: GPRC6A, the likely receptor of osteocalcin (OC), is expressed in mouse muscle. ucOC treatment augments insulin-stimulated skeletal muscle glucose uptake in C2C12 myotubes and following ex vivo muscle contraction. ucOC may partly account for the insulin sensitizing effect of exercise.


Assuntos
Resistência à Insulina/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/fisiologia , Osteocalcina/farmacologia , Animais , Relação Dose-Resposta a Droga , Técnicas de Silenciamento de Genes/métodos , Glucose/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Fibras Musculares Esqueléticas/efeitos dos fármacos , Fibras Musculares Esqueléticas/metabolismo , Proteínas Musculares/metabolismo , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Osteocalcina/administração & dosagem , Receptores Acoplados a Proteínas G/metabolismo , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/farmacologia , Técnicas de Cultura de Tecidos
8.
Osteoporos Int ; 26(8): 2137-46, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25876879

RESUMO

UNLABELLED: We tested whether cortical porosity of the proximal femur measured using StrAx1.0 software provides additional information to areal bone mineral density (aBMD) or Fracture Risk Assessment Tool (FRAX) in differentiating women with and without fracture. Porosity was associated with fracture independent of aBMD and FRAX and identified additional women with fractures than by osteoporosis or FRAX thresholds. INTRODUCTION: Neither aBMD nor the FRAX captures cortical porosity, a major determinant of bone strength. We therefore tested whether combining porosity with aBMD or FRAX improves identification of women with fractures. METHODS: We quantified femoral neck (FN) aBMD using dual-energy X-ray absorptiometry, FRAX score, and femoral subtrochanteric cortical porosity using StrAx1.0 software in 211 postmenopausal women aged 54-94 years with nonvertebral fractures and 232 controls in Tromsø, Norway. Odds ratios (ORs) were calculated using logistic regression analysis. RESULTS: Women with fractures had lower FN aBMD, higher FRAX score, and higher cortical porosity than controls (all p < 0.001). Each standard deviation higher porosity was associated with fracture independent of FN aBMD (OR 1.39; 95% confidence interval 1.11-1.74) and FRAX score (OR 1.58; 1.27-1.97) in all women combined. Porosity was also associated with fracture independent of FRAX score in subgroups with normal FN aBMD (OR 1.88; 1.21-2.94), osteopenia (OR 1.40; 1.06-1.85), but not significantly in those with osteoporosis (OR 1.48; 0.68-3.23). Of the 211 fracture cases, only 18 women (9%) were identified using FN aBMD T-score < -2.5, 45 women (21%) using FRAX threshold >20%, whereas porosity >80th percentile identified 61 women (29%). Porosity identified 26% additional women with fractures than identified by the osteoporosis threshold and 21% additional women with fractures than by this FRAX threshold. CONCLUSIONS: Cortical porosity is a risk factor for fracture independent of aBMD and FRAX and improves identification of women with fracture.


Assuntos
Fêmur/patologia , Fraturas por Osteoporose/diagnóstico , Absorciometria de Fóton/métodos , Idoso , Idoso de 80 Anos ou mais , Densidade Óssea/fisiologia , Doenças Ósseas Metabólicas/complicações , Doenças Ósseas Metabólicas/diagnóstico , Estudos de Casos e Controles , Feminino , Colo do Fêmur/fisiopatologia , Humanos , Pessoa de Meia-Idade , Osteoporose Pós-Menopausa/complicações , Osteoporose Pós-Menopausa/diagnóstico , Fraturas por Osteoporose/etiologia , Fraturas por Osteoporose/fisiopatologia , Porosidade , Medição de Risco/métodos , Fatores de Risco , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X/métodos
10.
Osteoporos Int ; 26(6): 1781-90, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25792491

