title: Clustering of strength, physical function, muscle, and adiposity characteristics and risk of disability in older adults.
abstract: OBJECTIVE
  To empirically identify groupings of strength, physical performance, adiposity, and lean mass and test how such groupings of these interrelated measures may relate to disability risk.
  
  
  METHODS
  Prospective Health, Aging and Body Composition Study.
  
  
  METHODS
  Two U.S. clinical centers.
  
  
  METHODS
  One thousand two hundred sixty-three women and 1,221 men.
  
  
  METHODS
  Weight, strength (knee extension, grip); walking speed, chair stands, dual X-ray absorptiometry (fat and lean mass for total body, arm, and leg; percent fat), and thigh computed tomography scans (muscle area, muscle density). Analyses were stratified according to sex. Factor analysis reduced these variables into a smaller number of components, and proportional hazards models assessed risk of major disability for the components identified.
  
  
  RESULTS
  In both sexes, factor analysis reduced the 14 individual variables into three components that explained 76% to 77% of the data variance: Factor 1, an adiposity component, with strong loading by fat mass, weight, and muscle density; Factor 2, a strength and lean body size component with strong loading by lean mass, weight, and strength; Factor 3, a physical performance component with positive loading by walking speed and chair stand performance. Factor 1 (adiposity) and Factor 3 (performance) but not Factor 2 (strength and lean body size) were associated with disability over 6.1 ± 2.6 years.
  
  
  CONCLUSIONS
  The adiposity and physical performance constructs but not the strength and lean body size construct were associated with disability risk, suggesting that adiposity and performance should be considered as risk factors for disability.
authors.affiliation: Research Institute, California Pacific Medical Center, San Francisco, California, USA. pcawthon@sfcc-cpmc.net
authors.forename: Peggy M
authors.initials: PM
authors.lastname: Cawthon
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Fox
authors.forename: Shravanthi R
authors.initials: SR
authors.lastname: Gandra
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Delmonico
authors.forename: Chiun-Fang
authors.initials: CF
authors.lastname: Chiou
authors.forename: Mary S
authors.initials: MS
authors.lastname: Anthony
authors.forename: Paolo
authors.initials: P
authors.lastname: Caserotti
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kritchevsky
authors.forename: Anne B
authors.initials: AB
authors.lastname: Newman
authors.forename: Bret H
authors.initials: BH
authors.lastname: Goodpaster
authors.forename: Suzanne
authors.initials: S
authors.lastname: Satterfield
authors.forename: Steven R
authors.initials: SR
authors.lastname: Cummings
authors.forename: Tamara B
authors.initials: TB
authors.lastname: Harris
mesh_terms: D015502:Absorptiometry, Photon; D000203:Activities of Daily Living; D050154:Adiposity / Q000502:physiology*; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001823:Body Composition / Q000502:physiology; D001835:Body Weight; D004185:Disability Evaluation; D005163:Factor Analysis, Statistical; D005260:Female; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D011446:Prospective Studies; D012307:Risk Factors; D013848:Thigh / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed; D014481:United States; D016138:Walking / Q000502:physiology