Lifetime of Learning Might Thwart Dementia
Even taking up intellectual pursuits in mid-life appears to aid the brain
Lastly, all were examined to see if they carried a specific variant of the APOE gene, considered the most significant genetic risk factor for late-onset Alzheimer's.
At the time of the study's launch, mental functioning was lower among carriers of the APOE4 genotype, and among those who scored lowest on education, job, and/or activity measures, the researchers determined. Lower mental functioning scores were also seen among older participants and men.
However, APOE4 carriers who ranked near the top in terms of all measures of lifetime intellectual engagement -- including education, occupation and activity routines -- saw their risk for dementia delayed by nearly nine years, compared with those whose intellectual stimulation ranking hovered near the bottom.
Digging deeper, Vemuri and her associates also found that regardless of educational and professional background, all participants who routinely engaged in intellectually stimulating activities in middle-age and their later years also ended up seeing their relative risk for dementia drop.
The dementia protection afforded by routine intellectual activity alone was weaker than when intellectual activity was also paired up with stimulating jobs and education.
But in a twist, the authors found that those with the lowest educational and occupational scores actually gained the most protection against dementia by embarking on intellectual activities from middle-age onward.
"This was a little surprising," said Vemuri. "But it turns out that even if you don't have a lifetime of educational and occupational development, intellectual activity in later life can really help -- perhaps delaying cognitive impairment by at least three years."
Cheryl Grady, a professor with the University of Toronto's department of psychology and psychiatry, said the findings are both "interesting" and encouraging.
"The association between lower cognitive function and lower education has been known for some time," she said. "But as far as I know no one has [previously] shown that midlife cognitive activity and education interact."
However, the association seen in this study does not prove a cause-and-effect relationship.
But, Grady added, "It looks like the bottom-line is that it's never too late to exercise your brain, and that is good news."