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Ten Brinke L.F.,Maastricht University | Bolandzadeh N.,UBC | Bolandzadeh N.,Djavad Mowafaghian Center for Brain Health | Nagamatsu L.S.,UBC | And 8 more authors.
British Journal of Sports Medicine | Year: 2015

Background: Mild cognitive impairment (MCI) is a well-recognised risk factor for dementia and represents a vital opportunity for intervening. Exercise is a promising strategy for combating cognitive decline by improving brain structure and function. Specifically, aerobic training (AT) improved spatial memory and hippocampal volume in healthy community-dwelling older adults. In older women with probable MCI, we previously demonstrated that resistance training (RT) and AT improved memory. In this secondary analysis, we investigated: (1) the effect of RT and AT on hippocampal volume and (2) the association between change in hippocampal volume and change in memory. Methods: 86 women aged 70-80 years with probable MCI were randomly assigned to a 6-month, twice-weekly programme of: (1) AT, (2) RT or (3) balance and tone training (BAT; ie, control). At baseline and trial completion, participants performed a 3T MRI scan to determine hippocampal volume. Verbal memory and learning were assessed by Rey's Auditory Verbal Learning Test. Results: Compared with the BAT group, AT significantly improved left, right and total hippocampal volumes ( p≤0.03). After accounting for baseline cognitive function and experimental group, increased left hippocampal volume was independently associated with reduced verbal memory and learning performance as indexed by loss after interference (r=0.42, p=0.03). Conclusions: Aerobic training signi ficantly increased hippocampal volume in older women with probable MCI. More research is needed to ascertain the relevance of exercise-induced changes in hippocampal volume on memory performance in older adults with MCI. Trail registration number NCT00958867. © 2015, BMJ Publishing Group. All rights reserved.


Pang M.Y.C.,Hong Kong Polytechnic University | Ashe M.C.,University of British Columbia | Ashe M.C.,Vancouver Coastal Health Research Institute | Ashe M.C.,Center for Hip Health and Mobility | And 3 more authors.
Osteoporosis International | Year: 2010

The purpose of this study was to identify the determinants of the bone strength index of the distal tibia epiphysis in chronic stroke patients. The results showed that lower cardiovascular fitness, more muscle atrophy, poorer mobility, and more severe spasticity were independently associated with lower tibial bone strength index. Introduction To identify the determinants of the bone strength index (BSI) at the distal tibia in chronic stroke patients Methods Sixty-three chronic stroke survivors underwent scanning of the distal tibia at the 4% site on both sides using peripheral quantitative computed tomography. The primary outcomes were trabecular bone mineral density (BMD; milligram per cubic centimeter), total BMD (milligram per cubic centimeter), total bone area (square millimeter), and BSI (square gram per centimeter to the power of four). Cardiovascular fitness, leg lean mass, gait velocity, and spasticity were also measured. Results Scans from 45 subjects were deemed to have acceptable quality and were included for subsequent analysis. The paretic side had significantly lower trabecular BMD, total BMD, and BSI than the nonparetic side (p < 0.05). However, the total bone area demonstrated no significant side-to-side difference (p > 0.05). After adjusting for relevant biological factors, peak oxygen consumption, leg muscle mass, and gait velocity remained positively associated with tibial BSI on both sides (R2 change = 6.9-14.2%), whereas spasticity of the paretic leg was negatively associated with tibial BSI on the same side (R2 change = 4.8%). Conclusions Cardiovascular function, muscle atrophy, mobility, and spasticity are independently associated with BSI of the distal tibia epiphysis among chronic stroke patients. © International Osteoporosis Foundation and National Osteoporosis Foundation 2009.