RESUMO

UNLABELLED: We investigated change in health-related quality of life due to fracture in Australian adults aged over 50 years. Fractures reduce quality of life with the loss sustained at least over 12 months. At a population level, the loss was equivalent to 65 days in full health per fracture. PURPOSE: We aimed to quantify the change in health-related quality of life (HRQoL) that occurred as a consequence of a fracture using the EQ-5D-3 L questionnaire. METHODS: Adults aged ≥50 years with a low to moderate energy fracture were recruited from eight study centres across Australia. This prospective study included an 18-month follow-up of participants recruited within 2 weeks of a fracture (hip, wrist, humerus, vertebral and ankle). Information collected at baseline and 4, 12 and 18 months included characteristics of participants such as income level, education and prior fracture status. At 12 months post-fracture, the cumulative loss of quality of life was estimated using multivariate regression analysis to identify the predictors of HRQoL loss. RESULTS: Mean HRQoL for all participants before fracture was 0.86, with wrist fracture having the highest pre-fracture HRQoL (0.90), while vertebral fracture had the lowest (0.80). HRQoL declined to 0.42 in the immediate post-fracture period. Only participants with a wrist, humerus or ankle fracture returned to their pre-fracture HRQoL after 18 months. An increased loss of HRQoL over 12 months was associated with HRQoL prior to the fracture, hospitalisation, education and fracture site. The multiple regression explained 30 % of the variation in the cumulative HRQoL loss at 12 months post-fracture for all fractures. CONCLUSION: Low to moderate energy fractures reduce HRQoL, and this loss is sustained for at least 12 months or, in the case of hip and spine fractures, at least 18 months. At a population level, this represents an average loss of 65 days in full health per fragility fracture. This significant burden reinforces the need for cost-effective fracture prevention strategies.


Assuntos
Fraturas por Osteoporose/reabilitação , Qualidade de Vida , Idoso , Idoso de 80 Anos ou mais , Austrália , Efeitos Psicossociais da Doença , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Psicometria , Anos de Vida Ajustados por Qualidade de Vida , Fatores Socioeconômicos
11.
Calcif Tissue Int ; 97(3): 308-26, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25712256

RESUMO

Type 1 collagen matrix volume, its degree of completeness of its mineralization, the extent of collagen crosslinking and water content, and the non-collagenous proteins like osteopontin and osteocalcin comprise the main constituents of bone's material composition. Each influences material strength and change in different ways during advancing age, health, disease, and drug therapy. These traits are not quantifiable using bone densitometry and their plurality is better captured by the term bone 'qualities' than 'quality'. These qualities are the subject of this manuscript.


Assuntos
Densidade Óssea/fisiologia , Osso e Ossos/metabolismo , Colágeno/metabolismo , Osteocalcina/metabolismo , Osteopontina/metabolismo , Animais , Fenômenos Biomecânicos/fisiologia , Humanos
12.
Osteoporos Int ; 25(8): 2027-33, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24803329

RESUMO

UNLABELLED: In this longitudinal case-control study, acute fracture was associated with low serum testosterone, which was transient in 43% of men. While assessment of gonadal status is part of the assessment of bone fragility, measurement of testosterone in the early period after fracture may overestimate the prevalence of androgen deficiency. INTRODUCTION: Measurement of circulating testosterone is recommended in the evaluation of bone fragility in men. Since acute illness can transiently decrease circulating testosterone, we quantified the association of acute fracture and serum testosterone levels. METHODS: A case-control study was conducted involving 240 men with a radiologically confirmed minimal trauma fracture presenting to a tertiary referral hospital and 89 age-matched men without a history of minimal trauma fracture serving as controls. Follow-up testosterone levels 6 months after baseline were available for 98 cases and 27 controls. Results were expressed as the median and interquartile (IQR) range. RESULTS: Compared to controls, cases had lower total testosterone [TT, 7.2 (3.5, 10.8) vs 13.6 (10.9, 17.1) nmol/L, p < 0.001]. The 143 cases treated as inpatients had lower testosterone levels than the 97 cases treated as outpatients [TT 4.7 (2.3, 8.1) vs 10.3 (7.5, 12.7) nmol/L, p < 0.001]. Group differences in calculated free testosterone (cFT) were comparable to the group differences in TT. At follow-up, in 98 cases, median TT increased from 6.5 nmol/L (3.2, 8.5) to 9.6 nmol/L (6.9, 12.0) p < 0.0001, and SHBG remained unchanged. Of cases with low testosterone, 43% with TT <10 nmol/L and/or cFT <230 pmol/L at presentation were reclassified as androgen sufficient at follow-up. TT was unchanged in the controls. CONCLUSIONS: Low testosterone levels in men presenting with an acute fracture may, at least in part, be due to an acute, fracture-associated, stress response. To avoid over diagnosis, evaluation for testosterone deficiency should be deferred until recovery from the acute event.


