Turning to brainy pursuits in later years also helps delay the onset of the dreaded condition, according to a new study.

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As we age, “Am I losing my mind?” gradually morphs from a poignant Steven Sondheim lyric into a genuine fear. For most of us, avoiding cognitive impairment—or at least holding it off as long as possible—eventually becomes a high-priority concern.

So what can we do to keep sharp as we grow older? A just-released study from the Mayo Clinic finds the best medicine is living a life of the mind.

If, for whatever reason, that hasn’t been true for you (or an aging loved one), don’t despair: Turning to more cerebral leisure pursuits late in life can also help in a big way. But a good education and an intellectually demanding career seem to provide uniquely powerful protection.

“Lifetime intellectual enrichment might delay the onset of cognitive impairment and be used as a successful preventative intervention to reduce the impending dementia epidemic,” writes a research team led by Mayo Clinic radiologist Prashanthi Vemuri. Its study is published in the journal JAMA Neurology.

"Lifetime intellectual enrichment might delay the onset of cognitive impairment and be used as a successful preventative intervention to reduce the impending dementia epidemic."

Vemuri and her colleagues are talking about the public-health challenges that will inevitably arise as the American population ages. Dementia is not only emotionally devastating; it’s also economically draining, both for families and society as a whole.

With this in mind, they decided to measure the impact of two different measures of intellectual enrichment on cognitive decline: One based on educational attainment and occupation, and another based on mid- to late-life cognitive activity.

Their subjects were 1,995 elderly Minnesota residents who took part in the Mayo Clinic Study of Aging. The participants were 70 to 89 years old when they enrolled in the study in October 2004; 27 percent of them carried the APOE4 gene variant, which increases one’s risk for developing late-onset Alzheimer’s.

Participants first disclosed the number of years of schooling they completed, and described their primary occupation. “The same form was used to record their cognitive activities during the past 12 months (late life) and cognitive activities at 50 to 65 years of age (midlife),” the researchers write.

Examples of activities the researchers considered cognitively stimulating (if performed at least three times per week) included reading books and magazines, playing games and music, and participating in arts and crafts.

All participants then underwent a battery of neuropsychological tests designed to measure a variety of cognitive skills, including executive functioning, language, and memory.

"Higher levels of educational, occupational, and cognitive activity are independently associated with a lower risk of dementia," they report. Among people with the APOE4 variant, who are at relatively high risk for dementia, the difference is huge: The onset of cognitive impairment was delayed, on average, by more than eight and one-half years for people who ranked in the top 25 percent in terms of lifetime intellectual enrichment, compared to those in the bottom 25 percent.

Looking at specific methods of intellectual enrichment, the researchers report that the effect of higher education is particularly pronounced."We found that the number of years of protection provided by higher educational attainment (keeping cognitive activity constant) is at least five years, irrespective of sex and APOE4 carrier status," Vemuri and her colleagues write.

The researchers found that beefing up one's intellectual engagement in mid-life has a greater impact in staving off cognitive impairment among those with lower education levels, who were at higher risk. That makes intuitive sense: They had more ground to make up. And while they didn't get to the protective level of their better-educated counterparts, their efforts did pay off.

"The years of protection provided by high mid/late-life cognitive activity ... was at least 3.2 years for APOE4 carriers, and 7.3 years for non-carriers," the researchers report.

These results lead to a clear policy recommendation. "Although the optimal intervention time may be intellectual enrichment in early life," Vemuri and her colleagues write, "there are substantial benefits of using a public health campaign by providing intellectual enrichment to midlife to late-life individuals."