title: Association of spinal muscle composition and prevalence of hyperkyphosis in healthy community-dwelling older men and women.
abstract: BACKGROUND
  Older adults with hyperkyphosis are at increased risk of falls, fractures, and functional decline. Modifiable risk factors for hyperkyphosis have not been well studied. Our objective was to determine whether spinal muscle area and density are associated with hyperkyphosis, independent of age, race, sex, bone mineral density, and trunk fat.
  
  
  METHODS
  Using data from the Pittsburgh site of the Health, Aging, and Body Composition study, we performed a baseline cross-sectional analysis. Participants were black and white men and women 70-79 years old (N = 1172), independent in activities of daily living and able to walk &frac14; mile and up 10 steps without resting. We measured Cobb's angle of kyphosis from supine lateral scout computed tomography scans, and categorized hyperkyphosis as Cobb's angle >40°. Axial images from lateral scout computed tomography scans assessed spinal extensor muscle cross-sectional area and density (proxy for fat infiltration).
  
  
  RESULTS
  In our sample, 21% had hyperkyphosis. Prevalence in black men was 11%; in white men, 17%; in black women, 26%; and in white women, 30%. In multivariate analysis, each standard deviation increase in muscle density was associated with a 29% reduction in the odds of hyperkyphosis, independent of covariates. Muscle area was not significantly associated with hyperkyphosis.
  
  
  CONCLUSIONS
  Lower spinal muscle density is associated with hyperkyphosis in healthy community-dwelling older adults. This potentially modifiable risk factor could be targeted in exercise interventions. Randomized trials are needed to determine whether an exercise program targeting spinal muscle density reduces hyperkyphosis and in turn improves health outcomes.
authors: Department of Physical Therapy and Rehabilitation Science, University of California San Francisco, 1500 Owens, Suite 400, San Francisco, CA 94143, USA. wendy.katzman@ucsfmedctr.org
authors: Wendy
authors: W
authors: Katzman
authors: Peggy
authors: P
authors: Cawthon
authors: Gregory E
authors: GE
authors: Hicks
authors: Eric
authors: E
authors: Vittinghoff
authors: John
authors: J
authors: Shepherd
authors: Jane A
authors: JA
authors: Cauley
authors: Tamara
authors: T
authors: Harris
authors: Eleanor M
authors: EM
authors: Simonsick
authors: Elsa
authors: E
authors: Strotmeyer
authors: Catherine
authors: C
authors: Womack
authors: Deborah M
authors: DM
authors: Kado
mesh_terms: D000367:Age Factors; D000368:Aged; D001823:Body Composition / Q000502:physiology*; D015519:Bone Density; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D054526:Men's Health; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009135:Muscular Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D015995:Prevalence; D012016:Reference Values; D012307:Risk Factors; D017678:Sex Distribution; D012737:Sex Factors; D013131:Spine; D014481:United States / Q000453:epidemiology