Medicine (Western Health) - Research Publications
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ItemNo Preview AvailableExploring new balance and gait factors that are associated with osteosarcopenia in patients with a previous fall and/or fracture history(ELSEVIER IRELAND LTD, 2024-02)Osteosarcopenic individuals have poor muscle function and increased bone fragility, which results in a severe detriment to health outcomes. Hence, there is a necessity to discover easily accessible factors associated with osteosarcopenia to develop timely interventions. This study aimed to determine new sensitive balance and/or gait variables that are associated with osteosarcopenia in a population of older people with a history of falls and/or fractures. In a cross-sectional cohort study, 306 men and women aged ≥65 years completed a series of questionnaires, clinical assessments and muscle strength and function tests. Subsequently, participants were separated into osteopenia, osteoporosis and osteosarcopenia, groups for comparison and further analysis. Osteosarcopenia performed worse than osteopenia and osteoporosis in grip strength, gait speed, physical function scores and in multiple gait and balance indices (p<0.001). During posturography testing, there were larger elliptical areas with eyes open (p = 0.003), and eyes closed (p = 0.043) and increased sway velocity on a firm platform (p = 0.007) in the osteosarcopenia group, compared to osteoporosis. Limits of stability and eyes open ellipse area significantly contributed to the multivariable model (p = 0.029 and p = 0.038, respectively), suggesting that these balance parameters, along with grip strength, may be useful in identifying older adults with osteosarcopenia from those with only osteopenia/osteoporosis. Older adults with osteosarcopenia and a history of falls and/or fractures demonstrated inferior strength, function, and gait characteristics. This study identified indices of balance that were sensitive discriminators for osteosarcopenia and could be easily implemented into routine assessment.
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ItemNo Preview AvailableCognition in healthy older women is a predictor of 14‐year falls risk(Wiley, 2021-12)Background: Falls are a significant cause of injuries, loss of confidence, increased morbidity, and institutionalisation in all older people, with women at 50% greater risk than men. The relationship between dementia and falls is well established and 2/3 of all dementia occurs in women. In this study we explored risk factors associated with a 14 year falls risk in a community-based cohort of women, which included validated measures across a wide range of clinical domains including neuropsychological, mood, quality of life and biomarkers (including hormonal). Method: The Australian Women’s Healthy Aging Project is an longitudinal observation study, assessments every year (1991 –1999), followed by assessments in 2002, 2004, 2012 and 2014. The assessments included cognitive (as of 2002), blood, and cardiovascular disease risk assessment, and questions related to falls. After data cleaning, the remaining cohort consisted of 180 participants (Table 1). Missing data were imputed using mice random forest. To identify key risk factors associated with a 14 year falls risk, random survival (time to event) forest (RSF) machine learning was used. Result: The RSF model, using all 290+ possible predictive variables, performed well with an Out Of Bag (OOB, withheld data) prediction error (C-index) of 32.8%. The most predictive variables in the model were identified using the variable importance measure (VIM). The initial model was refined by taking the top 30 predictive variables and retraining the RSF. This refined model resulted in an improved OOB C-index of 5.8% (27%). The top 20 predictive variables, Figure 1, include those associated with cardiovascular disease risk, cognitive performance, and hormone levels (e.g., family history of heart attack, digit symbol coding, and estradiol levels). Conclusion: Ninety percent of the top 20 predictive risk variables for the 14 year fall risk in women, were from three key domains, cognition (40%), cardiovascular (25%) and hormone-related measurements (25%). Our data suggest that for long term prevention of falls these domains may be important reducing risk of falls in the senior female population.