Gorman E.,Center for Hip Health and Mobility | Gorman E.,University of British Columbia | Hanson H.M.,Center for Hip Health and Mobility | Hanson H.M.,University of British Columbia | And 6 more authors.
European Review of Aging and Physical Activity | Year: 2014

Accelerometers objectively monitor physical activity and sedentary patterns and are increasingly used in the research setting. It is important to maintain consistency in data analysis and reporting, therefore, we: (1) systematically identified studies using accelerometry (ActiGraph, Pensacola, FL, USA) to measure moderate-to-vigorous physical activity (MVPA) and sedentary time in older adults, and (2) based on the review findings, we used different cut-points obtained to analyze accelerometry data from a sample of community-dwelling older women. We identified 59 articles with cut-points ranging between 574 and 3,250 counts/min for MVPA and 50 and 500 counts/min for sedentary time. Using these cut-points and data from women (mean age, 70 years), the median MVPA minutes per day ranged between 4 and 80 min while percentage of sedentary time per day ranged between 62 % and 86 %. These data highlight (1) the importance of reporting detailed information on the analysis assumptions and (2) that results can differ greatly depending on analysis parameters. © 2013 The Author(s).


Nishiyama K.K.,University of Calgary | Nishiyama K.K.,McCaig Institute for Bone and Joint Health | Macdonald H.M.,University of British Columbia | Macdonald H.M.,Child and Family Research Institute | And 5 more authors.
Osteoporosis International | Year: 2013

High-resolution peripheral quantitative computed tomography (HR-pQCT) measurements of distal radius and tibia bone microarchitecture and finite element (FE) estimates of bone strength performed well at classifying postmenopausal women with and without previous fracture. The HR-pQCT measurements outperformed dual energy x-ray absorptiometry (DXA) at classifying forearm fractures and fractures at other skeletal sites. Introduction: Areal bone mineral density (aBMD) is the primary measurement used to assess osteoporosis and fracture risk; however, it does not take into account bone microarchitecture, which also contributes to bone strength. Thus, our objective was to determine if bone microarchitecture measured with HR-pQCT and FE estimates of bone strength could classify women with and without low-trauma fractures. Methods: We used HR-pQCT to assess bone microarchitecture at the distal radius and tibia in 44 postmenopausal women with a history of low-trauma fracture and 88 age-matched controls from the Calgary cohort of the Canadian Multicentre Osteoporosis Study (CaMos) study. We estimated bone strength using FE analysis and simulated distal radius aBMD from the HR-pQCT scans. Femoral neck (FN) and lumbar spine (LS) aBMD were measured with DXA. We used support vector machines (SVM) and a tenfold cross-validation to classify the fracture cases and controls and to determine accuracy. Results: The combination of HR-pQCT measures of microarchitecture and FE estimates of bone strength had the highest area under the receiver operating characteristic (ROC) curve of 0.82 when classifying forearm fractures compared to an area under the curve (AUC) of 0.71 from DXA-derived aBMD of the forearm and 0.63 from FN and spine DXA. For all fracture types, FE estimates of bone strength at the forearm alone resulted in an AUC of 0.69. Conclusion: Models based on HR-pQCT measurements of bone microarchitecture and estimates of bone strength performed better than DXA-derived aBMD at classifying women with and without prior fracture. In future, these models may improve prediction of individuals at risk of low-trauma fracture. © 2012 International Osteoporosis Foundation and National Osteoporosis Foundation.


Dunne T.J.,Vancouver Coastal Health Authority | Gaboury I.,Université de Sherbrooke | Ashe M.C.,Center for Hip Health and Mobility | Ashe M.C.,University of British Columbia
Journal of Evaluation in Clinical Practice | Year: 2014

Rationale, aims and objectives Acute inpatient falls are common and serious adverse events that lead to injury, prolonged hospitalization and increased cost of care. To determine the difference in total acute hospital care length of stay (LOS) for patients with and without an in-hospital fall (IHF), regardless of degree of harm. Methods This was a retrospective observational study at a 728-bed acute care teaching hospital. We used propensity scores to match 292 patients with 330 controls by case mix group, sex, Resource Intensity Weights and week of admission. We used two administrative databases: hospital fall incident reporting system and Discharge Abstract Database. We reviewed all IHF incidents for patients 18 years and older, admitted to inpatient acute care hospital units/programs between 1 November 2009 and 31 August 2011. Results The average LOS for IHF cases was 37.2 days [median 26.5 days; interquartile range (IQR) 14, 54] and 25.7 days (median 13 days; IQR 5, 33) for matched control patients. Survival analysis results indicated that patients who did not have an IHF were 2.4 times (95% CI 2.1, 2.7; P < 0.001) more likely to be discharged earlier from acute care than patients who had an IHF. Conclusions Experiencing either an injurious or a non-injurious fall during an acute care hospitalization was associated with prolonged LOS. © 2014 John Wiley & Sons, Ltd.


