title: Trunk lean mass and its association with 4 different measures of thoracic kyphosis in older community dwelling persons.
abstract: BACKGROUND
  The causes of age-related hyperkyphosis (HK) include osteoporosis, but only 1/3 of those most severely affected have vertebral fractures, suggesting that there are other important, and potentially modifiable causes. We hypothesized that muscle mass and quality may be important determinants of kyphosis in older persons.
  
  
  METHODS
  We recruited 72 persons >65 years to participate in a prospective study designed to evaluate kyphosis and fall risk. At the baseline visit, participants had their body composition measures completed using Dual Energy X-ray Absorptiometry (DXA). They had kyphosis measured in either the standing [S] or lying [L] position: 1) Cobb angle from DXA [L]; 2) Debrunner kyphometer [S]; 3) architect's flexicurve ruler [S]; and 4) blocks method [L]. Multivariable linear/logistic regression analyses were done to assess the association between each body composition and 4 kyphosis measures.
  
  
  RESULTS
  Women (n = 52) were an average age of 76.8 (SD 6.7) and men 80.5 (SD 7.8) years. They reported overall good/excellent health (93%), the average body mass index was 25.3 (SD 4.6) and 35% reported a fall in the past year. Using published cut-offs, about 20-30% were determined to have HK. For the standing assessments of kyphosis only, after adjusting for age, sex, weight and hip BMD, persons with lower TLM were more likely to be hyperkyphotic.
  
  
  CONCLUSIONS
  Lower TLM is associated with HK in older persons. The results were stronger when standing measures of kyphosis were used, suggesting that the effects of muscle on thoracic kyphosis are best appreciated under spinal loading conditions.
authors.affiliation: University of Hawaii, Honolulu, Hawaii, United States of America.
authors.forename: J
authors.initials: J
authors.lastname: Yamamoto
authors.affiliation: University of California, San Diego, La Jolla, California, United States of America.
authors.forename: J
authors.initials: J
authors.lastname: Bergstrom
authors.affiliation: University of California, San Diego, La Jolla, California, United States of America.
authors.forename: A
authors.initials: A
authors.lastname: Davis
authors.affiliation: University of California, San Diego, La Jolla, California, United States of America.
authors.forename: D
authors.initials: D
authors.lastname: Wing
authors.affiliation: Park Nicollet Osteoporosis Center and Institute for Research and Education, Minneapolis, Minnesota, United States of America.
authors.forename: J T
authors.initials: JT
authors.lastname: Schousboe
authors.affiliation: University of California, San Diego, La Jolla, California, United States of America.
authors.forename: J F
authors.initials: JF
authors.lastname: Nichols
authors.affiliation: University of California, San Diego, La Jolla, California, United States of America.
authors.forename: D M
authors.identifier: http://orcid.org/0000-0002-2582-5573
authors.initials: DM
authors.lastname: Kado
mesh_terms: D015502:Absorptiometry, Photon; D000058:Accidental Falls; D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition; D015519:Bone Density / Q000502:physiology; D005260:Female; D006801:Humans; D007738:Kyphosis / Q000503:physiopathology*; D008297:Male; D018482:Muscle, Skeletal / Q000473:pathology*; D011187:Posture / Q000502:physiology*; D011446:Prospective Studies; D013121:Spinal Curvatures / Q000503:physiopathology*; D013131:Spine / Q000473:pathology; D011795:Surveys and Questionnaires; D013904:Thoracic Vertebrae / Q000502:physiology; D060726:Torso / Q000502:physiology*