Meghan G Donaldson

University of British Columbia - Vancouver, Vancouver, British Columbia, Canada

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Publications (36)177.98 Total impact

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    ABSTRACT: Context: The United States Preventive Services Task Force (USPSTF) recommends osteoporosis screening for women younger than 65 years whose 10-year predicted risk of major osteoporotic fracture (MOF) is at least 9.3% using the Fracture Risk Assessment Tool. In postmenopausal women age 50-64 years old, it is uncertain how the USPSTF screening strategy compares with the Osteoporosis Self-Assessment Tool and the Simple Calculated Osteoporosis Risk Estimate (SCORE) in discriminating women who will and will not experience MOF. Objective: This study aimed to assess the sensitivity, specificity, and area under the receiver operating characteristic curve of the three strategies for discrimination of incident MOF over 10 years of follow-up among postmenopausal women age 50-64 years. Setting and Design: Prospective study, 1993-2008 at 40 US Centers. Participants: Participants of the Women's Health Initiative Observational Study and Clinical Trials (n = 62 492), age 50-64 years, not taking osteoporosis medication. Main Outcome Measures: Ten-year (observed) incidence of MOF. Results: For identifying women with incident MOF, sensitivity of the strategies ranged from 25.8-39.8%, specificity ranged from 60.7-65.8%, and area under the curve values ranged from 0.52-0.56. The sensitivity of the USPSTF strategy for identifying incident MOF ranged from 4.7% (3.3-6.0) among women age 50-54 years to 37.3% (35.4-39.1) for women age 60-64 years. Adjusting the thresholds to improve sensitivity resulted in decreased specificity. Conclusions: Our findings do not support use of the USPSTF strategy, Osteoporosis Self-Assessment Tool, or SCORE to identify younger postmenopausal women who are at higher risk of fracture. Our findings suggest that fracture prediction in younger postmenopausal women requires assessment of risk factors not included in currently available strategies.
    The Journal of clinical endocrinology and metabolism. 10/2014;
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    ABSTRACT: To quantify incremental effects of applying different criteria to identify men who are candidates for drug treatment to prevent fracture and to examine the extent to which fracture probabilities vary across distinct categories of men defined by these criteria.DESIGN: Cross sectional and longitudinal analysis of a prospective cohort study.SETTING: Multicenter Osteoporotic Fractures in Men (MrOS) study in the United States.PARTICIPANTS: 5880 untreated community dwelling men aged 65 years or over classified into four distinct groups: osteoporosis by World Health Organization criteria alone; osteoporosis by National Osteoporosis Foundation (NOF) but not WHO criteria; no osteoporosis but at high fracture risk (at or above NOF derived FRAX intervention thresholds recommended for US); and no osteoporosis and at low fracture risk (below NOF derived FRAX intervention thresholds recommended for US).MAIN OUTCOME MEASURES: Proportion of men identified for drug treatment; predicted 10 year probabilities of hip and major osteoporotic fracture calculated using FRAX algorithm with femoral neck bone mineral density; observed 10 year probabilities for confirmed incident hip and major osteoporotic (hip, clinical vertebral, wrist, or humerus) fracture events calculated using cumulative incidence estimation, accounting for competing risk of mortality.RESULTS: 130 (2.2%) men were identified as having osteoporosis by using the WHO definition, and an additional 422 were identified by applying the NOF definition (total osteoporosis prevalence 9.4%). Application of NOF derived FRAX intervention thresholds led to 936 (15.9%) additional men without osteoporosis being identified as at high fracture risk, raising the total prevalence of men potentially eligible for drug treatment to 25.3%. Observed 10 year hip fracture probabilities were 20.6% for men with osteoporosis by WHO criteria alone, 6.8% for men with osteoporosis by NOF (but not WHO) criteria, 6.4% for men without osteoporosis but classified as at high fracture risk, and 1.5% for men without osteoporosis and classified as at low fracture risk. A similar pattern was noted in observed fracture probabilities for major osteoporotic fracture. Among men with osteoporosis by WHO criteria, observed fracture probabilities were greater than FRAX predicted probabilities (20.6% v 9.5% for hip fracture and 30.0% v 17.4% for major osteoporotic fracture).CONCLUSIONS AND RELEVANCE: Choice of definition of osteoporosis and use of NOF derived FRAX intervention thresholds have major effects on the proportion of older men identified as warranting drug treatment to prevent fracture. Among men identified with osteoporosis by WHO criteria, who comprised 2% of the study population, actual observed fracture probabilities during 10 years of follow-up were highest and exceeded FRAX predicted fracture probabilities. On the basis of findings from randomized trials in women, these men are most likely to benefit from treatment. Expanding indications for treatment beyond this small group has uncertain value owing to lower observed fracture probabilities and uncertain benefits of treatment among men not selected on the basis of WHO criteria.
