title: Predictors of ageing-related decline across multiple cognitive functions.
abstract: It is critical to discover why some people's cognitive abilities age better than others'. We applied multivariate growth curve models to data from a narrow-age cohort measured on a multi-domain IQ measure at age 11 years and a comprehensive battery of thirteen measures of visuospatial, memory, crystallized, and processing speed abilities at ages 70, 73, and 76 years (n= 1091 at age 70). We found that 48% of the variance in change in performance on the thirteen cognitive measures was shared across all measures, an additional 26% was specific to the four ability domains, and 26% was test-specific. We tested the association of a wide variety of sociodemographic, fitness, health, and genetic variables with each of these cognitive change factors. Models that simultaneously included all covariates accounted for appreciable proportions of variance in the cognitive change factors (e.g. approximately one third of the variance in general cognitive change). However, beyond physical fitness and possession of theAPOEe4 allele, very few predictors were incrementally associated with cognitive change at statistically significant levels. The results highlight a small number of factors that predict differences in cognitive ageing, and underscore that correlates of cognitive level are not necessarily predictors of decline. Even larger samples will likely be required to identify additional variables with more modest associations with normal-range heterogeneity in aging-related cognitive declines.
authors.affiliation: Department of Psychology, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom; Centre for Cognitive Ageing and Cognitive Epidemiology, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom.
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Ritchie
authors.affiliation: Department of Psychology, University of Texas, Austin, TX 78712-1043, USA.
authors.forename: Elliot M
authors.initials: EM
authors.lastname: Tucker-Drob
authors.affiliation: Department of Psychology, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom; Centre for Cognitive Ageing and Cognitive Epidemiology, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom.
authors.forename: Simon R
authors.initials: SR
authors.lastname: Cox
authors.affiliation: Department of Psychology, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom.
authors.forename: Janie
authors.initials: J
authors.lastname: Corley
authors.affiliation: Department of Psychology, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom; Centre for Cognitive Ageing and Cognitive Epidemiology, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom.
authors.forename: Dominika
authors.initials: D
authors.lastname: Dykiert
authors.affiliation: Department of Psychology, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom.
authors.forename: Paul
authors.initials: P
authors.lastname: Redmond
authors.affiliation: Department of Psychology, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom.
authors.forename: Alison
authors.initials: A
authors.lastname: Pattie
authors.affiliation: Department of Psychology, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom.
authors.forename: Adele M
authors.initials: AM
authors.lastname: Taylor
authors.affiliation: Department of Psychology, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom; Centre for Cognitive Ageing and Cognitive Epidemiology, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom; Alzheimer Scotland Dementia Research Centre, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom.
authors.forename: Ruth
authors.initials: R
authors.lastname: Sibbett
authors.affiliation: Department of Psychology, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom; Centre for Cognitive Ageing and Cognitive Epidemiology, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom; Alzheimer Scotland Dementia Research Centre, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom.
authors.forename: John M
authors.initials: JM
authors.lastname: Starr
authors.affiliation: Department of Psychology, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom; Centre for Cognitive Ageing and Cognitive Epidemiology, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom.
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Deary
keywords: Cognitive ageing; Cognitive decline; Longitudinal; Structural equation modeling