title: Grip strength cutpoints for the identification of clinically relevant weakness.
abstract: BACKGROUND
  Weakness is common and contributes to disability, but no consensus exists regarding a strength cutpoint to identify persons at high risk. This analysis, conducted as part of the Foundation for the National Institutes of Health Sarcopenia Project, sought to identify cutpoints that distinguish weakness associated with mobility impairment, defined as gait speed less than 0.8 m/s.
  
  
  METHODS
  In pooled cross-sectional data (9,897 men and 10,950 women), Classification and Regression Tree analysis was used to derive cutpoints for grip strength associated with mobility impairment.
  
  
  RESULTS
  In men, a grip strength of 26-32 kg was classified as "intermediate" and less than 26 kg as "weak"; 11% of men were intermediate and 5% were weak. Compared with men with normal strength, odds ratios for mobility impairment were 3.63 (95% CI: 3.01-4.38) and 7.62 (95% CI 6.13-9.49), respectively. In women, a grip strength of 16-20 kg was classified as "intermediate" and less than 16 kg as "weak"; 25% of women were intermediate and 18% were weak. Compared with women with normal strength, odds ratios for mobility impairment were 2.44 (95% CI 2.20-2.71) and 4.42 (95% CI 3.94-4.97), respectively. Weakness based on these cutpoints was associated with mobility impairment across subgroups based on age, body mass index, height, and disease status. Notably, in women, grip strength divided by body mass index provided better fit relative to grip strength alone, but fit was not sufficiently improved to merit different measures by gender and use of a more complex measure.
  
  
  CONCLUSIONS
  Cutpoints for weakness derived from this large, diverse sample of older adults may be useful to identify populations who may benefit from interventions to improve muscle strength and function.
authors.affiliation: University of Maryland School of Medicine, 660W. Redwood St #221B, Baltimore, MD 21201. dalley@epi.umaryland.edu.
authors.forename: Dawn E
authors.initials: DE
authors.lastname: Alley
authors.forename: Michelle D
authors.initials: MD
authors.lastname: Shardell
authors.forename: Katherine W
authors.initials: KW
authors.lastname: Peters
authors.forename: Robert R
authors.initials: RR
authors.lastname: McLean
authors.forename: Thuy-Tien L
authors.initials: TT
authors.lastname: Dam
authors.forename: Anne M
authors.initials: AM
authors.lastname: Kenny
authors.forename: Maren S
authors.initials: MS
authors.lastname: Fragala
authors.forename: Tamara B
authors.initials: TB
authors.lastname: Harris
authors.forename: Douglas P
authors.initials: DP
authors.lastname: Kiel
authors.forename: Jack M
authors.initials: JM
authors.lastname: Guralnik
authors.forename: Luigi
authors.initials: L
authors.lastname: Ferrucci
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kritchevsky
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Studenski
authors.forename: Maria T
authors.initials: MT
authors.lastname: Vassileva
authors.forename: Peggy M
authors.initials: PM
authors.lastname: Cawthon
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D005684:Gait / Q000502:physiology*; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D051346:Mobility Limitation; D018908:Muscle Weakness / Q000175:diagnosis* / Q000503:physiopathology*; D055948:Sarcopenia / Q000175:diagnosis / Q000503:physiopathology*; D012737:Sex Factors; D014481:United States
keywords: Gait speed.; Grip strength; Muscle; Physical function; Sarcopenia
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