    BMJ Clinical Research 07/2014; 349:g4120. · 14.09 Impact Factor
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    ABSTRACT: The U.S. Preventive Services Task Force (USPSTF) recommends osteoporosis screening for women younger than 65 years whose 10-year predicted risk of major osteoporotic fracture is ≥ 9.3%. For identifying screening candidates among women aged 50-64 years, it is uncertain how the USPSTF strategy compares with the Osteoporosis Self-Assessment Tool (OST) and the Simple Calculated Osteoporosis Risk Estimate (SCORE). We examined data (1994-2012) from 5165 Women's Health Initiative participants aged 50-64. For the USPSTF (FRAX major fracture risk ≥ 9.3% calculated without BMD), OST (score <2), and SCORE (score >7) strategies, we assessed sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) to discriminate between those with and without femoral neck (FN) T-score ≤ -2.5. Sensitivity, specificity, and AUC for identifying FN T-score ≤ -2.5 were 34.1%, 85.8%, and 0.60 for USPSTF (FRAX), 74.0%, 70.8%, and 0.72 for SCORE, and 79.8%, 66.3%, and 0.73 for OST. The USPSTF strategy identified about 1/3(rd) of women aged 50-64 with FN T-scores ≤ -2.5. Among women aged 50-64 years, the USPSTF strategy was modestly better than chance alone and inferior to conventional SCORE and OST strategies in discriminating between women with and without FN T-score ≤ -2.5. © 2014 American Society for Bone and Mineral Research.
    Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 01/2014; · 6.04 Impact Factor
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    ABSTRACT: For older adults, the ability to navigate walking routes in the outdoor environment allows them to remain active and socially engaged, facilitating community participation and independence. In order to enhance outdoor walking, it is important to understand the interaction of older adults within their local environments and the influence of broader stakeholder priorities that impact these environments. Thus, we aimed to synthesize perspectives from stakeholders to identify elements of the built and social environments that influence older adults' ability to walk outdoors. We applied a concept mapping approach with the input of diverse stakeholders (N=75) from British Columbia, Canada in 2012. A seven-cluster map best represented areas that influence older adults' outdoor walking. Priority areas identified included sidewalks, crosswalks, and neighbourhood features. Individual perceptions and elements of the built and social environment intersect to influence walking behaviours, although targeted studies that address this area are needed.
    Preventive Medicine 09/2013; · 3.50 Impact Factor
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    ABSTRACT: The WHO Fracture Risk Assessment Tool (FRAX; http://www.shef.ac.uk/FRAX) estimates the 10-year probability of major osteoporotic fracture. Clodronate and bazedoxifene reduced nonvertebral and clinical fracture more effectively on a relative scale in women with higher FRAX scores. We used data from the Fracture Intervention Trial (FIT) to evaluate the interaction between FRAX score and treatment with alendronate. We combined the Clinical Fracture (CF) arm and Vertebral Fracture (VF) arm of FIT. The CF and VF arm of FIT randomized 4432 and 2027 women, respectively, to placebo or alendronate for 4 and 3 years, respectively. FRAX risk factors were assessed at baseline. FRAX scores were calculated by WHO. We used Poisson regression models to assess the interaction between alendronate and FRAX score on the risk of nonvertebral, clinical, major osteoporotic, and radiographic vertebral fractures. Overall, alendronate significantly reduced the risk of nonvertebral fracture (incidence rate ratio [IRR] 0.86; 95% confidence interval [CI], 0.75-0.99), but the effect was greater for femoral neck (FN) bone mineral density (BMD) T-score ≤ -2.5 (IRR 0.76; 95% CI, 0.62-0.93) than for FN T-score > -2.5 (IRR 0.96; 95% CI, 0.80-1.16) (p = 0.02, interaction between alendronate and FN BMD). However, there was no evidence of an interaction between alendronate and FRAX score with FN BMD for risk of nonvertebral fracture (interaction p = 0.61). The absolute benefit of alendronate was greatest among women with highest FRAX scores. Results were similar for clinical fractures, major osteoporotic fractures, and radiographic vertebral fractures and whether or not FRAX scores included FN BMD. Among this cohort of women with low bone mass there was no significant interaction between FRAX score and alendronate for nonvertebral, clinical or major osteoporotic fractures, or radiographic vertebral fractures. These results suggest that the effect of alendronate on a relative scale does not vary by FRAX score. A randomized controlled trial testing the effect of antifracture agents among women with high FRAX score but without osteoporosis is warranted.
    Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 04/2012; 27(8):1804-10. · 6.04 Impact Factor
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    ABSTRACT: BACKGROUND: Fall-related hip fractures result in significant personal and societal consequences; importantly, up to half of older adults with hip fracture never regain their previous level of mobility. Strategies of follow-up care for older adults after fracture have improved investigation for osteoporosis; but managing bone health alone is not enough. Prevention of fractures requires management of both bone health and falls risk factors (including the contributing role of cognition, balance and continence) to improve outcomes. METHODS/DESIGN: This is a parallel group, pragmatic randomized controlled trial to test the effectiveness of a post-fracture clinic compared with usual care on mobility for older adults following their hospitalization for hip fracture. Participants randomized to the intervention will attend a fracture follow-up clinic where a geriatrician and physiotherapist will assess and manage their mobility and other health issues. Depending on needs identified at the clinical assessment, participants may receive individualized and group-based outpatient physiotherapy, and a home exercise program. Our primary objective is to assess the effectiveness of a novel post-discharge fracture management strategy on the mobility of older adults after hip fracture. We will enrol 130 older adults (65 years+) who have sustained a hip fracture in the previous three months, and were admitted to hospital from home and are expected to be discharged home. We will exclude older adults who prior to the fracture were: unable to walk 10 meters; diagnosed with dementia and/or significant comorbidities that would preclude their participation in the clinical service. Eligible participants will be randomly assigned to the Intervention or Usual Care groups by remote allocation. Treatment allocation will be concealed; investigators, measurement team and primary data analysts will be blinded to group allocation. Our primary outcome is mobility, operationalized as the Short Physical Performance Battery at 12 months. Secondary outcomes include frailty, rehospitalizations, falls risk factors, quality of life, as well as physical activity and sedentary behaviour. We will conduct an economic evaluation to determine health related costs in the first year, and a process evaluation to ascertain the acceptance of the program by older adults, as well as clinicians and staff within the clinic. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov: NCT01254942.