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ItemRelationship Between Plasma Homocysteine and Bone Density, Lean Mass, Muscle Strength and Physical Function in 1480 Middle-Aged and Older Adults: Data from NHANES(SPRINGER, 2023-01)Hyperhomocysteinemia induces oxidative stress and chronic inflammation (both of which are catabolic to bone and muscle); thus, we examined the association between homocysteine and body composition and physical function in middle-aged and older adults. Data from the National Health and Nutrition Examination Survey was used to build regression models. Plasma homocysteine (fluorescence immunoassay) was used as the exposure and bone mineral density (BMD; dual-energy X-ray absorptiometry; DXA), lean mass (DXA), knee extensor strength (isokinetic dynamometer; newtons) and gait speed (m/s) were used as outcomes. Regression models were adjusted for confounders (age, sex, race/Hispanic origin, height, fat mass %, physical activity, smoking status, alcohol intakes, cardiovascular disease, diabetes, cancer and vitamin B12). All models accounted for complex survey design by using sampling weights provided by NHANES. 1480 adults (median age: 64 years [IQR: 56, 73]; 50.3% men) were included. In multivariable models, homocysteine was inversely associated with knee extensor strength (β = 0.98, 95% CI 0.96, 0.99, p = 0.012) and gait speed (β = 0.85, 95% CI 0.78, 0.94, p = 0.003) and borderline inversely associated with femur BMD (β = 0.84, 95% CI 0.69, 1.03, p = 0.086). In the sub-group analysis of older adults (≥ 65 years), homocysteine was inversely associated with gait speed and femur BMD (p < 0.05) and the slope for knee extensor strength and whole-body BMD were in the same direction. No significant associations were observed between homocysteine and total or appendicular lean mass in the full or sub-group analysis. We found inverse associations between plasma homocysteine and muscle strength/physical function, and borderline significant inverse associations for femur BMD.
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ItemNo Preview AvailableFactor analysis to determine relative contributions of strength, physical performance, body composition and muscle mass to disability and mobility disability outcomes in older men(PERGAMON-ELSEVIER SCIENCE LTD, 2022-05)BACKGROUND: It is not known how measures of body composition, strength and physical performance are interrelated or how empirical groupings of these measures relate to disability and mobility disability. METHODS: Muscle mass was assessed by D3-creatine dilution (D3Cr muscle mass) in 1345 men (84.1 ± 4.1 years) enrolled in the Osteoporotic Fractures in Men (MrOS) study. Participants completed anthropomorphic measures, walk speed, grip strength, chair stands, and dual x-ray absorptiometry (DXA) estimated appendicular lean mass (ALM) and body fat percentage. Men reported limitations in mobility, activities of daily living (ADLs) and instrumental ADLs at initial and over 2.2 ± 0.3 years. Factor analysis reduced variables into related groups and negative binomial models calculated relative risk (RR) of factors with mobility and disability outcomes. RESULTS: Factor analysis reduced 10 variables into four factors: Factor 1, body composition, including ALM, body fat percentage, weight and muscle mass; Factor 2, body size and lean mass, including height, weight and ALM; Factor 3, muscle mass, strength and performance, including walk speed, chair stands, grip strength, and muscle mass; and Factor 4, lean mass and weight, including ALM and weight. Only Factor 3 was significantly associated (p-value < .001) with prevalent disability (RR per standard deviation increment in factor score (reflecting higher muscle mass, strength and physical performance) 0.44, 0.35-0.56) and mobility disability (RR 0.22, 0.17 0.28), and incident mobility disability (RR 0.37, 0.27-0.50). CONCLUSION: D3Cr muscle mass was the only body composition variable that co-segregated with strength and physical performance measures, and contributed to a factor that was associated with disability outcomes in older men.
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ItemNo Preview AvailableValidation of a Semiautomatic Image Analysis Software for the Quantification of Musculoskeletal Tissues(SPRINGER, 2022-03)Accurate quantification of bone, muscle, and their components is still an unmet need in the musculoskeletal field. Current methods to quantify tissue volumes in 3D images are expensive, labor-intensive, and time-consuming; thus, a reliable, valid, and quick application is highly needed. Tissue Compass is a standalone software for semiautomatic segmentation and automatic quantification of musculoskeletal organs. To validate the software, cross-sectional micro-CT scans images of rat femur (n = 19), and CT images of hip and abdomen (n = 100) from the Osteoporotic Fractures in Men (MrOS) Study were used to quantify bone, hematopoietic marrow (HBM), and marrow adipose tissue (MAT) using commercial manual software as a comparator. Also, abdominal CT scans (n = 100) were used to quantify psoas muscle volumes and intermuscular adipose tissue (IMAT) using the same software. We calculated Pearson's correlation coefficients, individual intra-class correlation coefficients (ICC), and Bland-Altman limits of agreement together with Bland-Altman plots to show the inter- and intra-observer agreement between Tissue Compass and commercially available software. In the animal study, the agreement between Tissue Compass and commercial software was r > 0.93 and ICC > 0.93 for rat femur measurements. Bland-Altman limits of agreement was - 720.89 (- 1.5e+04, 13,074.00) for MAT, 4421.11 (- 1.8e+04, 27,149.73) for HBM and - 6073.32 (- 2.9e+04, 16,388.37) for bone. The inter-observer agreement for QCT human study between two observers was r > 0.99 and ICC > 0.99. Bland-Altman limits of agreement was 0.01 (- 0.07, 0.10) for MAT in hip, 0.02 (- 0.08, 0.12) for HBM in hip, 0.05 (- 0.15, 0.25) for bone in hip, 0.02 (- 0.18, 0.22) for MAT in L1, 0.00 (- 0.16, 0.16) for HBM in L1, and 0.02 (- 0.23, 0.27) for bone in L1. The intra-observer agreement for QCT human study between the two applications was r > 0.997 and ICC > 0.99. Bland-Altman limits of agreement was 0.03 (- 0.13, 0.20) for MAT in hip, 0.05 (- 0.08, 0.18) for HBM in hip, 0.05 (- 0.24, 0.34) for bone in hip, - 0.02 (- 0.34, 0.31) for MAT in L1, - 0.14 (- 0.44, 0.17) for HBM in L1, - 0.29 (- 0.62, 0.05) for bone in L1, 0.03 (- 0.08, 0.15) for IMAT in psoas, and 0.02 (- 0.35, 0.38) for muscle in psoas. Compared to a conventional application, Tissue Compass demonstrated high accuracy and non-inferiority while also facilitating easier analyses. Tissue Compass could become the tool of choice to diagnose tissue loss/gain syndromes in the future by requiring a small number of CT sections to detect tissue volumes and fat infiltration.
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ItemProgressive Resistance Training for Concomitant Increases in Muscle Strength and Bone Mineral Density in Older Adults: A Systematic Review and Meta-Analysis(ADIS INT LTD, 2022-08)BACKGROUND: Older adults experience considerable muscle and bone loss that are closely interconnected. The efficacy of progressive resistance training programs to concurrently reverse/slow the age-related decline in muscle strength and bone mineral density (BMD) in older adults remains unclear. OBJECTIVES: We aimed to quantify concomitant changes in lower-body muscle strength and BMD in older adults following a progressive resistance training program and to determine how these changes are influenced by mode (resistance only vs. combined resistance and weight-bearing exercises), frequency, volume, load, and program length. METHODS: MEDLINE/PubMed and Embase databases were searched for articles published in English before 1 June, 2021. Randomized controlled trials reporting changes in leg press or knee extension one repetition maximum and femur/hip or lumbar spine BMD following progressive resistance training in men and/or women ≥ 65 years of age were included. A random-effects meta-analysis and meta-regression determined the effects of resistance training and the individual training characteristics on the percent change (∆%) in muscle strength (standardized mean difference) and BMD (mean difference). The quality of the evidence was assessed using the Cochrane risk-of-bias tool (version 2.0) and Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) criteria. RESULTS: Seven hundred and eighty studies were identified and 14 were included. Progressive resistance training increased muscle strength (∆ standardized mean difference = 1.1%; 95% confidence interval 0.73, 1.47; p ≤ 0.001) and femur/hip BMD (∆ mean difference = 2.77%; 95% confidence interval 0.44, 5.10; p = 0.02), but not BMD of the lumbar spine (∆ mean difference = 1.60%; 95% confidence interval - 1.44, 4.63; p = 0.30). The certainty for improvement was greater for muscle strength compared with BMD, evidenced by less heterogeneity (I2 = 78.1% vs 98.6%) and a higher overall quality of evidence. No training characteristic significantly affected both outcomes (p > 0.05), although concomitant increases in strength and BMD were favored by higher training frequencies, increases in strength were favored by resistance only and higher volumes, and increases in BMD were favored by combined resistance plus weight-bearing exercises, lower volumes, and higher loads. CONCLUSIONS: Progressive resistance training programs concomitantly increase lower-limb muscle strength and femur/hip bone mineral density in older adults, with greater certainty for strength improvement. Thus, to maximize the efficacy of progressive resistance training programs to concurrently prevent muscle and bone loss in older adults, it is recommended to incorporate training characteristics more likely to improve BMD.
