title: Changes in bone mineral density may predict the risk of fracture differently in older adults according to fall history.
abstract: OBJECTIVE
  To determine whether the association between change in bone mass density (BMD) over 4 years and risk of hip and nonvertebral fracture differs according to an individual's history of falls.
  
  
  METHODS
  Population-based cohort study.
  
  
  METHODS
  Framingham, Massachusetts.
  
  
  METHODS
  Individuals with two measures of BMD at the femoral neck (mean age 78.8; 310 male, 492 female).
  
  
  METHODS
  Cox proportional hazards models were used to estimate hazard ratios (HRs) for the association between percentage change in BMD (per sex-specific standard deviation) and risk of incident hip and nonvertebral fracture. Models were stratified based on history of falls (≥1 falls in the past year) and recurrent falls (≥2 falls) ascertained at the time of the second BMD test. Interactions were tested by including the term "fall history * change in BMD" in the models.
  
  
  RESULTS
  Mean change in BMD was -0.6%/year; 27.8% of participants reported falls, and 10.8% reported recurrent falls. Seventy-six incident hip and 175 incident nonvertebral fractures occurred over a median follow-up of 9.0 years. There was no difference in the association between change in BMD and hip fracture according to history of falls (P for interaction = .57). The HR associated with change in BMD and nonvertebral fracture was 1.31 (95% confidence interval (CI) = 1.10-1.56) in participants without a history of falls and 0.95 (95% CI 0.70-1.28) in those with a fall (interaction P = .07). Results for recurrent fallers were similar.
  
  
  CONCLUSIONS
  The effect of BMD loss on risk of nonvertebral fracture may be greater in persons without a history of falls. It is possible that change in BMD contributes less to fracture risk when a strong risk factor for fracture, such as falls, is present.
authors.affiliation: Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts; Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Sarah D
authors.initials: SD
authors.lastname: Berry
authors.forename: Robert R
authors.initials: RR
authors.lastname: McLean
authors.forename: Marian T
authors.initials: MT
authors.lastname: Hannan
authors.forename: L Adrienne
authors.initials: LA
authors.lastname: Cupples
authors.forename: Douglas P
authors.initials: DP
authors.lastname: Kiel
mesh_terms: D015502:Absorptiometry, Photon; D000058:Accidental Falls / Q000706:statistics & numerical data*; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D050723:Fractures, Bone / Q000453:epidemiology / Q000209:etiology*; D015577:Geriatric Assessment; D006801:Humans; D015994:Incidence; D008297:Male; D010024:Osteoporosis / Q000503:physiopathology*; D018570:Risk Assessment; D012307:Risk Factors
keywords: bone mineral density change; falls; hip fracture; nonvertebral fracture; recurrent falls