Having More Education Does Not Slow Down Brain Aging
Post by Shireen Parimoo
The takeaway
Higher educational attainment does not protect against brain volume loss that typically occurs in older age.
What's the science?
Educational attainment is thought to slow down the effects of aging on the brain. For example, studies have shown that older adults with more years of education have larger brain region volumes than those with fewer years of education. However, much of this research is cross-sectional (i.e. occurring at one point in time), and little is known about the longitudinal impact of education on brain aging. This week in PNAS, Nyberg and colleagues assessed the long-term impact of educational attainment on rates of brain volume loss.
How did they do it?
The authors used two large longitudinal datasets: the UK Biobank (UKB) and the European Lifebrain project (LB) for their study. Participants reported their educational attainment and completed two or three structural MRI scanning sessions over a period of two to four years. Educational attainment for the LB sample was measured as years of education, whereas participants in the UKB were categorized based on whether they had a college/university degree or not. Estimates of total brain volume and hippocampal volume, which are known to atrophy in older age, were obtained.
The authors performed both cross-sectional and longitudinal analyses to examine the relationship between age, brain volume, and educational attainment. The cross-sectional analysis was based on age and the brain volume at the final timepoint, and provided insight into whether participants with more education also have larger volumes. In contrast, the longitudinal analysis was based on baseline age and time since the first scan. This analysis allowed them to determine whether higher educational attainment was associated with a slower rate of brain volume change over time, particularly in older adults. Finally, they conducted a Bayesian hypothesis test in the LB sample to assess the competing hypotheses that education is or is not associated with the rate at which brain volume changes in older age.
What did they find?
Higher education was associated with greater cortical volume around the left central sulcus in the cross-sectional analysis but was not associated with the rate of volume change over time. Longitudinal analyses revealed that in the LB sample, occipital and lateral temporal areas showed greater volume loss in older ages (LB). Similarly, increasing age in the UKB sample was associated with more volume loss in the medial parietal, lateral, and medial frontal and temporal areas. However, these volume changes over time were not associated with educational attainment. Moreover, though hippocampal volume also decreased in older age in both the LB and UKB samples, the rate of hippocampal volume loss was not related to education. Thus, education is related to brain volume at a given point in time, but it does not slow down the rate at which brain volume changes in older age.
What's the impact?
This study found that higher educational attainment does not serve as a protective factor against the rate of regional brain atrophy. These findings are interesting because while they show that more education is associated with larger brain region volume, they contradict the notion that it has a protective effect on brain aging.