title: Sarcopenia-related parameters and incident disability in older persons: results from the "invecchiare in Chianti" study.
abstract: BACKGROUND
  Current operational definitions of sarcopenia are based on algorithms' simultaneous considering measures of skeletal muscle mass and muscle-specific as well as global function. We hypothesize that quantitative and qualitative sarcopenia-related parameters may not be equally predictive of incident disability, thus presenting different clinical relevance.
  
  
  METHODS
  Data are from 922 elder adults (mean age = 73.9 years) with no activities of daily living (ADL) impairment recruited in the "Invecchiare in Chianti" study. Incident disability in ≥1 ADL defined the outcome of interest. The specific capacities of following sarcopenia-related parameters at predicting incident ADL disability were compared: residuals of skeletal muscle mass, fat-adjusted residuals of skeletal muscle mass, muscle density, ankle extension strength, ratio ankle extension strength/muscle mass, gait speed, and handgrip strength.
  
  
  RESULTS
  During the follow-up (median = 9.1 years), 188 (20.4%) incident ADL disability events were reported. Adjusted models showed that only gait speed was significantly associated with the outcome in both men (per standard deviation [SD] = 0.23 m/s increase, hazard ratio [HR] = 0.46, 95% confidence interval [CI] = 0.33-0.63; p < .001) and women (per SD = 0.24 m/s increase, HR = 0.64, 95% CI = 0.50-0.82; p < .001). In women, the fat-adjusted lean mass residual (per SD = 4.41 increase, HR = 0.79, 95% CI = 0.65-0.96; p = .02) and muscle density (per SD = 3.60 increase, HR = 0.76, 95% CI = 0.61-0.93; p = .01) were the only other parameters that predicted disability. In men, several of the tested variables (except muscle mass measures) reported significant results.
  
  
  CONCLUSIONS
  Gender strongly influences which sarcopenia-related parameters predict disability. Gait speed was a powerful predictor of disability in both men and women, but its nonmuscle-specific nature should impose caution about its inclusion in definitions of sarcopenia.
authors.affiliation: Gérontopôle, Centre Hospitalier Universitaire de Toulouse, Toulouse, France. INSERM UMR1027, Université de Toulouse III Paul Sabatier, Toulouse, France. macesari@gmail.com.
authors.forename: Matteo
authors.initials: M
authors.lastname: Cesari
authors.affiliation: Gérontopôle, Centre Hospitalier Universitaire de Toulouse, Toulouse, France. INSERM UMR1027, Université de Toulouse III Paul Sabatier, Toulouse, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Rolland
authors.affiliation: Gérontopôle, Centre Hospitalier Universitaire de Toulouse, Toulouse, France. INSERM UMR1027, Université de Toulouse III Paul Sabatier, Toulouse, France.
authors.forename: Gabor
authors.initials: G
authors.lastname: Abellan Van Kan
authors.affiliation: Azienda Sanitaria di Firenze, Florence, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Bandinelli
authors.affiliation: Gérontopôle, Centre Hospitalier Universitaire de Toulouse, Toulouse, France. INSERM UMR1027, Université de Toulouse III Paul Sabatier, Toulouse, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Vellas
authors.affiliation: National Institute on Aging, National Institutes of Health, Baltimore, Maryland.
authors.forename: Luigi
authors.initials: L
authors.lastname: Ferrucci
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000375:Aging; D015992:Body Mass Index; D006233:Persons with Disabilities / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D005684:Gait; D015577:Geriatric Assessment / Q000379:methods; D018737:Hand Strength; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008297:Male; D053580:Muscle Strength; D011237:Predictive Value of Tests; D015995:Prevalence; D012107:Research Design; D012307:Risk Factors; D055948:Sarcopenia / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D017678:Sex Distribution
keywords: Body composition; Disability; Gait speed.; Sarcopenia; Skeletal muscle