Davis J.C.,Vancouver Coastal Health Research Institute | Davis J.C.,University of British Columbia | Bryan S.,Vancouver Coastal Health Research Institute | Bryan S.,University of British Columbia | And 4 more authors.
BMC Geriatrics | Year: 2012

Background: Our research sought to understand how falls risk, cognitive function, and daily function are associated with health related quality of life (using the EuroQol-5D) and quality of life (using the ICECAP-O) among older adults with mobility impairments. Methods. The EQ-5D and ICECAP-O were administered at 12 months post first clinic attendance at the Vancouver Falls Prevention Clinic. We report descriptive statistics for all baseline characteristics collected at first clinic visit and primary outcomes of interest. Using multivariate stepwise linear regression, we assessed the construct validity of the EQ-5D and ICECAP-O using three dependent measures that are recognized indicators of "impaired mobility" - physiological falls risk, general balance and mobility, and cognitive status among older adults. Results: We report data on 215 seniors who attended the Vancouver Falls Prevention Clinic and received their first clinic assessment. Patients had a mean age of 79.3 (6.2) years. After accounting for known covariates (i.e., age and sex), the ICECAP-O domains explained a greater amount of variation in each of the three dependent measures compared with the EQ-5D domains. Conclusion: Both the EQ-5D and ICECAP-O demonstrate associations with falls risk and general balance and mobility; however, only the ICECAP-O was associated with cognitive status among older adults with mobility impairments. Trial registration. ClinicalTrials.gov Identifier: NCT01022866. © 2012 Davis et al.; licensee BioMed Central Ltd.


Chudyk A.M.,University of British Columbia | Winters M.,Simon Fraser University | Gorman E.,Center for Hip Health and Mobility | McKay H.A.,University of British Columbia | Ashe M.C.,University of British Columbia
Journal of Aging and Physical Activity | Year: 2014

The authors investigated the use of Google Earth's Street View option to audit the presence of built environment features that support older adults' walking. Two raters conducted virtual (Street View) and in-the-field audits of 48 street segments surrounding urban and suburban assisted living sites in metropolitan Vancouver, BC, Canada. The authors determined agreement using absolute agreement. Their findings indicate that Street View may identify the presence of features that promote older adults' walking, including sidewalks, benches, public washrooms, and destinations. However, Street View may not be as reliable as in-the-field audits to identify details associated with certain items, such as counts of trees or street lights; presence, features, and height of curb cuts; and sidewalk continuity, condition, and slope. Thus, the appropriateness of virtual audits to identify microscale built environment features associated with older adults' walking largely depends on the purpose of the audits - specifically, whether the measurer seeks to capture highly detailed features of the built environment. © 2014 Human Kinetics, Inc.


Robinovitch S.N.,Simon Fraser University | Feldman F.,Fraser Health Authority | Yang Y.,Simon Fraser University | Schonnop R.,Simon Fraser University | And 4 more authors.
The Lancet | Year: 2013

