title: Mobility predicts change in older adults' health-related quality of life: evidence from a Vancouver falls prevention prospective cohort study.
abstract: BACKGROUND
  Older adults with mobility impairments are prone to reduced health related quality of life (HRQoL) is highly associated with mobility impairments. The consequences of falls have detrimental impact on mobility. Hence, ascertaining factors explaining variation among individuals' quality of life is critical for promoting healthy ageing, particularly among older fallers. Hence, the primary objective of our study was to identify key factors that explain variation in HRQoL among community dwelling older adults at risk of falls.
  
  
  METHODS
  We conducted a longitudinal analysis of a 12-month prospective cohort study at the Vancouver Falls Prevention Clinic (n = 148 to 286 depending on the analysis). We constructed linear mixed models where assessment month (0, 6, 12) was entered as a within-subjects repeated measure, the intercept was specified as a random effect, and predictors and covariates were entered as between-subjects fixed effects. We also included the predictors by sex and predictor by sex by time interaction terms in order to investigate sex differences in the relations between the predictor variable and the outcome variable, the EQ-5D.
  
  
  RESULTS
  Our primary analysis demonstrated a significant mobility (assessed using the Short Performance Physical Battery and the Timed Up and Go) by time interaction (p < 0.05) and mobility by time by sex interaction (p < 0.05). The sensitivity analyses demonstrated some heterogeneity of these findings using an imputed and a complete case analysis.
  
  
  CONCLUSIONS
  Mobility may be an important predictor of changes in HRQoL over time. As such, mobility is a critical factor to target for future intervention strategies aimed at maintaining or improving HRQoL in late life.
authors.affiliation: Centre for Clinical Epidemiology and Evaluation, University of British Columbia and Vancouver Coastal Health Research Institute (VCHRI), 828 West 10th Avenue, Vancouver, BC, V6T 2B5, Canada. jennifer.davis@ubc.ca.
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Davis
authors.affiliation: Centre for Clinical Epidemiology and Evaluation, University of British Columbia and Vancouver Coastal Health Research Institute (VCHRI), 828 West 10th Avenue, Vancouver, BC, V6T 2B5, Canada. Stirling.Bryan@ubc.ca.
authors.forename: Stirling
authors.initials: S
authors.lastname: Bryan
authors.affiliation: Department of Physical Therapy, University of British Columbia, 2177 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada. john.best@ubc.ca.|Aging, Mobility, and Cognitive Neuroscience Lab, University of British Columbia, 2211 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada. john.best@ubc.ca.|Djavad Mowafaghian Centre for Brain Health, University of British Columbia & VCHRI, 2215 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada. john.best@ubc.ca.|Center for Hip Health and Mobility, University of British Columbia & VCHRI, 828 West 10th Avenue, Vancouver, BC, V5Z 1E2, Canada. john.best@ubc.ca.
authors.forename: John R
authors.initials: JR
authors.lastname: Best
authors.affiliation: Department of Physical Therapy, University of British Columbia, 2177 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada. lli@arthritisresearch.ca.|Arthritis Research Centre of Canada, 5591 No. 3 Road, Richmond, BC, V6X 2C7, Canada. lli@arthritisresearch.ca.
authors.forename: Linda C
authors.initials: LC
authors.lastname: Li
authors.affiliation: Department of Physical Therapy, University of British Columbia, 2177 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada. liang.hsu@hiphealth.ca.|Aging, Mobility, and Cognitive Neuroscience Lab, University of British Columbia, 2211 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada. liang.hsu@hiphealth.ca.|Djavad Mowafaghian Centre for Brain Health, University of British Columbia & VCHRI, 2215 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada. liang.hsu@hiphealth.ca.|Center for Hip Health and Mobility, University of British Columbia & VCHRI, 828 West 10th Avenue, Vancouver, BC, V5Z 1E2, Canada. liang.hsu@hiphealth.ca.
authors.forename: Chun Liang
authors.initials: CL
authors.lastname: Hsu
authors.affiliation: Aging, Mobility, and Cognitive Neuroscience Lab, University of British Columbia, 2211 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada. caitlin.gomez@hiphealth.ca.
authors.forename: Caitlin
authors.initials: C
authors.lastname: Gomez
authors.affiliation: Aging, Mobility, and Cognitive Neuroscience Lab, University of British Columbia, 2211 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada. kelly.vertes@hiphealth.ca.
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Vertes
authors.affiliation: Department of Physical Therapy, University of British Columbia, 2177 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada. teresa.ambrose@ubc.ca.|Aging, Mobility, and Cognitive Neuroscience Lab, University of British Columbia, 2211 Wesbrook Mall, Vancouver, BC, V6T 2B5, Canada. teresa.ambrose@ubc.ca.|Djavad Mowafaghian Centre for Brain Health, University of British Columbia & VCHRI, 2215 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada. teresa.ambrose@ubc.ca.|Center for Hip Health and Mobility, University of British Columbia & VCHRI, 828 West 10th Avenue, Vancouver, BC, V5Z 1E2, Canada. teresa.ambrose@ubc.ca.
authors.forename: Teresa
authors.initials: T
authors.lastname: Liu-Ambrose
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control / Q000706:statistics & numerical data*; D000368:Aged; D000369:Aged, 80 and over; D001955:British Columbia / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D015577:Geriatric Assessment; D006304:Health Status; D006801:Humans; D008297:Male; D051346:Mobility Limitation; D011446:Prospective Studies; D011788:Quality of Life; D012111:Residence Characteristics