Research Paper|Volume 12, Issue 20|pp 20888—20914

Is cardiovascular fitness associated with structural brain integrity in midlife? Evidence from a population-representative birth cohort study

Tracy d’Arbeloff¹, Megan Cooke^2,³, Annchen R. Knodt¹, Maria Sison¹, Tracy R. Melzer^4,⁵, David Ireland⁶, Richie Poulton⁶, Sandhya Ramrakha⁶, Terrie E. Moffitt^1,^7,^8,⁹, Avshalom Caspi^1,^7,^8,⁹, Ahmad R. Hariri¹

¹Department of Psychology and Neuroscience, Duke University, Durham, NC 27708, USA
²Center for Addiction Medicine, Department of Psychiatry, Massachusetts General Hospital, Boston, MA 02114, USA
³Harvard Medical School, Boston, MA 02115, USA
⁴New Zealand Brain Research Institute, Christchurch, New Zealand
⁵Department of Medicine, University of Otago, Christchurch, New Zealand
⁶Dunedin Multidisciplinary Health and Development Research Unit, Department of Psychology, University of Otago, Dunedin, NZ
⁷Social, Genetic, and Developmental Psychiatry Research Centre, Institute of Psychiatry, Psychology, and Neuroscience, King’s College London, De Crespigny Park, Denmark Hill, London, UK
⁸Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC 27708, USA
⁹Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA

Received: May 15, 2020Accepted: August 9, 2020Published: October 21, 2020

https://doi.org/10.18632/aging.104112

Copyright: © 2020 d’Arbeloff et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

Improving cardiovascular fitness may buffer against age-related cognitive decline and mitigate dementia risk by staving off brain atrophy. However, it is unclear if such effects reflect factors operating in childhood (neuroselection) or adulthood (neuroprotection). Using data from 807 members of the Dunedin Study, a population-representative birth cohort, we investigated associations between cardiovascular fitness and structural brain integrity at age 45, and the extent to which associations reflected possible neuroselection or neuroprotection by controlling for childhood IQ. Higher fitness, as indexed by VO₂Max, was not associated with average cortical thickness, total surface area, or subcortical gray matter volume including the hippocampus. However, higher fitness was associated with thicker cortex in prefrontal and temporal regions as well as greater cerebellar gray matter volume. Higher fitness was also associated with decreased hippocampal fissure volume. These associations were unaffected by the inclusion of childhood IQ in analyses. In contrast, a higher rate of decline in cardiovascular fitness from 26 to 45 years was not robustly associated with structural brain integrity. Our findings are consistent with a neuroprotective account of adult cardiovascular fitness but suggest that effects are not uniformly observed across the brain and reflect contemporaneous fitness more so than decline over time.