Tom C Russ1, Sarah E Harris2, G David Batty3. 1. Prevention Group, Edinburgh Dementia for Clinical Brain Sciences, University of Edinburgh, Edinburgh, England; Division of Psychiatry, Edinburgh Dementia for Clinical Brain Sciences, University of Edinburgh, Edinburgh, England; Centre From the Alzheimer Scotland Dementia Research Centre, Edinburgh Dementia for Clinical Brain Sciences, University of Edinburgh, Edinburgh, England; Department of Psychology, Lothian Birth Cohorts, University of Edinburgh, Edinburgh, England. Electronic address: T.C.Russ@ed.ac.uk. 2. Department of Psychology, Lothian Birth Cohorts, University of Edinburgh, Edinburgh, England. 3. Centre From the Alzheimer Scotland Dementia Research Centre, Edinburgh Dementia for Clinical Brain Sciences, University of Edinburgh, Edinburgh, England; UCL Research Department of Epidemiology & Public Health, University College London, London, Scotland.