Assuntos
Fraturas por Osteoporose/sangue , Testosterona/sangue , Absorciometria de Fóton/métodos , Doença Aguda , Idoso , Idoso de 80 Anos ou mais , Densidade Óssea/fisiologia , Estudos de Casos e Controles , Comorbidade , Seguimentos , Articulação do Quadril/fisiopatologia , Humanos , Vértebras Lombares/fisiopatologia , Masculino , Pessoa de Meia-Idade , Fraturas por Osteoporose/fisiopatologia , Testosterona/deficiência
13.
Osteoporos Int ; 24(7): 2043-8, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23371360

RESUMO

UNLABELLED: Bone remodelling is inhibited by high repetitive loading. However, in subchondral bone of racehorses in training, eroded surface doubled in association with fatigue fracture and there was greater surrounding trabecular bone volume suggesting trabecular modelling unloads the bone focally, allowing damage repair by remodelling. INTRODUCTION: Remodelling replaces damaged bone with new bone but is suppressed during high magnitude repetitive loading when damage is most likely. However, in cortical bone of racehorses, at sites of fatigue fracture, focal porosity, consistent with remodelling, is observed in proportion to the extent of surrounding callus. Focal areas of porosity are also observed at sites of fatigue damage in subchondral bone. We hypothesised that fatigued subchondral bone, like damaged cortical bone, is remodelled focally in proportion to the modelling of surrounding trabecular bone. METHODS: Eroded and mineralizing surfaces and bone area were measured using backscattered scanning electron microscopy of post-mortem specimens of the distal third metacarpal bone in 11 racehorses with condylar fractures (cases) and eight racehorses in training without fractures (controls). RESULTS: Cases had a two-fold greater eroded surface per unit area at the fracture site than controls (0.81 ± 0.10 vs. 0.40 ± 0.12 mm(-1), P = 0.021) but not at an adjacent site (0.22 ± 0.09 vs. 0.30 ± 0.11 mm(-1), P = 0.59). Area fraction of surrounding trabecular bone was higher in cases than controls (81 ± 2 vs. 72 ± 2 %, P = 0.0020) and the eroded surface at the fracture site correlated with the surrounding trabecular area (adjusted R (2) = 0.63, P = 0.0010). CONCLUSION: In conclusion, exercise-induced inhibition of remodelling is offset at sites of fatigue fracture. Modelling of trabecular bone may contribute to unloading these regions, allowing repair by remodelling.


Assuntos
Remodelação Óssea/fisiologia , Fraturas de Estresse/veterinária , Doenças dos Cavalos/fisiopatologia , Condicionamento Físico Animal/fisiologia , Animais , Feminino , Fraturas de Estresse/patologia , Fraturas de Estresse/fisiopatologia , Doenças dos Cavalos/patologia , Cavalos , Masculino , Ossos Metacarpais/ultraestrutura , Microscopia Eletrônica de Varredura , Suporte de Carga/fisiologia
14.
Bone ; 54(1): 8-20, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23334082