Background Falls in elderly people are a major health burden, especially in the long-term care environment. Yet little objective evidence is available for how and why falls occur in this population. We aimed to provide such evidence by analysing real-life falls in long-term care captured on video. Methods We did this observational study between April 20, 2007, and June 23, 2010, in two long-term care facilities in British Columbia, Canada. Digital video cameras were installed in common areas (dining rooms, lounges, hallways). When a fall occurred, facility staff completed an incident report and contacted our teams so that we could collect video footage. A team reviewed each fall video with a validated questionnaire that probed the cause of imbalance and activity at the time of falling. We then tested whether diff erences existed in the proportion of participants falling due to the various causes, and while engaging in various activities, with generalised linear models, repeated measures logistic regression, and log-linear Poisson regression. Findings We captured 227 falls from 130 individuals (mean age 78 years, SD 10). The most frequent cause of falling was incorrect weight shifting, which accounted for 41% (93 of 227) of falls, followed by trip or stumble (48, 21%), hit or bump (25, 11%), loss of support (25, 11%), and collapse (24, 11%). Slipping accounted for only 3% (six) of falls. The three activities associated with the highest proportion of falls were forward walking (54 of 227 falls, 24%), standing quietly (29 falls, 13%), and sitting down (28 falls, 12%). Compared with previous reports from the long-term care setting, we identifi ed a higher occurrence of falls during standing and transferring, a lower occurrence during walking, and a larger proportion due to centre-of-mass perturbations than base-of-support perturbations. Interpretation By providing insight into the sequences of events that most commonly lead to falls, our results should lead to more valid and eff ective approaches for balance assessment and fall prevention in long-term care. Funding Canadian Institutes for Health Research.


Voss C.,University of British Columbia | Winters M.,Simon Fraser University | Frazer A.,Center for Hip Health and Mobility | McKay H.,University of British Columbia
Preventive Medicine Reports | Year: 2015

Background: Walking and cycling to school is a source of physical activity (PA). Little is known about public transit use for travel to school and whether it is a physically active alternative to car use for those who live too far to walk. Purpose: To describe school-trip characteristics, including PA, across travel modes and to assess the association between PA with walk distance. Methods: High school students (13.3. ±. 0.7. years, 37% female) from Downtown Vancouver wore accelerometers (GT3X. +) and global positioning systems (GPS) (QStarz BT-Q1000XT) for 7. days in October 2012. We included students with valid school-trip data (. n=. 100 trips made by n=. 42 students). We manually identified school-trips and mode from GPS and calculated trip duration, distance, speed, and trip-based moderate-to-vigorous PA (MVPA; min). We assessed between-mode differences and associations using multilevel regression analyses (spring 2014). Results: Students accrued 9.1. min (±. 5.1) of trip-based MVPA, which was no different between walk and transit trips (. p=. 0.961). Walking portions of transit trips were similar to walking trips in terms of distance (. p=. 0.265) and duration (. p=. 0.493). Walk distance was associated with MVPA in a dose-response manner. Conclusions: Public transit use can contribute meaningfully toward daily PA. Thus, school policies that promote active school-travel should consider including public transit. © 2015.


Nishiyama K.K.,University of Calgary | Nishiyama K.K.,McCaig Institute for Bone and Joint Health | Gilchrist S.,University of British Columbia | Gilchrist S.,Center for Hip Health and Mobility | And 6 more authors.
Journal of Biomechanics | Year: 2013

Finite element (FE) analysis based on quantitative computed tomography (QCT) images is an emerging tool to estimate bone strength in a specific patient or specimen; however, it is limited by the computational power required and the associated time required to generate and solve the models. Thus, our objective was to develop a fast, validated method to estimate whole bone structural stiffness and failure load in addition to a sensitivity analysis of varying boundary conditions. We performed QCT scans on twenty fresh-frozen proximal femurs (age: 77±13 years) and mechanically tested the femurs in a configuration that simulated a sideways fall on the hip. We used custom software to generate the FE models with boundary conditions corresponding to the mechanical tests and solved the linear models to estimate bone structural stiffness and estimated failure load. For the sensitivity analysis, we varied the internal rotation angle of the femoral neck from -30° to 45° at 15° intervals and estimated structural stiffness at each angle. We found both the FE estimates of structural stiffness (R2=0.89, p<0.01) and failure load (R2=0.81, p<0.01) to be in high agreement with the values found by mechanical testing. An important advantage of these methods was that the models of approximately 500,000 elements took less than 11min to solve using a standard desktop workstation. In this study we developed and validated a method to quickly and accurately estimate proximal femur structural stiffness and failure load using QCT-driven FE methods. © 2013 Elsevier Ltd.

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