title: The role of cognitive reserve on terminal decline: a cross-cohort analysis from two European studies: OCTO-Twin, Sweden, and Newcastle 85+, UK.
abstract: OBJECTIVE
  Cognitive performance shows a marked deterioration in close proximity to death, as postulated by the terminal decline hypothesis. The effect of education on the rate of terminal decline in the oldest people (i.e. persons 85+ years) has been controversial and not entirely understood. In the current study, we investigated the rate of decline prior to death with a special focus on the role of education and socioeconomic position, in two European longitudinal studies of ageing: the Origins of Variance in the Old-Old: Octogenarian Twins (OCTO-Twin) and the Newcastle 85+ study.
  
  
  METHODS
  A process-based approach was used in which individuals' cognitive scores were aligned according to distance to death. In a coordinated analysis, multilevel models were employed to examine associations between different markers of cognitive reserve (education and socioeconomic position) and terminal decline using the mini-mental state examination (MMSE), controlling for age at baseline, sex, dementia incidence and time to death from the study entry to the time of death within each cohort.
  
  
  RESULTS
  The current findings suggest that education was positively associated with higher MMSE scores prior to death in the OCTO-Twin, but not in the Newcastle 85+ study, independent of socioeconomic position and other factors such as baseline age, sex and time to death from the study entry. However, education was not associated with the rate of terminal decline in both of these studies.
  
  
  CONCLUSIONS
  Our results offer only partial support to the cognitive reserve hypothesis and cognitive performance prior to death.
authors.affiliation: MRC Unit for Lifelong Health and Ageing at University College London, London, UK.
authors.forename: Dorina
authors.initials: D
authors.lastname: Cadar
authors.affiliation: Institute of Health and Society, Newcastle University, Newcastle, UK.
authors.forename: Blossom C M
authors.initials: BC
authors.lastname: Stephan
authors.affiliation: Institute of Health and Society, Newcastle University, Newcastle, UK.
authors.forename: Carol
authors.initials: C
authors.lastname: Jagger
authors.affiliation: Department of Psychology, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Boo
authors.initials: B
authors.lastname: Johansson
authors.affiliation: Department of Psychology, University of Victoria, Victoria, Canada.
authors.forename: Scott M
authors.initials: SM
authors.lastname: Hofer
authors.affiliation: Department of Psychology, University of Victoria, Victoria, Canada.
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Piccinin
authors.affiliation: MRC Unit for Lifelong Health and Ageing at University College London, London, UK.
authors.forename: Graciela
authors.initials: G
authors.lastname: Muniz-Terrera
mesh_terms: D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology; D000704:Analysis of Variance; D003072:Cognition Disorders / Q000401:mortality* / Q000523:psychology; D058245:Cognitive Reserve / Q000502:physiology*; D003704:Dementia / Q000453:epidemiology* / Q000523:psychology; D004522:Educational Status; D004739:England / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D009483:Neuropsychological Tests; D012307:Risk Factors; D012959:Socioeconomic Factors; D013548:Sweden / Q000453:epidemiology; D014427:Twins
keywords: MMSE; cognition; cognitive reserve; death; dementia; education; longitudinal study; mixed multilevel; terminal decline