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ItemEffects of 3 months of multi-nutrient supplementation on the immune system and muscle and respiratory function of older adults in aged care (The Pomerium Study): protocol for a randomised controlled trial(BMJ PUBLISHING GROUP, 2022-05)INTRODUCTION: Immunosenescence leads to increased morbidity and mortality associated with viral infections and weaker vaccine responses. This has been well documented for seasonal influenza and the current pandemic with SARS-CoV-2 (COVID-19), which disproportionately impact older adults, particularly those in residential aged care facilities. Inadequate nutrient intakes associated with impaired immunity, respiratory and muscle function are likely to augment the effects of immunosenescence. In this study, we test whether the impact of inadequate nutrition can be reversed using multi-nutrient supplementation, consequently enhancing vaccine responses, reducing the risk of viral infections and improving respiratory and muscle function. METHODS AND ANALYSIS: The Pomerium Study is a 3-month, single-blind, randomised, controlled trial testing the effects of two daily servings of an oral multi-nutrient supplement (330 kcal, 20 g protein, 1.5 g calcium 3-hydroxy-3-methylbutyrate monohydrate (CaHMB), 449 mg calcium, 500 IU vitamin D3 and 25 vitamins and minerals) on the immune system and muscle and respiratory function of older adults in aged care in Melbourne, Australia. 160 older adults (≥75 years old) will be recruited from aged care facilities and randomised to treatment (multi-nutrient supplement) or control (usual care). The primary outcome is a change in T-cell subsets CD8 + and CD28null counts at months 1 and 3. Secondary outcomes measured at baseline and month 3 are multiple markers of immunosenescence (also at 1 month), body composition (bioimpedance), handgrip strength (dynamometer), physical function (short physical performance battery), respiratory function (spirometry) and quality of life (EQ-5D-5L). Incidence and complications of COVID-19 and/or viral infections (ie, hospitalisation, complications or death) will be recorded throughout the trial, including 3 months after supplementation is ceased. ETHICS AND DISSEMINATION: This study was approved by Melbourne Health Human Research Ethics Committee (Ref No. HREC/73985/MH-2021, ERM Ref No. RMH73985, Melbourne Health Site Ref No. 2021.115). Written informed consent will be obtained from participants. Results will be published in peer-reviewed journals and made available to key aged care stakeholders, including providers, residents, and government bodies. TRIAL REGISTRATION NUMBER: ACTRN12621000420842.
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ItemAssociation Between Tryptophan Metabolites, Physical Performance, and Frailty in Older Persons(SAGE PUBLICATIONS LTD, 2022-01)Frailty is defined as a syndrome of physiological decline in late life, characterized by marked vulnerability to adverse health outcomes. A robust biomarker for frailty is still lacking. Tryptophan (TRP) metabolism through the kynurenine pathway (KP) plays essential roles in aging, the musculoskeletal system, and physical performance. In this study, we quantified 7 KP metabolites, including kynurenine (KYN), kynurenine acid (KYNA), quinolinic acid (QUIN), picolinic acid (PIC), 3-hydroxykynurenine (3-HK), 3-hydroxyanthranilic acid (3-HAA), and anthranilic acid (AA) using ultra-high-performance liquid chromatography and gas chromatography-mass spectrometry in the serum of 85 participants (median age 75; 65% female; 28 non-frail, 29 pre-frail, and 28 frail) at the Nepean Osteoporosis and Frailty (NOF) Study. We looked at the association between TRP metabolites and physical performance, sarcopenia, and frailty. After adjusting for age and sex, our results showed that KYN and KYN/TRP were associated with higher interleukin (IL)-6 levels (r = .324 and r = .390, respectively). KYNA and its ratios to other products (mainly KYNA/KYN, KYNA/QUIN, and KYNA/PIC) were associated with a lower likelihood of frailty by Fried's criteria (OR 0.93 [0.88, 0.98], P = .009) and Rockwood index (r = -.241, P = .028) as well as a lower likelihood of sarcopenia (OR 0.88 [0.78, 1.00], P = .049). QUIN and QUIN/KYN showed an association with increased IL-6 (r = .293 and .204 respectively), higher likelihood of frailty (OR 1.02 [1.00, 1.04], P = .029 and OR 6.43 [2.23, 18.51], P = .001 respectively) and lower physical function (r = -.205 and r = -.292). In conclusion, different TRP metabolites have various associations with physical performance, frailty, and sarcopenia. Defining the underlying mechanisms may permit the development and validation of new biomarkers and therapeutics for frailty and musculoskeletal conditions targeting specific metabolites of the TRP catabolic pathway.
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