title: Physical frailty, disability, and dynamics in health perceptions: a preliminary mediation model.
abstract: OBJECTIVE
  Frailty is a condition characterized by loss of functional reserve and altered homeostatic capacity. The aging process is related with complex indicators of physiological state. This study aims, with a preliminary mediation model, to reveal the possible role of mediator of health perceptions variability in the relationship between frailty and disability.
  
  
  METHODS
  A longitudinal study (100 days) was performed. Data from 92 institutionalized older adults were used in the analysis. Frailty was assessed in baseline using the Italian version of the Survey of Health, Ageing and Retirement in Europe - Frailty Instrument; health perceptions were assessed on a daily basis by three visual analog scale questions; and disability was measured in baseline and post-test using the Katz Activities of Daily Living questionnaire. The product-of-coefficient mediation approach was used to test direct and indirect effects of frailty.
  
  
  RESULTS
  Results showed that daily variability of health perceptions plays the role of mediator between frailty and disability. In all the steps, statistically significant results were found.
  
  
  CONCLUSIONS
  This preliminary result may indicate that physical frailty increases the variability in health perceptions contributing to disability.
authors.affiliation: Department of Psychology, University of Torino, Torino, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Mulasso
authors.affiliation: Department of Psychology, University of Torino, Torino, Italy.
authors.forename: Mattia
authors.initials: M
authors.lastname: Roppolo
authors.affiliation: Department of Psychology, University of Torino, Torino, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Rabaglietti
mesh_terms: D000203:Activities of Daily Living / Q000523:psychology*; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D004185:Disability Evaluation; D005260:Female; D016330:Frail Elderly / Q000523:psychology / Q000706:statistics & numerical data*; D015577:Geriatric Assessment / Q000379:methods*; D006801:Humans; D007558:Italy; D008137:Longitudinal Studies; D008297:Male; D008962:Models, Theoretical; D012044:Regression Analysis; D011795:Surveys and Questionnaires
keywords: dynamic systems; functional decline; health outcomes; loss of autonomy; variability