title: Operational definitions of successful aging: a systematic review.
abstract: BACKGROUND
  Half a century after the inception of the term "successful aging (SA)," a consensus definition has not emerged. The current study aims to provide a comprehensive snapshot of operational definitions of SA.
  
  
  METHODS
  A systematic review across MedLine, PsycInfo, CINAHL, EMBASE, and ISI Web of Knowledge of quantitative operational definitions of SA was conducted.
  
  
  RESULTS
  Of the 105 operational definitions, across 84 included studies using unique models, 92.4% (97) included physiological constructs (e.g. physical functioning), 49.5% (52) engagement constructs (e.g. involvement in voluntary work), 48.6% (51) well-being constructs (e.g. life satisfaction), 25.7% (27) personal resources (e.g. resilience), and 5.7% (6) extrinsic factors (e.g. finances). Thirty-four definitions consisted of a single construct, 28 of two constructs, 27 of three constructs, 13 of four constructs, and two of five constructs. The operational definitions utilized in the included studies identify between <1% and >90% of study participants as successfully aging.
  
  
  CONCLUSIONS
  The heterogeneity of these results strongly suggests the multidimensionality of SA and the difficulty in categorizing usual versus successful aging. Although the majority of operationalizations reveal a biomedical focus, studies increasingly use psychosocial and lay components. Lack of consistency in the definition of SA is a fundamental weakness of SA research.
authors.affiliation: Department of Public Health and Primary Care, Cambridge Institute of Public Health, University of Cambridge, Cambridge, UK.
authors.forename: Theodore D
authors.initials: TD
authors.lastname: Cosco
authors.affiliation: Centre for Global Mental Health, Department of Health Services and Population Research, Institute of Psychiatry, King's College London, London, UK.
authors.forename: A Matthew
authors.initials: AM
authors.lastname: Prina
authors.affiliation: Parc Sanitari, Sant Joan de Deu, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Jaime
authors.initials: J
authors.lastname: Perales
authors.affiliation: Institute of Health and Society, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: Blossom C M
authors.initials: BC
authors.lastname: Stephan
authors.affiliation: Department of Public Health and Primary Care, Cambridge Institute of Public Health, University of Cambridge, Cambridge, UK.
authors.forename: Carol
authors.initials: C
authors.lastname: Brayne
mesh_terms: D000203:Activities of Daily Living / Q000145:classification / Q000523:psychology; D000223:Adaptation, Psychological; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology*; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D011788:Quality of Life / Q000523:psychology; D055500:Resilience, Psychological; D012917:Social Adjustment; D012959:Socioeconomic Factors