Associations between education and brain structure at age 73 years, adjusted for age 11 IQ

Cox, S. R. et al. (2016) Associations between education and brain structure at age 73 years, adjusted for age 11 IQ. Neurology, 87(17), pp. 1820-1826. (doi: 10.1212/WNL.0000000000003247) (PMID:27664981) (PMCID:PMC5089529)

Abstract

Objective: To investigate how associations between education and brain structure in older age were affected by adjusting for IQ measured at age 11. Methods: We analyzed years of full-time education and measures from an MRI brain scan at age 73 in 617 community-dwelling adults born in 1936. In addition to average and vertex-wise cortical thickness, we measured total brain atrophy and white matter tract fractional anisotropy. Associations between brain structure and education were tested, covarying for sex and vascular health; a second model also covaried for age 11 IQ. Results: The significant relationship between education and average cortical thickness (β = 0.124, p = 0.004) was reduced by 23% when age 11 IQ was included (β = 0.096, p = 0.041). Initial associations between longer education and greater vertex-wise cortical thickness were significant in bilateral temporal, medial-frontal, parietal, sensory, and motor cortices. Accounting for childhood intelligence reduced the number of significant vertices by >90%; only bilateral anterior temporal associations remained. Neither education nor age 11 IQ was significantly associated with total brain atrophy or tract-averaged fractional anisotropy. Conclusions: The association between years of education and brain structure ≈60 years later was restricted to cortical thickness in this sample; however, the previously reported associations between longer education and a thicker cortex are likely to be overestimates in terms of both magnitude and distribution. This finding has implications for understanding, and possibly ameliorating, life-course brain health.

• Item Type: Articles
• Additional Information: This work was supported by a Research Into Ageing programme grant (I.J.D. and J.M.S.) and the Age UK–funded Disconnected Mind project (http://www.disconnectedmind.ed.ac.uk; I.J.D., J.M.S., and J.M.W.), with additional funding from the UK Medical Research Council (I.J.D., J.M.S., J.M.W., and M.E.B.) under grants G0701120, G1001245, and MR/M013111/1, and by a Scottish Funding Council Early Career Researcher grant to the SINAPSE Collaboration (Scottish Imaging Network–A Platform for Scientific Excellence; http://www.sinapse.ac.uk; D.A.D.). J.M.W. is supported by the Scottish Funding Council through the SINAPSE Collaboration. The work was undertaken within the University of Edinburgh Centre for Clinical Brain Sciences and Centre for Cognitive Aging and Cognitive Epidemiology (http://www.ccace.ed.ac.uk), part of the cross-council Lifelong Health and Wellbeing Initiative (MR/K026992/1). Funding from the UK Biotechnology and Biological Sciences Research Council and the Medical Research Council are gratefully acknowledged. This study was not industry funded. This work was supported by a Research Into Ageing programme grant (I.J.D. and J.M.S.), which continues as the Age UK–funded Disconnected Mind project (I.J.D., J.M.S., and J.M.W.). It was also supported by the UK Medical Research Council (I.J.D., J.M.S., J.M.W., and M.E.B.) and the Row Fogo Charitable Trust (M.V.H.).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Dickie, Dr David Alexander
• Authors: Cox, S. R., Dickie, D. A., Ritchie, S. J., Karama, S., Pattie, A., Royle, N. A., Corley, J., Aribisala, B. S., Valdés Hernández, M., Muñoz Maniega, S., Starr, J. M., Bastin, M. E., Evans, A. C., Wardlaw, J. M., and Deary, I. J.
• College/School: College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health
• Journal Name: Neurology
• Publisher: American Academy of Neurology
• ISSN: 0028-3878
• ISSN (Online): 1526-632X
• Published Online: 24 September 2016
• Copyright Holders: Copyright © 2016 American Academy of Neurology
• First Published: First published in Neurology 87(17):1820-1826
• Publisher Policy: Reproduced under a Creative Commons License