    BMC Geriatrics 06/2011; 11:30. · 2.34 Impact Factor
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    ABSTRACT: Type 2 diabetes mellitus (DM) is associated with higher bone mineral density (BMD) and paradoxically with increased fracture risk. It is not known if low BMD, central to fracture prediction in older adults, identifies fracture risk in patients with DM. To determine if femoral neck BMD T score and the World Health Organization Fracture Risk Algorithm (FRAX) score are associated with hip and nonspine fracture risk in older adults with type 2 DM. Data from 3 prospective observational studies with adjudicated fracture outcomes (Study of Osteoporotic Fractures [December 1998-July 2008]; Osteoporotic Fractures in Men Study [March 2000-March 2009]; and Health, Aging, and Body Composition study [April 1997-June 2007]) were analyzed in older community-dwelling adults (9449 women and 7436 men) in the United States. Self-reported incident fractures, which were verified by radiology reports. Of 770 women with DM, 84 experienced a hip fracture and 262 a nonspine fracture during a mean (SD) follow-up of 12.6 (5.3) years. Of 1199 men with DM, 32 experienced a hip fracture and 133 a nonspine fracture during a mean (SD) follow-up of 7.5 (2.0) years. Age-adjusted hazard ratios (HRs) for 1-unit decrease in femoral neck BMD T score in women with DM were 1.88 (95% confidence interval [CI], 1.43-2.48) for hip fracture and 1.52 (95% CI, 1.31-1.75) for nonspine fracture, and in men with DM were 5.71 (95% CI, 3.42-9.53) for hip fracture and 2.17 (95% CI, 1.75-2.69) for nonspine fracture. The FRAX score was also associated with fracture risk in participants with DM (HRs for 1-unit increase in FRAX hip fracture score, 1.05; 95% CI, 1.03-1.07, for women with DM and 1.16; 95% CI, 1.07-1.27, for men with DM; HRs for 1-unit increase in FRAX osteoporotic fracture score, 1.04; 95% CI, 1.02-1.05, for women with DM and 1.09; 95% CI, 1.04-1.14, for men with DM). However, for a given T score and age or for a given FRAX score, participants with DM had a higher fracture risk than those without DM. For a similar fracture risk, participants with DM had a higher T score than participants without DM. For hip fracture, the estimated mean difference in T score for women was 0.59 (95% CI, 0.31-0.87) and for men was 0.38 (95% CI, 0.09-0.66). Among older adults with type 2 DM, femoral neck BMD T score and FRAX score were associated with hip and nonspine fracture risk; however, in these patients compared with participants without DM, the fracture risk was higher for a given T score and age or for a given FRAX score.
    JAMA The Journal of the American Medical Association 06/2011; 305(21):2184-92. · 29.98 Impact Factor
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    ABSTRACT: Fracture prediction models help to identify individuals at high risk who may benefit from treatment. Area under the curve (AUC) is used to compare prediction models. However, the AUC has limitations and may miss important differences between models. Novel reclassification methods quantify how accurately models classify patients who benefit from treatment and the proportion of patients above/below treatment thresholds. We applied two reclassification methods, using the National Osteoporosis Foundation (NOF) treatment thresholds, to compare two risk models: femoral neck bone mineral density (BMD) and age (simple model) and FRAX (FRAX model). The Pepe method classifies based on case/noncase status and examines the proportion of each above and below thresholds. The Cook method examines fracture rates above and below thresholds. We applied these to the Study of Osteoporotic Fractures (SOF). There were 6036 (1037 fractures) and 6232 (389 fractures) participants with complete data for major osteoporotic and hip fracture, respectively. Both models for major osteoporotic fracture (0.68 versus 0.69) and hip fracture (0.75 versus 0.76) had similar AUCs. In contrast, using reclassification methods, each model classified a substantial number of women differently. Using the Pepe method, the FRAX model (versus the simple model) missed treating 70 (7%) cases of major osteoporotic fracture but avoided treating 285 (6%) noncases. For hip fracture, the FRAX model missed treating 31 (8%) cases but avoided treating 1026 (18%) noncases. The Cook method (both models, both fracture outcomes) had similar fracture rates above/below the treatment thresholds. Compared with the AUC, new methods provide more detailed information about how models classify patients.
    Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 02/2011; 26(8):1767-73. · 6.04 Impact Factor
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    ABSTRACT: Bone mineral density (BMD) is a strong predictor of fracture, yet most fractures occur in women without osteoporosis by BMD criteria. To improve fracture risk prediction, the World Health Organization recently developed a country-specific fracture risk index of clinical risk factors (FRAX) that estimates 10-year probabilities of hip and major osteoporotic fracture. Within differing baseline BMD categories, we evaluated 6252 women aged 65 or older in the Study of Osteoporotic Fractures using FRAX 10-year probabilities of hip and major osteoporotic fracture (ie, hip, clinical spine, wrist, and humerus) compared with incidence of fractures over 10 years of follow-up. Overall ability of FRAX to predict fracture risk based on initial BMD T-score categories (normal, low bone mass, and osteoporosis) was evaluated with receiver-operating-characteristic (ROC) analyses using area under the curve (AUC). Over 10 years of follow-up, 368 women incurred a hip fracture, and 1011 a major osteoporotic fracture. Women with low bone mass represented the majority (n = 3791, 61%); they developed many hip (n = 176, 48%) and major osteoporotic fractures (n = 569, 56%). Among women with normal and low bone mass, FRAX (including BMD) was an overall better predictor of hip fracture risk (AUC = 0.78 and 0.70, respectively) than major osteoporotic fractures (AUC = 0.64 and 0.62). Simpler models (eg, age + prior fracture) had similar AUCs to FRAX, including among women for whom primary prevention is sought (no prior fracture or osteoporosis by BMD). The FRAX and simpler models predict 10-year risk of incident hip and major osteoporotic fractures in older US women with normal or low bone mass.
    Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 02/2011; 26(8):1774-82. · 6.04 Impact Factor
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    ABSTRACT: The new US National Osteoporosis Foundation's (NOF's) Clinician's Guide to Prevention and Treatment of Osteoporosis includes criteria for recommending pharmacologic treatment based on history of hip or vertebral fracture, femoral neck or spine bone mineral density (BMD) T-scores of -2.5 or less, and presence of low bone mass at the femoral neck or spine plus a 10-year risk of hip fracture of 3% or greater or of major osteoporotic fracture of 20% or greater. The proportion of men who would be recommended for treatment by these guidelines is not known. We applied the NOF criteria for treatment to men participating in the Osteoporotic Fractures in Men Study (MrOS). To determine how the MrOS population differs from the general US population of Caucasian men aged 65 years and older, we compared men in MrOS with men who participated in the National Health and Nutrition Examination Survey (NHANES) III on criteria included in the NOF treatment guidelines that were common to both cohorts. Compared with NHANES III, men in MrOS had higher femoral neck BMD values. Application of NOF guidelines to MrOS data estimated that at least 34% of US white men aged 65 years and older and 49% of those aged 75 years and older would be recommended for drug treatment. Application of the new NOF guidelines would result in recommending a very large proportion of white men in the United States for pharmacologic treatment of osteoporosis, for many of whom the efficacy of treatment is unknown.
    Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 02/2010; 25(7):1506-11. · 6.04 Impact Factor
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    ABSTRACT: A Web-based risk assessment tool (FRAX) using clinical risk factors with and without femoral neck bone mineral density (BMD) has been incorporated into clinical guidelines regarding treatment to prevent fractures. However, it is uncertain whether prediction with FRAX models is superior to that based on parsimonious models. We conducted a prospective cohort study in 6252 women 65 years or older to compare the value of FRAX models that include BMD with that of parsimonious models based on age and BMD alone for prediction of fractures. We also compared FRAX models without BMD with simple models based on age and fracture history alone. Fractures (hip, major osteoporotic [hip, clinical vertebral, wrist, or humerus], and any clinical fracture) were ascertained during 10 years of follow-up. Area under the curve (AUC) statistics from receiver operating characteristic curve analysis were compared between FRAX models and simple models. The AUC comparisons showed no differences between FRAX models with BMD and simple models with age and BMD alone in discriminating hip (AUC, 0.75 for the FRAX model and 0.76 for the simple model; P = .26), major osteoporotic (AUC, 0.68 for the FRAX model and 0.69 for the simple model; P = .51), and clinical fracture (AUC, 0.64 for the FRAX model and 0.63 for the simple model; P = .16). Similarly, performance of parsimonious models containing age and fracture history alone was nearly identical to that of FRAX models without BMD. The proportion of women in each quartile of predicted risk who actually experienced a fracture outcome did not differ between FRAX and simple models (P > or = .16). Simple models based on age and BMD alone or age and fracture history alone predicted 10-year risk of hip, major osteoporotic, and clinical fracture as well as more complex FRAX models.