RESUMO

A transitional or cortico-trabecular junctional zone exists at any location composed of both cortical and trabecular bones such as the metaphyses of tubular bones and short bones like the femoral neck. The transitional zone comprises the inner cortex adjacent to the medullary canal and trabeculae abutting against the cortex contiguous with the endocortical surface. This is a site of vigorous remodeling. Intracortical remodeling cavitates the inner cortex expanding this transitional zone at the price of compact-appearing cortex so that it contains porosity, cortical fragments that resemble trabeculae, and trabeculae abutting the eroding cortex. The porosity of the transitional zone is an important source of bone loss. It reduces bone strength exponentially and is a quantifiable `fingerprint' of structural deterioration. A new automated method of segmentation of bone from background and bone into its compact-appearing cortex, transitional zone, and trabecular compartment is described, with a new approach to quantification of cortical porosity. Segmentation is achieved by automatically selecting attenuation profile curves perpendicular to the periosteal surface. Local bone edges are identified as the beginning and the end of the rising and falling S-shaped portions of the curve enabling the delineation of the compartments. Analyzing ~3600 consecutive overlapping profiles around the perimeter of each cross-sectional slice segments the compartments. Porosity is quantified as the average void volume fraction of all voxels within each compartment. To assess accuracy at the distal radius and tibia, µCT images of cadaveric specimens imaged at 19 µm voxel size served as the gold standard. To assess accuracy at the proximal femur, scanning electron microscopy (SEM) images of specimens collected at 2.5 µm resolution served as the gold standard. Agreement between HRpQCT and the gold standards for segmentation and quantification of porosity at the distal radius and tibia ranged from R(2)=0.87 to 0.99, and for the proximal femur ranged from 0.93 to 0.99. The precision error in vivo for segmentation and quantification of porosity in HRpQCT images at the distal radius, given by the root mean square error of the coefficient of variation, ranged from 0.54% for porosity of the transitional zone to 3.98% for area of the compact-appearing cortex. Segmentation of the transitional zone minimizes errors in apportioning cortical fragments and cortical porosity to the medullary compartment and so is likely to allow accurate assessment of fracture risk and the morphological effects of growth, aging, diseases and therapies.


Assuntos
Osso e Ossos/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Tomografia Computadorizada por Raios X/métodos , Osso e Ossos/ultraestrutura , Fêmur/diagnóstico por imagem , Humanos , Porosidade , Rádio (Anatomia)/diagnóstico por imagem , Padrões de Referência , Análise de Regressão , Reprodutibilidade dos Testes , Tíbia/diagnóstico por imagem , Microtomografia por Raio-X
15.
Osteoporos Int ; 23(12): 2769-74, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22836278

RESUMO

UNLABELLED: Guidelines concerning the definition of failure of therapies used to reduce the risk of fracture are provided. INTRODUCTION: This study aims to provide guidelines concerning the definition of failure of therapies used to reduce the risk of fracture. METHODS: A working group of the Committee of Scientific Advisors of the International Osteoporosis Foundation was convened to define outcome variables that may assist clinicians in decision making. RESULTS: In the face of limited evidence, failure of treatment may be inferred when two or more incident fractures have occurred during treatment, when serial measurements of bone remodelling markers are not suppressed by anti-resorptive therapy and where bone mineral density continues to decrease. CONCLUSION: The provision of pragmatic criteria to define failure to respond to treatment provides an unmet clinical need and may stimulate research into an important issue.


Assuntos
Conservadores da Densidade Óssea/uso terapêutico , Osteoporose/tratamento farmacológico , Fraturas por Osteoporose/prevenção & controle , Biomarcadores/sangue , Densidade Óssea/efeitos dos fármacos , Remodelação Óssea/efeitos dos fármacos , Humanos , Osteoporose/sangue , Osteoporose/fisiopatologia , Fraturas por Osteoporose/sangue , Fraturas por Osteoporose/fisiopatologia , Falha de Tratamento , Resultado do Tratamento
16.
Osteoporos Int ; 23(10): 2461-7, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22215183

