title: Mild cognitive impairment predicts institutionalization among older men: a population-based cohort study.
abstract: BACKGROUND
  There is a lack of evidence on the contribution of mild cognitive impairment (MCI) to institutionalization in older adults. This study aimed to evaluate a range of risk factors including MCI of institutionalization in older men.
  
  
  METHODS
  Men aged ≥70 years (n = 1705), participating in the Concord Health and Ageing in Men Project, Sydney, Australia were studied. Participants completed self-reported questionnaires and underwent comprehensive clinical assessments during 2005-2007. Institutionalization was defined as entry into a nursing home facility or hostel at any time over an average of 5 years of follow-up. Cox regression analysis was conducted to generate hazard ratios (HR) with 95% confidence intervals (CI).
  
  
  RESULTS
  A total of 125 (7.3%) participants were institutionalized. Piecewise Cox proportional models were generated and divided at 3.4 years (1250 days) of follow-up due to violation of the proportional hazards assumption for the association between MCI and institutionalization (χ(2) = 6.44, p = 0.01). Dementia, disability in Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL), poor grip strength, few social interactions, being a Non-English speaking immigrant and age were predictive of institutionalization during both time periods, whereas MCI (HR = 4.39, 95%CI 2.17-8.87) only predicted institutionalization in the period beyond 3.4 years of follow-up. Being married (HR = 0.42, 95%CI: 0.24-0.72) was protective only during the period after 3.4 years of follow-up.
  
  
  CONCLUSIONS
  In this study, the strongest predictors of institutionalization were dementia, MCI, ADL and IADL disability. MCI was not a predictor of early institutionalization but became a significant predictor beyond 3.4 years of follow-up.
authors.affiliation: Department of Clinical Pharmacology, Royal North Shore Hospital, Sydney, New South Wales, Australia. danijela.gnjidic@sydney.edu.au
authors.forename: Danijela
authors.initials: D
authors.lastname: Gnjidic
authors.forename: Fiona F
authors.initials: FF
authors.lastname: Stanaway
authors.forename: Robert
authors.initials: R
authors.lastname: Cumming
authors.forename: Louise
authors.initials: L
authors.lastname: Waite
authors.forename: Fiona
authors.initials: F
authors.lastname: Blyth
authors.forename: Vasi
authors.initials: V
authors.lastname: Naganathan
authors.forename: David J
authors.initials: DJ
authors.lastname: Handelsman
authors.forename: David G
authors.initials: DG
authors.lastname: Le Couteur
mesh_terms: D000203:Activities of Daily Living; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D060825:Cognitive Dysfunction / Q000175:diagnosis*; D015331:Cohort Studies; D003704:Dementia / Q000175:diagnosis; D005500:Follow-Up Studies; D006801:Humans; D007326:Institutionalization / Q000706:statistics & numerical data*; D008297:Male; D015233:Models, Statistical