    Archives of internal medicine 12/2009; 169(22):2087-94. · 11.46 Impact Factor
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    ABSTRACT: We applied the 2008 National Osteoporosis Foundation (NOF) Guidelines to Framingham Osteoporosis Study participants and found nearly one half of Caucasian postmenopausal women and one sixth of men aged 50 years and older would be recommended for osteoporosis treatment. Given the high proportion of persons recommended for treatment, NOF Guidelines may need to be re-evaluated with respect to budget impact. Little is known about the public health impact of the NOF Guidelines. Therefore, we determined the proportion of US Caucasians recommended for treatment of osteoporosis according to NOF Guidelines (2003 and 2008). One thousand nine hundred and forty-six postmenopausal women and 1,681 men aged > or =50 years from the Framingham Study with information on bone mineral density (1987-2001) were included. Information on clinical predictors was used to estimate the 10-year probability of hip and major osteoporotic fracture by FRAX (version 3.0). Overall proportion of women meeting treatment criterion was less when the 2008 NOF Guidelines were applied (41.1%) compared with 2003 Guidelines (47.8%). The proportion of women aged <65 years meeting treatment criterion was much less when applying 2008 Guidelines (23.1% in 2003, 8.3% in 2008), whereas the proportion of women aged >75 years increased slightly (78.3% in 2003, 86.0% in 2008). Seventeen percent of men aged > or =50 years met treatment criterion (2.5% aged 50-64 years, 49.8% aged >75 years). Nearly one half of Caucasian postmenopausal women and one sixth of men aged 50 years and older would be recommended for osteoporosis treatment according to 2008 NOF Guidelines. Given the high proportion of persons recommended for treatment, NOF Guidelines may need to be re-evaluated with respect to budget impact.
    Osteoporosis International 11/2009; 21(1):53-60. · 4.04 Impact Factor
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    ABSTRACT: The validity of the WHO 10-yr probability of major osteoporotic fracture model (FRAX) for prediction of vertebral fracture has not been tested. We analyzed how well FRAX for major osteoporotic fractures, with and without femoral neck BMD (FN BMD), predicted the risk of vertebral fracture. We also compared the predictive validity of FRAX, FN BMD, and prevalent vertebral fracture detected by radiographs at baseline alone or in combination to predict future vertebral fracture. We analyzed data from the placebo groups of FIT (3.8-yr follow-up, n = 3221) with ORs and areas under receiver operating characteristics (ROC) curves (AUC). FRAX with and without FN BMD predicted incident radiographic vertebral fracture. The AUC was significantly greater for FRAX with FN BMD (AUC = 0.71) than FRAX without FN BMD (AUC = 0.68; p = 0.002). Prevalent vertebral fracture plus age and FN BMD (AUC = 0.76) predicted incident radiographic vertebral fracture as well as a combination of prevalent vertebral fracture and FRAX with FN BMD (AUC = 0.75; p = 0.76). However, baseline vertebral fracture status plus age and FN BMD (AUC = 0.76) predicted incident radiographic vertebral fracture significantly better than FRAX with FN BMD (AUC = 0.71; p = 0.0017). FRAX for major osteoporotic fractures (with and without FN BMD) predicts vertebral fracture. However, once FN BMD and age are known, the eight additional risk factors in FRAX do not significantly improve the prediction of vertebral fracture. A combination of baseline radiographic vertebral fracture, FN BMD, and age is the strongest predictor of future vertebral fracture.
    Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 06/2009; 24(11):1793-9. · 6.04 Impact Factor
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    ABSTRACT: Many falls occur among older adults with no traditional risk factors. We examined potential independent effects of lifestyle on fall risk. Not smoking and going outdoors frequently or infrequently were independently associated with more falls, indicating lifestyle-related behavioral and environmental risk factors are important causes of falls in older women. Physical and lifestyle risk factors for falls and population attributable risks (PAR) were examined. We conducted a 4-year prospective study of 8,378 community-dwelling women (mean age = 71 years, SD = 3) enrolled in the Study of Osteoporotic Fractures. Data on number of falls were self-reported every 4 months. Fall rates were calculated (# falls/woman-years). Poisson regression was used to estimate relative risks (RR). Physical risk factors (p < or = 0.05 for all) included tall height (RR = 0.89 per 5 in.), dizziness (RR = 1.16), fear of falling (RR = 1.20), self-reported health decline (RR = 1.19), difficulty with Instrumental Activities of Daily Living (IADLs) (RR = 1.12, per item), fast usual-paced walking speed (RR = 1.18, per 2 SD), and use of antidepressants (RR = 1.20), benzodiazepines (RR = 1.11), or anticonvulsants (RR = 1.62). Protective physical factors (p < or = 0.05 for all) included good visual acuity (RR = 0.87, per 2 SD) and good balance (RR = 0.85 vs. poor). Lifestyle predicted fewer falls including current smoking (RR = 0.76), going outdoors at least twice weekly but not more than once a day (RR = 0.89 and vs. twice daily). High physical activity was associated with more falls but only among IADL impaired women. Five potentially modifiable physical risk factors had PAR > or = 5%. Fall interventions addressing modifiable physical risk factors with PAR > or = 5% while considering environmental/behavioral risk factors are indicated.