RESUMO

UNLABELLED: Sunlight deprivation results in vitamin D deficiency but serum vitamin D levels can be maintained above 50 nmol/L when supplemented with 50,000 IU at least every alternate month. INTRODUCTION: Antarctic expeditioners are exposed to prolonged sunlight deprivation resulting in vitamin D deficiency. We hypothesised that monthly dosing of 50,000 IU vitamin D (~1,600 IU daily) will increase serum 25-hydroxyvitamin D (25(OH)D), suppress parathyroid hormone (PTH) and improve bone mineral density (BMD), 50,000 IU alternate months (~800 IU daily) will maintain these measures, while a single 50,000 IU dose pre-departure (~1,00 IU daily) will not be protective. METHODS: This was a randomised double-blind study involving 110 healthy adults: 91 males, mean age 41 years (range 24-65 years) working in Antarctica for up to 12 months, who we administered 50,000 IU vitamin D3 monthly, alternate months or a single dose pre-departure. Serum 25(OH)D, PTH, osteocalcin, CTx and calcium were assessed at baseline, mid- and end of expedition. Proximal femur and lumbar spine BMD were assessed pre- and post-expedition. RESULTS: Baseline 25(OH)D was 59 ± 14 nmol/L. By mid-expedition, 25(OH)D increased by 7 nmol/L in those supplemented monthly (p < 0.05) and remained unchanged in those supplemented in alternate months. In those given a single dose pre-departure, 25(OH)D decreased by 8 nmol/L (p < 0.05) and PTH increased by 27% (p < 0.09). Serum osteocalcin increased by ~22% in all groups but BMD remained unchanged. If serum 25(OH)D was >50 nmol/L at baseline, 25(OH)D was maintained above this level with all regimens. If 25(OH)D was <50 nmol/L at baseline, monthly or alternate month regimens were needed to achieve levels >50 nmol/L, the single pre-departure dose was ineffective. CONCLUSION: During sunlight deprivation of up to 12 months, serum 25(OH)D levels can be maintained above 50 nmol/L when expeditioners are provided with 50,000 I U at least every alternate month.


Assuntos
Suplementos Nutricionais , Expedições , Deficiência de Vitamina D/prevenção & controle , Vitamina D/uso terapêutico , Adulto , Idoso , Regiões Antárticas , Cálcio/sangue , Método Duplo-Cego , Esquema de Medicação , Feminino , Fêmur/fisiopatologia , Humanos , Vértebras Lombares/fisiopatologia , Masculino , Pessoa de Meia-Idade , Osteocalcina/sangue , Hormônio Paratireóideo/sangue , Luz Solar , Vitamina D/administração & dosagem , Vitamina D/análogos & derivados , Vitamina D/sangue , Deficiência de Vitamina D/complicações , Deficiência de Vitamina D/fisiopatologia , Adulto Jovem
17.
Osteoporos Int ; 23(2): 411-22, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21853371

RESUMO

Chinese have similar vertebral fracture prevalence but lower incidence of hip and distal forearm fractures than in Caucasians. The underlying structural and biomechanical basis of racial differences in bone fragility is still largely undefined but Chinese assemble their smaller appendicular skeleton with thicker cortices and trabeculae compared with Caucasians. Vertebral fracture prevalence is similar by race, but the incidence of hip and distal forearm fractures is lower in Chinese than in Caucasians. This racial dimorphism cannot be explained by differences in areal bone mineral density (aBMD) as aBMD is lower in Chinese mainly due to their smaller size. The underlying structural and biomechanical basis of racial differences in bone fragility is still largely undefined but Chinese assemble their smaller appendicular skeleton with more mineralised bone matrix within it; the cortices are thicker and perhaps less porous while trabeculae are fewer but thicker and more connected. This configuration produces a bone with a lower surface/volume ratio, which in turn reduces the surface available for remodelling to occur upon so that the lower surface/volume ratio may make the bone less exposed to remodelling and the thicker cortices and trabeculae less vulnerable to remodelling when it does occur during advancing age. However, prospective studies are needed to define racial differences at the age of onset, rate of bone loss from the intracortical, endocortical and trabecular components of the endosteal envelope and bone formation upon the periosteal envelope; notions of bone 'loss' are derived mainly from cross-sectional studies. Studies of the site- and surface-specific changes in bone modelling and remodelling are needed to better define racial differences in bone fragility in old age.


