title: The association of age with rate of cognitive decline in elderly individuals residing in supporting care facilities.
abstract: OBJECTIVE
  This study examines the effect of age on rate of cognitive decline in different stages of dementia, of nursing home and assisted-living residents.
  
  
  METHODS
  In this longitudinal study, the Mini Mental State Examination (MMSE) was used to measure rate of cognitive decline in subjects who were nondemented [Clinical Dementia Rating (CDR)=0; n=353], questionably demented (CDR=0.5; n=121), or frankly demented (CDR≥1; n=213) at baseline.
  
  
  RESULTS
  A generalized estimating equation was used to model the MMSE scores over time (mean follow-up 2.9±2.0 y). The generalized estimating equation model had the MMSE scores at successive follow-up time points as dependent variables and had linear and quadratic age, follow-up time from baseline, CDR at baseline, and all the interactions among them as independent variables, controlling for MMSE at baseline, sex, race, and education. The mean age of the entire sample was 85.2±7.4 years at baseline. There were no significant interactions of linear age effects with rate of cognitive decline. The analysis of interaction of quadratic age with rate of cognitive decline showed complex relationships: in the nondemented group, there was no substantial quadratic association of age with the rate of cognitive decline (P=0.13); in the questionable demented group, the oldest subjects declined relatively faster (P=0.02); and in the demented group, the youngest and oldest subjects tended to decline relatively less than subjects in the intermediate ages (P=0.07).
  
  
  CONCLUSIONS
  This study adds an additional aspect to the complexity of the association between age and rate of cognitive decline, showing that the direction and amplitude of this effect differs according to the stage along the course of cognitive decline.
authors.affiliation: Psychiatric Division, Sheba Medical center, Israel. ramitrs@hotmail.com
authors.forename: Ramit
authors.initials: R
authors.lastname: Ravona-Springer
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Luo
authors.forename: James
authors.initials: J
authors.lastname: Schmeidler
authors.forename: Michael
authors.initials: M
authors.lastname: Wysocki
authors.forename: Gerson T
authors.initials: GT
authors.lastname: Lesser
authors.forename: Michael A
authors.initials: MA
authors.lastname: Rapp
authors.forename: Karen
authors.initials: K
authors.lastname: Dahlman
authors.forename: Hillel T
authors.initials: HT
authors.lastname: Grossman
authors.forename: Vahram
authors.initials: V
authors.lastname: Haroutunian
authors.forename: Michal Schnaider
authors.initials: MS
authors.lastname: Beeri
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology*; D010054:Brief Psychiatric Rating Scale; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D005260:Female; D005500:Follow-Up Studies; D006707:Homes for the Aged / Q000639:trends*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009735:Nursing Homes / Q000639:trends*