    Osteoporosis International 04/2009; 20(12):2025-34. · 4.04 Impact Factor
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    ABSTRACT: The new U.S. National Osteoporosis Foundation Clinician's Guide to Prevention and Treatment of Osteoporosis includes criteria for recommending pharmacologic treatment based on history of hip or vertebral fracture, femoral neck (FN), or spine BMD T-scores <or=-2.5 and presence of low bone mass at the FN or spine plus a 10-yr risk of hip fracture >or=3% or of major osteoporotic fracture >or=20%. The proportion of women who would be recommended for treatment by these guidelines is not known. We applied the NOF criteria for treatment to women participating in the Study of Osteoporotic Fractures (SOF). To determine how the SOF population differs from the general U.S. population of white women >or=65 yr of age, we compared women in SOF with women who participated in the National Health and Nutrition Examination Survey (NHANES) III on criteria included in the NOF treatment guidelines that were common to both cohorts. Compared with NHANES III, women in SOF had higher FN BMD and were younger. Application of NOF guidelines to SOF data estimated that at least 72% of U.S. white women >or=65 yr of age and 93% of those >or=75 yr of age would be recommended for drug treatment. Application of the new NOF Guidelines would result in recommending a very large proportion of white women in the United States for pharmacologic treatment of osteoporosis.
    Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 01/2009; 24(4):675-80. · 6.04 Impact Factor
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    ABSTRACT: there are several well-developed statistical methods for analysing recurrent events. Although there are guidelines for reporting the design and methodology of randomised controlled trials (RCTs), analysis guidelines do not exist to guide the analysis for RCTs with recurrent events. Application of statistical methods that do not account for recurrent events may provide erroneous results when used to test the efficacy of an intervention. It is unknown what proportion of RCTs of falls prevention studies have utilised statistical methods that incorporate recurrent events. we conducted a systematic review of RCTs of interventions to prevent falls in community-dwelling older persons. We searched Medline from 1994 to November 2006. We determined the proportion of studies that reported using three statistical methods appropriate for the analysis of recurrent events (negative binomial regression, Andersen-Gill extension of the Cox model and the WLW marginal model). fewer than one-third of 83 papers that reported falls as an outcome utilised any appropriate statistical method (negative binomial regression, Andersen-Gill extension of the Cox model and Cox marginal model) to analyse recurrent events and fewer than 15% utilised graphical methods to represent falls data. RCTs that have a recurrent event end-point should include an analysis appropriate for recurrent event data such as negative binomial regression, Andersen-Gill extension of the Cox model and/or the WLW marginal model. We recommend that researchers and clinicians seek consultation with a statistician with expertise in recurrent event methodology.
    Age and Ageing 01/2009; 38(2):151-5. · 3.82 Impact Factor
  • T Liu-Ambrose, M G Donaldson
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    ABSTRACT: In recent years, there has been a strong interest in physical activity as a primary behavioural prevention strategy against cognitive decline. A number of large prospective cohort studies have highlighted the protective role of regular physical activity in lowering the risk of cognitive impairment and dementia. Most prospective intervention studies of exercise and cognition to date have focused on aerobic-based exercise training. These studies highlight that aerobic-based exercise training enhances both brain structure and function. However, it has been suggested that other types of exercise training, such as resistance training, may also benefit cognition. The purpose of this brief review is to examine the evidence regarding resistance training and cognitive benefits. Three recent randomised exercise trials involving resistance training among seniors provide evidence that resistance training may have cognitive benefits. Resistance training may prevent cognitive decline among seniors via mechanisms involving insulin-like growth factor I and homocysteine. A side benefit of resistance training, albeit a very important one, is its established role in reducing morbidity among seniors. Resistance training specifically moderates the development of sarcopenia. The multifactorial deleterious sequelae of sarcopenia include increased falls and fracture risk as well as physical disability. Thus, clinicians should consider encouraging their clients to undertake both aerobic-based exercise training and resistance training not only for "physical health" but also because of the almost certain benefits for "brain health".