Assuntos
Povo Asiático/estatística & dados numéricos , Fraturas por Osteoporose/etnologia , População Branca/estatística & dados numéricos , Densidade Óssea/ética , Densidade Óssea/fisiologia , Desenvolvimento Ósseo/fisiologia , Fraturas do Quadril/etnologia , Fraturas do Quadril/fisiopatologia , Humanos , Fraturas por Osteoporose/patologia , Fraturas por Osteoporose/fisiopatologia , Fraturas da Coluna Vertebral/etnologia , Fraturas da Coluna Vertebral/fisiopatologia
18.
Osteoporos Int ; 23(1): 53-8, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21691843

RESUMO

UNLABELLED: We examined prevalent and recent vertebral fractures in 1 year as predictors of new vertebral fractures over subsequent 2 years using data from RCT placebo patients. We found that prevalent and recent vertebral fractures strongly and independently predicted subsequent vertebral fractures including those which were severe. INTRODUCTION: While several studies have shown that prevalent vertebral fractures (pVFx) increase the risk of new vertebral fractures (VFx), the impact of recent vertebral fractures on future fractures is less studied. METHODS: Data from the placebo arm of the HORIZON Pivotal Fracture Trial, an international trial of zoledronic acid in postmenopausal, osteoporotic women between 65 and 85 years, were used. We included the subset of 2677 women with annual spinal radiographs to study the impact of vertebral fractures in year 1 (Y1 VF) on those occurring in years 2 and 3 using morphometric and semiquantitative (SQ) criteria. In addition, a subset of severe VFx was defined using SQ criteria. Logistic regression examined the impact of pVFx and Y1 VF on all incident VFx and on severe incident VFx. RESULTS: Two hundred fourty-five (9.1%) women sustained a new VFx in years 2-3. VFx risk in years 2-3 was 3.9% in those without pVFx or VFy1 and 29.8% in those with both risk factors. Both pVF and VFy1 remained independent predictors for future VF when they were both entered into a logistic regression model (odds ratio (OR) = 3.3; 95% confidence interval (CI), 2.3-4.7; OR = 3.7, 95% CI, 2.3, 5.8, respectively). ORs were similar after adjustment. Of the total number of women, 4.1% had severe VFx. PVFx and Y1 VF were also significant predictors of severe VFx; however, Y1 VF appeared more strongly predictive of severe VFx. CONCLUSIONS: Prevalent and incident vertebral fractures are highly predictive of subsequent new and severe vertebral fractures. Women with both of these risk factors are likely to benefit from anti-osteoporosis treatment.


Assuntos
Fraturas por Osteoporose/epidemiologia , Fraturas da Coluna Vertebral/epidemiologia , Idoso , Idoso de 80 Anos ou mais , Densidade Óssea , Conservadores da Densidade Óssea/uso terapêutico , Difosfonatos/uso terapêutico , Métodos Epidemiológicos , Feminino , Colo do Fêmur/fisiopatologia , Humanos , Imidazóis/uso terapêutico , Osteoporose Pós-Menopausa/complicações , Osteoporose Pós-Menopausa/tratamento farmacológico , Osteoporose Pós-Menopausa/epidemiologia , Osteoporose Pós-Menopausa/fisiopatologia , Fraturas por Osteoporose/tratamento farmacológico , Fraturas por Osteoporose/fisiopatologia , Prognóstico , Fraturas da Coluna Vertebral/etiologia , Fraturas da Coluna Vertebral/fisiopatologia , Fraturas da Coluna Vertebral/prevenção & controle , Índices de Gravidade do Trauma , Ácido Zoledrônico
19.
Osteoporos Int ; 22(11): 2789-98, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21509585

