Education and age-related differences in cortical thickness and volume across the lifespan

Abstract

This study investigated whether relationships between age and measures of gray matter in the brain differed across the lifespan and by years of education. The hypothesis is that year to year differences in brain measures vary across the lifespan and are affected by the years of education someone has. Cortical thickness and subcortical volume were measured from 391 healthy adults (age range: 19-80 years). Brain measures were predicted using a quadratic age effect and moderating effects of education using linear regression. Results demonstrate that 12 brain regions had significant moderating effects of age and education on brain measures. These are brain regions where the effect of age on gray matter varied across the lifespan and across levels of education. The results highlighted that when the moderating effects of education are absent from the model, age and brain measures were linearly related. The moderating effects reveal complex age-brain dynamics and support theories of brain maintenance, suggesting that lifestyle factors limit the negative effects of advancing age. Greater education was related to maintained gray matter until later ages. This protection came at a cost, which indicated that year to year decline in gray matter was larger in late life in those with greater levels of education. Improving our understanding of how age and individual differences affect gray matter measures is an important step toward improving the clinical utility of cortical thickness and volume. This article is part of the Virtual Special Issue titled "COGNITIVE NEUROSCIENCE OF HEALTHY AND PATHOLOGICAL AGING". The full issue can be found on ScienceDirect at https://www.sciencedirect.com/journal/neurobiology-of-aging/special-issue/105379XPWJP.

Keywords: Aging; Brain maintenance; Cortical thickness; Education; Reserve; Subcortical volume.