As America ages, the specter of cognitive decline looms. In a 2012 AARP membership survey, 87 percent of respondents said they were extremely or very concerned about “staying mentally sharp.” As there’s currently no cure for Alzheimer’s or dementia, their concern is not unwarranted.
There is a prevailing idea, though, that staying mentally active could help keep the disease at bay. A new study out of the Mayo Clinic, published in JAMA Neurology, lends some more credence to this theory. The longitudinal study looked at nearly 2,000 Minnesotans aged 70 to 89 and followed up with them every 15 months for an average of six years. Of these people, 277 had mild cognitive impairment (the rest were cognitively normal) and 20 to 30 percent of them had the APOE4 gene, which gives a person a 67 percent chance of developing Alzheimer’s.
The researchers gathered information about the level of education participants had received, and the complexity of their primary occupation. Then subjects were asked about their cognitive activities both at midlife (50 to 65 years old) and during the past 12 months. Those activities included crafts, reading, socializing, working on computers, or playing music.
Participants underwent a “neuropsychological battery of tests,” evaluating the executive, language, memory, and visuospatial performance of their brains. The researchers found that “the protective effect of intellectual enrichment is primarily manifested as a relatively consistent higher cognitive performance over time.” Higher education levels, and more occupational and cognitive activity were independently associated with a lower risk of dementia as well.
Mental stimulation throughout a person’s life helped decrease the risk more than if they started cognitive activities in mid-life, but those with lower education levels benefitted more from mid and late life activity than those with higher education levels.
“Doing cognitive activities at least three times a week was highly protective,” says Dr. Prashanthi Vemuri, an assistant professor of radiology at the Mayo Clinic and lead author on the study.
The difference was measured in years. Those who had more education got at least five years of protection; mid and late life cognitive activity provided about three years of protection on average for APOE4 gene carriers and about seven years for non-carriers. The overall effect of “lifetime intellectual enrichment”—all these factors taken together—was strong. Those who ranked in the 75th percentile could delay the onset of cognitive impairment by more than eight years, compared to those with low lifetime intellectual achievement (the 25th percentile).
“If you start early, your brain is probably sharper than starting later,” Vemuri says, “But it’s never too late, that’s one strong message from the study.”