RESUMO

UNLABELLED: The consensus views on osteoporosis in men are reported. INTRODUCTION: A workshop was convened within a meeting on osteoporosis in men to identify areas of consensus amongst the panel (the authors) and the participants of the meeting. METHODS: A public debate with an expert panel on preselected topics was conducted. RESULTS AND CONCLUSIONS: Consensus views were reached on diagnostic criteria and several aspects on the pathophysiology and treatment of osteoporosis in men.


Assuntos
Densidade Óssea/fisiologia , Osteoporose , Absorciometria de Fóton , Acidentes por Quedas/estatística & dados numéricos , Androgênios/uso terapêutico , Índice de Massa Corporal , Feminino , Colo do Fêmur/diagnóstico por imagem , Humanos , Masculino , Osteoporose/diagnóstico , Osteoporose/epidemiologia , Osteoporose/terapia , Fraturas por Osteoporose/epidemiologia , Padrões de Referência , Fatores de Risco , Fatores Sexuais , Globulina de Ligação a Hormônio Sexual/metabolismo , Testosterona/sangue , Testosterona/uso terapêutico
20.
Osteoporos Int ; 22(5): 1621-6, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-20734028

RESUMO

SUMMARY: The purpose of this study was to examine if the reduction in glucose post-exercise is mediated by undercarboxylated osteocalcin (unOC). Obese men were randomly assigned to do aerobic or power exercises. The change in unOC levels was correlated with the change in glucose levels post-exercise. The reduction in glucose post-acute exercise may be partly related to increased unOC. INTRODUCTION: Osteocalcin (OC) in its undercarboxylated (unOC) form may contribute to the regulation of glucose homeostasis. As exercise reduces serum glucose and improves insulin sensitivity in obese individuals and individuals with type 2 diabetes (T2DM), we hypothesised that this benefit was partly mediated by unOC. METHODS: Twenty-eight middle-aged (52.4 ± 1.2 years, mean ± SEM), obese (BMI = 32.1 ± 0.9 kg m(-2)) men were randomly assigned to do either 45 min of aerobic (cycling at 75% of VO(2peak)) or power (leg press at 75% of one repetition maximum plus jumping sequence) exercises. Blood samples were taken at baseline and up to 2 h post-exercise. RESULTS: At baseline, unOC was negatively correlated with glucose levels (r = -0.53, p = 0.003) and glycosylated haemoglobin (HbA1c) (r = -0.37, p = 0.035). Both aerobic and power exercises reduced serum glucose (from 7.4 ± 1.2 to 5.1 ± 0.5 mmol L(-1), p = 0.01 and 8.5 ± 1.2 to 6.0 ± 0.6 mmol L(-1), p = 0.01, respectively). Aerobic exercise significantly increased OC, unOC and high-molecular-weight adiponectin, while power exercise had a limited effect on OC and unOC. Overall, those with higher baseline glucose and HbA1c had greater reductions in glucose levels after exercise (r = -0.46, p = 0.013 and r = -0.43, p = 0.019, respectively). In a sub-group of obese people with T2DM, the percentage change in unOC levels was correlated with the percentage change in glucose levels post-exercise (r = -0.51, p = 0.038). CONCLUSIONS: This study reports that the reduction in serum glucose post-acute exercise (especially aerobic exercise) may be partly related to increased unOC.


Assuntos
Exercício Físico/fisiologia , Obesidade/sangue , Osteocalcina/sangue , Antropometria/métodos , Glicemia/metabolismo , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/etiologia , Diabetes Mellitus Tipo 2/fisiopatologia , Hemoglobinas Glicadas/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Força Muscular/fisiologia , Obesidade/complicações , Obesidade/fisiopatologia , Osteocalcina/fisiologia
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