    British journal of sports medicine 12/2008; 43(1):25-7. · 3.67 Impact Factor
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    ABSTRACT: To primarily ascertain the effect of the Otago Exercise Program (OEP) on physiological falls risk, functional mobility, and executive functioning after 6 months in older adults with a recent history of falls and to ascertain the effect of the OEP on falls during a 1-year follow-up period. Randomized controlled trial. Dedicated falls clinics. Seventy-four adults aged 70 and older who presented to a healthcare professional after a fall. The OEP, a home-based program that consists of resistance training and balance training exercises. Physiological falls risk was assessed using the Physiological Profile Assessment. Functional mobility was assessed using the Timed Up and Go Test. Three central executive functions were assessed: set shifting, using the Trail Making Test Part B; updating, using the verbal digits backward test; and response inhibition, using the Stroop Color-Word Test. Falls were prospectively monitored using daily calendars. At 6 months, there was no significant between-group difference in physiological falls risk or functional mobility (P>or= .33). There was a significant between-group difference in response inhibition (P=.05). A falls histogram revealed two outliers. With these cases removed, using negative binomial regression, the unadjusted incidence rate ratio of falls in the OEP group compared with the control group was 0.56. The adjusted incidence rate ratio was 0.47. The OEP may reduce falls by improving cognitive performance.
    Journal of the American Geriatrics Society 10/2008; 56(10):1821-30. · 4.22 Impact Factor
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    Lisa Kuramoto, Boris G Sobolev, Meghan G Donaldson
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    ABSTRACT: Evidence-based medicine has been advanced by the use of standards for reporting the design and methodology of randomized controlled trials (RCT). Indeed, without this information it is difficult to assess the quality of evidence from an RCT. Although a variety of statistical methods are available for the analysis of recurrent events, reporting the effect of an intervention on outcomes that recur is an area that remains poorly understood in clinical research. The purpose of this paper is to outline guidelines for reporting results from RCTs where the outcome of interest is a recurrent event. We used a simulation study to relate an event process and results from analyses of the gamma-Poisson, independent-increment, conditional, and marginal Cox models. We reviewed the utility of regression models for the rate of a recurrent event by articulating the associated study questions, preenting the risk sets, and interpreting the regression coefficients. Based on a single data set produced by simulation, we reported and contrasted results from statistical methods for evaluating treatment effect from an RCT with a recurrent outcome. We showed that each model has different study questions, assumptions, risk sets, and rate ratio interpretation, and so inferences should consider the appropriateness of the model for the RCT. Our guidelines for reporting results from an RCT involving a recurrent event suggest that the study question and the objectives of the trial, such as assessing comparable groups and estimating effect size, should determine the statistical methods. The guidelines should allow clinical researchers to report appropriate measures from an RCT for understanding the effect of intervention on the occurrence of a recurrent event.
    BMC Medical Research Methodology 02/2008; 8:35. · 2.21 Impact Factor
  • IBMS BoneKEy 01/2008; 5(4):137-141.

Publication Stats

703 Citations
177.98 Total Impact Points

Institutions

  • 2001–2014
    • University of British Columbia - Vancouver
      • • Centre for Clinical Epidemiology and Evaluation
      • • Centre for Hip Health and Mobility
      Vancouver, British Columbia, Canada
  • 2009–2012
    • California Pacific Medical Center Research Institute
      • Research Institute
      San Francisco, CA, United States
    • Minneapolis Veterans Affairs Hospital
      Minneapolis, Minnesota, United States
  • 2011
    • Kaiser Permanente
      • Center for Health Research (Oregon, Hawaii, and Georgia)
      Oakland, California, United States
  • 2007–2008
    • Vancouver Coastal Health
      Vancouver, British Columbia, Canada
  • 2006
    • Centre for Hip Health and Mobility
      Vancouver, British Columbia, Canada